x86/apic: Force native_apic_mem_read() to use the MOV instruction

When done from a virtual machine, instructions that touch APIC memory
must be emulated. By convention, MMIO accesses are typically performed
via io.h helpers such as readl() or writeq() to simplify instruction
emulation/decoding (ex: in KVM hosts and SEV guests) [0].

Currently, native_apic_mem_read() does not follow this convention,
allowing the compiler to emit instructions other than the MOV
instruction generated by readl(). In particular, when the kernel is
compiled with clang and run as a SEV-ES or SEV-SNP guest, the compiler
would emit a TESTL instruction which is not supported by the SEV-ES
emulator, causing a boot failure in that environment. It is likely the
same problem would happen in a TDX guest as that uses the same
instruction emulator as SEV-ES.

To make sure all emulators can emulate APIC memory reads via MOV, use
the readl() function in native_apic_mem_read(). It is expected that any
emulator would support MOV in any addressing mode as it is the most
generic and is what is usually emitted currently.

The TESTL instruction is emitted when native_apic_mem_read() is inlined
into apic_mem_wait_icr_idle(). The emulator comes from
insn_decode_mmio() in arch/x86/lib/insn-eval.c. It's not worth it to
extend insn_decode_mmio() to support more instructions since, in theory,
the compiler could choose to output nearly any instruction for such
reads which would bloat the emulator beyond reason.

[0] https://lore.kernel.org/all/20220405232939.73860-12-kirill.shutemov@linux.intel.com/

[ bp: Massage commit message, fix typos. ]

Signed-off-by: Adam Dunlap <acdunlap@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Kevin Loughlin <kevinloughlin@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240318230927.2191933-1-acdunlap@google.com

x86/cpu/topology: Rework possible CPU management

Managing possible CPUs is an unreadable and uncomprehensible maze. Aside of
that it's backwards because it applies command line limits after
registering all APICs.

Rewrite it so that it:

- Applies the command line limits upfront so that only the allowed amount
of APIC IDs can be registered.

- Applies eventual late restrictions in an understandable way

- Uses simple min_t() calculations which are trivial to follow.

- Provides a separate function for resetting to UP mode late in the
bringup process.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210252.290098853@linutronix.de

x86/cpu/topology: Provide separate APIC registration functions

generic_processor_info() aside of being a complete misnomer is used for
both early boot registration and ACPI CPU hotplug.

While it's arguable that this can share some code, it results in code which
is hard to understand and kept around post init for no real reason.

Also the call sites do lots of manual fiddling in topology related
variables instead of having proper interfaces for the purpose which handle
the topology internals correctly.

Provide topology_register_apic(), topology_hotplug_apic() and
topology_hotunplug_apic() which have the extra magic of the call sites
incorporated and for now are wrappers around generic_processor_info().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210251.605007456@linutronix.de

x86/cpu/topology: Move registration out of APIC code

The APIC/CPU registration sits in the middle of the APIC code. In fact this
is a topology evaluation function and has nothing to do with the inner
workings of the local APIC.

Move it out into a file which reflects what this is about.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210251.543948812@linutronix.de

x86/apic: Use a proper define for invalid ACPI CPU ID

The ACPI ID for CPUs is preset with U32_MAX which is completely non
obvious. Use a proper define for it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154640.177504138@linutronix.de

x86/apic: Remove yet another dubious callback

Paranoia is not wrong, but having an APIC callback which is in most
implementations a complete NOOP and in one actually looking whether the
APICID of an upcoming CPU has been registered. The same APICID which was
used to bring the CPU out of wait for startup.

That's paranoia for the paranoia sake. Remove the voodoo.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154640.116510935@linutronix.de

x86/apic: Remove the pointless writeback of boot_cpu_physical_apicid

There is absolutely no point to write the APIC ID which was read from the
local APIC earlier, back into the local APIC for the 64-bit UP case.

Remove that along with the apic callback which is solely there for this
pointless exercise.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154640.055288922@linutronix.de

x86/apic: Remove check_apicid_used() and ioapic_phys_id_map()

No more users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154639.243307499@linutronix.de

x86/cpu/topology: Make the APIC mismatch warnings complete

Detect all possible combinations of mismatch right in the CPUID evaluation
code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240212154638.867699078@linutronix.de

x86/apic: Remove unused phys_pkg_id() callback

Now that the core code does not use this monstrosity anymore, it's time to
put it to rest.

The only real purpose was to read the APIC ID on UV and VSMP systems for
the actual evaluation. That's what the core code does now.

For doing the actual shift operation there is truly no APIC callback
required.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Wang Wendy <wendy.wang@intel.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20240212153625.516536121@linutronix.de

x86/apic: Drop apic::delivery_mode

This field is set to APIC_DELIVERY_MODE_FIXED in all cases, and is read
exactly once. Fold the constant in uv_program_mmr() and drop the field.

Searching for the origin of the stale HyperV comment reveals commit
a31e58e129f7 ("x86/apic: Switch all APICs to Fixed delivery mode") which
notes:

As a consequence of this change, the apic::irq_delivery_mode field is
now pointless, but this needs to be cleaned up in a separate patch.

6 years is long enough for this technical debt to have survived.

[ bp: Fold in
https://lore.kernel.org/r/20231121123034.1442059-1-andrew.cooper3@citrix.com
]

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20231102-x86-apic-v1-1-bf049a2a0ed6@citrix.com

x86/apic: Provide apic_force_nmi_on_cpu()

When SMT siblings are soft-offlined and parked in one of the play_dead()
variants they still react on NMI, which is problematic on affected Intel
CPUs. The default play_dead() variant uses MWAIT on modern CPUs, which is
not guaranteed to be safe when updated concurrently.

Right now late loading is prevented when not all SMT siblings are online,
but as they still react on NMI, it is possible to bring them out of their
park position into a trivial rendezvous handler.

Provide a function which allows to do that. I does sanity checks whether
the target is in the cpus_booted_once_mask and whether the APIC driver
supports it.

Mark X2APIC and XAPIC as capable, but exclude 32bit and the UV and NUMACHIP
variants as that needs feedback from the relevant experts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.603100036@linutronix.de

x86/apic: Use u32 for wakeup_secondary_cpu[_64]()

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085113.233274223@linutronix.de

x86/apic: Use u32 for [gs]et_apic_id()

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085113.172569282@linutronix.de

x86/apic: Use u32 for phys_pkg_id()

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width even if that callback going to be removed soonish.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085113.113097126@linutronix.de

x86/apic: Use u32 for cpu_present_to_apicid()

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width and fixup a few related usage sites for consistency sake.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085113.054064391@linutronix.de

x86/apic: Use u32 for check_apicid_used()

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width and move the default implementation to local.h as there are
no users outside the apic directory.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085112.981956102@linutronix.de

x86/apic: Use u32 for APIC IDs in global data

APIC IDs are used with random data types u16, u32, int, unsigned int,
unsigned long.

Make it all consistently use u32 because that reflects the hardware
register width and fixup the most obvious usage sites of that.

The APIC callbacks will be addressed separately.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230814085112.922905727@linutronix.de

x86/apic: Turn on static calls

Convert all the APIC callback inline wrappers from apic->foo() to
static_call(apic_call_foo)(), except for the safe_wait_icr_idle() one which
is only used during SMP bringup when sending INIT/SIPI. That really can do
the conditional callback. The regular wait_icr_idle() matters as it is used
in irq_work_raise(), so X2APIC machines spare the conditional.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>

x86/apic: Provide static call infrastructure for APIC callbacks

Declare and define the static calls for the hotpath APIC callbacks. Note
this deliberately uses STATIC_CALL_NULL() because otherwise it would be
required to have the definitions in the 32bit and the 64bit default APIC
implementations and it's hard to keep the calls in sync. The other option
would be to have stub functions for each callback type. Not pretty either

So the NULL capable calls are used and filled in during early boot after
the static key infrastructure has been initialized. The calls will be
static_call() except for the wait_irc_idle() callback which is valid to be
NULL for X2APIC systems.

Update the calls when a new APIC driver is installed and when a callback
override is invoked.

Export the trampolines for the two calls which are used in KVM and MCE
error inject modules.

Test the setup and let the next step convert the inline wrappers to make it
effective.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Wrap IPI calls into helper functions

Move them to one place so the static call conversion gets simpler.

No functional change.

[ dhansen: merge against recent x86/apic changes ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Mark all hotpath APIC callback wrappers __always_inline

There is no value for instrumentation to look at those wrappers and with the
upcoming conversion to static calls even less so.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Replace acpi_wake_cpu_handler_update() and apic_set_eoi_cb()

Switch them over to apic_update_callback() and remove the code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Provide apic_update_callback()

There are already two variants of update mechanism for particular callbacks
and virtualization just writes into the data structure.

Provide an interface and use a shadow data structure to preserve callbacks
so they can be reapplied when the APIC driver is replaced.

The extra data structure is intentional as any new callback needs to be
also updated in the core code. This also prepares for static calls.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Provide common init infrastructure

In preparation for converting the hotpath APIC callbacks to static keys,
provide common initialization infrastructure.

Lift apic_install_drivers() from probe_64.c and convert all places which
switch the apic instance by storing the pointer to use apic_install_driver()
as a first step.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Wrap apic->native_eoi() into a helper

Prepare for converting the hotpath APIC callbacks to static calls.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Nuke ack_APIC_irq()

Yet another wrapper of a wrapper gone along with the outdated comment
that this compiles to a single instruction.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Remove pointless arguments from [native_]eoi_write()

Every callsite hands in the same constants which is a pointless exercise
and cannot be optimized by the compiler due to the indirect calls.

Use the constants in the eoi() callbacks and remove the arguments.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Sanitize APIC ID range validation

Now that everything has apic::max_apic_id set and the eventual update for
the x2APIC case is in place, switch the apic_id_valid() helper to use
apic::max_apic_id and remove the apic::apic_id_valid() callback.

[ dhansen: Fix subject typo ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Prepare x2APIC for using apic::max_apic_id

In order to remove the apic::apic_id_valid() callback and switch to
checking apic::max_apic_id, it is required to update apic::max_apic_id when
the APIC initialization code overrides it via x2apic_set_max_apicid().

Make the existing booleans a bitfield and add a flag which lets the update
function and the core code which switches the driver detect whether the
apic instance wants to have that update or not and apply it if required.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Add max_apic_id member

There is really no point to have a callback which compares numbers.

Add a field which allows each APIC to store the maximum APIC ID supported
and fill it in for all APIC incarnations.

The next step will remove the callback.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Wrap APIC ID validation into an inline

Prepare for removing the callback and making this as simple comparison to
an upper limit, which is the obvious solution to do for limit checks...

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Move safe wait_icr_idle() next to apic_mem_wait_icr_idle()

Move it next to apic_mem_wait_icr_idle(), rename it so that it's clear what
it does and rewrite it in readable form.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Allow apic::safe_wait_icr_idle() to be NULL

Remove tons of NOOP callbacks by making the invocation of
safe_wait_icr_idle() conditional in the inline wrapper.

Will be replaced by a static_call_cond() later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Allow apic::wait_icr_idle() to be NULL

Nuke more NOOP callbacks and make the invocation conditional. Will be
replaced with a static call later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Consolidate wait_icr_idle() implementations

Two copies and also needlessly public. Move it into ipi.c so it can be
inlined. Rename it to apic_mem_wait_icr_idle().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Mop up apic::apic_id_registered()

Really not a hotpath and again no reason for having a gazillion of empty
callbacks returning 1. Make it return bool and provide one shared
implementation for the remaining users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Mop up *setup_apic_routing()

default_setup_apic_routing() is a complete misnomer. On 64bit it does the
actual APIC probing and on 32bit it is used to force select the bigsmp APIC
and to emit a redundant message in the apic::setup_apic_routing() callback.

Rename the 64bit and 32bit function so they reflect what they are doing and
remove the useless APIC callback.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Nuke apic::apicid_to_cpu_present()

This is only used on 32bit and is a wrapper around
physid_set_mask_of_physid() in all 32bit APIC drivers.

Remove the callback and use physid_set_mask_of_physid() in the code
directly,

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Nuke empty init_apic_ldr() callbacks

apic::init_apic_ldr() is only invoked when the APIC is initialized. So
there is really no point in having:

- Default empty callbacks all over the place

- Two implementations of the actual LDR init function where one is
just unreadable gunk but does exactly the same as the other.

Make the apic::init_apic_ldr() invocation conditional, remove the empty
callbacks and consolidate the two implementation into one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic/32: Remove pointless default_acpi_madt_oem_check()

On 32bit there is no APIC implementing the acpi_madt_oem_check() except XEN
PV, but that does not matter at all.

generic_apic_probe() runs before ACPI tables are parsed. This selects the
XEN APIC if there is no command line override because the XEN APIC driver
is the first to be probed.

If there is a command line override then the XEN PV driver won't be
selected in the MADT OEM check either.

As there is no other MADT check implemented for 32bit APICs, this whole
excercise is a NOOP and can be removed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic/32: Sanitize logical APIC ID handling

apic::x86_32_early_logical_apicid() is yet another historical joke.

It is used to preset the x86_cpu_to_logical_apicid per CPU variable during
APIC enumeration with:

- 1 shifted left by the CPU number
- the physical APIC ID in case of bigsmp

The latter is hillarious because bigsmp uses physical destination mode
which never can use the logical APIC ID.

It gets even worse. As bigsmp can be enforced late in the boot process the
probe function overwrites the per CPU variable which is never used for this
APIC type once again.

Remove that gunk and store 1 << cpunr unconditionally if and only if the
CPU number is less than 8, because the default logical destination mode
only allows up to 8 CPUs.

This is just an intermediate step before removing the per CPU insanity
completely. Stay tuned.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Remove check_phys_apicid_present()

The only silly usage site is gone. Remove the gunk which was even outright
wrong in the bigsmp_32 case which returned true unconditionally.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Make some APIC init functions bool

Quite some APIC init functions are pure boolean, but use the success = 0,
fail < 0 model. That's confusing as hell when reading through the code.

Convert them to boolean.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Consolidate boot_cpu_physical_apicid initialization sites

boot_cpu_physical_apicid is written in random places and in the last
consequence filled with the APIC ID read from the local APIC. That causes
it to have inconsistent state when the MPTABLE is broken. As a consequence
tons of moronic checks are sprinkled all over the place.

Consolidate the code and read it exactly once when either X2APIC mode is
detected early or when the APIC mapping is established.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Nuke unused apic::inquire_remote_apic()

Put it to the other historical leftovers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Get rid of hard_smp_processor_id()

No point in having a wrapper around read_apic_id().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Remove pointless x86_bios_cpu_apicid

It's a useless copy of x86_cpu_to_apicid.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/apic: Rename disable_apic

It reflects a state and not a command. Make it bool while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)

x86/smpboot: Support parallel startup of secondary CPUs

In parallel startup mode the APs are kicked alive by the control CPU
quickly after each other and run through the early startup code in
parallel. The real-mode startup code is already serialized with a
bit-spinlock to protect the real-mode stack.

In parallel startup mode the smpboot_control variable obviously cannot
contain the Linux CPU number so the APs have to determine their Linux CPU
number on their own. This is required to find the CPUs per CPU offset in
order to find the idle task stack and other per CPU data.

To achieve this, export the cpuid_to_apicid[] array so that each AP can
find its own CPU number by searching therein based on its APIC ID.

Introduce a flag in the top bits of smpboot_control which indicates that
the AP should find its CPU number by reading the APIC ID from the APIC.

This is required because CPUID based APIC ID retrieval can only provide the
initial APIC ID, which might have been overruled by the firmware. Some AMD
APUs come up with APIC ID = initial APIC ID + 0x10, so the APIC ID to CPU
number lookup would fail miserably if based on CPUID. Also virtualization
can make its own APIC ID assignements. The only requirement is that the
APIC IDs are consistent with the APCI/MADT table.

For the boot CPU or in case parallel bringup is disabled the control bits
are empty and the CPU number is directly available in bit 0-23 of
smpboot_control.

[ tglx: Initial proof of concept patch with bitlock and APIC ID lookup ]
[ dwmw2: Rework and testing, commit message, CPUID 0x1 and CPU0 support ]
[ seanc: Fix stray override of initial_gs in common_cpu_up() ]
[ Oleksandr Natalenko: reported suspend/resume issue fixed in
x86_acpi_suspend_lowlevel ]
[ tglx: Make it read the APIC ID from the APIC instead of using CPUID,
split the bitlock part out ]

Co-developed-by: Thomas Gleixner <tglx@linutronix.de>
Co-developed-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.411554373@linutronix.de

x86/apic: Provide cpu_primary_thread mask

Make the primary thread tracking CPU mask based in preparation for simpler
handling of parallel bootup.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.186599880@linutronix.de

x86/smpboot: Remove the CPU0 hotplug kludge

This was introduced with commit e1c467e69040 ("x86, hotplug: Wake up CPU0
via NMI instead of INIT, SIPI, SIPI") to eventually support physical
hotplug of CPU0:

"We'll change this code in the future to wake up hard offlined CPU0 if
real platform and request are available."

11 years later this has not happened and physical hotplug is not officially
supported. Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.768845190@linutronix.de

x86/apic: Handle no CONFIG_X86_X2APIC on systems with x2APIC enabled by BIOS

A kernel that was compiled without CONFIG_X86_X2APIC was unable to boot on
platforms that have x2APIC already enabled in the BIOS before starting the
kernel.

The kernel was supposed to panic with an approprite error message in
validate_x2apic() due to the missing X2APIC support.

However, validate_x2apic() was run too late in the boot cycle, and the
kernel tried to initialize the APIC nonetheless. This resulted in an
earlier panic in setup_local_APIC() because the APIC was not registered.

In my experiments, a panic message in setup_local_APIC() was not visible
in the graphical console, which resulted in a hang with no indication
what has gone wrong.

Instead of calling panic(), disable the APIC, which results in a somewhat
working system with the PIC only (and no SMP). This way the user is able to
diagnose the problem more easily.

Disabling X2APIC mode is not an option because it's impossible on systems
with locked x2APIC.

The proper place to disable the APIC in this case is in check_x2apic(),
which is called early from setup_arch(). Doing this in
__apic_intr_mode_select() is too late.

Make check_x2apic() unconditionally available and remove the empty stub.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reported-by: Robert Elliott (Servers) <elliott@hpe.com>
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/d573ba1c-0dc4-3016-712a-cc23a8a33d42@molgen.mpg.de
Link: https://lore.kernel.org/lkml/20220911084711.13694-3-mat.jonczyk@o2.pl
Link: https://lore.kernel.org/all/20221129215008.7247-1-mat.jonczyk@o2.pl

profile: setup_profiling_timer() is moslty not implemented

The setup_profiling_timer() is mostly un-implemented by many
architectures. In many places it isn't guarded by CONFIG_PROFILE which is
needed for it to be used. Make it a weak symbol in kernel/profile.c and
remove the 'return -EINVAL' implementations from the kenrel.

There are a couple of architectures which do return 0 from the
setup_profiling_timer() function but they don't seem to do anything else
with it. To keep the /proc compatibility for now, leave these for a
future update or removal.

On ARM, this fixes the following sparse warning:
arch/arm/kernel/smp.c:793:5: warning: symbol 'setup_profiling_timer' was not declared. Should it be static?

Link: https://lkml.kernel.org/r/20220721195509.418205-1-ben-linux@fluff.org
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/acpi/x86/boot: Add multiprocessor wake-up support

Secondary CPU startup is currently performed with something called
the "INIT/SIPI protocol". This protocol requires assistance from
VMMs to boot guests. As should be a familiar story by now, that
support can not be provded to TDX guests because TDX VMMs are
not trusted by guests.

To remedy this situation a new[1] "Multiprocessor Wakeup Structure"
has been added to to an existing ACPI table (MADT). This structure
provides the physical address of a "mailbox". A write to the mailbox
then steers the secondary CPU to the boot code.

Add ACPI MADT wake structure parsing support and wake support. Use
this support to wake CPUs whenever it is present instead of INIT/SIPI.

While this structure can theoretically be used on 32-bit kernels,
there are no 32-bit TDX guest kernels. It has not been tested and
can not practically *be* tested on 32-bit. Make it 64-bit only.

1. Details about the new structure can be found in ACPI v6.4, in the
"Multiprocessor Wakeup Structure" section.

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-22-kirill.shutemov@linux.intel.com

x86/boot: Add a trampoline for booting APs via firmware handoff

Historically, x86 platforms have booted secondary processors (APs)
using INIT followed by the start up IPI (SIPI) messages. In regular
VMs, this boot sequence is supported by the VMM emulation. But such a
wakeup model is fatal for secure VMs like TDX in which VMM is an
untrusted entity. To address this issue, a new wakeup model was added
in ACPI v6.4, in which firmware (like TDX virtual BIOS) will help boot
the APs. More details about this wakeup model can be found in ACPI
specification v6.4, the section titled "Multiprocessor Wakeup Structure".

Since the existing trampoline code requires processors to boot in real
mode with 16-bit addressing, it will not work for this wakeup model
(because it boots the AP in 64-bit mode). To handle it, extend the
trampoline code to support 64-bit mode firmware handoff. Also, extend
IDT and GDT pointers to support 64-bit mode hand off.

There is no TDX-specific detection for this new boot method. The kernel
will rely on it as the sole boot method whenever the new ACPI structure
is present.

The ACPI table parser for the MADT multiprocessor wake up structure and
the wakeup method that uses this structure will be added by the following
patch in this series.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-21-kirill.shutemov@linux.intel.com

x86/apic: Mark _all_ legacy interrupts when IO/APIC is missing

PIC interrupts do not support affinity setting and they can end up on
any online CPU. Therefore, it's required to mark the associated vectors
as system-wide reserved. Otherwise, the corresponding irq descriptors
are copied to the secondary CPUs but the vectors are not marked as
assigned or reserved. This works correctly for the IO/APIC case.

When the IO/APIC is disabled via config, kernel command line or lack of
enumeration then all legacy interrupts are routed through the PIC, but
nothing marks them as system-wide reserved vectors.

As a consequence, a subsequent allocation on a secondary CPU can result in
allocating one of these vectors, which triggers the BUG() in
apic_update_vector() because the interrupt descriptor slot is not empty.

Imran tried to work around that by marking those interrupts as allocated
when a CPU comes online. But that's wrong in case that the IO/APIC is
available and one of the legacy interrupts, e.g. IRQ0, has been switched to
PIC mode because then marking them as allocated will fail as they are
already marked as system vectors.

Stay consistent and update the legacy vectors after attempting IO/APIC
initialization and mark them as system vectors in case that no IO/APIC is
available.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Imran Khan <imran.f.khan@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210519233928.2157496-1-imran.f.khan@oracle.com

x86/apic: Add extra serialization for non-serializing MSRs

Jan Kiszka reported that the x2apic_wrmsr_fence() function uses a plain
MFENCE while the Intel SDM (10.12.3 MSR Access in x2APIC Mode) calls for
MFENCE; LFENCE.

Short summary: we have special MSRs that have weaker ordering than all
the rest. Add fencing consistent with current SDM recommendations.

This is not known to cause any issues in practice, only in theory.

Longer story below:

The reason the kernel uses a different semantic is that the SDM changed
(roughly in late 2017). The SDM changed because folks at Intel were
auditing all of the recommended fences in the SDM and realized that the
x2apic fences were insufficient.

Why was the pain MFENCE judged insufficient?

WRMSR itself is normally a serializing instruction. No fences are needed
because the instruction itself serializes everything.

But, there are explicit exceptions for this serializing behavior written
into the WRMSR instruction documentation for two classes of MSRs:
IA32_TSC_DEADLINE and the X2APIC MSRs.

Back to x2apic: WRMSR is *not* serializing in this specific case.
But why is MFENCE insufficient? MFENCE makes writes visible, but
only affects load/store instructions. WRMSR is unfortunately not a
load/store instruction and is unaffected by MFENCE. This means that a
non-serializing WRMSR could be reordered by the CPU to execute before
the writes made visible by the MFENCE have even occurred in the first
place.

This means that an x2apic IPI could theoretically be triggered before
there is any (visible) data to process.

Does this affect anything in practice? I honestly don't know. It seems
quite possible that by the time an interrupt gets to consume the (not
yet) MFENCE'd data, it has become visible, mostly by accident.

To be safe, add the SDM-recommended fences for all x2apic WRMSRs.

This also leaves open the question of the _other_ weakly-ordered WRMSR:
MSR_IA32_TSC_DEADLINE. While it has the same ordering architecture as
the x2APIC MSRs, it seems substantially less likely to be a problem in
practice. While writes to the in-memory Local Vector Table (LVT) might
theoretically be reordered with respect to a weakly-ordered WRMSR like
TSC_DEADLINE, the SDM has this to say:

In x2APIC mode, the WRMSR instruction is used to write to the LVT
entry. The processor ensures the ordering of this write and any
subsequent WRMSR to the deadline; no fencing is required.

But, that might still leave xAPIC exposed. The safest thing to do for
now is to add the extra, recommended LFENCE.

[ bp: Massage commit message, fix typos, drop accidentally added
newline to tools/arch/x86/include/asm/barrier.h. ]

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200305174708.F77040DD@viggo.jf.intel.com

x86/apic: Always provide irq_compose_msi_msg() method for vector domain

This shouldn't be dependent on PCI_MSI. HPET and I/O-APIC can deliver
interrupts through MSI without having any PCI in the system at all.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-10-dwmw2@infradead.org

x86/apic: Cleanup destination mode

apic::irq_dest_mode is actually a boolean, but defined as u32 and named in
a way which does not explain what it means.

Make it a boolean and rename it to 'dest_mode_logical'

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-9-dwmw2@infradead.org

x86/apic: Get rid of apic:: Dest_logical

struct apic has two members which store information about the destination
mode: dest_logical and irq_dest_mode.

dest_logical contains a mask which was historically used to set the
destination mode in IPI messages. Over time the usage was reduced and the
logical/physical functions were seperated.

There are only a few places which still use 'dest_logical' but they can
use 'irq_dest_mode' instead.

irq_dest_mode is actually a boolean where 0 means physical destination mode
and 1 means logical destination mode. Of course the name does not reflect
the functionality. This will be cleaned up in a subsequent change.

Remove apic::dest_logical and fixup the remaining users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-8-dwmw2@infradead.org

x86/apic: Cleanup delivery mode defines

The enum ioapic_irq_destination_types and the enumerated constants starting
with 'dest_' are gross misnomers because they describe the delivery mode.

Rename then enum and the constants so they actually make sense.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-6-dwmw2@infradead.org

x86/apic: Fix x2apic enablement without interrupt remapping

Currently, Linux as a hypervisor guest will enable x2apic only if there are
no CPUs present at boot time with an APIC ID above 255.

Hotplugging a CPU later with a higher APIC ID would result in a CPU which
cannot be targeted by external interrupts.

Add a filter in x2apic_apic_id_valid() which can be used to prevent such
CPUs from coming online, and allow x2apic to be enabled even if they are
present at boot time.

Fixes: ce69a784504 ("x86/apic: Enable x2APIC without interrupt remapping under KVM")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-2-dwmw2@infradead.org

treewide: Convert macro and uses of __section(foo) to __section("foo")

Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/msi: Move compose message callback where it belongs

Composing the MSI message at the MSI chip level is wrong because the
underlying parent domain is the one which knows how the message should be
composed for the direct vector delivery or the interrupt remapping table
entry.

The interrupt remapping aware PCI/MSI chip does that already. Make the
direct delivery chip do the same and move the composition of the direct
delivery MSI message to the vector domain irq chip.

This prepares for the upcoming device MSI support to avoid having
architecture specific knowledge in the device MSI domain irq chips.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200826112331.157603198@linutronix.de

x86/entry: Convert various hypervisor vectors to IDTENTRY_SYSVEC

Convert various hypervisor vectors to IDTENTRY_SYSVEC:

- Implement the C entry point with DEFINE_IDTENTRY_SYSVEC
- Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC
- Remove the ASM idtentries in 64-bit
- Remove the BUILD_INTERRUPT entries in 32-bit
- Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.647997594@linutronix.de

x86/entry: Convert various system vectors

Convert various system vectors to IDTENTRY_SYSVEC:

- Implement the C entry point with DEFINE_IDTENTRY_SYSVEC
- Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC
- Remove the ASM idtentries in 64-bit
- Remove the BUILD_INTERRUPT entries in 32-bit
- Remove the old prototypes

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202119.464812973@linutronix.de

x86/apic/msi: Plug non-maskable MSI affinity race

Evan tracked down a subtle race between the update of the MSI message and
the device raising an interrupt internally on PCI devices which do not
support MSI masking. The update of the MSI message is non-atomic and
consists of either 2 or 3 sequential 32bit wide writes to the PCI config
space.

- Write address low 32bits
- Write address high 32bits (If supported by device)
- Write data

When an interrupt is migrated then both address and data might change, so
the kernel attempts to mask the MSI interrupt first. But for MSI masking is
optional, so there exist devices which do not provide it. That means that
if the device raises an interrupt internally between the writes then a MSI
message is sent built from half updated state.

On x86 this can lead to spurious interrupts on the wrong interrupt
vector when the affinity setting changes both address and data. As a
consequence the device interrupt can be lost causing the device to
become stuck or malfunctioning.

Evan tried to handle that by disabling MSI accross an MSI message
update. That's not feasible because disabling MSI has issues on its own:

If MSI is disabled the PCI device is routing an interrupt to the legacy
INTx mechanism. The INTx delivery can be disabled, but the disablement is
not working on all devices.

Some devices lose interrupts when both MSI and INTx delivery are disabled.

Another way to solve this would be to enforce the allocation of the same
vector on all CPUs in the system for this kind of screwed devices. That
could be done, but it would bring back the vector space exhaustion problems
which got solved a few years ago.

Fortunately the high address (if supported by the device) is only relevant
when X2APIC is enabled which implies interrupt remapping. In the interrupt
remapping case the affinity setting is happening at the interrupt remapping
unit and the PCI MSI message is programmed only once when the PCI device is
initialized.

That makes it possible to solve it with a two step update:

1) Target the MSI msg to the new vector on the current target CPU

2) Target the MSI msg to the new vector on the new target CPU

In both cases writing the MSI message is only changing a single 32bit word
which prevents the issue of inconsistency.

After writing the final destination it is necessary to check whether the
device issued an interrupt while the intermediate state #1 (new vector,
current CPU) was in effect.

This is possible because the affinity change is always happening on the
current target CPU. The code runs with interrupts disabled, so the
interrupt can be detected by checking the IRR of the local APIC. If the
vector is pending in the IRR then the interrupt is retriggered on the new
target CPU by sending an IPI for the associated vector on the target CPU.

This can cause spurious interrupts on both the local and the new target
CPU.

1) If the new vector is not in use on the local CPU and the device
affected by the affinity change raised an interrupt during the
transitional state (step #1 above) then interrupt entry code will
ignore that spurious interrupt. The vector is marked so that the
'No irq handler for vector' warning is supressed once.

2) If the new vector is in use already on the local CPU then the IRR check
might see an pending interrupt from the device which is using this
vector. The IPI to the new target CPU will then invoke the handler of
the device, which got the affinity change, even if that device did not
issue an interrupt

3) If the new vector is in use already on the local CPU and the device
affected by the affinity change raised an interrupt during the
transitional state (step #1 above) then the handler of the device which
uses that vector on the local CPU will be invoked.

expose issues in device driver interrupt handlers which are not prepared to
handle a spurious interrupt correctly. This not a regression, it's just
exposing something which was already broken as spurious interrupts can
happen for a lot of reasons and all driver handlers need to be able to deal
with them.

Reported-by: Evan Green <evgreen@chromium.org>
Debugged-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Evan Green <evgreen@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87imkr4s7n.fsf@nanos.tec.linutronix.de

x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode

Tony reported a boot regression caused by the recent workaround for systems
which have a disabled (clock gate off) PIT.

On his machine the kernel fails to initialize the PIT because
apic_needs_pit() does not take into account whether the local APIC
interrupt delivery mode will actually allow to setup and use the local
APIC timer. This should be easy to reproduce with acpi=off on the
command line which also disables HPET.

Due to the way the PIT/HPET and APIC setup ordering works (APIC setup can
require working PIT/HPET) the information is not available at the point
where apic_needs_pit() makes this decision.

To address this, split out the interrupt mode selection from
apic_intr_mode_init(), invoke the selection before making the decision
whether PIT is required or not, and add the missing checks into
apic_needs_pit().

Fixes: c8c4076723da ("x86/timer: Skip PIT initialization on modern chipsets")
Reported-by: Anthony Buckley <tony.buckley000@gmail.com>
Tested-by: Anthony Buckley <tony.buckley000@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Daniel Drake <drake@endlessm.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206125
Link: https://lore.kernel.org/r/87sgk6tmk2.fsf@nanos.tec.linutronix.de

x86/apic/flat64: Remove the IPI shorthand decision logic

All callers of apic->send_IPI_all() and apic->send_IPI_allbutself() contain
the decision logic for shorthand invocation already and invoke
send_IPI_mask() if the prereqisites are not satisfied.

Remove the now redundant decision logic in the APIC code and the duplicate
helper in probe_64.c.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105221.042964120@linutronix.de

x86/apic: Provide and use helper for send_IPI_allbutself()

To support IPI shorthands wrap invocations of apic->send_IPI_allbutself()
in a helper function, so the static key controlling the shorthand mode is
only in one place.

Fixup all callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.492691679@linutronix.de

x86/apic: Add static key to Control IPI shorthands

The IPI shorthand functionality delivers IPI/NMI broadcasts to all CPUs in
the system. This can have similar side effects as the MCE broadcasting when
CPUs are waiting in the BIOS or are offlined.

The kernel tracks already the state of offlined CPUs whether they have been
brought up at least once so that the CR4 MCE bit is set to make sure that
MCE broadcasts can't brick the machine.

Utilize that information and compare it to the cpu_present_mask. If all
present CPUs have been brought up at least once then the broadcast side
effect is mitigated by disabling regular interrupt/IPI delivery in the APIC
itself and by the cpu offline check at the begin of the NMI handler.

Use a static key to switch between broadcasting via shorthands or sending
the IPI/NMI one by one.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.386410643@linutronix.de

x86/hotplug: Silence APIC and NMI when CPU is dead

In order to support IPI/NMI broadcasting via the shorthand mechanism side
effects of shorthands need to be mitigated:

Shorthand IPIs and NMIs hit all CPUs including unplugged CPUs

Neither of those can be handled on unplugged CPUs for obvious reasons.

It would be trivial to just fully disable the APIC via the enable bit in
MSR_APICBASE. But that's not possible because clearing that bit on systems
based on the 3 wire APIC bus would require a hardware reset to bring it
back as the APIC would lose track of bus arbitration. On systems with FSB
delivery APICBASE could be disabled, but it has to be guaranteed that no
interrupt is sent to the APIC while in that state and it's not clear from
the SDM whether it still responds to INIT/SIPI messages.

Therefore stay on the safe side and switch the APIC into soft disabled mode
so it won't deliver any regular vector to the CPU.

NMIs are still propagated to the 'dead' CPUs. To mitigate that add a check
for the CPU being offline on early nmi entry and if so bail.

Note, this cannot use the stop/restart_nmi() magic which is used in the
alternatives code. A dead CPU cannot invoke nmi_enter() or anything else
due to RCU and other reasons.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907241723290.1791@nanos.tec.linutronix.de

x86/apic/uv: Make x2apic_extra_bits static

Not used outside of the UV apic source.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105219.725264153@linutronix.de

x86/apic: Silence -Wtype-limits compiler warnings

There are many compiler warnings like this,

In file included from ./arch/x86/include/asm/smp.h:13,
from ./arch/x86/include/asm/mmzone_64.h:11,
from ./arch/x86/include/asm/mmzone.h:5,
from ./include/linux/mmzone.h:969,
from ./include/linux/gfp.h:6,
from ./include/linux/mm.h:10,
from arch/x86/kernel/apic/io_apic.c:34:
arch/x86/kernel/apic/io_apic.c: In function 'check_timer':
./arch/x86/include/asm/apic.h:37:11: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
if ((v) <= apic_verbosity) \
^~
arch/x86/kernel/apic/io_apic.c:2160:2: note: in expansion of macro
'apic_printk'
apic_printk(APIC_QUIET, KERN_INFO "..TIMER: vector=0x%02X "
^~~~~~~~~~~
./arch/x86/include/asm/apic.h:37:11: warning: comparison of unsigned
expression >= 0 is always true [-Wtype-limits]
if ((v) <= apic_verbosity) \
^~
arch/x86/kernel/apic/io_apic.c:2207:4: note: in expansion of macro
'apic_printk'
apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
^~~~~~~~~~~

APIC_QUIET is 0, so silence them by making apic_verbosity type int.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1562621805-24789-1-git-send-email-cai@lca.pw

x86/timer: Skip PIT initialization on modern chipsets

Recent Intel chipsets including Skylake and ApolloLake have a special
ITSSPRC register which allows the 8254 PIT to be gated. When gated, the
8254 registers can still be programmed as normal, but there are no IRQ0
timer interrupts.

Some products such as the Connex L1430 and exone go Rugged E11 use this
register to ship with the PIT gated by default. This causes Linux to fail
to boot:

Kernel panic - not syncing: IO-APIC + timer doesn't work! Boot with
apic=debug and send a report.

The panic happens before the framebuffer is initialized, so to the user, it
appears as an early boot hang on a black screen.

Affected products typically have a BIOS option that can be used to enable
the 8254 and make Linux work (Chipset -> South Cluster Configuration ->
Miscellaneous Configuration -> 8254 Clock Gating), however it would be best
to make Linux support the no-8254 case.

Modern sytems allow to discover the TSC and local APIC timer frequencies,
so the calibration against the PIT is not required. These systems have
always running timers and the local APIC timer works also in deep power
states.

So the setup of the PIT including the IO-APIC timer interrupt delivery
checks are a pointless exercise.

Skip the PIT setup and the IO-APIC timer interrupt checks on these systems,
which avoids the panic caused by non ticking PITs and also speeds up the
boot process.

Thanks to Daniel for providing the changelog, initial analysis of the
problem and testing against a variety of machines.

Reported-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Daniel Drake <drake@endlessm.com>
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: linux@endlessm.com
Cc: rafael.j.wysocki@intel.com
Cc: hdegoede@redhat.com
Link: https://lkml.kernel.org/r/20190628072307.24678-1-drake@endlessm.com

x86/apic: Make apic_bsp_setup() static

No user outside of apic.c. Remove the stale and bogus function comment
while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 223

Based on 1 normalized pattern(s):

subject to the gnu public license v 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 9 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171440.130801526@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/apic: Rename 'lapic_timer_frequency' to 'lapic_timer_period'

This variable is a period unit (number of clock cycles per jiffy),
not a frequency (which is number of cycles per second).

Give it a more appropriate name.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Daniel Drake <drake@endlessm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: len.brown@intel.com
Cc: linux@endlessm.com
Cc: rafael.j.wysocki@intel.com
Link: http://lkml.kernel.org/r/20190509055417.13152-2-drake@endlessm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d

The last missing piece to having vmx_l1d_flush() take interrupts after
VMEXIT into account is to set the kvm_cpu_l1tf_flush_l1d per-cpu flag on
irq entry.

Issue calls to kvm_set_cpu_l1tf_flush_l1d() from entering_irq(),
ipi_entering_ack_irq(), smp_reschedule_interrupt() and
uv_bau_message_interrupt().

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Revert "x86/apic: Ignore secondary threads if nosmt=force"

Dave Hansen reported, that it's outright dangerous to keep SMT siblings
disabled completely so they are stuck in the BIOS and wait for SIPI.

The reason is that Machine Check Exceptions are broadcasted to siblings and
the soft disabled sibling has CR4.MCE = 0. If a MCE is delivered to a
logical core with CR4.MCE = 0, it asserts IERR#, which shuts down or
reboots the machine. The MCE chapter in the SDM contains the following
blurb:

Because the logical processors within a physical package are tightly
coupled with respect to shared hardware resources, both logical
processors are notified of machine check errors that occur within a
given physical processor. If machine-check exceptions are enabled when
a fatal error is reported, all the logical processors within a physical
package are dispatched to the machine-check exception handler. If
machine-check exceptions are disabled, the logical processors enter the
shutdown state and assert the IERR# signal. When enabling machine-check
exceptions, the MCE flag in control register CR4 should be set for each
logical processor.

Reverting the commit which ignores siblings at enumeration time solves only
half of the problem. The core cpuhotplug logic needs to be adjusted as
well.

This thoughtful engineered mechanism also turns the boot process on all
Intel HT enabled systems into a MCE lottery. MCE is enabled on the boot CPU
before the secondary CPUs are brought up. Depending on the number of
physical cores the window in which this situation can happen is smaller or
larger. On a HSW-EX it's about 750ms:

MCE is enabled on the boot CPU:

[ 0.244017] mce: CPU supports 22 MCE banks

The corresponding sibling #72 boots:

[ 1.008005] .... node #0, CPUs: #72

That means if an MCE hits on physical core 0 (logical CPUs 0 and 72)
between these two points the machine is going to shutdown. At least it's a
known safe state.

It's obvious that the early boot can be hit by an MCE as well and then runs
into the same situation because MCEs are not yet enabled on the boot CPU.
But after enabling them on the boot CPU, it does not make any sense to
prevent the kernel from recovering.

Adjust the nosmt kernel parameter documentation as well.

Reverts: 2207def700f9 ("x86/apic: Ignore secondary threads if nosmt=force")
Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tony Luck <tony.luck@intel.com>

x86/apic: Ignore secondary threads if nosmt=force

nosmt on the kernel command line merely prevents the onlining of the
secondary SMT siblings.

nosmt=force makes the APIC detection code ignore the secondary SMT siblings
completely, so they even do not show up as possible CPUs. That reduces the
amount of memory allocations for per cpu variables and saves other
resources from being allocated too large.

This is not fully equivalent to disabling SMT in the BIOS because the low
level SMT enabling in the BIOS can result in partitioning of resources
between the siblings, which is not undone by just ignoring them. Some CPUs
can use the full resources when their sibling is not onlined, but this is
depending on the CPU family and model and it's not well documented whether
this applies to all partitioned resources. That means depending on the
workload disabling SMT in the BIOS might result in better performance.

Linus analysis of the Intel manual:

The intel optimization manual is not very clear on what the partitioning
rules are.

I find:

"In general, the buffers for staging instructions between major pipe
stages are partitioned. These buffers include µop queues after the
execution trace cache, the queues after the register rename stage, the
reorder buffer which stages instructions for retirement, and the load
and store buffers.

In the case of load and store buffers, partitioning also provided an
easier implementation to maintain memory ordering for each logical
processor and detect memory ordering violations"

but some of that partitioning may be relaxed if the HT thread is "not
active":

"In Intel microarchitecture code name Sandy Bridge, the micro-op queue
is statically partitioned to provide 28 entries for each logical
processor, irrespective of software executing in single thread or
multiple threads. If one logical processor is not active in Intel
microarchitecture code name Ivy Bridge, then a single thread executing
on that processor core can use the 56 entries in the micro-op queue"

but I do not know what "not active" means, and how dynamic it is. Some of
that partitioning may be entirely static and depend on the early BIOS
disabling of HT, and even if we park the cores, the resources will just be
wasted.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

x86/smp: Provide topology_is_primary_thread()

If the CPU is supporting SMT then the primary thread can be found by
checking the lower APIC ID bits for zero. smp_num_siblings is used to build
the mask for the APIC ID bits which need to be taken into account.

This uses the MPTABLE or ACPI/MADT supplied APIC ID, which can be different
than the initial APIC ID in CPUID. But according to AMD the lower bits have
to be consistent. Intel gave a tentative confirmation as well.

Preparatory patch to support disabling SMT at boot/runtime.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Provide apic_ack_irq()

apic_ack_edge() is explicitely for handling interrupt affinity cleanup when
interrupt remapping is not available or disable.

Remapped interrupts and also some of the platform specific special
interrupts, e.g. UV, invoke ack_APIC_irq() directly.

To address the issue of failing an affinity update with -EBUSY the delayed
affinity mechanism can be reused, but ack_APIC_irq() does not handle
that. Adding this to ack_APIC_irq() is not possible, because that function
is also used for exceptions and directly handled interrupts like IPIs.

Create a new function, which just contains the conditional invocation of
irq_move_irq() and the final ack_APIC_irq().

Reuse the new function in apic_ack_edge().

Preparatory change for the real fix.

Fixes: dccfe3147b42 ("x86/vector: Simplify vector move cleanup")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Song Liu <songliubraving@fb.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <liu.song.a23@gmail.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: stable@vger.kernel.org
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tariq Toukan <tariqt@mellanox.com>
Link: https://lkml.kernel.org/r/20180604162224.471925894@linutronix.de

x86/apic: Fix signedness bug in APIC ID validity checks

The APIC ID as parsed from ACPI MADT is validity checked with the
apic->apic_id_valid() callback, which depends on the selected APIC type.

For non X2APIC types APIC IDs >= 0xFF are invalid, but values > 0x7FFFFFFF
are detected as valid. This happens because the 'apicid' argument of the
apic_id_valid() callback is type 'int'. So the resulting comparison

apicid < 0xFF

evaluates to true for all unsigned int values > 0x7FFFFFFF which are handed
to default_apic_id_valid(). As a consequence, invalid APIC IDs in !X2APIC
mode are considered valid and accounted as possible CPUs.

Change the apicid argument type of the apic_id_valid() callback to u32 so
the evaluation is unsigned and returns the correct result.

[ tglx: Massaged changelog ]

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: jgross@suse.com
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1523322966-10296-1-git-send-email-lirongqing@baidu.com

x86/apic: Finish removing unused callbacks

The ->cpu_mask_to_apicid() and ->vector_allocation_domain() callbacks are
now unused, so remove them.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: baab1e84b112 ("x86/apic: Remove unused callbacks")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803251403540.80485@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Make setup_local_APIC() static

This function isn't used outside of apic.c, so let's mark it static.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bhe@redhat.com
Cc: ebiederm@xmission.com
Link: http://lkml.kernel.org/r/20180214062554.21020-1-douly.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Simplify init_bsp_APIC() usage

Since CONFIG_X86_64 selects CONFIG_X86_LOCAL_APIC, the following
condition:

#if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC)

is equivalent to:

#if defined(CONFIG_X86_LOCAL_APIC)

... and we can eliminate that #ifdef by providing an empty
init_bsp_APIC() stub in the !CONFIG_X86_LOCAL_APIC case.

Also add some comments to explain why we call init_bsp_APIC().

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: mroos@linux.ee
Cc: ville.syrjala@linux.intel.com
Link: http://lkml.kernel.org/r/20180117073748.23905-1-douly.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Revert "x86/apic: Remove init_bsp_APIC()"

This reverts commit b371ae0d4a194b178817b0edfb6a7395c7aec37a. It causes
boot hangs on old P3/P4 systems when the local APIC is enforced in UP mode.

Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/20171128145350.21560-1-ville.syrjala@linux.intel.com

x86/irq: Simplify hotplug vector accounting

Before a CPU is taken offline the number of active interrupt vectors on the
outgoing CPU and the number of vectors which are available on the other
online CPUs are counted and compared. If the active vectors are more than
the available vectors on the other CPUs then the CPU hot-unplug operation
is aborted. This again uses loop based search and is inaccurate.

The bitmap matrix allocator has accurate accounting information and can
tell exactly whether the vector space is sufficient or not.

Emit a message when the number of globaly reserved (unallocated) vectors is
larger than the number of available vectors after offlining a CPU because
after that point request_irq() might fail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213156.351193962@linutronix.de

x86/irq/vector: Initialize matrix allocator

Initialize the matrix allocator and add the proper accounting points to the
code.

No functional change, just preparation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213155.108410660@linutronix.de

x86/apic: Add replacement for cpu_mask_to_apicid()

As preparation for replacing the vector allocator, provide a new function
which takes a cpu number instead of a cpu mask to calculate/lookup the
resulting APIC destination id.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>

x86/apic: Get rid of apic->target_cpus

The target_cpus() callback of the apic struct is not really useful. Some
APICs return cpu_online_mask and others cpus_all_mask. The latter is bogus
as it does not take holes in the cpus_possible_mask into account.

Replace it with cpus_online_mask which makes the most sense and remove the
callback.

The usage sites will be removed in a later step anyway, so get rid of it
now to have incremental changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213154.070850916@linutronix.de

x86/apic: Reorganize struct apic

struct apic has just grown over time by adding function pointers in random
places. Reorganize it so it becomes more cache line friendly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.913642524@linutronix.de

x86/apic: Move common APIC callbacks

Move more apic struct specific functions out of the header and the apic
management code into the common source file.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.834421893@linutronix.de

x86/apic: Sanitize 32/64bit APIC callbacks

The 32bit and the 64bit implementation of default_cpu_present_to_apicid()
and default_check_phys_apicid_present() are exactly the same, but
implemented and located differently.

Move them to common apic code and get rid of the pointless difference.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.757329991@linutronix.de

x86/apic: Move APIC noop specific functions

Move more inlines to the place where they belong.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.677743545@linutronix.de

x86/apic: Move probe32 specific APIC functions

The apic functions which are used in probe_32.c are implemented as inlines
or in apic.c. There is no reason to have them at random places.

Move them to the actual usage site and make them static.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.596768194@linutronix.de

x86/apic: Sanitize return value of check_apicid_used()

The check is boolean, but the function returns unsigned long for no value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.516730518@linutronix.de

x86/apic: Sanitize return value of apic.set_apic_id()

The set_apic_id() callback returns an unsigned long value which is handed
in to apic_write() as the value argument u32.

Adjust the return value so it returns u32 right away.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.437208268@linutronix.de

x86/apic: Remove init_bsp_APIC()

init_bsp_APIC() which works for the virtual wire mode is used in ISA irq
initialization at boot time.

With the new APIC interrupt delivery mode scheme, which initializes the
APIC before the first interrupt is expected, init_bsp_APIC() is not longer
required and can be removed.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-13-git-send-email-douly.fnst@cn.fujitsu.com

x86/apic: Unify interrupt mode setup for UP system

In UniProcessor kernel with UP_LATE_INIT=y, the interrupt delivery mode is
initialized in up_late_init().

Use the new unified apic_intr_mode_init() function and remove
APIC_init_uniprocessor().

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-8-git-send-email-douly.fnst@cn.fujitsu.com

x86/apic: Mark the apic_intr_mode extern for sanity check cleanup

Calling native_smp_prepare_cpus() to prepare for SMP bootup, does some
sanity checking, enables APIC mode and disables SMP feature.

Now, APIC mode setup has been unified to apic_intr_mode_init(), some sanity
checks are redundant and need to be cleanup.

Mark the apic_intr_mode extern to refine the switch and remove the
redundant sanity check.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-7-git-send-email-douly.fnst@cn.fujitsu.com

x86/apic: Move logical APIC ID away from apic_bsp_setup()

apic_bsp_setup() sets and returns logical APIC ID for initializing
cpu0_logical_apicid in a SMP-capable system.

The id has nothing to do with the initialization of local APIC and I/O
APIC. And apic_bsp_setup() should be called for interrupt mode setup only.

Move the id setup into a separate helper function for cleanup and mark
apic_bsp_setup() void.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-5-git-send-email-douly.fnst@cn.fujitsu.com

x86/apic: Prepare for unifying the interrupt delivery modes setup

There are three places which initialize the interrupt delivery modes:

1) init_bsp_APIC() which is called early might setup the through-local-APIC
virtual wire mode on non SMP systems.

2) In an SMP-capable system, native_smp_prepare_cpus() tries to switch to
symmetric I/O model.

3) In UP system with UP_LATE_INIT=y, the local APIC and I/O APIC are set up
in smp_init().

There is no technical reason to make these initializations at random places
and run the kernel with the potentially wrong mode through the early boot
stage, but it has a problematic side effect: The late switch to symmetric
I/O mode causes dump-capture kernel to hang when the kernel command line
option 'notsc' is active.

Provide a new function to unify that three positions. Preparatory patch to
initialize an interrupt mode directly.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yinghai@kernel.org
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/1505293975-26005-3-git-send-email-douly.fnst@cn.fujitsu.com

x86/apic: Add irq_data argument to apic->cpu_mask_to_apicid()

The decision to which CPUs an interrupt is effectively routed happens in
the various apic->cpu_mask_to_apicid() implementations

To support effective affinity masks this information needs to be updated in
irq_data. Add a pointer to irq_data to the callbacks and feed it through
the call chain.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235446.720739075@linutronix.de

x86/apic: Move cpumask and to core code

All implementations of apic->cpu_mask_to_apicid_and() and the two incoming
cpumasks to search for the target.

Move that operation to the call site and rename it to cpu_mask_to_apicid()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235446.641575516@linutronix.de

x86/apic: Move flat_cpu_mask_to_apicid_and() into C source

No point in having inlines assigned to function pointers at multiple
places. Just bloats the text.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235446.405975721@linutronix.de

x86/apic: Remove the SET_APIC_ID(x) macro

The SET_APIC_ID() macro obfusates the code. Remove it to increase
readability and add a comment to the apic struct to document that the
callback is required on 64-bit.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/1488971270-14359-1-git-send-email-douly.fnst@cn.fujitsu.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>

We want to simplify <linux/sched.h>'s header dependencies, but one
roadblock to that is <asm/apic.h>'s inclusion of pm.h,
which brings in other, problematic headers.

Remove it, as it appears to be entirely spurious, apic.h does not
actually make use of any PM facilities.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/MSR: Carve out bare minimum accessors

Add __rdmsr() and __wrmsr() which *only* read and write an MSR with
exception handling. Those are going to be used in early code, like the
microcode loader, which cannot stomach tracing code piggybacking on the
MSR operation.

While at it, get rid of __native_write_msr_notrace().

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-3-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Remove empty idle.h header

One include less is always a good thing(tm). Good riddance.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20161209182912.2726-6-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/idle: Remove enter_idle(), exit_idle()

Upon removal of the is_idle flag, these routines became NOPs.

Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/822f2c22cc5890f7b8ea0eeec60277eb44505b4e.1479449716.git.len.brown@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Prevent tracing on apic_msr_write_eoi()

The following RCU lockdep warning led to adding irq_enter()/irq_exit() into
smp_reschedule_interrupt():

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
no locks held by swapper/1/0.

do_trace_write_msr
native_write_msr
native_apic_msr_eoi_write
smp_reschedule_interrupt
reschedule_interrupt

As Peterz pointed out:

| So now we're making a very frequent interrupt slower because of debug
| code.
|
| The thing is, many many smp_reschedule_interrupt() invocations don't
| actually execute anything much at all and are only sent to tickle the
| return to user path (which does the actual preemption).
|
| Having to do the whole irq_enter/irq_exit dance just for this unlikely
| debug case totally blows.

Use the wrmsr_notrace() variant in native_apic_msr_write_eoi, annotate the
kvm variant with notrace and add a native_apic_eoi callback to the apic
structure so KVM guests are covered as well.

This allows to revert the irq_enter/irq_exit dance in
smp_reschedule_interrupt().

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Mike Galbraith <efault@gmx.de>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1478488420-5982-3-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Order irq_enter/exit() calls correctly vs. ack_APIC_irq()

===============================
[ INFO: suspicious RCU usage. ]
4.8.0-rc6+ #5 Not tainted
-------------------------------
./arch/x86/include/asm/msr-trace.h:47 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
no locks held by swapper/2/0.

stack backtrace:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.8.0-rc6+ #5
Hardware name: Dell Inc. OptiPlex 7020/0F5C5X, BIOS A03 01/08/2015
0000000000000000 ffff8d1bd6003f10 ffffffff94446949 ffff8d1bd4a68000
0000000000000001 ffff8d1bd6003f40 ffffffff940e9247 ffff8d1bbdfcf3d0
000000000000080b 0000000000000000 0000000000000000 ffff8d1bd6003f70
Call Trace:
<IRQ> [<ffffffff94446949>] dump_stack+0x99/0xd0
[<ffffffff940e9247>] lockdep_rcu_suspicious+0xe7/0x120
[<ffffffff9448e0d5>] do_trace_write_msr+0x135/0x140
[<ffffffff9406e750>] native_write_msr+0x20/0x30
[<ffffffff9406503d>] native_apic_msr_eoi_write+0x1d/0x30
[<ffffffff9405b17e>] smp_trace_call_function_interrupt+0x1e/0x270
[<ffffffff948cb1d6>] trace_call_function_interrupt+0x96/0xa0
<EOI> [<ffffffff947200f4>] ? cpuidle_enter_state+0xe4/0x360
[<ffffffff947200df>] ? cpuidle_enter_state+0xcf/0x360
[<ffffffff947203a7>] cpuidle_enter+0x17/0x20
[<ffffffff940df008>] cpu_startup_entry+0x338/0x4d0
[<ffffffff9405bfc4>] start_secondary+0x154/0x180

This can be reproduced readily by running ftrace test case of kselftest.

Move the irq_enter() call before ack_APIC_irq(), because irq_enter() tells
the RCU susbstems to end the extended quiescent state, so that the
following trace call in ack_APIC_irq() works correctly. The same applies to
exiting_ack_irq() which calls ack_APIC_irq() after irq_exit().

[ tglx: Massaged changelog ]

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474198491-3738-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/timers/apic: Inform TSC deadline clockevent device about recalibration

This patch eliminates a source of imprecise APIC timer interrupts,
which imprecision may result in double interrupts or even late
interrupts.

The TSC deadline clockevent devices' configuration and registration
happens before the TSC frequency calibration is refined in
tsc_refine_calibration_work().

This results in the TSC clocksource and the TSC deadline clockevent
devices being configured with slightly different frequencies: the former
gets the refined one and the latter are configured with the inaccurate
frequency detected earlier by means of the "Fast TSC calibration using PIT".

Within the APIC code, introduce the notifier function
lapic_update_tsc_freq() which reconfigures all per-CPU TSC deadline
clockevent devices with the current tsc_khz.

Call it from the TSC code after TSC calibration refinement has happened.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/20160714152255.18295-3-nicstange@gmail.com
[ Pushed #ifdef CONFIG_X86_LOCAL_APIC into header, improved changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Remove the unused struct apic::apic_id_mask field

The only user verify_local_APIC() had been removed by commit:

4399c03c6780 ("x86/apic: Remove verify_local_APIC()")

... so there is no need to keep it.

Signed-off-by: Wei Jiangang <weijg.fnst@cn.fujitsu.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: bsd@redhat.com
Cc: david.vrabel@citrix.com
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1468463046-20849-1-git-send-email-weijg.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/cpufeature: Remove cpu_has_x2apic

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459266123-21878-5-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()

Since 4.4, I've been able to trigger this occasionally:

===============================
[ INFO: suspicious RCU usage. ]
4.5.0-rc7-think+ #3 Not tainted
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20160315012054.GA17765@codemonkey.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

-------------------------------
./arch/x86/include/asm/msr-trace.h:47 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 1
RCU used illegally from extended quiescent state!
no locks held by swapper/3/0.

stack backtrace:
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.5.0-rc7-think+ #3
ffffffff92f821e0 1f3e5c340597d7fc ffff880468e07f10 ffffffff92560c2a
ffff880462145280 0000000000000001 ffff880468e07f40 ffffffff921376a6
ffffffff93665ea0 0000cc7c876d28da 0000000000000005 ffffffff9383dd60
Call Trace:
<IRQ> [<ffffffff92560c2a>] dump_stack+0x67/0x9d
[<ffffffff921376a6>] lockdep_rcu_suspicious+0xe6/0x100
[<ffffffff925ae7a7>] do_trace_write_msr+0x127/0x1a0
[<ffffffff92061c83>] native_apic_msr_eoi_write+0x23/0x30
[<ffffffff92054408>] smp_trace_call_function_interrupt+0x38/0x360
[<ffffffff92d1ca60>] trace_call_function_interrupt+0x90/0xa0
<EOI> [<ffffffff92ac5124>] ? cpuidle_enter_state+0x1b4/0x520

Move the entering_irq() call before ack_APIC_irq(), because entering_irq()
tells the RCU susbstems to end the extended quiescent state, so that the
following trace call in ack_APIC_irq() works correctly.

Suggested-by: Andi Kleen <ak@linux.intel.com>
Fixes: 4787c368a9bc "x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt()"
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org

x86/cpufeature: Carve out X86_FEATURE_*

Move them to a separate header and have the following
dependency:

x86/cpufeatures.h <- x86/processor.h <- x86/cpufeature.h

This makes it easier to use the header in asm code and not
include the whole cpufeature.h and add guards for asm.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1453842730-28463-5-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Introduce apic_extnmi command line parameter

This patch introduces a command line parameter apic_extnmi:

apic_extnmi=( bsp|all|none )

The default value is "bsp" and this is the current behavior: only the
Boot-Strapping Processor receives an external NMI.

"all" allows external NMIs to be broadcast to all CPUs. This would
raise the success rate of panic on NMI when BSP hangs in NMI context
or the external NMI is swallowed by other NMI handlers on the BSP.

If you specify "none", no CPUs receive external NMIs. This is useful for
the dump capture kernel so that it cannot be shot down by accidentally
pressing the external NMI button (on platforms which have it) while
saving a crash dump.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bandan Das <bsd@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20151210014632.25437.43778.stgit@softrs
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Add a single-target IPI function to the apic

We still fall back on the "send mask" versions if an apic definition
doesn't have the single-target version, but at least this allows the
(trivial) case for the common clustered x2apic case.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Daniel J Blueman <daniel@numascale.com>
Link: http://lkml.kernel.org/r/20151104220848.737120838@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/x2apic: Make stub functions available even if !CONFIG_X86_LOCAL_APIC

Some CONFIG_X86_X2APIC functions, especially x2apic_enabled(), are not
declared if !CONFIG_X86_LOCAL_APIC. However, the same stubs that work
for !CONFIG_X86_X2APIC are okay even if there is no local APIC support
at all.

Avoid the introduction of #ifdefs by moving the x2apic declarations
completely outside the CONFIG_X86_LOCAL_APIC block. (Unfortunately,
diff generation messes up the actual change that this patch makes).
There is no semantic change because CONFIG_X86_X2APIC depends on
CONFIG_X86_LOCAL_APIC.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Feng Wu <feng.wu@intel.com>
Link: http://lkml.kernel.org/r/1443435991-35750-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/smpboot: Remove APIC.wait_for_init_deassert and atomic init_deasserted

Both the per-APIC flag ".wait_for_init_deassert",
and the global atomic_t "init_deasserted"
are dead code -- remove them.

For all APIC types, "wait_for_master()"
prevents an AP from proceeding until the BSP has set
cpu_callout_mask, making "init_deasserted" {unnecessary}:

BSP: <de-assert INIT>
...
BSP: {set init_deasserted}
AP: wait_for_master()
set cpu_initialized_mask
wait for cpu_callout_mask
BSP: test cpu_initialized_mask
BSP: set cpu_callout_mask
AP: test cpu_callout_mask
AP: {wait for init_deasserted}
...
AP: <touch APIC>

Deleting the {dead code} above is necessary to enable
some parallelism in a future patch.

Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jan H. Schönherr <jschoenh@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/de4b3a9bab894735e285870b5296da25ee6a8a5a.1439739165.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Consolidate irq entering inlines

smp.c and irq_work.c implement the same inline helper. Move it to
apic.h and use it everywhere.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

x86/apic: Remove verify_local_APIC()

__verify_local_APIC() is detritus from the early APIC days.
Its return value isn't used anywhere and the information it
prints when debug is enabled is already part of APIC
initialization messages printed to syslog. Off with it!

Signed-off-by: Bandan Das <bsd@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/jpgy4mcsxsq.fsf@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/asm: Cleanup prefetch primitives

This is based on a patch originally by hpa.

With the current improvements to the alternatives, we can simply use %P1
as a mem8 operand constraint and rely on the toolchain to generate the
proper instruction sizes. For example, on 32-bit, where we use an empty
old instruction we get:

apply_alternatives: feat: 6*32+8, old: (c104648b, len: 4), repl: (c195566c, len: 4)
c104648b: alt_insn: 90 90 90 90
c195566c: rpl_insn: 0f 0d 4b 5c

...

apply_alternatives: feat: 6*32+8, old: (c18e09b4, len: 3), repl: (c1955948, len: 3)
c18e09b4: alt_insn: 90 90 90
c1955948: rpl_insn: 0f 0d 08

...

apply_alternatives: feat: 6*32+8, old: (c1190cf9, len: 7), repl: (c1955a79, len: 7)
c1190cf9: alt_insn: 90 90 90 90 90 90 90
c1955a79: rpl_insn: 0f 0d 0d a0 d4 85 c1

all with the proper padding done depending on the size of the
replacement instruction the compiler generates.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>

x86/apic: Fix the devicetree build in certain configs

Without this patch:

LD init/built-in.o
arch/x86/built-in.o: In function `dtb_lapic_setup': kernel/devicetree.c:155:
undefined reference to `apic_force_enable'
Makefile:923: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jan Beulich <JBeulich@suse.com>
Link: http://lkml.kernel.org/r/1422905231-16067-1-git-send-email-ricardo.ribalda@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Reuse apic_bsp_setup() for UP APIC setup

Extend apic_bsp_setup() so the same code flow can be used for
APIC_init_uniprocessor().

Folded Jiangs fix to provide proper ordering of the UP setup.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211704.084765674@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/smpboot: Move apic init code to apic.c

We better provide proper functions which implement the required code
flow in the apic code rather than letting the smpboot code open code
it. That allows to make more functions static and confines the APIC
functionality to apic.c where it belongs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211703.907616730@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/x2apic: Split enable and setup function

enable_x2apic() is a convoluted unreadable mess because it is used for
both enablement in early boot and for setup in cpu_init().

Split the code into x2apic_enable() for enablement and x2apic_setup()
for setup of (secondary cpus). Make use of the new state tracking to
simplify the logic.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.129287153@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/x2apic: Disable x2apic from nox2apic setup

There is no point in postponing the hardware disablement of x2apic. It
can be disabled right away in the nox2apic setup function.

Disable it right away and set the state to DISABLED . This allows to
remove all the nox2apic conditionals all over the place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211703.051214090@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/x2apic: Move code in conditional region

No point in having try_to_enable_x2apic() outside of the
CONFIG_X86_X2APIC section and having inline functions and more ifdefs
to deal with it. Move the code into the existing ifdef section and
remove the inline cruft.

Fixup the printk about not enabling interrupt remapping as suggested
by Boris.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.795388613@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Check x2apic early

No point in delaying the x2apic detection for the CONFIG_X86_X2APIC=n
case to enable_IR_x2apic(). We rather detect that before we try to
setup anything there.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.702479404@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/ioapic: Check x2apic really

The x2apic_preenabled flag is just a horrible hack and if X2APIC
support is disabled it does not reflect the actual hardware
state. Check the hardware instead.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20150115211702.541280622@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Make x2apic_mode depend on CONFIG_X86_X2APIC

No point in having a static variable around which is always 0. Let the
compiler optimize code out if disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.363274310@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Avoid open coded x2apic detection

enable_IR_x2apic() grew a open coded x2apic detection. Implement a
proper helper function which shares the code with the already existing
x2apic_enabled().

Made it use rdmsrl_safe as suggested by Boris.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20150115211702.285038186@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86, apic: Remove enable_apic_mode callback

The enable_apic_mode() apic callback is never called, so remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302352320.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove setup_portio_remap callback

Since commit b5660ba76b41 ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the setup_portio_remap() apic callback has been obsolete. Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302351480.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove multi_timer_check callback

Since commit b5660ba76b41 ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the multi_timer_check() apic callback has been obsolete. Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302351120.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove check_apicid_present callback

The check_apicid_present() apic callback is never called, so remove it
and functions that implement it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302350160.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove mps_oem_check callback

Since commit b5660ba76b41 ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the mps_oem_check() apic callback has been obsolete. Remove it.

This allows generic_mps_oem_check() to be removed as well.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302349390.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove smp_callin_clear_local_apic callback

Since commit b5660ba76b41 ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the smp_callin_clear_local_apic() apic callback has been obsolete.
Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302349040.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Replace trampoline physical addresses with defaults

The trampoline_phys_{high,low} members of struct apic are always
initialized to DEFAULT_TRAMPOLINE_PHYS_HIGH and TRAMPOLINE_PHYS_LOW,
respectively. Hardwire the constants and remove the unneeded members.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302348330.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, apic: Remove x86_32_numa_cpu_node callback

Since commit b5660ba76b41 ("x86, platforms: Remove NUMAQ") removed NUMAQ,
the x86_32_numa_cpu_node() apic callback has been obsolete. Remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1407302348060.17503@chino.kir.corp.google.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, vsmp: Remove is_vsmp_box() from apic_is_clustered_box()

When a vSMP Foundation box is detected, the function apic_cluster_num() counts
the number of APIC clusters found. If more than one found, a multi board
configuration is assumed, and TSC marked as unstable. This behavior is
incorrect as vSMP Foundation may use processors from single node only, attached
to memory of other nodes - and such node may have more than one APIC cluster
(typically any recent intel box has more than single APIC_CLUSTERID(x)).

To fix this, we simply remove the code which detects a vSMP Foundation box and
affects apic_is_clusted_box() return value. This can be done because later the
kernel checks by itself if the TSC is stable using the
check_tsc_sync_[source|target]() functions and marks TSC as unstable if needed.

Acked-by: Shai Fultheim <shai@scalemp.com>
Signed-off-by: Oren Twaig <oren@scalemp.com>
Link: http://lkml.kernel.org/r/1404036068-11674-1-git-send-email-oren@scalemp.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, mpparse: Simplify arch/x86/include/asm/mpspec.h

Simplify arch/x86/include/asm/mpspec.h by
1) Change max_physical_apicid to static as it's only used in apic.c.
2) Kill declaration of mpc_default_type, it's never defined.
3) Delete default_acpi_madt_oem_check(), it has already been declared
in apic.h.
4) Make default_acpi_madt_oem_check() depends on CONFIG_X86_LOCAL_APIC
instead of CONFIG_X86_64 to support i386.
5) Change mp_override_legacy_irq(), mp_config_acpi_legacy_irqs() and
mp_register_gsi() as static because they are only used in acpi/boot.c.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1402302011-23642-4-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86, cpufeature: Convert more "features" to bugs

X86_FEATURE_FXSAVE_LEAK, X86_FEATURE_11AP and
X86_FEATURE_CLFLUSH_MONITOR are not really features but synthetic bits
we use for applying different bug workarounds. Call them what they
really are, and make sure they get the proper cross-CPU behavior (OR
rather than AND).

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1403042783-23278-1-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86/apic: Always define nox2apic and define it as initdata

The "nox2apic" variable can be defined as __initdata since it is
only used for bootstrap. It can now unconditionally be defined
since it will later be freed.

At the same time, it is also better off as a bool.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354380.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Remove unused function prototypes

Some function prototypes declared in asm/apic.h are never
defined, so remove them.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354210.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Switch wait_for_init_deassert() to a bool flag

Now that there is only a single wait_for_init_deassert()
function, just convert the member of struct apic to a bool to
determine whether we need to wait for init_deassert to become
non-zero.

There are no more callers of default_wait_for_init_deassert(),
so fold it into the caller.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042354010.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Only use default_wait_for_init_deassert()

es7000_wait_for_init_deassert() is functionally equivalent to
default_wait_for_init_deassert(), so remove the duplicate code
and use only a single function.

Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1402042353030.7839@chino.kir.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/ioapic/kcrash: Prevent crash_kexec() from deadlocking on ioapic_lock

Prevent crash_kexec() from deadlocking on ioapic_lock. When
crash_kexec() is executed on a CPU, the CPU will take ioapic_lock
in disable_IO_APIC(). So if the cpu gets an NMI while locking
ioapic_lock, a deadlock will happen.

In this patch, ioapic_lock is zapped/initialized before disable_IO_APIC().

You can reproduce this deadlock the following way:

1. Add mdelay(1000) after raw_spin_lock_irqsave() in
native_ioapic_set_affinity()@arch/x86/kernel/apic/io_apic.c

Although the deadlock can occur without this modification, it will increase
the potential of the deadlock problem.

2. Build and install the kernel

3. Set up the OS which will run panic() and kexec when NMI is injected
# echo "kernel.unknown_nmi_panic=1" >> /etc/sysctl.conf
# vim /etc/default/grub
add "nmi_watchdog=0 crashkernel=256M" in GRUB_CMDLINE_LINUX line
# grub2-mkconfig

4. Reboot the OS

5. Run following command for each vcpu on the guest
# while true; do echo <CPU num> > /proc/irq/<IO-APIC-edge or IO-APIC-fasteoi>/smp_affinitity; done;
By running this command, cpus will get ioapic_lock for setting affinity.

6. Inject NMI (push a dump button or execute 'virsh inject-nmi <domain>' if you
use VM). After injecting NMI, panic() is called in an nmi-handler context.
Then, kexec will normally run in panic(), but the operation will be stopped
by deadlock on ioapic_lock in crash_kexec()->machine_crash_shutdown()->
native_machine_crash_shutdown()->disable_IO_APIC()->clear_IO_APIC()->
clear_IO_APIC_pin()->ioapic_read_entry().

Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20130820070107.28245.83806.stgit@yunodevel
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86, trace: Introduce entering/exiting_irq()

When implementing tracepoints in interrupt handers, if the tracepoints are
simply added in the performance sensitive path of interrupt handers,
it may cause potential performance problem due to the time penalty.

To solve the problem, an idea is to prepare non-trace/trace irq handers and
switch their IDTs at the enabling/disabling time.

So, let's introduce entering_irq()/exiting_irq() for pre/post-
processing of each irq handler.

A way to use them is as follows.

Non-trace irq handler:
smp_irq_handler()
{
entering_irq(); /* pre-processing of this handler */
__smp_irq_handler(); /*
* common logic between non-trace and trace handlers
* in a vector.
*/
exiting_irq(); /* post-processing of this handler */

}

Trace irq_handler:
smp_trace_irq_handler()
{
entering_irq(); /* pre-processing of this handler */
trace_irq_entry(); /* tracepoint for irq entry */
__smp_irq_handler(); /*
* common logic between non-trace and trace handlers
* in a vector.
*/
trace_irq_exit(); /* tracepoint for irq exit */
exiting_irq(); /* post-processing of this handler */

}

If tracepoints can place outside entering_irq()/exiting_irq() as follows,
it looks cleaner.

smp_trace_irq_handler()
{
trace_irq_entry();
smp_irq_handler();
trace_irq_exit();
}

But it doesn't work.
The problem is with irq_enter/exit() being called. They must be called before
trace_irq_enter/exit(), because of the rcu_irq_enter() must be called before
any tracepoints are used, as tracepoints use rcu to synchronize.

As a possible alternative, we may be able to call irq_enter() first as follows
if irq_enter() can nest.

smp_trace_irq_hander()
{
irq_entry();
trace_irq_entry();
smp_irq_handler();
trace_irq_exit();
irq_exit();
}

But it doesn't work, either.
If irq_enter() is nested, it may have a time penalty because it has to check if it
was already called or not. The time penalty is not desired in performance sensitive
paths even if it is tiny.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/51C3238D.9040706@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

sections: fix section conflicts in arch/x86

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Revert "apic: fix kvm build on UP without IOAPIC"

This reverts commit f9808b7fd422b965cea52e05ba470e0a473c53d3.
After commit 'kvm: switch to apic_set_eoi_write, apic_write'
the stubs are no longer needed as kvm does not look at apicdrivers anymore.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

apic: add apic_set_eoi_write for PV use

KVM PV EOI optimization overrides eoi_write apic op with its own
version. Add an API for this to avoid meddling with core x86 apic driver
data structures directly.

For KVM use, we don't need any guarantees about when the switch to the
new op will take place, so it could in theory use this API after SMP init,
but it currently doesn't, and restricting callers to early init makes it
clear that it's safe as it won't race with actual APIC driver use.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Avi Kivity <avi@redhat.com>

x86/apic/x2apic: Limit the vector reservation to the user specified mask

For the x2apic cluster mode, vector for an interrupt is
currently reserved on all the cpu's that are part of the x2apic
cluster. But the interrupts will be routed only to the cluster
(derived from the first cpu in the mask) members specified in
the mask. So there is no need to reserve the vector in the
unused cluster members.

Modify __assign_irq_vector() to reserve the vectors based on the
user specified irq destination mask. If the new mask is a proper
subset of the currently used mask, cleanup the vector allocation
on the unused cpu members.

Also, allow the apic driver to tune the vector domain based on
the affinity mask (which in most cases is the user-specified
mask).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/1340656709-11423-3-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Optimize cpu traversal in __assign_irq_vector() using domain membership

Currently __assign_irq_vector() goes through each cpu in the
specified mask until it finds a free vector in all the cpu's
that are part of the same interrupt domain. We visit all the
interrupt domain sibling cpus to reserve the free vector. So,
when we fail to find a free vector in an interrupt domain, it is
safe to continue our search with a cpu belonging to a new
interrupt domain. No need to go through each cpu, if the domain
containing that cpu is already visited.

Use the irq_cfg's old_domain to track the visited domains and
optimize the cpu traversal while finding a free vector in the
given cpumask.

NOTE: We can also optimize the search by using for_each_cpu() and
skip the current cpu, if it is not the first cpu in the mask
returned by the vector_allocation_domain(). But re-using the
cfg->old_domain to track the visited domains will be slightly
faster.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/1340656709-11423-2-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

apic: fix kvm build on UP without IOAPIC

On UP i386, when APIC is disabled
# CONFIG_X86_UP_APIC is not set
# CONFIG_PCI_IOAPIC is not set

code looking at apicdrivers never has any effect but it
still gets compiled in. In particular, this causes
build failures with kvm, but it generally bloats the kernel
unnecessarily.

Fix by defining both __apicdrivers and __apicdrivers_end
to be NULL when CONFIG_X86_LOCAL_APIC is unset: I verified
that as the result any loop scanning __apicdrivers gets optimized out by
the compiler.

Warning: a .config with apic disabled doesn't seem to boot
for me (even without this patch). Still verifying why,
meanwhile this patch is compile-tested only.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

x86/apic: Eliminate cpu_mask_to_apicid() operation

Since there are only two locations where cpu_mask_to_apicid() is
called from, remove the operation and use only
cpu_mask_to_apicid_and() instead.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Suggested-and-acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120614074935.GE3383@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Add read_mostly declaration/definition to variables from smp.h

Add "read-mostly" qualifier to the following variables in
smp.h:

- cpu_sibling_map
- cpu_core_map
- cpu_llc_shared_map
- cpu_llc_id
- cpu_number
- x86_cpu_to_apicid
- x86_bios_cpu_apicid
- x86_cpu_to_logical_apicid

As long as all the variables above are only written during the
initialization, this change is meant to prevent the false
sharing. More specifically, on vSMP Foundation platform
x86_cpu_to_apicid shared the same internode_cache_line with
frequently written lapic_events.

From the analysis of the first 33 per_cpu variables out of 219
(memories they describe, to be more specific) the 8 have read_mostly
nature (tlb_vector_offset, cpu_loops_per_jiffy, xen_debug_irq, etc.)
and 25 are frequently written (irq_stack_union, gdt_page,
exception_stacks, idt_desc, etc.).

Assuming that the spread of the rest of the per_cpu variables is
similar, identifying the read mostly memories will make more sense
in terms of long-term code maintenance comparing to identifying
frequently written memories.

Signed-off-by: Vlad Zolotarov <vlad@scalemp.com>
Acked-by: Shai Fultheim <shai@scalemp.com>
Cc: Shai Fultheim (Shai@ScaleMP.com) <Shai@scalemp.com>
Cc: ido@wizery.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1719258.EYKzE4Zbq5@vlad
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Make cpu_mask_to_apicid() operations check cpu_online_mask

Currently cpu_mask_to_apicid() should not get a offline CPU with
the cpumask. Otherwise some apic drivers might try to access
non-existent per-cpu variables (i.e. x2apic). In that regard
cpu_mask_to_apicid() and cpu_mask_to_apicid_and() operations are
inconsistent.

This fix makes the two operations do not rely on calling
functions and always return the apicid for only online CPUs. As
result, the meaning and implementations of cpu_mask_to_apicid()
and cpu_mask_to_apicid_and() operations become straight.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131624.GG4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Make cpu_mask_to_apicid() operations return error code

Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and()
implementations have few shortcomings:

1. A value returned by cpu_mask_to_apicid() is written to
hardware registers unconditionally. Should BAD_APICID get ever
returned it will be written to a hardware too. But the value of
BAD_APICID is not universal across all hardware in all modes and
might cause unexpected results, i.e. interrupts might get routed
to CPUs that are not configured to receive it.

2. Because the value of BAD_APICID is not universal it is
counter- intuitive to return it for a hardware where it does not
make sense (i.e. x2apic).

3. cpu_mask_to_apicid_and() operation is thought as an
complement to cpu_mask_to_apicid() that only applies a AND mask
on top of a cpumask being passed. Yet, as consequence of 18374d8
commit the two operations are inconsistent in that of:
cpu_mask_to_apicid() should not get a offline CPU with the cpumask
cpu_mask_to_apicid_and() should not fail and return BAD_APICID
These limitations are impossible to realize just from looking at
the operations prototypes.

Most of these shortcomings are resolved by returning a error
code instead of BAD_APICID. As the result, faults are reported
back early rather than possibilities to cause a unexpected
behaviour exist (in case of [1]).

The only exception is setup_timer_IRQ0_pin() routine. Although
obviously controversial to this fix, its existing behaviour is
preserved to not break the fragile check_timer() and would
better addressed in a separate fix.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Avoid useless scanning thru a cpumask in assign_irq_vector()

In case of static vector allocation domains (i.e. flat) if all
vector numbers are exhausted, an attempt to assign a new vector
will lead to useless scans through all CPUs in the cpumask, even
though it is known that each new pass would fail. Make this
corner case less painful by letting report whether the vector
allocation domain depends on passed arguments or not and stop
scanning early.

The same could have been achived by introducing a static flag to
the apic operations. But let's allow vector_allocation_domain()
have more intelligence here and decide dynamically, in case we
would need it in the future.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131542.GE4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Factor out default vector_allocation_domain() operation

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120607131449.GC4759@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Factor out default cpu_mask_to_apicid() operations

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120605112340.GA11454@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Factor out default target_cpus() operation

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20120605112324.GA11449@dhcp-26-207.brq.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Implement EIO micro-optimization

We know both register and value for eoi beforehand,
so there's no need to check it and no need to do math
to calculate the msr. Saves instructions/branches
on each EOI when using x2apic.

I looked at the objdump output to verify that the
generated code looks right and actually is shorter.

The real improvemements will be on the KVM guest side
though, those come in a later patch.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/e019d1a125316f10d3e3a4b2f6bda41473f4fb72.1337184153.git.mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Add apic->eoi_write() callback

Add eoi_write callback so that kvm can override
eoi accesses without touching the rest of the apic.
As a side-effect, this will enable a micro-optimization
for apics using msr.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/0df425d746c49ac2ecc405174df87752869629d2.1337184153.git.mst@redhat.com
[ tidied it up a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/apic: Use symbolic APIC_EOI_ACK

Use the symbol instead of hard-coded numbers,
now that the reason for the value is documented
where the constant is defined we don't need to
duplicate this explanation in code.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: gleb@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/ecbe4c79d69c172378e47e5a587ff5cd10293c9f.1337184153.git.mst@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Disintegrate asm/system.h for X86

Disintegrate asm/system.h for X86.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
cc: x86@kernel.org

x86/apic: Add separate apic_id_valid() functions for selected apic drivers

As suggested by Suresh Siddha and Yinghai Lu:

For x2apic pre-enabled systems, apic driver is set already early
through early_acpi_boot_init()/early_acpi_process_madt()/
acpi_parse_madt()/default_acpi_madt_oem_check() path so that
apic_id_valid() checking will be sufficient during MADT and SRAT
parsing.

For non-x2apic pre-enabled systems, all apic ids should be less
than 255.

This allows us to substitute the checks in
arch/x86/kernel/acpi/boot.c::acpi_parse_x2apic() and
arch/x86/mm/srat.c::acpi_numa_x2apic_affinity_init() with
apic->apic_id_valid().

In addition we can avoid feigning the x2apic cpu feature in the
NumaChip apic code.

The following apic drivers have separate apic_id_valid()
functions which will accept x2apic type IDs :

x2apic_phys
x2apic_cluster
x2apic_uv_x
apic_numachip

Signed-off-by: Steffen Persvold <sp@numascale.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Daniel J Blueman <daniel@numascale-asia.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/1331925935-13372-1-git-send-email-sp@numascale.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform: Move APIC ID validity check into platform APIC code

Move APIC ID validity check into platform APIC code, so it can
be overridden when needed. For NumaChip systems, always trust
MADT, as it's constructed with high APIC IDs.

Behaviour verifies on standard x86 systems and on NumaChip
systems with this, and compile-tested with allyesconfig.

Signed-off-by: Daniel J Blueman <daniel@numascale-asia.com>
Reviewed-by: Steffen Persvold <sp@numascale.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1331709454-27966-1-git-send-email-daniel@numascale-asia.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, x2apic: Allow "nox2apic" to disable x2apic mode setup by BIOS

Currently "nox2apic" boot parameter was not enabling x2apic mode if the cpu,
kernel are all capable of enabling x2apic mode and the OS handover
happened in xapic mode.

However If the bios enabled x2apic prior to OS handover, using "nox2apic"
boot parameter had no effect.

If the boot cpu's apicid is < 255, enable "nox2apic" boot parameter to
disable the x2apic mode setup by the bios. This will enable the kernel to
fallback to xapic mode and bringup only the cpu's which has apic-id < 255.

-v2: fix patch error and two compiling warning
make disable_x2apic to be __init

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/CAE9FiQUeB-3uxJAMiHsz=uPWoFv5Hg1pVepz7aU6YtqOxMC-=Q@mail.gmail.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, x2apic: Fallback to xapic when BIOS doesn't setup interrupt-remapping

On some of the recent Intel SNB platforms, by default bios is pre-enabling
x2apic mode in the cpu with out setting up interrupt-remapping.
This case was resulting in the kernel to panic as the cpu is already in
x2apic mode but the OS was not able to enable interrupt-remapping (which
is a pre-req for using x2apic capability).

On these platforms all the apic-ids are < 255 and the kernel can fallback to
xapic mode if the bios has not enabled interrupt-remapping (which is
mostly the case if the bios has not exported interrupt-remapping tables to the
OS).

Reported-by: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86: Convert per-cpu counter icr_read_retry_count into a member of irq_stat

LAPIC related statistics are grouped inside the per-cpu
structure irq_stat, so there is no need for icr_read_retry_count
to be a standalone per-cpu variable.

This patch moves icr_read_retry_count to where it belongs.

Suggested-y: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Add per-cpu stat counter for APIC ICR read tries

In the IPI delivery slow path (NMI delivery) we retry the ICR
read to check for delivery completion a limited number of times.

[ The reason for the limited retries is that some of the places
where it is used (cpu boot, kdump, etc) IPI delivery might not
succeed (due to a firmware bug or system crash, for example)
and in such a case it is better to give up and resume
execution of other code. ]

This patch adds a new entry to /proc/interrupts, RTR, which
tells user space the number of times we retried the ICR read in
the IPI delivery slow path.

This should give some insight into how well the APIC
message delivery hardware is working - if the counts are way
too large then we are hitting a (very-) slow path way too
often.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/n/tip-vzsp20lo2xdzh5f70g0eis2s@git.kernel.org
[ extended the changelog ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86/apic: Allow use of lapic timer early calibration result

lapic timer calibration can be combined with tsc in platform
specific calibration functions. if such calibration result is
obtained early, we can skip the redundant calibration loops.

Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

apic, i386/bigsmp: Fix false warnings regarding logical APIC ID mismatches

These warnings (generally one per CPU) are a result of
initializing x86_cpu_to_logical_apicid while apic_default is
still in use, but the check in setup_local_APIC() being done
when apic_bigsmp was already used as an override in
default_setup_apic_routing():

Overriding APIC driver with bigsmp
Enabling APIC mode: Physflat. Using 5 I/O APICs
------------[ cut here ]------------
WARNING: at .../arch/x86/kernel/apic/apic.c:1239
...
CPU 1 irqstacks, hard=f1c9a000 soft=f1c9c000
Booting Node 0, Processors #1
smpboot cpu 1: start_ip = 9e000
Initializing CPU#1
------------[ cut here ]------------
WARNING: at .../arch/x86/kernel/apic/apic.c:1239
setup_local_APIC+0x137/0x46b() Hardware name: ...
CPU1 logical APIC ID: 2 != 8
...

Fix this (for the time being, i.e. until
x86_32_early_logical_apicid() will get removed again, as Tejun
says ought to be possible) by overriding the previously stored
values at the point where the APIC driver gets overridden.

v2: Move this and the pre-existing override logic into
arch/x86/kernel/apic/bigsmp_32.c.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: <stable@kernel.org> (2.6.39 and onwards)
Link: http://lkml.kernel.org/r/4E835D16020000780005844C@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

atomic: use <linux/atomic.h>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86, apic: Make apic drivers static

Apic probe now looks at the apic drivers listed in the
.apicdrivers section. Remove apic_probe[] and make each apic
driver static.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: steiner@sgi.com
Cc: gorcunov@openvz.org
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20110521005526.341718626@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Clean up bigsmp apic selection code

Make generic_bigsmp_probe() return struct apic *. This will
avoid exporting apic_bigsmp, which will be consistent with
others.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: steiner@sgi.com
Cc: gorcunov@openvz.org
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20110521005526.252703851@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Introduce .apicdrivers section to find the list of apic drivers

This will pave the way for each apic driver to be self-contained
and eliminate the need for apic_probe[].

Order in which apic drivers are listed in the .apicdrivers
section is important, as this determines the apic probe order.
And this is enforced by the ordering of apic driver files in the
Makefile and the macros apic_driver()/apic_drivers().

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: steiner@sgi.com
Cc: gorcunov@openvz.org
Cc: yinghai@kernel.org
Link: http://lkml.kernel.org/r/20110521005526.068775085@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86-32, NUMA: Make apic->x86_32_numa_cpu_node() optional

NUMAQ is the only meaningful user of this callback and
setup_local_APIC() the only callsite. Stop torturing everyone else by
making the callback optional and removing all the boilerplate
implementations and assignments.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>

x86: Stop including <linux/delay.h> in two asm header files

Stop including <linux/delay.h> in x86 header files which don't
need it. This will let the compiler complain when this header is
not included by source files when it should, so that
contributors can fix the problem before building on other
architectures starts to fail.

Credits go to Geert for the idea.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: James E.J. Bottomley <James.Bottomley@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
LKML-Reference: <20110325152014.297890ec@endymion.delvare>
[ this also fixes an upstream build bug in drivers/media/rc/ite-cir.c ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Clean up apic.c and apic.h

This patch moves some functions and variables into init
sections, makes a function static and removes some lines of
cruft.

Signed-off-by: Henrik Kretzschmar <henne@nachtwindheim.de>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <1299826956-8607-2-git-send-email-henne@nachtwindheim.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: dt: Cleanup local apic setup

Up to now we force enable the local apic in the devicetree setup
uncoditionally and set smp_found_config unconditionally to 1 when a
devicetree blob is available. This breaks, when local apic is disabled
in the Kconfig.

Make it consistent by initializing device tree explicitely before
smp_get_config() so a non lapic configuration could be used as well.
To be functional that would require to implement PIT as an interrupt
host, but the only user of this code until now is ce4100 which
requires apics to be available. So we leave this up to those who need
it.

Tested-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Fix section mismatch in LAPIC initialization

Additionally doing things conditionally upon smp_processor_id()
being zero is generally a bad idea, as this means CPU 0 cannot
be offlined and brought back online later again.

While there may be other places where this is done, I think adding
more of those should be avoided so that some day SMP can really
become "symmetrical".

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <4D525C7E0200007800030EE1@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Replace apic->apicid_to_node() with ->x86_32_numa_cpu_node()

apic->apicid_to_node() is 32bit specific apic operation which
determines NUMA node for a CPU. Depending on the APIC
implementation, it can be easier to determine NUMA node from
either physical or logical apicid. Currently,
->apicid_to_node() takes @logical_apicid and calls
hard_smp_processor_id() if the physical apicid is needed.

This prevents NUMA mapping from being queried from a different
CPU, which in turn makes it impossible to initialize NUMA
mapping before SMP bringup.

This patch replaces apic->apicid_to_node() with
->x86_32_numa_cpu_node() which takes @cpu, from which both
logical and physical apicids can easily be determined. While at
it, drop duplicate implementations from bigsmp_32 and summit_32,
and use the default one.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: eric.dumazet@gmail.com
Cc: yinghai@kernel.org
Cc: brgerst@gmail.com
Cc: gorcunov@gmail.com
Cc: shaohui.zheng@intel.com
Cc: rientjes@google.com
LKML-Reference: <1295789862-25482-13-git-send-email-tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Add apic->x86_32_early_logical_apicid()

On x86_32, the mapping between cpu and logical apic ID differs
depending on the specific apic implementation in use. The
mapping is initialized while bringing up CPUs; however, this
makes early inits ignore memory topology.

Add a x86_32 specific apic->x86_32_early_logical_apicid() which
is called early during boot to query the mapping. The mapping
is later verified against the result of init_apic_ldr(). The
method is allowed to return BAD_APICID if it can't be determined
early.

noop variant which always returns BAD_APICID is implemented and
added to all x86_32 apic implementations.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: eric.dumazet@gmail.com
Cc: yinghai@kernel.org
Cc: brgerst@gmail.com
Cc: gorcunov@gmail.com
Cc: penberg@kernel.org
Cc: shaohui.zheng@intel.com
Cc: rientjes@google.com
LKML-Reference: <1295789862-25482-8-git-send-email-tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Kill apic->cpu_to_logical_apicid()

After the previous patch, apic->cpu_to_logical_apicid() is no
longer used. Kill it.

For apic types with custom cpu_to_logical_apicid() which is also
used for other purposes, remove the function and modify its
users to do the mapping directly.

#ifdef's on CONFIG_SMP in es7000_32 and summit_32 are ignored
during conversion as they are not used for UP kernels.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: eric.dumazet@gmail.com
Cc: yinghai@kernel.org
Cc: brgerst@gmail.com
Cc: gorcunov@gmail.com
Cc: penberg@kernel.org
Cc: shaohui.zheng@intel.com
Cc: rientjes@google.com
LKML-Reference: <1295789862-25482-7-git-send-email-tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Replace cpu_2_logical_apicid[] with early percpu variable

Unlike x86_64, on x86_32, the mapping from cpu to logical apicid
may vary depending on apic in use. cpu_2_logical_apicid[] array
is used for this mapping. Replace it with early percpu variable
x86_cpu_to_logical_apicid to make it better aligned with other
mappings.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: eric.dumazet@gmail.com
Cc: yinghai@kernel.org
Cc: brgerst@gmail.com
Cc: gorcunov@gmail.com
Cc: penberg@kernel.org
Cc: shaohui.zheng@intel.com
Cc: rientjes@google.com
LKML-Reference: <1295789862-25482-5-git-send-email-tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Remove early_init_lapic_mapping()

It is almost the same as smp_register_lapic_addr(). We just need to
let smp_read_mpc() call smp_register_lapic_addr() when early==1.

Add the apic_printk to smp_register_lapic_address()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
LKML-Reference: <4CFDF681.3030509@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86, apic: Unify identical register_lapic_address() functions

They are the same, move the common function to apic.c to allow
further cleanups.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Len Brown <lenb@kernel.org>
LKML-Reference: <4CFDF675.4060305@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Address gcc4.6 "set but not used" warnings in apic.h

native_apic_msr_read() and x2apic_enabled() use rdmsr(msr, low, high),
but only use the low part.

gcc4.6 complains about this:
.../apic.h:144:11: warning: variable 'high' set but not used [-Wunused-but-set-variable]

rdmsr() is just a wrapper around rdmsrl() which splits the 64bit value
into low and high, so using rdmsrl() directly solves this.

[tglx: Changed the variables to u64 as suggested by Cyrill. It's less
confusing and has no code impact as this is 64bit only anyway.
Massaged changelog as well. ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <1289251229-19589-1-git-send-email-andi@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Allow platforms to force enable apic

Some embedded x86 platforms don't setup the APIC in the
BIOS/bootloader and would be forced to add "lapic" on the kernel
command line. That's a bit akward.

Split out the force enable code from detect_init_APIC() and allow
platform code to call it from the platform setup. That avoids the
command line parameter and possible replication of the MSR dance in
the force enable code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1287510389-8388-1-git-send-email-dirk.brandewie@gmail.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>

apic, x86: Use BIOS settings for IBS and MCE threshold interrupt LVT offsets

We want the BIOS to setup the EILVT APIC registers. The offsets
were hardcoded and BIOS settings were overwritten by the OS.
Now, the subsystems for MCE threshold and IBS determine the LVT
offset from the registers the BIOS has setup. If the BIOS setup
is buggy on a family 10h system, a workaround enables IBS. If
the OS determines an invalid register setup, a "[Firmware Bug]:
" error message is reported.

We need this change also for upcomming cpu families.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1286360874-1471-3-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Allow to use certain functions without APIC built-in support

In case even if the kernel is configured so that
no APIC support is built-in we still may allow
to use certain apic functions as dummy calls.

In particular we start using it in perf-events code.

Note that this is not that same as NOOP apic driver (which
is used if APIC support is present but no physical APIC is
available), this is for the case when we don't have apic code
compiled in at all.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20100317104356.011052632@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic: Do not use stacked physid_mask_t

We should not use physid_mask_t as a stack based
variable in apic code. This type depends on MAX_APICS
parameter which may be huge enough.

Especially it became a problem with apic NOOP driver which
is portable between 32 bit and 64 bit environment
(where we have really huge MAX_APICS).

So apic driver should operate with pointers and a caller
in turn should aware of allocation physid_mask_t variable.

As a side (but positive) effect -- we may use already
implemented physid_set_mask_of_physid function eliminating
default_apicid_to_cpu_present completely.

Note that physids_coerce and physids_promote turned into static
inline from macro (since macro hides the fact that parameter is
being interpreted as unsigned long, make it explicit).

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
LKML-Reference: <20091109220659.GA5568@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Introduce the NOOP apic driver

Introduce NOOP APIC driver. We should use it in case if apic was
disabled due to hardware of software/firmware problems (including
user requested to disable it case).

The driver is attempting to catch any inappropriate apic operation
call with warning issue.

Also it is possible to use some apic operation like IPI calls,
read/write without checking for apic presence which should make
callers code easier.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: yinghai@kernel.org
Cc: macro@linux-mips.org
LKML-Reference: <20091013201022.534682104@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: Fix missed handling of discrete apics

In case of discrete (pretty old) apics we may have cpu_has_apic bit
not set but have to check if smp_found_config (MP spec) is there
and apic was not disabled.

Also don't forget to print apic/io-apic for such case as well.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20090915071230.GA10604@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic namespace cleanup

boot_cpu_physical_apicid is a global variable and used as function
argument as well. Rename the function arguments to avoid confusion.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86: Move percpu clockevents setup to x86_init_ops

paravirt overrides the setup of the default apic timers as per cpu
timers. Moorestown needs to override that as well.

Move it to x86_init_ops setup and create a separate x86_cpuinit struct
which holds the function for the secondary evtl. hotplugabble CPUs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/apic: Enable x2APIC without interrupt remapping under KVM

KVM would like to provide x2APIC interface to a guest without emulating
interrupt remapping device. The reason KVM prefers guest to use x2APIC
is that x2APIC interface is better virtualizable and provides better
performance than mmio xAPIC interface:

- msr exits are faster than mmio (no page table walk, emulation)
- no need to read back ICR to look at the busy bit
- one 64 bit ICR write instead of two 32 bit writes
- shared code with the Hyper-V paravirt interface

Included patch changes x2APIC enabling logic to enable it even if IR
initialization failed, but kernel runs under KVM and no apic id is
greater than 255 (if there is one spec requires BIOS to move to x2apic
mode before starting an OS).

-v2: fix build
-v3: fix bug causing compiler warning

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: "avi@redhat.com" <avi@redhat.com>
LKML-Reference: <20090720122417.GR5638@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Detect use of extended APIC ID for AMD CPUs

Booting a 32-bit kernel on Magny-Cours results in the following panic:

...
Using APIC driver default
...
Overriding APIC driver with bigsmp
...
Getting VERSION: 80050010
Getting VERSION: 80050010
Getting ID: 10000000
Getting ID: ef000000
Getting LVT0: 700
Getting LVT1: 10000
Kernel panic - not syncing: Boot APIC ID in local APIC unexpected (16 vs 0)
Pid: 1, comm: swapper Not tainted 2.6.30-rcX #2
Call Trace:
[<c05194da>] ? panic+0x38/0xd3
[<c0743102>] ? native_smp_prepare_cpus+0x259/0x31f
[<c073b19d>] ? kernel_init+0x3e/0x141
[<c073b15f>] ? kernel_init+0x0/0x141
[<c020325f>] ? kernel_thread_helper+0x7/0x10

The reason is that default_get_apic_id handled extension of local APIC
ID field just in case of XAPIC.

Thus for this AMD CPU, default_get_apic_id() returns 0 and
bigsmp_get_apic_id() returns 16 which leads to the respective kernel
panic.

This patch introduces a Linux specific feature flag to indicate
support for extended APIC id (8 bits instead of 4 bits width) and sets
the flag on AMD CPUs if applicable.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: <stable@kernel.org>
LKML-Reference: <20090608135509.GA12431@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: x2apic, IR: Clean up X86_X2APIC and INTR_REMAP config checks

Add x2apic_supported() to clean up CONFIG_X86_X2APIC checks.

Fix CONFIG_INTR_REMAP checks.

[ Impact: cleanup ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: dwmw2@infradead.org
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Weidong Han <weidong.han@intel.com>
LKML-Reference: <20090420200450.128993000@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, intr-remap: enable interrupt remapping early

Currently, when x2apic is not enabled, interrupt remapping
will be enabled in init_dmars(), where it is too late to remap
ioapic interrupts, that is, ioapic interrupts are really in
compatibility mode, not remappable mode.

This patch always enables interrupt remapping before ioapic
setup, it guarantees all interrupts will be remapped when
interrupt remapping is enabled. Thus it doesn't need to set
the compatibility interrupt bit.

[ Impact: refactor intr-remap init sequence, enable fuller remap mode ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: allen.m.kay@intel.com
Cc: fenghua.yu@intel.com
LKML-Reference: <1239957736-6161-4-git-send-email-weidong.han@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, intr-remap: fix ack for interrupt remapping

Shouldn't call ack_apic_edge() in ir_ack_apic_edge(), because
ack_apic_edge() does more than just ack: it also does irq migration
in the non-interrupt-remapping case. But there is no such need for
interrupt-remapping case, as irq migration is done in the process
context.

Similarly, ir_ack_apic_level() shouldn't call ack_apic_level, and
instead should do the local cpu's EOI + directed EOI to the io-apic.

ack_x2APIC_irq() is not neccessary, because ack_APIC_irq() will use MSR
write for x2apic, and uncached write for non-x2apic.

[ Impact: simplify/standardize intr-remap IRQ acking, fix on !x2apic ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: allen.m.kay@intel.com
Cc: fenghua.yu@intel.com
LKML-Reference: <1239957736-6161-3-git-send-email-weidong.han@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic - introduce dummy apic operations

Impact: refactor, speed up and robustize code

In case if apic was disabled by kernel option
or by hardware limits we can use dummy operations
in apic->write to simplify the ack_APIC_irq() code.

At the lame time the patch fixes the missed EOI in
do_IRQ function (which has place if kernel is compiled
as X86-32 and interrupt without handler happens where
apic was not asked to be disabled via kernel option).

Note that native_apic_write_dummy() consists of
WARN_ON_ONCE to catch any buggy writes on enabled
APICs. Could be removed after some time of testing.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.724788431@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: clean up declarations and variables

Impact: cleanup, no code changed

- syscalls.h update declarations due to unifications
- irq.c declare smp_generic_interrupt() before it gets used
- process.c declare sys_fork() and sys_vfork() before they get used
- tsc.c rename tsc_khz shadowed variable
- apic/probe_32.c declare apic_default before it gets used
- apic/nmi.c prev_nmi_count should be unsigned
- apic/io_apic.c declare smp_irq_move_cleanup_interrupt() before it gets used
- mm/init.c declare direct_gbpages and free_initrd_mem before they get used

Signed-off-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x2apic/intr-remap: decouple interrupt remapping from x2apic

interrupt remapping must be enabled before enabling x2apic, but
interrupt remapping doesn't depend on x2apic, it can be used
separately. Enable interrupt remapping in init_dmars even x2apic
is not supported.

[dwmw2: Update Kconfig accordingly, fix build with INTR_REMAP && !X2APIC]

Signed-off-by: Weidong Han <weidong.han@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Intel IOMMU Suspend/Resume Support - Interrupt Remapping

This patch enables suspend/resume for interrupt remapping. During suspend,
interrupt remapping is disabled. When resume, interrupt remapping is enabled
again.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Revert "x86: don't compile vsmp_64 for 32bit"

Partial revert of commit 129d8bc828e011bda0b7110a097bf3a0167f966e
titled 'x86: don't compile vsmp_64 for 32bit'

Commit reverted to compile vsmp_64.c if CONFIG_X86_64 is defined,
since is_vsmp_box() needs to indicate that TSCs are not synchronized, and
hence, not a valid time source, even when CONFIG_X86_VSMP is not defined.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: shai@scalex86.org
LKML-Reference: <20090324061429.GH7278@localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: use default_cpu_mask_to_apicid for 64bit

Impact: cleanup

Use online_mask directly on 64bit too.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <49C94DAE.9070300@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: add x2apic_wrmsr_fence() to x2apic flush tlb paths

Impact: optimize APIC IPI related barriers

Uncached MMIO accesses for xapic are inherently serializing and hence
we don't need explicit barriers for xapic IPI paths.

x2apic MSR writes/reads don't have serializing semantics and hence need
a serializing instruction or mfence, to make all the previous memory
stores globally visisble before the x2apic msr write for IPI.

Add x2apic_wrmsr_fence() in flush tlb path to x2apic specific paths.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "steiner@sgi.com" <steiner@sgi.com>
Cc: Nick Piggin <npiggin@suse.de>
LKML-Reference: <1237313814.27006.203.camel@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, x2apic: fix clear_local_APIC() in the presence of x2apic

Impact: cleanup, paranoia

We were not clearing the local APIC in clear_local_APIC() in the
presence of x2apic. Fix it.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86: UV, SGI RTC: add generic system vector, build fix on UP

Make ack_APIC_irq() build on !SMP && !APIC too.

Cc: Dimitri Sivanich <sivanich@sgi.com>
LKML-Reference: <20090304185605.GA24419@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic: simplify secondary CPU wakeup methods

Impact: cleanup

- rename apic->wakeup_cpu to apic->wakeup_secondary_cpu, to
make it apparent that this is an SMP-only method

- handle NULL ->wakeup_secondary_cpus to mean the default INIT
wakeup sequence - this allows simplification of the APIC
driver templates.

Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: remove update_apic from x86_quirks, fix

Impact: build fix

wakeup_secondary_cpu_via_init(), the default platform method for
booting a secondary CPU, is always used on UP due to probe_32.c,
if CONFIG_X86_LOCAL_APIC is enabled but SMP is off.

So provide a UP wrapper inline as well.

Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: don't compile vsmp_64 for 32bit

Impact: cleanup

that is only needed when CONFIG_X86_VSMP is defined with 64bit
also remove dead code about PCI, because CONFIG_X86_VSMP depends on PCI

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: remove update_apic from x86_quirks

Impact: cleanup

x86_quirks->update_apic() calling looks crazy. so try to remove it:

1. every apic take wakeup_cpu member directly
2. separate es7000_apic to es7000_apic_cluster
3. use uv_wakeup_cpu directly

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: select x2apic ops in early apic probe only if x2apic mode is enabled

If BIOS hands over the control to OS in legacy xapic mode, select
legacy xapic related ops in the early apic probe and shift to x2apic
ops later in the boot sequence, only after enabling x2apic mode.

If BIOS hands over the control in x2apic mode, select x2apic related
ops in the early apic probe.

This fixes the early boot panic, where we were selecting x2apic ops,
while the cpu is still in legacy xapic mode.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: rename 'genapic' to 'apic'

Impact: cleanup

Now that all APIC code is consolidated there's nothing 'gen' about
apics anymore - so rename 'struct genapic' to 'struct apic'.

This shortens the code and is nicer to read as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: remove ->store_NMI_vector()

Impact: cleanup

It's not used by anything anymore.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: clean up the cpu_2_logical_apiciddeclaration

extern declarations were scattered in 4 files - consolidate them
into apic.h.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: merge genapic.h into apic.h

Impact: cleanup

Reduce the number of include files to worry about.
Also, most of the users of APIC facilities had to
include genapic.h already, which embedded apic.h,
so the distinction was meaningless.

[ include apic.h from genapic.h for compatibility. ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: fold apic_ops into genapic

Impact: cleanup

make it simpler, don't need have one extra struct.

v2: fix the sgi_uv build

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: add x2apic config

Impact: cleanup

so could deselect x2apic
and INTR_REMAP will select x2apic

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, apic: make generic_apic_probe() generally available

Impact: build fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: make apic_* operations inline functions

Mainly to get proper type-checking and consistency.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

x86: remove subarchitecture support

Remove the 32-bit subarchitecture support code.

All subarchitectures but Voyager have been converted. Voyager will be
done later or will be removed.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: remove mach_apic.h

Spread mach_apic.h definitions into genapic.h. (with some knock-on effects
on smp.h and apic.h.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: remove mach_apicdef.h

Move its definitions into apic.h.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86, smp: eliminate asm/mach-default/mach_wakecpu.h

Spread mach_wakecpu.h's definitions into apic.h and genapic.h
and remove mach_wakecpu.h.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: apic.c: xapic_icr_read and x2apic_icr_read should be static

Impact: cleanup, reduce kernel size a bit, avoid sparse warning

Fixes sparse warning:
arch/x86/kernel/apic.c:270:5: warning: symbol 'x2apic_icr_read' was not declared. Should it be static?

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86: apic.c x2apic_preenabled and disable_x2apic should be static

Impact: cleanup, reduce kernel size a bit, avoid sparse warning

Fixes sparse warning:

arch/x86/kernel/apic.c:103:5: warning: symbol 'disable_x2apic' was not declared. Should it be static?

Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: call machine_shutdown and stop all CPUs in native_machine_halt

Impact: really halt all CPUs on halt

Function machine_halt (resp. native_machine_halt) is empty for x86
architectures. When command 'halt -f' is invoked, the message "System
halted." is displayed but this is not really true because all CPUs are
still running.

There are also similar inconsistencies for other arches (some uses
power-off for halt or forever-loop with IRQs enabled/disabled).

IMO there should be used the same approach for all architectures OR
what does the message "System halted" really mean?

This patch fixes it for x86.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: Fix ASM_X86__ header guards

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>