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objtool: Handle __sanitize_cov*() tail calls

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commit f56dae88a81fded66adf2bea9922d1d98d1da14f upstream.

Turns out the compilers also generate tail calls to __sanitize_cov*(),
make sure to also patch those out in noinstr code.

Fixes: 0f1441b44e ("objtool: Fix noinstr vs KCOV")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20210624095147.818783799@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
[bwh: Backported to 5.10:
 - objtool doesn't have any mcount handling
 - Write the NOPs as hex literals since we can't use <asm/nops.h>]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Zijlstra
2021-06-24 11:41:02 +02:00
committed by Greg Kroah-Hartman
parent 9d7ec2418a
commit acc0be56b4
3 changed files with 86 additions and 58 deletions
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20
tools/objtool/arch/x86/decode.c
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@@ -586,6 +586,26 @@ const char *arch_nop_insn(int len)
return nops[len-1];
}
#define BYTE_RET 0xC3
const char *arch_ret_insn(int len)
{
static const char ret[5][5] = {
{ BYTE_RET },
{ BYTE_RET, 0x90 },
{ BYTE_RET, 0x66, 0x90 },
{ BYTE_RET, 0x0f, 0x1f, 0x00 },
{ BYTE_RET, 0x0f, 0x1f, 0x40, 0x00 },
};
if (len < 1 || len > 5) {
WARN("invalid RET size: %d\n", len);
return NULL;
}
return ret[len-1];
}
/* asm/alternative.h ? */
#define ALTINSTR_FLAG_INV (1 << 15)