linux.git/arch/arc/kernel/entry.S, branch v6.1.168 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git ARC: implement syscall tracepoints 2022-04-25T20:09:47+00:00 Sergey Matyukevich sergey.matyukevich@synopsys.com 2022-04-14T08:17:23+00:00 fb0b54909b153ac6195378fa8ddee3f7531f8e51 Implement all the bits required to support HAVE_SYSCALL_TRACEPOINTS according to Documentation/trace/ftrace-design.rst. Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org> 
Implement all the bits required to support HAVE_SYSCALL_TRACEPOINTS
according to Documentation/trace/ftrace-design.rst.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
ARC: entry: fix syscall_trace_exit argument 2022-04-18T19:14:20+00:00 Sergey Matyukevich sergey.matyukevich@synopsys.com 2022-04-14T08:17:22+00:00 b1c6ecfdd06907554518ec384ce8e99889d15193 Function syscall_trace_exit expects pointer to pt_regs. However r0 is also used to keep syscall return value. Restore pointer to pt_regs before calling syscall_trace_exit. Cc: <stable@vger.kernel.org> Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org> 
Function syscall_trace_exit expects pointer to pt_regs. However
r0 is also used to keep syscall return value. Restore pointer
to pt_regs before calling syscall_trace_exit.

Cc: <stable@vger.kernel.org>
Signed-off-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
ARC: mm: move MMU specific bits out of entry code ... 2021-08-24T21:25:48+00:00 Vineet Gupta vgupta@kernel.org 2019-09-16T17:54:34+00:00 a79a9c765f95a73e087f11f0994297cd69987bda ... to avoid polluting shared entry code (across three ISA variants) with ISA/MMU specific code. Cc: Jose Abreu <joabreu@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@kernel.org> 
... to avoid polluting shared entry code (across three ISA variants)
with ISA/MMU specific code.

Cc: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
ARC: entry: fix off-by-one error in syscall number validation 2021-05-10T19:38:59+00:00 Vineet Gupta vgupta@synopsys.com 2021-04-23T19:16:25+00:00 3433adc8bd09fc9f29b8baddf33b4ecd1ecd2cdc We have NR_syscall syscalls from [0 .. NR_syscall-1]. However the check for invalid syscall number is "> NR_syscall" as opposed to >=. This off-by-one error erronesously allows "NR_syscall" to be treated as valid syscall causeing out-of-bounds access into syscall-call table ensuing a crash (holes within syscall table have a invalid-entry handler but this is beyond the array implementing the table). This problem showed up on v5.6 kernel when testing glibc 2.33 (v5.10 kernel capable, includng faccessat2 syscall 439). The v5.6 kernel has NR_syscalls=439 (0 to 438). Due to the bug, 439 passed by glibc was not handled as -ENOSYS but processed leading to a crash. Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/48 Reported-by: Shahab Vahedi <shahab@synopsys.com> Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
We have NR_syscall syscalls from [0 .. NR_syscall-1].
However the check for invalid syscall number is "> NR_syscall" as
opposed to >=. This off-by-one error erronesously allows "NR_syscall"
to be treated as valid syscall causeing out-of-bounds access into
syscall-call table ensuing a crash (holes within syscall table have a
invalid-entry handler but this is beyond the array implementing the
table).

This problem showed up on v5.6 kernel when testing glibc 2.33 (v5.10
kernel capable, includng faccessat2 syscall 439). The v5.6 kernel has
NR_syscalls=439 (0 to 438). Due to the bug, 439 passed by glibc was
not handled as -ENOSYS but processed leading to a crash.

Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/48
Reported-by: Shahab Vahedi <shahab@synopsys.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: unbork 5.11 bootup: fix snafu in _TIF_NOTIFY_SIGNAL handling 2021-01-07T22:04:42+00:00 Vineet Gupta vgupta@synopsys.com 2021-01-06T20:34:36+00:00 bb12433bf56e76789c6b08b36c546f745a6aa6e1 Linux 5.11.rcX was failing to boot on ARC HSDK board. Turns out we have a couple of issues, this being the first one, and I'm to blame as I didn't pay attention during review. TIF_NOTIFY_SIGNAL support requires checking multiple TIF_* bits in kernel return code path. Old code only needed to check a single bit so BBIT0 <TIF_SIGPENDING> worked. New code needs to check multiple bits so AND <bit-mask> instruction. So needs to use bit mask variant _TIF_SIGPENDING Cc: Jens Axboe <axboe@kernel.dk> Fixes: 53855e12588743ea128 ("arc: add support for TIF_NOTIFY_SIGNAL") Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/34 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
Linux 5.11.rcX was failing to boot on ARC HSDK board. Turns out we have
a couple of issues, this being the first one, and I'm to blame as I
didn't pay attention during review.

TIF_NOTIFY_SIGNAL support requires checking multiple TIF_* bits in
kernel return code path. Old code only needed to check a single bit so
BBIT0 <TIF_SIGPENDING> worked. New code needs to check multiple bits so
AND <bit-mask> instruction. So needs to use bit mask variant _TIF_SIGPENDING

Cc: Jens Axboe <axboe@kernel.dk>
Fixes: 53855e12588743ea128 ("arc: add support for TIF_NOTIFY_SIGNAL")
Link: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/34
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
arc: add support for TIF_NOTIFY_SIGNAL 2020-11-09T15:16:55+00:00 Jens Axboe axboe@kernel.dk 2020-10-12T13:15:37+00:00 53855e12588743ea128ee31f913d1c6e2f1d32c8 Wire up TIF_NOTIFY_SIGNAL handling for arc. Cc: linux-snps-arc@lists.infradead.org Acked-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Wire up TIF_NOTIFY_SIGNAL handling for arc.

Cc: linux-snps-arc@lists.infradead.org
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE 2020-06-16T19:56:37+00:00 Vineet Gupta vgupta@synopsys.com 2020-05-20T05:28:32+00:00 00fdec98d9881bf5173af09aebd353ab3b9ac729 Trap handler for syscall tracing reads EFA (Exception Fault Address), in case strace wants PC of trap instruction (EFA is not part of pt_regs as of current code). However this EFA read is racy as it happens after dropping to pure kernel mode (re-enabling interrupts). A taken interrupt could context-switch, trigger a different task's trap, clobbering EFA for this execution context. Fix this by reading EFA early, before re-enabling interrupts. A slight side benefit is de-duplication of FAKE_RET_FROM_EXCPN in trap handler. The trap handler is common to both ARCompact and ARCv2 builds too. This just came out of code rework/review and no real problem was reported but is clearly a potential problem specially for strace. Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
Trap handler for syscall tracing reads EFA (Exception Fault Address),
in case strace wants PC of trap instruction (EFA is not part of pt_regs
as of current code).

However this EFA read is racy as it happens after dropping to pure
kernel mode (re-enabling interrupts). A taken interrupt could
context-switch, trigger a different task's trap, clobbering EFA for this
execution context.

Fix this by reading EFA early, before re-enabling interrupts. A slight
side benefit is de-duplication of FAKE_RET_FROM_EXCPN in trap handler.
The trap handler is common to both ARCompact and ARCv2 builds too.

This just came out of code rework/review and no real problem was reported
but is clearly a potential problem specially for strace.

Cc: <stable@vger.kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Merge tag 'arc-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc 2020-01-31T19:26:11+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-01-31T19:26:11+00:00 b7e573bb4a7a511741f8942b1fb03cfe602ee57f Pull ARC updates from Vineet Gupta: - Wire up clone3 syscall - ARCv2 FPU state save/restore across context switch - AXS10x platform and misc fixes * tag 'arc-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARCv2: fpu: preserve userspace fpu state ARC: fpu: declutter code, move bits out into fpu.h ARC: wireup clone3 syscall ARC: [plat-axs10x]: Add missing multicast filter number to GMAC node ARC: update feature support for jump-labels 
Pull ARC updates from Vineet Gupta:

 - Wire up clone3 syscall

 - ARCv2 FPU state save/restore across context switch

 - AXS10x platform and misc fixes

* tag 'arc-5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: fpu: preserve userspace fpu state
  ARC: fpu: declutter code, move bits out into fpu.h
  ARC: wireup clone3 syscall
  ARC: [plat-axs10x]: Add missing multicast filter number to GMAC node
  ARC: update feature support for jump-labels
ARC: wireup clone3 syscall 2020-01-16T00:08:12+00:00 Vineet Gupta vgupta@synopsys.com 2020-01-16T00:08:12+00:00 bd71c453db91ecb464405411f2821d040f2a0d44 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
sched/rt, ARC: Use CONFIG_PREEMPTION 2019-12-08T13:37:32+00:00 Thomas Gleixner tglx@linutronix.de 2019-10-15T19:17:51+00:00 916591722c7543570843b54d5896121146b498f5 CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the entry code over to use CONFIG_PREEMPTION. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: linux-snps-arc@lists.infradead.org Link: https://lore.kernel.org/r/20191015191821.11479-5-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org> 
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Link: https://lore.kernel.org/r/20191015191821.11479-5-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>