arch/x86: Fix typos

Fix typos, most reported by "codespell arch/x86". Only touches comments,
no code changes.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240103004011.1758650-1-helgaas@kernel.org

x86/platform/uv: Rework NMI "action" modparam handling

Rework NMI "action" modparam handling:

- Replace the uv_nmi_action string with an enum; and
- Use sysfs_match_string() for string parsing in param_set_action()

No change in functionality intended.

Suggested-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230916130653.243532-1-hdegoede@redhat.com

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/platform/uv: Refactor code using deprecated strcpy()/strncpy() interfaces to use strscpy()

Both `strncpy` and `strcpy` are deprecated for use on NUL-terminated
destination strings [1].

A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on its destination buffer argument which is
_not_ the case for `strncpy` or `strcpy`!

In this case, we can drop both the forced NUL-termination and the `... -1` from:
| strncpy(arg, val, ACTION_LEN - 1);
as `strscpy` implicitly has this behavior.

Also include slight refactor to code removing possible new-line chars as
per Yang Yang's work at [3]. This reduces code size and complexity by
using more robust and better understood interfaces.

Co-developed-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings[1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://lore.kernel.org/all/202212091545310085328@zte.com.cn/ [3]
Link: https://github.com/KSPP/linux/issues/90
Link: https://lore.kernel.org/r/20230824-strncpy-arch-x86-platform-uv-uv_nmi-v2-1-e16d9a3ec570@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86: replace cpumask_weight with cpumask_empty where appropriate

In some cases, arch/x86 code calls cpumask_weight() to check if any bit of
a given cpumask is set. We can do it more efficiently with cpumask_empty()
because cpumask_empty() stops traversing the cpumask as soon as it finds
first set bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>

x86: Replace cpumask_weight() with cpumask_empty() where appropriate

In some cases, x86 code calls cpumask_weight() to check if any bit of a
given cpumask is set.

This can be done more efficiently with cpumask_empty() because
cpumask_empty() stops traversing the cpumask as soon as it finds first set
bit, while cpumask_weight() counts all bits unconditionally.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20220210224933.379149-17-yury.norov@gmail.com

x86/platform/uv: Update NMI Handler for UV5

Update NMI handler for UV5 hardware. A platform register changed, and
UV5 only uses one of the two NMI methods used on previous hardware.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220406195149.228164-2-steve.wahl@hpe.com

x86/platform/uv: Remove dead !CONFIG_KEXEC_CORE code

The !CONFIG_KEXEC_CORE code in arch/x86/platform/uv/uv_nmi.c was unused, untested
and didn't even build for 7 years. Since we fixed this by requiring X86_UV to
depend on CONFIG_KEXEC_CORE, remove the (now) dead code.

Also move the uv_nmi_kexec_failed definition back up to where the other file-scope
global variables are defined.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Cc: linux-kernel@vger.kernel.org

x86/platform/uv: Add more to secondary CPU kdump info

Add call to run_crash_ipi_callback() to gather more info of what the
secondary CPUs were doing to help with failure analysis.

Excerpt from Georges:

'It is only changing where crash secondaries will be stalling after
having taken care of properly laying down "crash note regs". Please
note that "crash note regs" are a key piece of data used by crash dump
debuggers to provide a reliable backtrace of running processors.'

Secondary change pursuant to

a5f526ecb075 ("CodingStyle: Inclusive Terminology"):

change master/slave to main/secondary.

[ bp: Massage commit message. ]

Signed-off-by: Georges Aureau <georges.aureau@hpe.com>
Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lkml.kernel.org/r/20210311151028.82678-1-mike.travis@hpe.com

x86: Fix various typos in comments

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org

x86/platform/uv: Remove unused variable in UV5 NMI handler

Remove an unused variable.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201013154731.132565-1-mike.travis@hpe.com

x86/platform/uv: Update Copyrights to conform to HPE standards

Add Copyrights to those files that have been updated for UV5 changes.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201005203929.148656-14-mike.travis@hpe.com

x86/platform/uv: Update for UV5 NMI MMR changes

The UV NMI MMR addresses and fields moved between UV4 and UV5
necessitating a rewrite of the UV NMI handler. Adjust references
to accommodate those changes.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lkml.kernel.org/r/20201005203929.148656-13-mike.travis@hpe.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86: Fix various typos in comments

Go over arch/x86/ and fix common typos in comments,
and a typo in an actual function argument name.

No change in functionality intended.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Fix Sparse warnings about non-static functions

Functions x86_vector_debug_show(), uv_handle_nmi() and uv_nmi_setup_common()
are local to the source and do not need to be in global scope, so make them
static.

Fixes up various sparse warnings.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Mike Travis <mike.travis@hpe.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-janitors@vger.kernel.org
Cc: travis@sgi.com
Link: http://lkml.kernel.org/r/20171206173358.24388-1-colin.king@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>

We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

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>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/UV/NMI: Fix uneccessary kABI breakage

The addition of support for UV Hubless systems unneccessarily broke
the kABI for a symbol that is not used by external kernel modules.
Remove the symbol from the EXPORT list.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Russ Anderson <russ.anderson@hpe.com>
Link: http://lkml.kernel.org/r/20170215001129.068078379@asylum.americas.sgi.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/platform/UV: Clean up the NMI code to match current coding style

Update UV NMI to current coding style.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@hpe.com>
Link: http://lkml.kernel.org/r/20170125163518.419094259@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/UV: Initialize PCH GPP_D_0 NMI Pin to be NMI source

The initialize PCH NMI I/O function is separate and may be moved to BIOS
for security reasons. This function detects whether the PCH NMI config
has already been done and if not, it will then initialize the PCH here.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170125163518.089387859@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/UV: Verify NMI action is valid, default is standard

Verify that the NMI action being set is valid. The default NMI action
changes from the non-standard 'kdb' to the more standard 'dump'.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Alex Thorlton <athorlton@sgi.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170125163517.922751779@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/UV: Add basic CPU NMI health check

Add a low impact health check triggered by the system NMI command
that essentially checks which CPUs are responding to external NMI's.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Alex Thorlton <athorlton@sgi.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170125163517.756690240@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/UV: Add Support for UV4 Hubless NMIs

Merge new UV Hubless NMI support into existing UV NMI handler.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Russ Anderson <rja@hpe.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Dimitri Sivanich <sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170125163517.585269837@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/dumpstack: Remove kernel text addresses from stack dump

Printing kernel text addresses in stack dumps is of questionable value,
especially now that address randomization is becoming common.

It can be a security issue because it leaks kernel addresses. It also
affects the usefulness of the stack dump. Linus says:

"I actually spend time cleaning up commit messages in logs, because
useless data that isn't actually information (random hex numbers) is
actively detrimental.

It makes commit logs less legible.

It also makes it harder to parse dumps.

It's not useful. That makes it actively bad.

I probably look at more oops reports than most people. I have not
found the hex numbers useful for the last five years, because they are
just randomized crap.

The stack content thing just makes code scroll off the screen etc, for
example."

The only real downside to removing these addresses is that they can be
used to disambiguate duplicate symbol names. However such cases are
rare, and the context of the stack dump should be enough to be able to
figure it out.

There's now a 'faddr2line' script which can be used to convert a
function address to a file name and line:

$ ./scripts/faddr2line ~/k/vmlinux write_sysrq_trigger+0x51/0x60
write_sysrq_trigger+0x51/0x60:
write_sysrq_trigger at drivers/tty/sysrq.c:1098

Or gdb can be used:

$ echo "list *write_sysrq_trigger+0x51" |gdb ~/k/vmlinux |grep "is in"
(gdb) 0xffffffff815b5d83 is in driver_probe_device (/home/jpoimboe/git/linux/drivers/base/dd.c:378).

(But note that when there are duplicate symbol names, gdb will only show
the first symbol it finds. faddr2line is recommended over gdb because
it handles duplicates and it also does function size checking.)

Here's an example of what a stack dump looks like after this change:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: sysrq_handle_crash+0x45/0x80
PGD 36bfa067 [ 29.650644] PUD 7aca3067
Oops: 0002 [#1] PREEMPT SMP
Modules linked in: ...
CPU: 1 PID: 786 Comm: bash Tainted: G E 4.9.0-rc1+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014
task: ffff880078582a40 task.stack: ffffc90000ba8000
RIP: 0010:sysrq_handle_crash+0x45/0x80
RSP: 0018:ffffc90000babdc8 EFLAGS: 00010296
RAX: ffff880078582a40 RBX: 0000000000000063 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000292
RBP: ffffc90000babdc8 R08: 0000000b31866061 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000007 R14: ffffffff81ee8680 R15: 0000000000000000
FS: 00007ffb43869700(0000) GS:ffff88007d400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007a3e9000 CR4: 00000000001406e0
Stack:
ffffc90000babe00 ffffffff81572d08 ffffffff81572bd5 0000000000000002
0000000000000000 ffff880079606600 00007ffb4386e000 ffffc90000babe20
ffffffff81573201 ffff880036a3fd00 fffffffffffffffb ffffc90000babe40
Call Trace:
__handle_sysrq+0x138/0x220
? __handle_sysrq+0x5/0x220
write_sysrq_trigger+0x51/0x60
proc_reg_write+0x42/0x70
__vfs_write+0x37/0x140
? preempt_count_sub+0xa1/0x100
? __sb_start_write+0xf5/0x210
? vfs_write+0x183/0x1a0
vfs_write+0xb8/0x1a0
SyS_write+0x58/0xc0
entry_SYSCALL_64_fastpath+0x1f/0xc2
RIP: 0033:0x7ffb42f55940
RSP: 002b:00007ffd33bb6b18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000046 RCX: 00007ffb42f55940
RDX: 0000000000000002 RSI: 00007ffb4386e000 RDI: 0000000000000001
RBP: 0000000000000011 R08: 00007ffb4321ea40 R09: 00007ffb43869700
R10: 00007ffb43869700 R11: 0000000000000246 R12: 0000000000778a10
R13: 00007ffd33bb5c00 R14: 0000000000000007 R15: 0000000000000010
Code: 34 e8 d0 34 bc ff 48 c7 c2 3b 2b 57 81 be 01 00 00 00 48 c7 c7 e0 dd e5 81 e8 a8 55 ba ff c7 05 0e 3f de 00 01 00 00 00 0f ae f8 <c6> 04 25 00 00 00 00 01 5d c3 e8 4c 49 bc ff 84 c0 75 c3 48 c7
RIP: sysrq_handle_crash+0x45/0x80 RSP: ffffc90000babdc8
CR2: 0000000000000000

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/69329cb29b8f324bb5fcea14d61d224807fb6488.1477405374.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform: Audit and remove any unnecessary uses of module.h

Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends. That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig. The advantage
in doing so is that module.h itself sources about 15 other headers;
adding significantly to what we feed cpp, and it can obscure what
headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance
for the presence of either and replace as needed.

One module.h was converted to moduleparam.h since the file had
multiple module_param() in it, and another file had an instance of
MODULE_DEVICE_TABLE deleted, since that is a no-op when builtin.

Finally, the 32 bit build coverage of olpc_ofw revealed a couple
implicit includes, which were pretty self evident to fix based on
what gcc was complaining about.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.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/20160714001901.31603-6-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/uv: Include clocksource.h for clocksource_touch_watchdog()

This build failure triggers on 64-bit allmodconfig:

arch/x86/platform/uv/uv_nmi.c:493:2: error: implicit declaration of function ‘clocksource_touch_watchdog’ [-Werror=implicit-function-declaration]

which is caused by recent changes exposing a missing clocksource.h include
in uv_nmi.c:

cc1e24fdb064 x86/vdso: Remove pvclock fixmap machinery

this file got clocksource.h indirectly via fixmap.h - that stealth route
of header inclusion is now gone.

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>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/platform/uv: Implement simple dump failover if kdump fails

The ability to trigger a kdump using the system NMI command
was added by

commit 12ba6c990fab ("x86/UV: Add kdump to UV NMI handler")
Author: Mike Travis <travis@sgi.com>
Date: Mon Sep 23 16:25:03 2013 -0500

This is useful because when kdump is working the information
gathered is more informative than the original per CPU stack
traces or "dump" option. However a number of things can go
wrong with kdump and then the stack traces are more useful than
nothing.

The two most common reasons for kdump to not be available are:

1) if a problem occurs during boot before the kdump service is
started, or
2) the kdump daemon failed to start.

In either case the call to crash_kexec() returns unexpectedly.

When this happens uv_nmi_kdump() also sets the
uv_nmi_kexec_failed flag which causes the slave CPU's to also
return to the NMI handler. Upon this unexpected return to the
NMI handler, the NMI handler will revert to the "dump" action
which uses show_regs() to obtain a process trace dump for all
the CPU's.

Other minor changes:
The "dump" action now generates both the show_regs() stack trace
and show instruction pointer information. Whereas the "ips"
action only shows instruction pointers for non-idle CPU's. This
is more like an abbreviated "ps" display.

Change printk(KERN_DEFAULT...) --> pr_info()

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: George Beshers <gbeshers@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hedi Berriche <hedi@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kexec: split kexec_load syscall from kexec core code

There are two kexec load syscalls, kexec_load another and kexec_file_load.
kexec_file_load has been splited as kernel/kexec_file.c. In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled. But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel. KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig. Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/params: constify struct kernel_param_ops uses

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

* allnoconfig
* allmodconfig
* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

x86: use %*pb[l] to print bitmaps including cpumasks and nodemasks

printk and friends can now format bitmaps using '%*pb[l]'. cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

* Unnecessary buffer size calculation and condition on the lenght
removed from intel_cacheinfo.c::show_shared_cpu_map_func().

* uv_nmi_nr_cpus_pr() got overly smart and implemented "..."
abbreviation if the output stretched over the predefined 1024 byte
buffer. Replaced with plain printk.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

uv: Replace __get_cpu_var

Use __this_cpu_read instead.

Cc: Hedi Berriche <hedi@sgi.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/printk: use symbolic defines for console loglevels

... instead of naked numbers.

Stuff in sysrq.c used to set it to 8 which is supposed to mean above
default level so set it to DEBUG instead as we're terminating/killing all
tasks and we want to be verbose there.

Also, correct the check in x86_64_start_kernel which should be >= as
we're clearly issuing the string there for all debug levels, not only
the magical 10.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/uv/nmi, kgdb/kdb: Fix UV NMI handler when KDB not configured

Fix UV call into kgdb to depend only on whether KGDB is defined
and not both KGDB and KDB. This allows the power nmi command to
use the gdb remote connection if enabled. Note new action of
'kgdb' needs to be set as well to indicate user wants to wait
for gdb to be connected. If it's set to 'kdb' then an error
message is displayed if KDB is not configured.

Also note that if both KGDB and KDB are enabled, then the action
of 'kgdb' or 'kdb' has no affect on which is used. See the KGDB
documentation for further information.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20140114162551.635540667@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/uv/nmi: Fix Sparse warnings

Make uv_register_nmi_notifier() and uv_handle_nmi_ping() static
to address sparse warnings.

Fix problem where uv_nmi_kexec_failed is unused when
CONFIG_KEXEC is not defined.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20140114162551.480872353@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kgdb/kdb: Fix no KDB config problem

Some code added to the debug_core module had KDB dependencies
that it shouldn't have. Move the KDB dependent REASON back to
the caller to remove the dependency in the debug core code.

Update the call from the UV NMI handler to conform to the new
interface.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Russ Anderson <rja@sgi.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20140114162551.318251993@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/dumpstack: Fix printk_address for direct addresses

Consider a kernel crash in a module, simulated the following way:

static int my_init(void)
{
char *map = (void *)0x5;
*map = 3;
return 0;
}
module_init(my_init);

When we turn off FRAME_POINTERs, the very first instruction in
that function causes a BUG. The problem is that we print IP in
the BUG report using %pB (from printk_address). And %pB
decrements the pointer by one to fix printing addresses of
functions with tail calls.

This was added in commit 71f9e59800e5ad4 ("x86, dumpstack: Use
%pB format specifier for stack trace") to fix the call stack
printouts.

So instead of correct output:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa01ac000>] my_init+0x0/0x10 [pb173]

We get:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000005
IP: [<ffffffffa0152000>] 0xffffffffa0151fff

To fix that, we use %pS only for stack addresses printouts (via
newly added printk_stack_address) and %pB for regs->ip (via
printk_address). I.e. we revert to the old behaviour for all
except call stacks. And since from all those reliable is 1, we
remove that parameter from printk_address.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: joe@perches.com
Cc: jirislaby@gmail.com
Link: http://lkml.kernel.org/r/1382706418-8435-1-git-send-email-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Revert "x86/UV: Add uvtrace support"

This reverts commit 8eba18428ac926f436064ac281e76d36d51bd631.

uv_trace() is not used by anything, nor is uv_trace_nmi_func, nor
uv_trace_func.

That's not how we do instrumentation code in the kernel: we add
tracepoints, printk()s, etc. so that everyone not just those with
magic kernel modules can debug a system.

So remove this unused (and misguied) piece of code.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/n/tip-tumfBffmr4jmnt8Gyxanoblg@git.kernel.org

x86/UV: Add call to KGDB/KDB from NMI handler

This patch restores the capability to enter KDB (and KGDB) from
the UV NMI handler. This is needed because the UV system
console is not capable of sending the 'break' signal to the
serial console port. It is also useful when the kernel is hung
in such a way that it isn't responding to normal external I/O,
so sending 'g' to sysreq-trigger does not work either.

Another benefit of the external NMI command is that all the cpus
receive the NMI signal at roughly the same time so they are more
closely aligned timewise.

It utilizes the newly added kgdb_nmicallin function to gain
entry to KGDB/KDB by the master. The slaves still enter via the
standard kgdb_nmicallback function. It also uses the new
'send_ready' pointer to tell KGDB/KDB to signal the slaves when
to proceed into the KGDB slave loop.

It is enabled when the nmi action is set to "kdb" and the kernel
is built with CONFIG_KDB enabled. Note that if kgdb is
connected that interface will be used instead.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20131002151418.089692683@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Check for alloc_cpumask_var() failures properly in uv_nmi_setup()

GCC warned about:

arch/x86/platform/uv/uv_nmi.c: In function ‘uv_nmi_setup’:
arch/x86/platform/uv/uv_nmi.c:664:2: warning: the address of ‘uv_nmi_cpu_mask’ will always evaluate as ‘true’

The reason is this code:

alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL);
BUG_ON(!uv_nmi_cpu_mask);

which is not the way to check for alloc_cpumask_var() failures - its
return code should be checked instead.

Cc: Mike Travis <travis@sgi.com>
Link: http://lkml.kernel.org/n/tip-2pXRemsjupmvonbpmmnzleo1@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Add uvtrace support

This patch adds support for the uvtrace module by providing a
skeleton call to the registered trace function. It also
provides another separate 'NMI' tracer that is triggered by the
system wide 'power nmi' command.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212501.185052551@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Add kdump to UV NMI handler

If a system has hung and it no longer responds to external
events, this patch adds the capability of doing a standard kdump
and system reboot then triggered by the system NMI command.

It is enabled when the nmi action is changed to "kdump" and the
kernel is built with CONFIG_KEXEC enabled.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212500.660567460@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Add summary of cpu activity to UV NMI handler

The standard NMI handler dumps the states of all the cpus. This
includes a full register dump and stack trace. This can be way
more information than what is needed. This patch adds a
"summary" dump that is basically a form of the "ps" command. It
includes the symbolic IP address as well as the command field
and basic process information.

It is enabled when the nmi action is changed to "ips".

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212500.507922930@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Update UV support for external NMI signals

The current UV NMI handler has not been updated for the changes
in the system NMI handler and the perf operations. The UV NMI
handler reads an MMR in the UV Hub to check to see if the NMI
event was caused by the external 'system NMI' that the operator
can initiate on the System Mgmt Controller.

The problem arises when the perf tools are running, causing
millions of perf events per second on very large CPU count
systems. Previously this was okay because the perf NMI handler
ran at a higher priority on the NMI call chain and if the NMI
was a perf event, it would stop calling other NMI handlers
remaining on the NMI call chain.

Now the system NMI handler calls all the handlers on the NMI
call chain including the UV NMI handler. This causes the UV NMI
handler to read the MMRs at the same millions per second rate.
This can lead to significant performance loss and possible
system failures. It also can cause thousands of 'Dazed and
Confused' messages being sent to the system console. This
effectively makes perf tools unusable on UV systems.

To avoid this excessive overhead when perf tools are running,
this code has been optimized to minimize reading of the MMRs as
much as possible, by moving to the NMI_UNKNOWN notifier chain.
This chain is called only when all the users on the standard
NMI_LOCAL call chain have been called and none of them have
claimed this NMI.

There is an exception where the NMI_LOCAL notifier chain is
used. When the perf tools are in use, it's possible that the UV
NMI was captured by some other NMI handler and then either
ignored or mistakenly processed as a perf event. We set a
per_cpu ('ping') flag for those CPUs that ignored the initial
NMI, and then send them an IPI NMI signal. The NMI_LOCAL
handler on each cpu does not need to read the MMR, but instead
checks the in memory flag indicating it was pinged. There are
two module variables, 'ping_count' indicating how many requested
NMI events occurred, and 'ping_misses' indicating how many stray
NMI events. These most likely are perf events so it shows the
overhead of the perf NMI interrupts and how many MMR reads were avoided.

This patch also minimizes the reads of the MMRs by having the
first cpu entering the NMI handler on each node set a per HUB
in-memory atomic value. (Having a per HUB value avoids sending
lock traffic over NumaLink.) Both types of UV NMIs from the SMI
layer are supported.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212500.353547733@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/UV: Move NMI support

This patch moves the UV NMI support from the x2apic file to a
new separate uv_nmi.c file in preparation for the next sequence
of patches. It prevents upcoming bloat of the x2apic file, and
has the added benefit of putting the upcoming /sys/module
parameters under the name 'uv_nmi' instead of 'x2apic_uv_x',
which was obscure.

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jason Wessel <jason.wessel@windriver.com>
Link: http://lkml.kernel.org/r/20130923212500.183295611@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>