[PATCH v5 12/21] powerpc: Introduce a function for reporting instruction length

[Jordan Niethe]

Currently all instructions have the same length, but in preparation for
prefixed instructions introduce a function for returning instruction
length.

Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
---
 arch/powerpc/include/asm/inst.h | 5 +++++
 arch/powerpc/kernel/kprobes.c   | 6 ++++--
 arch/powerpc/kernel/uprobes.c   | 2 +-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index 369b35ce964c..70b37a35a91a 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -17,6 +17,11 @@ static inline u32 ppc_inst_val(struct ppc_inst x)
 	return x.val;
 }
 
+static inline bool ppc_inst_len(struct ppc_inst x)
+{
+	return sizeof(struct ppc_inst);
+}
+
 static inline int ppc_inst_opcode(struct ppc_inst x)
 {
 	return x.val >> 26;
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index ff53e5ef7e40..8d17cfdcdc54 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -474,14 +474,16 @@ NOKPROBE_SYMBOL(trampoline_probe_handler);
  */
 int kprobe_post_handler(struct pt_regs *regs)
 {
+	int len;
 	struct kprobe *cur = kprobe_running();
 	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
 	if (!cur || user_mode(regs))
 		return 0;
 
+	len = ppc_inst_len(ppc_inst_read((struct ppc_inst *)cur->ainsn.insn));
 	/* make sure we got here for instruction we have a kprobe on */
-	if (((unsigned long)cur->ainsn.insn + 4) != regs->nip)
+	if (((unsigned long)cur->ainsn.insn + len) != regs->nip)
 		return 0;
 
 	if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
@@ -490,7 +492,7 @@ int kprobe_post_handler(struct pt_regs *regs)
 	}
 
 	/* Adjust nip to after the single-stepped instruction */
-	regs->nip = (unsigned long)cur->addr + 4;
+	regs->nip = (unsigned long)cur->addr + len;
 	regs->msr |= kcb->kprobe_saved_msr;
 
 	/*Restore back the original saved kprobes variables and continue. */
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index 31c870287f2b..8e63afa012ba 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c
@@ -112,7 +112,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 	 * support doesn't exist and have to fix-up the next instruction
 	 * to be executed.
 	 */
-	regs->nip = utask->vaddr + MAX_UINSN_BYTES;
+	regs->nip = utask->vaddr + ppc_inst_len(auprobe->insn);
 
 	user_disable_single_step(current);
 	return 0;
-- 
2.17.1