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Revision f2d7b53c0153f2daa8bc8f1ff29b5a1e03a36458 authored by Alexander Potapenko on 02 November 2022, 10:15:00 UTC, committed by Alexander Potapenko on 02 November 2022, 10:55:06 UTC 
x86/traps: avoid KMSAN bugs originating from handle_bug()
 
There is a case in exc_invalid_op handler that is executed outside the
irqentry_enter()/irqentry_exit() region when an UD2 instruction is used
to encode a call to __warn().

In that case the `struct pt_regs` passed to the interrupt handler is
never unpoisoned by KMSAN (this is normally done in irqentry_enter()),
which leads to false positives inside handle_bug().

Use kmsan_unpoison_entry_regs() to explicitly unpoison those registers
before using them.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Alexander Potapenko <glider@google.com>
1 parent 4dbc4d5
Raw File
cmpdi2.c 
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 */

#include <linux/export.h>

#include <linux/libgcc.h>

word_type notrace __cmpdi2(long long a, long long b)
{
	const DWunion au = {
		.ll = a
	};
	const DWunion bu = {
		.ll = b
	};

	if (au.s.high < bu.s.high)
		return 0;
	else if (au.s.high > bu.s.high)
		return 2;

	if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
		return 0;
	else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
		return 2;

	return 1;
}
EXPORT_SYMBOL(__cmpdi2);
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