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authorTom Musta <tmusta@us.ibm.com>2013-08-22 09:25:28 -0500
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-08-27 14:36:08 +1000
commit17e8de7e1878bbd45f3e268932e997496ddbbfe7 (patch)
treef7dc643d8809b2701be9d7547ddb680c19f2fd02
parentf748edafac858404be6c8dd67160c2032d97ddf5 (diff)
powerpc: Unaligned stores and stmw are broken in emulation code
The stmw instruction was incorrectly decoded as an update form instruction and thus the RA register was being clobbered. Also, the utility routine to write memory to unaligned addresses breaks the operation into smaller aligned accesses but was incorrectly incrementing the address by only one; it needs to increment the address by the size of the smaller aligned chunk. Signed-off-by: Tom Musta <tmusta@us.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/lib/sstep.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 99c7fc16dc0d..a7ee978fb860 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -100,8 +100,10 @@ static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs
ea = (signed short) instr; /* sign-extend */
if (ra) {
ea += regs->gpr[ra];
- if (instr & 0x04000000) /* update forms */
- regs->gpr[ra] = ea;
+ if (instr & 0x04000000) { /* update forms */
+ if ((instr>>26) != 47) /* stmw is not an update form */
+ regs->gpr[ra] = ea;
+ }
}
return truncate_if_32bit(regs->msr, ea);
@@ -279,7 +281,7 @@ static int __kprobes write_mem_unaligned(unsigned long val, unsigned long ea,
err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
if (err)
return err;
- ++ea;
+ ea += c;
}
return 0;
}