mips: Implement arch_irqs_disabled()

Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200826101653.GE1362448@hirez.programming.kicks-ass.net

MIPS: Make DIEI support as a config option

DI(Disable Interrupt) and EI(Enable Interrupt) instructions is required by
MIPSR2/MIPSR6, however, it appears to be buggy on some processors such as
Loongson-3A1000. Thus we make it as a config option to allow disable it at
compile time with CPU_MIPSR2 selected.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: chenhc@lemote.com
Cc: paul.burton@mips.com
Cc: linux-kernel@vger.kernel.org

MIPS: Loongson: Rename LOONGSON1 to LOONGSON32

Now old Loongson-2E/2F use LOONGSON2EF and will be removed in future,
newer Loongson-2/3 use LOONGSON64. So rename LOONGSON1 to LOONGSON32
will make the naming style more unified.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
[paulburton@kernel.org: Fix checkpatch whitespace warning in irqflags.h]
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: linux-mips@vger.kernel.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Huacai Chen <chenhuacai@gmail.com>

MIPS: Loongson64: Rename CPU TYPES

CPU_LOONGSON2 -> CPU_LOONGSON2EF
CPU_LOONGSON3 -> CPU_LOONGSON64

As newer loongson-2 products (2G/2H/2K1000) can share kernel
implementation with loongson-3 while 2E/2F are less similar with
other LOONGSON64 products.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: chenhc@lemote.com
Cc: paul.burton@mips.com

MIPS: Loongson32: workaround di issue

GS232 core used in Loongson-1 processors has a bug that
di instruction doesn't save the irqflag immediately.

Workaround by set irqflag in CP0 before di instructions
as same as Loongson-3.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: keguang.zhang@gmail.com

MIPS: Loongson-3: Introduce CONFIG_LOONGSON3_ENHANCEMENT

New Loongson 3 CPU (since Loongson-3A R2, as opposed to Loongson-3A R1,
Loongson-3B R1 and Loongson-3B R2) has many enhancements, such as FTLB,
L1-VCache, EI/DI/Wait/Prefetch instruction, DSP/DSPv2 ASE, User Local
register, Read-Inhibit/Execute-Inhibit, SFB (Store Fill Buffer), Fast
TLB refill support, etc.

This patch introduce a config option, CONFIG_LOONGSON3_ENHANCEMENT, to
enable those enhancements which are not probed at run time. If you want
a generic kernel to run on all Loongson 3 machines, please say 'N'
here. If you want a high-performance kernel to run on new Loongson 3
machines only, please say 'Y' here.

Some additional explanations:
1) SFB locates between core and L1 cache, it causes memory access out
of order, so writel/outl (and other similar functions) need a I/O
reorder barrier.
2) Loongson 3 has a bug that di instruction can not save the irqflag,
so arch_local_irq_save() is modified. Since CPU_MIPSR2 is selected
by CONFIG_LOONGSON3_ENHANCEMENT, generic kernel doesn't use ei/di
at all.
3) CPU_HAS_PREFETCH is selected by CONFIG_LOONGSON3_ENHANCEMENT, so
MIPS_CPU_PREFETCH (used by uasm) probing is also put in this patch.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J . Hill <sjhill@realitydiluted.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12755/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Cleanup the unused __arch_local_irq_restore() function

In history, __arch_local_irq_restore() is only used by SMTC. However,
SMTC support has been removed since 3.16, this patch remove the unused
function.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12159/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS/IRQCHIP: Move irq_chip from arch/mips to drivers/irqchip.

While at it, rename it because in drivers/irqchip no longer every CPU is
a MIPS.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: asm: irqflags: Add MIPS R6 related definitions

Add the MIPS R6 related definitions to the IRQ related macros

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

MIPS: MT: Remove SMTC support

Nobody is maintaining SMTC anymore and there also seems to be no userbase.
Which is a pity - the SMTC technology primarily developed by Kevin D.
Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT
ASE's power and elegance.

Based on Markos Chandras <Markos.Chandras@imgtec.com> patch
https://patchwork.linux-mips.org/patch/6719/ which while very similar did
no longer apply cleanly when I tried to merge it plus some additional
post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to
merge once upon a time.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Get rid of the use of .macro in C code.

It fails with LTO and probably has always been a fragile.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: Make irqflags.h functions preempt-safe for non-mipsr2 cpus

For non MIPSr2 processors, such as the BMIPS 5000, calls to
arch_local_irq_disable() and others may be preempted, and in doing
so a stale value may be restored to c0_status. This fix disables
preemption for such processors prior to the call and enables it
after the call.

Those functions that needed this fix have been "outlined" to
mips-atomic.c, as they are no longer good candidates for inlining.

This bug was observed in a BMIPS 5000, occuring once every few hours
in a continuous reboot test. It was traced to the write_lock_irq()
function which was being invoked in release_task() in exit.c.
By placing a number of "nops" inbetween the mfc0/mtc0 pair in
arch_local_irq_disable(), which is called by write_lock_irq(), we
were able to greatly increase the occurance of this bug. Similarly,
the application of this commit silenced the bug.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: Kevin Cernekee cernekee@gmail.com
Cc: Jim Quinlan <jim2101024@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/4321/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

Fix IRQ flag handling naming

Fix the IRQ flag handling naming. In linux/irqflags.h under one configuration,
it maps:

local_irq_enable() -> raw_local_irq_enable()
local_irq_disable() -> raw_local_irq_disable()
local_irq_save() -> raw_local_irq_save()
...

and under the other configuration, it maps:

raw_local_irq_enable() -> local_irq_enable()
raw_local_irq_disable() -> local_irq_disable()
raw_local_irq_save() -> local_irq_save()
...

This is quite confusing. There should be one set of names expected of the
arch, and this should be wrapped to give another set of names that are expected
by users of this facility.

Change this to have the arch provide:

flags = arch_local_save_flags()
flags = arch_local_irq_save()
arch_local_irq_restore(flags)
arch_local_irq_disable()
arch_local_irq_enable()
arch_irqs_disabled_flags(flags)
arch_irqs_disabled()
arch_safe_halt()

Then linux/irqflags.h wraps these to provide:

raw_local_save_flags(flags)
raw_local_irq_save(flags)
raw_local_irq_restore(flags)
raw_local_irq_disable()
raw_local_irq_enable()
raw_irqs_disabled_flags(flags)
raw_irqs_disabled()
raw_safe_halt()

with type checking on the flags 'arguments', and then wraps those to provide:

local_save_flags(flags)
local_irq_save(flags)
local_irq_restore(flags)
local_irq_disable()
local_irq_enable()
irqs_disabled_flags(flags)
irqs_disabled()
safe_halt()

with tracing included if enabled.

The arch functions can now all be inline functions rather than some of them
having to be macros.

Signed-off-by: David Howells <dhowells@redhat.com> [X86, FRV, MN10300]
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> [Tile]
Signed-off-by: Michal Simek <monstr@monstr.eu> [Microblaze]
Tested-by: Catalin Marinas <catalin.marinas@arm.com> [ARM]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [AVR]
Acked-by: Tony Luck <tony.luck@intel.com> [IA-64]
Acked-by: Hirokazu Takata <takata@linux-m32r.org> [M32R]
Acked-by: Greg Ungerer <gerg@uclinux.org> [M68K/M68KNOMMU]
Acked-by: Ralf Baechle <ralf@linux-mips.org> [MIPS]
Acked-by: Kyle McMartin <kyle@mcmartin.ca> [PA-RISC]
Acked-by: Paul Mackerras <paulus@samba.org> [PowerPC]
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [S390]
Acked-by: Chen Liqin <liqin.chen@sunplusct.com> [Score]
Acked-by: Matt Fleming <matt@console-pimps.org> [SH]
Acked-by: David S. Miller <davem@davemloft.net> [Sparc]
Acked-by: Chris Zankel <chris@zankel.net> [Xtensa]
Reviewed-by: Richard Henderson <rth@twiddle.net> [Alpha]
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp> [H8300]
Cc: starvik@axis.com [CRIS]
Cc: jesper.nilsson@axis.com [CRIS]
Cc: linux-cris-kernel@axis.com

MIPS: Move headfiles to new location below arch/mips/include

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>