x86/smp/32: Remove safe_smp_processor_id()

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The safe_smp_processor_id() function was originally implemented in:

  dc2bc768a0 ("stack overflow safe kdump: safe_smp_processor_id()")

to mitigate the CPU number corruption on a stack overflow.  At the time,
x86-32 stored the CPU number in thread_struct, which was located at the
bottom of the task stack and thus vulnerable to an overflow.

The CPU number is now located in percpu memory, so this workaround
is no longer needed.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20250303170115.2176553-1-brgerst@gmail.com

...

This commit is contained in:

Brian Gerst 2025-03-03 12:01:15 -05:00 • committed by Ingo Molnar

parent 399fd7a264

commit 604ea3e90b

5 changed files with 2 additions and 39 deletions

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1

arch/x86/include/asm/cpu.h

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6

arch/x86/include/asm/smp.h

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30

arch/x86/kernel/apic/ipi.c

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2

arch/x86/kernel/crash.c

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2

arch/x86/kernel/reboot.c

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