[POWERPC] Disallow kprobes on emulate_step and branch_taken
On powerpc, probing on emulate_step function will crash 2.6.18.1 when
it is triggered.
When kprobe is triggered, emulate_step() is on its kernel path and
will cause recursive kprobe fault. And branch_taken() is called
in emulate_step(). This disallows kprobes on both of them.
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 9590ba7..7e8ded0 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -9,6 +9,7 @@
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
+#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <asm/sstep.h>
#include <asm/processor.h>
@@ -25,7 +26,7 @@
/*
* Determine whether a conditional branch instruction would branch.
*/
-static int branch_taken(unsigned int instr, struct pt_regs *regs)
+static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
{
unsigned int bo = (instr >> 21) & 0x1f;
unsigned int bi;
@@ -51,7 +52,7 @@
* or -1 if the instruction is one that should not be stepped,
* such as an rfid, or a mtmsrd that would clear MSR_RI.
*/
-int emulate_step(struct pt_regs *regs, unsigned int instr)
+int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
{
unsigned int opcode, rd;
unsigned long int imm;