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selftests/powerpc: Fix prefixes in alignment_handler signal handler

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The signal handler in the alignment handler self test has the ability
to jump over the instruction that triggered the signal. It does this
by incrementing the PT_NIP in the user context by 4. If it were a
prefixed instruction this will mean that the suffix is then executed
which is incorrect. Instead check if the major opcode indicates a
prefixed instruction (e.g. it is 1) and if so increment PT_NIP by 8.

If ISA v3.1 is not available treat it as a word instruction even if
the major opcode is 1.

Fixes: 620a6473df ("selftests/powerpc: Add prefixed loads/stores to alignment_handler test")
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Fix 32-bit build, rename haveprefixes to prefixes_enabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200824131231.14008-1-jniethe5@gmail.com
This commit is contained in:
Jordan Niethe 2020-08-24 23:12:31 +10:00 committed by Michael Ellerman
parent 364b236a0b
commit db96221a68
1 changed files with 9 additions and 1 deletions
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10
tools/testing/selftests/powerpc/alignment/alignment_handler.c
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@ -62,6 +62,7 @@ int bufsize;
int debug;
int testing;
volatile int gotsig;
bool prefixes_enabled;
char *cipath = "/dev/fb0";
long cioffset;
@ -75,7 +76,12 @@ void sighandler(int sig, siginfo_t *info, void *ctx)
}
gotsig = sig;
#ifdef __powerpc64__
ucp->uc_mcontext.gp_regs[PT_NIP] += 4;
if (prefixes_enabled) {
u32 inst = *(u32 *)ucp->uc_mcontext.gp_regs[PT_NIP];
ucp->uc_mcontext.gp_regs[PT_NIP] += ((inst >> 26 == 1) ? 8 : 4);
} else {
ucp->uc_mcontext.gp_regs[PT_NIP] += 4;
}
#else
ucp->uc_mcontext.uc_regs->gregs[PT_NIP] += 4;
#endif
@ -646,6 +652,8 @@ int main(int argc, char *argv[])
exit(1);
}
prefixes_enabled = have_hwcap2(PPC_FEATURE2_ARCH_3_1);
rc |= test_harness(test_alignment_handler_vsx_206,
"test_alignment_handler_vsx_206");
rc |= test_harness(test_alignment_handler_vsx_207,