linux-stable.git/arch/arc/kernel/entry.S, branch v5.12.2 Linux kernel stable tree 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>
ARC: entry: EV_Trap expects r10 (vs. r9) to have exception cause 2019-07-08T08:24:44+00:00 Vineet Gupta vgupta@synopsys.com 2019-05-15T23:08:10+00:00 68e5c6f073bcf70da5f8eef88eb2d98f7c560bb6 avoids 1 MOV instruction in light of double load/store code Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
avoids 1 MOV instruction in light of double load/store code

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19T15:09:55+00:00 Thomas Gleixner tglx@linutronix.de 2019-06-04T08:11:33+00:00 d2912cb15bdda8ba4a5dd73396ad62641af2f520 Based on 2 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 version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 2 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 version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARC: Re-enable MMU upon Machine Check exception 2017-09-01T18:29:05+00:00 Jose Abreu Jose.Abreu@synopsys.com 2017-09-01T16:00:23+00:00 1ee55a8f7f6b7ca4c0c59e0b4b4e3584a085c2d3 I recently came upon a scenario where I would get a double fault machine check exception tiriggered by a kernel module. However the ensuing crash stacktrace (ksym lookup) was not working correctly. Turns out that machine check auto-disables MMU while modules are allocated in kernel vaddr spapce. This patch re-enables the MMU before start printing the stacktrace making stacktracing of modules work upon a fatal exception. Cc: stable@kernel.org Signed-off-by: Jose Abreu <joabreu@synopsys.com> Reviewed-by: Alexey Brodkin <abrodkin@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [vgupta: moved code into low level handler to avoid in 2 places] 
I recently came upon a scenario where I would get a double fault
machine check exception tiriggered by a kernel module.
However the ensuing crash stacktrace (ksym lookup) was not working
correctly.

Turns out that machine check auto-disables MMU while modules are allocated
in kernel vaddr spapce.

This patch re-enables the MMU before start printing the stacktrace
making stacktracing of modules work upon a fatal exception.

Cc: stable@kernel.org
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Reviewed-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: moved code into low level handler to avoid in 2 places]
ARC: entry: make ret_from_system_call local label 2016-09-30T21:48:21+00:00 Vineet Gupta vgupta@synopsys.com 2016-09-17T00:13:29+00:00 2dad1122d9d936cf120953324eaaa38c3ab20ac2 This essentially removes ENTRY() assembler annotation for this symbol since it didn't have a pairing END() This in ahead of introducing cfi pseudo ops in ENTRY/END which expects paired cfi_startproc/cfi_endproc | ../arch/arc/kernel/entry.S: Assembler messages: | ../arch/arc/kernel/entry.S:270: Error: previous CFI entry not closed (missing .cfi_endproc) | ../scripts/Makefile.build:326: recipe for target 'arch/arc/kernel/entry-arcv2.o' failed | make[4]: *** [arch/arc/kernel/entry-arcv2.o] Error 1 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
This essentially removes ENTRY() assembler annotation for this symbol
since it didn't have a pairing END()

This in ahead of introducing cfi pseudo ops in ENTRY/END which expects
paired cfi_startproc/cfi_endproc

| ../arch/arc/kernel/entry.S: Assembler messages:
| ../arch/arc/kernel/entry.S:270: Error: previous CFI entry not closed (missing .cfi_endproc)
| ../scripts/Makefile.build:326: recipe for target 'arch/arc/kernel/entry-arcv2.o' failed
| make[4]: *** [arch/arc/kernel/entry-arcv2.o] Error 1

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>