From: Paul Mackerras <paulus@samba.org>
This patch is from Ananth N Mavinakayanahalli <ananth@in.ibm.com>.
While processing a kprobe, we were currently not handling all available trap
variants available on PowerPC. This lead to the breakage of BUG() handling in
ppc64.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/ppc64/kernel/kprobes.c | 11 +++++++++--
25-akpm/include/asm-ppc64/kprobes.h | 5 +++++
2 files changed, 14 insertions(+), 2 deletions(-)
diff -puN arch/ppc64/kernel/kprobes.c~ppc64-kprobes-handle-trap-variants-while-processing-probes arch/ppc64/kernel/kprobes.c
--- 25/arch/ppc64/kernel/kprobes.c~ppc64-kprobes-handle-trap-variants-while-processing-probes 2005-03-07 20:41:25.000000000 -0800
+++ 25-akpm/arch/ppc64/kernel/kprobes.c 2005-03-07 20:41:25.000000000 -0800
@@ -105,9 +105,17 @@ static inline int kprobe_handler(struct
p = get_kprobe(addr);
if (!p) {
unlock_kprobes();
-#if 0
if (*addr != BREAKPOINT_INSTRUCTION) {
/*
+ * PowerPC has multiple variants of the "trap"
+ * instruction. If the current instruction is a
+ * trap variant, it could belong to someone else
+ */
+ kprobe_opcode_t cur_insn = *addr;
+ if (IS_TW(cur_insn) || IS_TD(cur_insn) ||
+ IS_TWI(cur_insn) || IS_TDI(cur_insn))
+ goto no_kprobe;
+ /*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
@@ -116,7 +124,6 @@ static inline int kprobe_handler(struct
*/
ret = 1;
}
-#endif
/* Not one of ours: let kernel handle it */
goto no_kprobe;
}
diff -puN include/asm-ppc64/kprobes.h~ppc64-kprobes-handle-trap-variants-while-processing-probes include/asm-ppc64/kprobes.h
--- 25/include/asm-ppc64/kprobes.h~ppc64-kprobes-handle-trap-variants-while-processing-probes 2005-03-07 20:41:25.000000000 -0800
+++ 25-akpm/include/asm-ppc64/kprobes.h 2005-03-07 20:41:25.000000000 -0800
@@ -35,6 +35,11 @@ typedef unsigned int kprobe_opcode_t;
#define BREAKPOINT_INSTRUCTION 0x7fe00008 /* trap */
#define MAX_INSN_SIZE 1
+#define IS_TW(instr) (((instr) & 0xfc0007fe) == 0x7c000008)
+#define IS_TD(instr) (((instr) & 0xfc0007fe) == 0x7c000088)
+#define IS_TDI(instr) (((instr) & 0xfc000000) == 0x08000000)
+#define IS_TWI(instr) (((instr) & 0xfc000000) == 0x0c000000)
+
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)((func_descr_t *)pentry)
/* Architecture specific copy of original instruction */
_