From 17e8de7e1878bbd45f3e268932e997496ddbbfe7 Mon Sep 17 00:00:00 2001 From: Tom Musta Date: Thu, 22 Aug 2013 09:25:28 -0500 Subject: [PATCH] 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/lib/sstep.c | 8 +++++--- 1 file 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; }