linux/arch/mips/kernel/entry.S

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2001 MIPS Technologies, Inc.
*/
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/compiler.h>
MIPS: Fix IRQ tracing & lockdep when rescheduling When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler from arch/mips/kernel/entry.S we disable interrupts. This is true regardless of whether we reach work_resched from syscall_exit_work, resume_userspace or by looping after calling schedule(). Although we disable interrupts in these paths we don't call trace_hardirqs_off() before calling into C code which may acquire locks, and we therefore leave lockdep with an inconsistent view of whether interrupts are disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are both enabled. Without tracing this interrupt state lockdep will print warnings such as the following once a task returns from a syscall via syscall_exit_partial with TIF_NEED_RESCHED set: [ 49.927678] ------------[ cut here ]------------ [ 49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8 [ 49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) [ 49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197 [ 49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4 [ 49.974431] 0000000000000000 0000000000000000 0000000000000000 000000000000004a [ 49.985300] ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8 [ 49.996194] 0000000000000001 0000000000000000 0000000000000000 0000000077c8030c [ 50.007063] 000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88 [ 50.017945] 0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498 [ 50.028827] 0000000000000000 0000000000000001 0000000000000000 0000000000000000 [ 50.039688] 0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc [ 50.050575] 00000000140084e0 0000000000000000 0000000000000000 0000000000040a00 [ 50.061448] 0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc [ 50.072327] ... [ 50.076087] Call Trace: [ 50.079869] [<ffffffff8010e1b0>] show_stack+0x80/0xa8 [ 50.086577] [<ffffffff805509bc>] dump_stack+0x10c/0x190 [ 50.093498] [<ffffffff8015dde0>] __warn+0xf0/0x108 [ 50.099889] [<ffffffff8015de34>] warn_slowpath_fmt+0x3c/0x48 [ 50.107241] [<ffffffff801c15b4>] check_flags.part.41+0x1dc/0x1e8 [ 50.114961] [<ffffffff801c239c>] lock_is_held_type+0x8c/0xb0 [ 50.122291] [<ffffffff809461b8>] __schedule+0x8c0/0x10f8 [ 50.129221] [<ffffffff80946a60>] schedule+0x30/0x98 [ 50.135659] [<ffffffff80106278>] work_resched+0x8/0x34 [ 50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]--- [ 50.148405] possible reason: unannotated irqs-off. [ 50.154600] irq event stamp: 400463 [ 50.159566] hardirqs last enabled at (400463): [<ffffffff8094edc8>] _raw_spin_unlock_irqrestore+0x40/0xa8 [ 50.171981] hardirqs last disabled at (400462): [<ffffffff8094eb98>] _raw_spin_lock_irqsave+0x30/0xb0 [ 50.183897] softirqs last enabled at (400450): [<ffffffff8016580c>] __do_softirq+0x4ac/0x6a8 [ 50.195015] softirqs last disabled at (400425): [<ffffffff80165e78>] irq_exit+0x110/0x128 Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off() when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking schedule() following the work_resched label because: 1) Interrupts are disabled regardless of the path we take to reach work_resched() & schedule(). 2) Performing the tracing here avoids the need to do it in paths which disable interrupts but don't call out to C code before hitting a path which uses the RESTORE_SOME macro that will call trace_hardirqs_on() or trace_hardirqs_off() as appropriate. We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling syscall_trace_leave() for similar reasons, ensuring that lockdep has a consistent view of state after we re-enable interrupts. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/15385/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-03-04 02:26:05 +03:00
#include <asm/irqflags.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/isadep.h>
#include <asm/thread_info.h>
#ifndef CONFIG_PREEMPTION
#define resume_kernel restore_all
#else
#define __ret_from_irq ret_from_exception
#endif
.text
.align 5
#ifndef CONFIG_PREEMPTION
FEXPORT(ret_from_exception)
local_irq_disable # preempt stop
b __ret_from_irq
#endif
FEXPORT(ret_from_irq)
LONG_S s0, TI_REGS($28)
FEXPORT(__ret_from_irq)
/*
* We can be coming here from a syscall done in the kernel space,
* e.g. a failed kernel_execve().
*/
resume_userspace_check:
LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
andi t0, t0, KU_USER
beqz t0, resume_kernel
resume_userspace:
local_irq_disable # make sure we dont miss an
# interrupt setting need_resched
# between sampling and return
LONG_L a2, TI_FLAGS($28) # current->work
andi t0, a2, _TIF_WORK_MASK # (ignoring syscall_trace)
bnez t0, work_pending
j restore_all
#ifdef CONFIG_PREEMPTION
resume_kernel:
local_irq_disable
lw t0, TI_PRE_COUNT($28)
bnez t0, restore_all
LONG_L t0, TI_FLAGS($28)
andi t1, t0, _TIF_NEED_RESCHED
beqz t1, restore_all
LONG_L t0, PT_STATUS(sp) # Interrupts off?
andi t0, 1
beqz t0, restore_all
PTR_LA ra, restore_all
j preempt_schedule_irq
#endif
FEXPORT(ret_from_kernel_thread)
jal schedule_tail # a0 = struct task_struct *prev
move a0, s1
jal s0
j syscall_exit
FEXPORT(ret_from_fork)
jal schedule_tail # a0 = struct task_struct *prev
FEXPORT(syscall_exit)
#ifdef CONFIG_DEBUG_RSEQ
move a0, sp
jal rseq_syscall
#endif
local_irq_disable # make sure need_resched and
# signals dont change between
# sampling and return
LONG_L a2, TI_FLAGS($28) # current->work
li t0, _TIF_ALLWORK_MASK
and t0, a2, t0
bnez t0, syscall_exit_work
restore_all: # restore full frame
.set noat
RESTORE_TEMP
RESTORE_AT
RESTORE_STATIC
restore_partial: # restore partial frame
#ifdef CONFIG_TRACE_IRQFLAGS
SAVE_STATIC
SAVE_AT
SAVE_TEMP
LONG_L v0, PT_STATUS(sp)
#if defined(CONFIG_CPU_R3000)
and v0, ST0_IEP
#else
and v0, ST0_IE
#endif
beqz v0, 1f
jal trace_hardirqs_on
b 2f
1: jal trace_hardirqs_off
2:
RESTORE_TEMP
RESTORE_AT
RESTORE_STATIC
#endif
RESTORE_SOME
RESTORE_SP_AND_RET
.set at
work_pending:
andi t0, a2, _TIF_NEED_RESCHED # a2 is preloaded with TI_FLAGS
beqz t0, work_notifysig
work_resched:
MIPS: Fix IRQ tracing & lockdep when rescheduling When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler from arch/mips/kernel/entry.S we disable interrupts. This is true regardless of whether we reach work_resched from syscall_exit_work, resume_userspace or by looping after calling schedule(). Although we disable interrupts in these paths we don't call trace_hardirqs_off() before calling into C code which may acquire locks, and we therefore leave lockdep with an inconsistent view of whether interrupts are disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are both enabled. Without tracing this interrupt state lockdep will print warnings such as the following once a task returns from a syscall via syscall_exit_partial with TIF_NEED_RESCHED set: [ 49.927678] ------------[ cut here ]------------ [ 49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8 [ 49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) [ 49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197 [ 49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4 [ 49.974431] 0000000000000000 0000000000000000 0000000000000000 000000000000004a [ 49.985300] ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8 [ 49.996194] 0000000000000001 0000000000000000 0000000000000000 0000000077c8030c [ 50.007063] 000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88 [ 50.017945] 0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498 [ 50.028827] 0000000000000000 0000000000000001 0000000000000000 0000000000000000 [ 50.039688] 0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc [ 50.050575] 00000000140084e0 0000000000000000 0000000000000000 0000000000040a00 [ 50.061448] 0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc [ 50.072327] ... [ 50.076087] Call Trace: [ 50.079869] [<ffffffff8010e1b0>] show_stack+0x80/0xa8 [ 50.086577] [<ffffffff805509bc>] dump_stack+0x10c/0x190 [ 50.093498] [<ffffffff8015dde0>] __warn+0xf0/0x108 [ 50.099889] [<ffffffff8015de34>] warn_slowpath_fmt+0x3c/0x48 [ 50.107241] [<ffffffff801c15b4>] check_flags.part.41+0x1dc/0x1e8 [ 50.114961] [<ffffffff801c239c>] lock_is_held_type+0x8c/0xb0 [ 50.122291] [<ffffffff809461b8>] __schedule+0x8c0/0x10f8 [ 50.129221] [<ffffffff80946a60>] schedule+0x30/0x98 [ 50.135659] [<ffffffff80106278>] work_resched+0x8/0x34 [ 50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]--- [ 50.148405] possible reason: unannotated irqs-off. [ 50.154600] irq event stamp: 400463 [ 50.159566] hardirqs last enabled at (400463): [<ffffffff8094edc8>] _raw_spin_unlock_irqrestore+0x40/0xa8 [ 50.171981] hardirqs last disabled at (400462): [<ffffffff8094eb98>] _raw_spin_lock_irqsave+0x30/0xb0 [ 50.183897] softirqs last enabled at (400450): [<ffffffff8016580c>] __do_softirq+0x4ac/0x6a8 [ 50.195015] softirqs last disabled at (400425): [<ffffffff80165e78>] irq_exit+0x110/0x128 Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off() when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking schedule() following the work_resched label because: 1) Interrupts are disabled regardless of the path we take to reach work_resched() & schedule(). 2) Performing the tracing here avoids the need to do it in paths which disable interrupts but don't call out to C code before hitting a path which uses the RESTORE_SOME macro that will call trace_hardirqs_on() or trace_hardirqs_off() as appropriate. We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling syscall_trace_leave() for similar reasons, ensuring that lockdep has a consistent view of state after we re-enable interrupts. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/15385/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-03-04 02:26:05 +03:00
TRACE_IRQS_OFF
jal schedule
local_irq_disable # make sure need_resched and
# signals dont change between
# sampling and return
LONG_L a2, TI_FLAGS($28)
andi t0, a2, _TIF_WORK_MASK # is there any work to be done
# other than syscall tracing?
beqz t0, restore_all
andi t0, a2, _TIF_NEED_RESCHED
bnez t0, work_resched
work_notifysig: # deal with pending signals and
# notify-resume requests
move a0, sp
li a1, 0
jal do_notify_resume # a2 already loaded
j resume_userspace_check
FEXPORT(syscall_exit_partial)
#ifdef CONFIG_DEBUG_RSEQ
move a0, sp
jal rseq_syscall
#endif
local_irq_disable # make sure need_resched doesn't
# change between and return
LONG_L a2, TI_FLAGS($28) # current->work
li t0, _TIF_ALLWORK_MASK
and t0, a2
beqz t0, restore_partial
SAVE_STATIC
syscall_exit_work:
LONG_L t0, PT_STATUS(sp) # returning to kernel mode?
andi t0, t0, KU_USER
beqz t0, resume_kernel
li t0, _TIF_WORK_SYSCALL_EXIT
and t0, a2 # a2 is preloaded with TI_FLAGS
beqz t0, work_pending # trace bit set?
local_irq_enable # could let syscall_trace_leave()
# call schedule() instead
MIPS: Fix IRQ tracing & lockdep when rescheduling When the scheduler sets TIF_NEED_RESCHED & we call into the scheduler from arch/mips/kernel/entry.S we disable interrupts. This is true regardless of whether we reach work_resched from syscall_exit_work, resume_userspace or by looping after calling schedule(). Although we disable interrupts in these paths we don't call trace_hardirqs_off() before calling into C code which may acquire locks, and we therefore leave lockdep with an inconsistent view of whether interrupts are disabled or not when CONFIG_PROVE_LOCKING & CONFIG_DEBUG_LOCKDEP are both enabled. Without tracing this interrupt state lockdep will print warnings such as the following once a task returns from a syscall via syscall_exit_partial with TIF_NEED_RESCHED set: [ 49.927678] ------------[ cut here ]------------ [ 49.934445] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3687 check_flags.part.41+0x1dc/0x1e8 [ 49.946031] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) [ 49.946355] CPU: 0 PID: 1 Comm: init Not tainted 4.10.0-00439-gc9fd5d362289-dirty #197 [ 49.963505] Stack : 0000000000000000 ffffffff81bb5d6a 0000000000000006 ffffffff801ce9c4 [ 49.974431] 0000000000000000 0000000000000000 0000000000000000 000000000000004a [ 49.985300] ffffffff80b7e487 ffffffff80a24498 a8000000ff160000 ffffffff80ede8b8 [ 49.996194] 0000000000000001 0000000000000000 0000000000000000 0000000077c8030c [ 50.007063] 000000007fd8a510 ffffffff801cd45c 0000000000000000 a8000000ff127c88 [ 50.017945] 0000000000000000 ffffffff801cf928 0000000000000001 ffffffff80a24498 [ 50.028827] 0000000000000000 0000000000000001 0000000000000000 0000000000000000 [ 50.039688] 0000000000000000 a8000000ff127bd0 0000000000000000 ffffffff805509bc [ 50.050575] 00000000140084e0 0000000000000000 0000000000000000 0000000000040a00 [ 50.061448] 0000000000000000 ffffffff8010e1b0 0000000000000000 ffffffff805509bc [ 50.072327] ... [ 50.076087] Call Trace: [ 50.079869] [<ffffffff8010e1b0>] show_stack+0x80/0xa8 [ 50.086577] [<ffffffff805509bc>] dump_stack+0x10c/0x190 [ 50.093498] [<ffffffff8015dde0>] __warn+0xf0/0x108 [ 50.099889] [<ffffffff8015de34>] warn_slowpath_fmt+0x3c/0x48 [ 50.107241] [<ffffffff801c15b4>] check_flags.part.41+0x1dc/0x1e8 [ 50.114961] [<ffffffff801c239c>] lock_is_held_type+0x8c/0xb0 [ 50.122291] [<ffffffff809461b8>] __schedule+0x8c0/0x10f8 [ 50.129221] [<ffffffff80946a60>] schedule+0x30/0x98 [ 50.135659] [<ffffffff80106278>] work_resched+0x8/0x34 [ 50.142397] ---[ end trace 0cb4f6ef5b99fe21 ]--- [ 50.148405] possible reason: unannotated irqs-off. [ 50.154600] irq event stamp: 400463 [ 50.159566] hardirqs last enabled at (400463): [<ffffffff8094edc8>] _raw_spin_unlock_irqrestore+0x40/0xa8 [ 50.171981] hardirqs last disabled at (400462): [<ffffffff8094eb98>] _raw_spin_lock_irqsave+0x30/0xb0 [ 50.183897] softirqs last enabled at (400450): [<ffffffff8016580c>] __do_softirq+0x4ac/0x6a8 [ 50.195015] softirqs last disabled at (400425): [<ffffffff80165e78>] irq_exit+0x110/0x128 Fix this by using the TRACE_IRQS_OFF macro to call trace_hardirqs_off() when CONFIG_TRACE_IRQFLAGS is enabled. This is done before invoking schedule() following the work_resched label because: 1) Interrupts are disabled regardless of the path we take to reach work_resched() & schedule(). 2) Performing the tracing here avoids the need to do it in paths which disable interrupts but don't call out to C code before hitting a path which uses the RESTORE_SOME macro that will call trace_hardirqs_on() or trace_hardirqs_off() as appropriate. We call trace_hardirqs_on() using the TRACE_IRQS_ON macro before calling syscall_trace_leave() for similar reasons, ensuring that lockdep has a consistent view of state after we re-enable interrupts. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: linux-mips@linux-mips.org Cc: stable <stable@vger.kernel.org> Patchwork: https://patchwork.linux-mips.org/patch/15385/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-03-04 02:26:05 +03:00
TRACE_IRQS_ON
move a0, sp
jal syscall_trace_leave
b resume_userspace
mips: Add MIPS Release 5 support There are five MIPS32/64 architecture releases currently available: from 1 to 6 except fourth one, which was intentionally skipped. Three of them can be called as major: 1st, 2nd and 6th, that not only have some system level alterations, but also introduced significant core/ISA level updates. The rest of the MIPS architecture releases are minor. Even though they don't have as much ISA/system/core level changes as the major ones with respect to the previous releases, they still provide a set of updates (I'd say they were intended to be the intermediate releases before a major one) that might be useful for the kernel and user-level code, when activated by the kernel or compiler. In particular the following features were introduced or ended up being available at/after MIPS32/64 Release 5 architecture: + the last release of the misaligned memory access instructions, + virtualisation - VZ ASE - is optional component of the arch, + SIMD - MSA ASE - is optional component of the arch, + DSP ASE is optional component of the arch, + CP0.Status.FR=1 for CP1.FIR.F64=1 (pure 64-bit FPU general registers) must be available if FPU is implemented, + CP1.FIR.Has2008 support is required so CP1.FCSR.{ABS2008,NAN2008} bits are available. + UFR/UNFR aliases to access CP0.Status.FR from user-space by means of ctc1/cfc1 instructions (enabled by CP0.Config5.UFR), + CP0.COnfig5.LLB=1 and eretnc instruction are implemented to without accidentally clearing LL-bit when returning from an interrupt, exception, or error trap, + XPA feature together with extended versions of CPx registers is introduced, which needs to have mfhc0/mthc0 instructions available. So due to these changes GNU GCC provides an extended instructions set support for MIPS32/64 Release 5 by default like eretnc/mfhc0/mthc0. Even though the architecture alteration isn't that big, it still worth to be taken into account by the kernel software. Finally we can't deny that some optimization/limitations might be found in future and implemented on some level in kernel or compiler. In this case having even intermediate MIPS architecture releases support would be more than useful. So the most of the changes provided by this commit can be split into either compile- or runtime configs related. The compile-time related changes are caused by adding the new CONFIG_CPU_MIPS32_R5/CONFIG_CPU_MIPSR5 configs and concern the code activating MIPSR2 or MIPSR6 already implemented features (like eretnc/LLbit, mthc0/mfhc0). In addition CPU_HAS_MSA can be now freely enabled for MIPS32/64 release 5 based platforms as this is done for CPU_MIPS32_R6 CPUs. The runtime changes concerns the features which are handled with respect to the MIPS ISA revision detected at run-time by means of CP0.Config.{AT,AR} bits. Alas these fields can be used to detect either r1 or r2 or r6 releases. But since we know which CPUs in fact support the R5 arch, we can manually set MIPS_CPU_ISA_M32R5/MIPS_CPU_ISA_M64R5 bit of c->isa_level and then use cpu_has_mips32r5/cpu_has_mips64r5 where it's appropriate. Since XPA/EVA provide too complex alterationss and to have them used with MIPS32 Release 2 charged kernels (for compatibility with current platform configs) they are left to be setup as a separate kernel configs. Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-05-21 17:07:14 +03:00
#if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR5) || \
defined(CONFIG_CPU_MIPSR6) || defined(CONFIG_MIPS_MT)
/*
* MIPS32R2 Instruction Hazard Barrier - must be called
*
* For C code use the inline version named instruction_hazard().
*/
LEAF(mips_ihb)
.set MIPS_ISA_LEVEL_RAW
jr.hb ra
nop
END(mips_ihb)
mips: Add MIPS Release 5 support There are five MIPS32/64 architecture releases currently available: from 1 to 6 except fourth one, which was intentionally skipped. Three of them can be called as major: 1st, 2nd and 6th, that not only have some system level alterations, but also introduced significant core/ISA level updates. The rest of the MIPS architecture releases are minor. Even though they don't have as much ISA/system/core level changes as the major ones with respect to the previous releases, they still provide a set of updates (I'd say they were intended to be the intermediate releases before a major one) that might be useful for the kernel and user-level code, when activated by the kernel or compiler. In particular the following features were introduced or ended up being available at/after MIPS32/64 Release 5 architecture: + the last release of the misaligned memory access instructions, + virtualisation - VZ ASE - is optional component of the arch, + SIMD - MSA ASE - is optional component of the arch, + DSP ASE is optional component of the arch, + CP0.Status.FR=1 for CP1.FIR.F64=1 (pure 64-bit FPU general registers) must be available if FPU is implemented, + CP1.FIR.Has2008 support is required so CP1.FCSR.{ABS2008,NAN2008} bits are available. + UFR/UNFR aliases to access CP0.Status.FR from user-space by means of ctc1/cfc1 instructions (enabled by CP0.Config5.UFR), + CP0.COnfig5.LLB=1 and eretnc instruction are implemented to without accidentally clearing LL-bit when returning from an interrupt, exception, or error trap, + XPA feature together with extended versions of CPx registers is introduced, which needs to have mfhc0/mthc0 instructions available. So due to these changes GNU GCC provides an extended instructions set support for MIPS32/64 Release 5 by default like eretnc/mfhc0/mthc0. Even though the architecture alteration isn't that big, it still worth to be taken into account by the kernel software. Finally we can't deny that some optimization/limitations might be found in future and implemented on some level in kernel or compiler. In this case having even intermediate MIPS architecture releases support would be more than useful. So the most of the changes provided by this commit can be split into either compile- or runtime configs related. The compile-time related changes are caused by adding the new CONFIG_CPU_MIPS32_R5/CONFIG_CPU_MIPSR5 configs and concern the code activating MIPSR2 or MIPSR6 already implemented features (like eretnc/LLbit, mthc0/mfhc0). In addition CPU_HAS_MSA can be now freely enabled for MIPS32/64 release 5 based platforms as this is done for CPU_MIPS32_R6 CPUs. The runtime changes concerns the features which are handled with respect to the MIPS ISA revision detected at run-time by means of CP0.Config.{AT,AR} bits. Alas these fields can be used to detect either r1 or r2 or r6 releases. But since we know which CPUs in fact support the R5 arch, we can manually set MIPS_CPU_ISA_M32R5/MIPS_CPU_ISA_M64R5 bit of c->isa_level and then use cpu_has_mips32r5/cpu_has_mips64r5 where it's appropriate. Since XPA/EVA provide too complex alterationss and to have them used with MIPS32 Release 2 charged kernels (for compatibility with current platform configs) they are left to be setup as a separate kernel configs. Co-developed-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-05-21 17:07:14 +03:00
#endif /* CONFIG_CPU_MIPSR2 - CONFIG_CPU_MIPSR6 or CONFIG_MIPS_MT */