Commit-ID: d241006354c550c7d22f304e2fdf90137fb8eaab
Gitweb: http://git.kernel.org/tip/d241006354c550c7d22f304e2fdf90137fb8eaab
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sat, 5 Apr 2014 21:06:10 +0200
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Thu, 17 Apr 2014 21:58:22 +0200
uprobes/x86: Emulate nop's using ops->emulate()
Finally we can kill the ugly (and very limited) code in __skip_sstep().
Just change branch_setup_xol_ops() to treat "nop" as jmp to the next insn.
Thanks to lib/insn.c, it is clever enough. OPCODE1() == 0x90 includes
"(rep;)+ nop;" at least, and (afaics) much more.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Jim Keniston <jkenisto@xxxxxxxxxx>
---
arch/x86/kernel/uprobes.c | 20 +-------------------
1 file changed, 1 insertion(+), 19 deletions(-)
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index c3baeaa..f3c4212 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -478,6 +478,7 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
switch (OPCODE1(insn)) {
case 0xeb: /* jmp 8 */
case 0xe9: /* jmp 32 */
+ case 0x90: /* prefix* + nop; same as jmp with .offs = 0 */
break;
default:
return -ENOSYS;
@@ -710,29 +711,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
regs->flags &= ~X86_EFLAGS_TF;
}
-/*
- * Skip these instructions as per the currently known x86 ISA.
- * rep=0x66*; nop=0x90
- */
static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- int i;
-
if (auprobe->ops->emulate)
return auprobe->ops->emulate(auprobe, regs);
-
- /* TODO: move this code into ->emulate() hook */
- for (i = 0; i < MAX_UINSN_BYTES; i++) {
- if (auprobe->insn[i] == 0x66)
- continue;
-
- if (auprobe->insn[i] == 0x90) {
- regs->ip += i + 1;
- return true;
- }
-
- break;
- }
return false;
}
--
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