ARC: Fix typos

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

Signed-off-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Vineet Gupta <vgupta@kern

ARC: Fix typos

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

Signed-off-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry: Add more common chores to EXCEPTION_PROLOGUE

THe high level structure of most ARC exception handlers is
1. save regfile with EXCEPTION_PROLOGUE
2. setup r0: EFA (not part of pt_regs)

ARC: entry: Add more common chores to EXCEPTION_PROLOGUE

THe high level structure of most ARC exception handlers is
1. save regfile with EXCEPTION_PROLOGUE
2. setup r0: EFA (not part of pt_regs)
3. setup r1: pointer to pt_regs (SP)
4. drop down to pure kernel mode (from exception)
5. call the Linux "C" handler

Remove the boiler plate code by moving #2, #3, #4 into #1.

The exceptions to most exceptions are syscall Trap and Machine check
which don't do some of above for various reasons, so call a newly
introduced variant EXCEPTION_PROLOGUE_KEEP_AE (same as original
EXCEPTION_PROLOGUE)

Tested-by: Pavel Kozlov <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry: EV_MachineCheck dont re-read ECR

Signed-off-by: Vineet Gupta <[email protected]>

ARC: entry: rework (non-functional)

- comments update
- rename syscall_trace_entry
- use PT_xxx in entry code

Signed-off-by: Vineet Gupta <[email protected]>

ARC: entry: use gp to cache task pointer (vs. r25)

The motivation is eventual ABI considerations for ARCv3 but even without
it this change us worthwhile as diffstat reduces 100 net lines

r25 is a c

ARC: entry: use gp to cache task pointer (vs. r25)

The motivation is eventual ABI considerations for ARCv3 but even without
it this change us worthwhile as diffstat reduces 100 net lines

r25 is a callee saved register, normally not saved by entry code in
pt_regs. However because of its usage in CONFIG_ARC_CURR_IN_REG it needs
to be. This in turn requires a whole bunch of special casing when we
need to access r25. Then there is distinction between user mode r25 vs.
kernel mode r25 - hence distinct SAVE_CALLEE_SAVED_{USER,KERNEL}

Instead use gp which is a scratch register and thus saved already in entry
code. This cleans things up significantly and much nocer on eyes:

- SAVE_CALLEE_SAVED_{USER,KERNEL} are now exactly same
- no special user_r25 slot in pt_reggs

Note that typical global asm registers are callee-saved (r25), but gp is
not callee-saved thus needs additional -ffixed-<reg> toggle

Signed-off-by: Vineet Gupta <[email protected]>

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ARC: implement syscall tracepoints

Implement all the bits required to support HAVE_SYSCALL_TRACEPOINTS
according to Documentation/trace/ftrace-design.rst.

Signed-off-by: Sergey Matyukevich <sergey.

ARC: implement syscall tracepoints

Implement all the bits required to support HAVE_SYSCALL_TRACEPOINTS
according to Documentation/trace/ftrace-design.rst.

Signed-off-by: Sergey Matyukevich <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry: fix syscall_trace_exit argument

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 sy

ARC: entry: fix syscall_trace_exit argument

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: <[email protected]>
Signed-off-by: Sergey Matyukevich <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: mm: move MMU specific bits out of entry code ...

... to avoid polluting shared entry code (across three ISA variants)
with ISA/MMU specific code.

Cc: Jose Abreu <[email protected]>
Signed-o

ARC: mm: move MMU specific bits out of entry code ...

... to avoid polluting shared entry code (across three ISA variants)
with ISA/MMU specific code.

Cc: Jose Abreu <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry: fix off-by-one error in syscall number validation

We have NR_syscall syscalls from [0 .. NR_syscall-1].
However the check for invalid syscall number is "> NR_syscall" as
opposed to >=. T

ARC: entry: fix off-by-one error in syscall number validation

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 <[email protected]>
Cc: <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: unbork 5.11 bootup: fix snafu in _TIF_NOTIFY_SIGNAL handling

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 bla

ARC: unbork 5.11 bootup: fix snafu in _TIF_NOTIFY_SIGNAL handling

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 <[email protected]>
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 <[email protected]>

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arc: add support for TIF_NOTIFY_SIGNAL

Wire up TIF_NOTIFY_SIGNAL handling for arc.

Cc: [email protected]
Acked-by: Vineet Gupta <[email protected]>
Signed-off-by: Jens Axboe <axb

arc: add support for TIF_NOTIFY_SIGNAL

Wire up TIF_NOTIFY_SIGNAL handling for arc.

Cc: [email protected]
Acked-by: Vineet Gupta <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

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ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE

Trap handler for syscall tracing reads EFA (Exception Fault Address),
in case strace wants PC of trap instruction (EFA is not part of pt_

ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE

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: <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: wireup clone3 syscall

Signed-off-by: Vineet Gupta <[email protected]>

sched/rt, ARC: Use CONFIG_PREEMPTION

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 CONFI

sched/rt, ARC: Use CONFIG_PREEMPTION

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 <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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ARC: entry: EV_Trap expects r10 (vs. r9) to have exception cause

avoids 1 MOV instruction in light of double load/store code

Signed-off-by: Vineet Gupta <[email protected]>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

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 <[email protected]>
Reviewed-by: Enrico Weigelt <[email protected]>
Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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ARC: Re-enable MMU upon Machine Check exception

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 stac

ARC: Re-enable MMU upon Machine Check exception

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: [email protected]
Signed-off-by: Jose Abreu <[email protected]>
Reviewed-by: Alexey Brodkin <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>
[vgupta: moved code into low level handler to avoid in 2 places]

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ARC: entry: make ret_from_system_call local label

This essentially removes ENTRY() assembler annotation for this symbol
since it didn't have a pairing END()

This in ahead of introducing cfi pseudo

ARC: entry: make ret_from_system_call local label

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 <[email protected]>

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ARC: dw2 unwind: switch to .eh_frame based unwinding

So finally after almost 8 years of dealing with .debug_frame, we are
finally switching to .eh_frame. The reason being stripped kernel
binaries ha

ARC: dw2 unwind: switch to .eh_frame based unwinding

So finally after almost 8 years of dealing with .debug_frame, we are
finally switching to .eh_frame. The reason being stripped kernel
binaries had non-functional unwinder as .debug_frame was gone.
Also, in general .eh_frame seems more common way of doing unwinding.

This also folds a revert of f52e126cc747 ("ARC: unwind: ensure that
.debug_frame is generated (vs. .eh_frame)") to ensure that we start
getting .eh_frame

Reported-by: Daniel Mentz <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: [arcompact] Handle bus error from userspace as Interrupt not exception

Bus errors from userspace on ARCompact based cores are handled by core
as a high priority L2 interrupt but current code tr

ARC: [arcompact] Handle bus error from userspace as Interrupt not exception

Bus errors from userspace on ARCompact based cores are handled by core
as a high priority L2 interrupt but current code treated it as interrupt
Handling an interrupt like exception is certainly not going to go unnoticed.
(and it worked so far as we never saw a Bus error from userspace until
IPPK guys tested a DDR controller with ECC error detection etc hence
needed to explicitly trigger/handle such errors)

- So move mem_service exception handler from common code into ARCv2 code.
- In ARCompact code, define mem_service as L2 interrupt handler which
just drops down to pure kernel mode and goes of to enqueue SIGBUS

Reported-by: Nelson Pereira <[email protected]>
Tested-by: Ana Martins <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: change some branchs to jumps to resolve linkage errors

When kernel's binary becomes large enough (32M and more) errors
may occur during the final linkage stage. It happens because
the build sys

ARC: change some branchs to jumps to resolve linkage errors

When kernel's binary becomes large enough (32M and more) errors
may occur during the final linkage stage. It happens because
the build system uses short relocations for ARC by default.
This problem may be easily resolved by passing -mlong-calls
option to GCC to use long absolute jumps (j) instead of short
relative branchs (b).

But there are fragments of pure assembler code exist which use
branchs in inappropriate places and cause a linkage error because
of relocations overflow.

First of these fragments is .fixup insertion in futex.h and
unaligned.c. It inserts a code in the separate section (.fixup)
with branch instruction. It leads to the linkage error when
kernel becomes large.

Second of these fragments is calling scheduler's functions
(common kernel code) from entry.S of ARC's code. When kernel's
binary becomes large it may lead to the linkage error because
scheduler may occur far enough from ARC's code in the final
binary.

Signed-off-by: Yuriy Kolerov <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry.S: micro-optimize Trap handler

Elide the need to re-read ECR in Trap handler by ensuring that
EXCEPTION_PROLOGUE does that at the very end just before returning
to Trap handler

ARCv2 EXC

ARC: entry.S: micro-optimize Trap handler

Elide the need to re-read ECR in Trap handler by ensuring that
EXCEPTION_PROLOGUE does that at the very end just before returning
to Trap handler

ARCv2 EXCEPTION_PROLOGUE already did that, so same for ARcompact and the
common trap handler adjusted to use cached ECR

Signed-off-by: Vineet Gupta <[email protected]>

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ARC: entry.S: move some code around for cache locality in return path

Signed-off-by: Vineet Gupta <[email protected]>

ARC: entry.S: split into ARCompact ISA specific, common bits

Signed-off-by: Vineet Gupta <[email protected]>

ARC: entry.S: Ensure that restore_regs is local to compilation unit

This fixes the possible link/relo errors, since restore_regs will be
provided by ISA code, but called from ARC common code.
The .L

ARC: entry.S: Ensure that restore_regs is local to compilation unit

This fixes the possible link/relo errors, since restore_regs will be
provided by ISA code, but called from ARC common code.
The .L prefix reassures binutils that it will be in same compilation
unit.

Signed-off-by: Vineet Gupta <[email protected]>

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