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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2017-04-19 18:21:04 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-04-20 23:18:56 +1000
commit1cabd2f8f720a0ed612139547acb655495b23e8b (patch)
treece49886287ef73d1ff879f7268331061c2f62402 /arch/powerpc/kernel/kprobes.c
parenta64e3f35a45f4a84148d0ba30a3c75c4c7076928 (diff)
powerpc/kprobes: Factor out code to emulate instruction into a helper
Factor out code to emulate instruction into a try_to_emulate() helper function. This makes no functional changes. Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/kprobes.c')
-rw-r--r--arch/powerpc/kernel/kprobes.c52
1 files changed, 31 insertions, 21 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 97b5eed1f76d..ed5a917c2edd 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -207,6 +207,35 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
regs->link = (unsigned long)kretprobe_trampoline;
}
+int __kprobes try_to_emulate(struct kprobe *p, struct pt_regs *regs)
+{
+ int ret;
+ unsigned int insn = *p->ainsn.insn;
+
+ /* regs->nip is also adjusted if emulate_step returns 1 */
+ ret = emulate_step(regs, insn);
+ if (ret > 0) {
+ /*
+ * Once this instruction has been boosted
+ * successfully, set the boostable flag
+ */
+ if (unlikely(p->ainsn.boostable == 0))
+ p->ainsn.boostable = 1;
+ } else if (ret < 0) {
+ /*
+ * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
+ * So, we should never get here... but, its still
+ * good to catch them, just in case...
+ */
+ printk("Can't step on instruction %x\n", insn);
+ BUG();
+ } else if (ret == 0)
+ /* This instruction can't be boosted */
+ p->ainsn.boostable = -1;
+
+ return ret;
+}
+
int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
@@ -302,18 +331,9 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
ss_probe:
if (p->ainsn.boostable >= 0) {
- unsigned int insn = *p->ainsn.insn;
+ ret = try_to_emulate(p, regs);
- /* regs->nip is also adjusted if emulate_step returns 1 */
- ret = emulate_step(regs, insn);
if (ret > 0) {
- /*
- * Once this instruction has been boosted
- * successfully, set the boostable flag
- */
- if (unlikely(p->ainsn.boostable == 0))
- p->ainsn.boostable = 1;
-
if (p->post_handler)
p->post_handler(p, regs, 0);
@@ -321,17 +341,7 @@ ss_probe:
reset_current_kprobe();
preempt_enable_no_resched();
return 1;
- } else if (ret < 0) {
- /*
- * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
- * So, we should never get here... but, its still
- * good to catch them, just in case...
- */
- printk("Can't step on instruction %x\n", insn);
- BUG();
- } else if (ret == 0)
- /* This instruction can't be boosted */
- p->ainsn.boostable = -1;
+ }
}
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;