linux-stable.git/arch/arm/lib, branch linux-6.3.y

locking/atomic: arm: fix sync ops

2023-07-11T17:39:26+00:00

[ Upstream commit dda5f312bb09e56e7a1c3e3851f2000eb2e9c879 ]

The sync_*() ops on arch/arm are defined in terms of the regular bitops
with no special handling. This is not correct, as UP kernels elide
barriers for the fully-ordered operations, and so the required ordering
is lost when such UP kernels are run under a hypervsior on an SMP
system.

Fix this by defining sync ops with the required barriers.

Note: On 32-bit arm, the sync_*() ops are currently only used by Xen,
which requires ARMv7, but the semantics can be implemented for ARMv6+.

Fixes: e54d2f61528165bb ("xen/arm: sync_bitops")
Signed-off-by: Mark Rutland 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20230605070124.3741859-2-mark.rutland@arm.com
Signed-off-by: Sasha Levin

ARM: 9290/1: uaccess: Fix KASAN false-positives

2023-03-06T15:25:08+00:00

__copy_to_user_memcpy() and __clear_user_memset() had been calling
memcpy() and memset() respectively, leading to false-positive KASAN
reports when starting userspace:

    [   10.707901] Run /init as init process
    [   10.731892] process '/bin/busybox' started with executable stack
    [   10.745234] ==================================================================
    [   10.745796] BUG: KASAN: user-memory-access in __clear_user_memset+0x258/0x3ac
    [   10.747260] Write of size 2687 at addr 000de581 by task init/1

Use __memcpy() and __memset() instead to allow userspace access, which
is of course the intent of these functions.

Signed-off-by: Andrew Jeffery 
Signed-off-by: Zev Weiss 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Russell King (Oracle)

ARM: 9279/1: support function error injection

2022-12-07T14:08:38+00:00

This enables HAVE_FUNCTION_ERROR_INJECTION by adding necessary
regs_set_return_value() and override_function_with_return().

Simply tested according to Documentation/fault-injection/fault-injection.rst.

Signed-off-by: Kefeng Wang 
Signed-off-by: Russell King (Oracle)

ARM: findbit: add unwinder information

2022-11-14T12:00:58+00:00

Add unwinder information so oops in the findbit functions can create a
proper backtrace.

Signed-off-by: Russell King (Oracle)

ARM: findbit: operate by words

2022-11-14T12:00:58+00:00

Convert the implementations to operate on words rather than bytes
which makes bitmap searching faster.

Signed-off-by: Russell King (Oracle)

ARM: findbit: convert to macros

2022-11-14T12:00:58+00:00

Since the pairs of _find_first and _find_next functions are pretty
similar, use macros to generate this code. This commit does not
change the generated code.

Signed-off-by: Russell King (Oracle)

ARM: findbit: provide more efficient ARMv7 implementation

2022-11-14T12:00:58+00:00

Provide a more efficient ARMv7 implementation to determine the first
set bit in the supplied value.

Signed-off-by: Russell King (Oracle)

ARM: findbit: document ARMv5 bit offset calculation

2022-11-14T12:00:57+00:00

Document the ARMv5 bit offset calculation code.

Signed-off-by: Russell King (Oracle)

ARM: 9263/1: use .arch directives instead of assembler command line flags

2022-11-08T18:36:17+00:00

Similar to commit a6c30873ee4a ("ARM: 8989/1: use .fpu assembler
directives instead of assembler arguments").

GCC and GNU binutils support setting the "sub arch" via -march=,
-Wa,-march, target function attribute, and .arch assembler directive.

Clang was missing support for -Wa,-march=, but this was implemented in
clang-13.

The behavior of both GCC and Clang is to
prefer -Wa,-march= over -march= for assembler and assembler-with-cpp
sources, but Clang will warn about the -march= being unused.

clang: warning: argument unused during compilation: '-march=armv6k'
[-Wunused-command-line-argument]

Since most assembler is non-conditionally assembled with one sub arch
(modulo arch/arm/delay-loop.S which conditionally is assembled as armv4
based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is
conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the
.arch assembler directive.

Add a few more instances found in compile testing as found by Arnd and
Nathan.

Link: https://github.com/llvm/llvm-project/commit/1d51c699b9e2ebc5bcfdbe85c74cc871426333d4
Link: https://bugs.llvm.org/show_bug.cgi?id=48894
Link: https://github.com/ClangBuiltLinux/linux/issues/1195
Link: https://github.com/ClangBuiltLinux/linux/issues/1315

Suggested-by: Arnd Bergmann 
Suggested-by: Nathan Chancellor 
Signed-off-by: Arnd Bergmann 
Tested-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Russell King (Oracle)

ARM: 9233/1: stacktrace: Skip frame pointer boundary check for call_with_stack()

2022-10-04T10:09:47+00:00

When using the frame pointer unwinder, it was found that the stack trace
output of stack_trace_save() is incomplete if the stack contains
call_with_stack():

 [0x7f00002c] dump_stack_task+0x2c/0x90 [hrtimer]
 [0x7f0000a0] hrtimer_hander+0x10/0x18 [hrtimer]
 [0x801a67f0] __hrtimer_run_queues+0x1b0/0x3b4
 [0x801a7350] hrtimer_run_queues+0xc4/0xd8
 [0x801a597c] update_process_times+0x3c/0x88
 [0x801b5a98] tick_periodic+0x50/0xd8
 [0x801b5bf4] tick_handle_periodic+0x24/0x84
 [0x8010ffc4] twd_handler+0x38/0x48
 [0x8017d220] handle_percpu_devid_irq+0xa8/0x244
 [0x80176e9c] generic_handle_domain_irq+0x2c/0x3c
 [0x8052e3a8] gic_handle_irq+0x7c/0x90
 [0x808ab15c] generic_handle_arch_irq+0x60/0x80
 [0x8051191c] call_with_stack+0x1c/0x20

For the frame pointer unwinder, unwind_frame() checks stackframe::fp by
stackframe::sp. Since call_with_stack() switches the SP from one stack
to another, stackframe::fp and stackframe: :sp will point to different
stacks, so we can no longer check stackframe::fp by stackframe::sp. Skip
checking stackframe::fp at this point to avoid this problem.

Signed-off-by: Li Huafei 
Reviewed-by: Linus Waleij 
Signed-off-by: Russell King (Oracle)