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Diffstat (limited to 'arch/s390/kernel/ftrace.c')
-rw-r--r--arch/s390/kernel/ftrace.c61
1 files changed, 45 insertions, 16 deletions
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 82c19899574..6c79f1b44fe 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -57,6 +57,44 @@
unsigned long ftrace_plt;
+static inline void ftrace_generate_orig_insn(struct ftrace_insn *insn)
+{
+#ifdef CC_USING_HOTPATCH
+ /* brcl 0,0 */
+ insn->opc = 0xc004;
+ insn->disp = 0;
+#else
+ /* stg r14,8(r15) */
+ insn->opc = 0xe3e0;
+ insn->disp = 0xf0080024;
+#endif
+}
+
+static inline int is_kprobe_on_ftrace(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_KPROBES
+ if (insn->opc == BREAKPOINT_INSTRUCTION)
+ return 1;
+#endif
+ return 0;
+}
+
+static inline void ftrace_generate_kprobe_nop_insn(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_KPROBES
+ insn->opc = BREAKPOINT_INSTRUCTION;
+ insn->disp = KPROBE_ON_FTRACE_NOP;
+#endif
+}
+
+static inline void ftrace_generate_kprobe_call_insn(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_KPROBES
+ insn->opc = BREAKPOINT_INSTRUCTION;
+ insn->disp = KPROBE_ON_FTRACE_CALL;
+#endif
+}
+
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
@@ -72,16 +110,9 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
return -EFAULT;
if (addr == MCOUNT_ADDR) {
/* Initial code replacement */
-#ifdef CC_USING_HOTPATCH
- /* We expect to see brcl 0,0 */
- ftrace_generate_nop_insn(&orig);
-#else
- /* We expect to see stg r14,8(r15) */
- orig.opc = 0xe3e0;
- orig.disp = 0xf0080024;
-#endif
+ ftrace_generate_orig_insn(&orig);
ftrace_generate_nop_insn(&new);
- } else if (old.opc == BREAKPOINT_INSTRUCTION) {
+ } else if (is_kprobe_on_ftrace(&old)) {
/*
* If we find a breakpoint instruction, a kprobe has been
* placed at the beginning of the function. We write the
@@ -89,9 +120,8 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
* bytes of the original instruction so that the kprobes
* handler can execute a nop, if it reaches this breakpoint.
*/
- new.opc = orig.opc = BREAKPOINT_INSTRUCTION;
- orig.disp = KPROBE_ON_FTRACE_CALL;
- new.disp = KPROBE_ON_FTRACE_NOP;
+ ftrace_generate_kprobe_call_insn(&orig);
+ ftrace_generate_kprobe_nop_insn(&new);
} else {
/* Replace ftrace call with a nop. */
ftrace_generate_call_insn(&orig, rec->ip);
@@ -111,7 +141,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old)))
return -EFAULT;
- if (old.opc == BREAKPOINT_INSTRUCTION) {
+ if (is_kprobe_on_ftrace(&old)) {
/*
* If we find a breakpoint instruction, a kprobe has been
* placed at the beginning of the function. We write the
@@ -119,9 +149,8 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* bytes of the original instruction so that the kprobes
* handler can execute a brasl if it reaches this breakpoint.
*/
- new.opc = orig.opc = BREAKPOINT_INSTRUCTION;
- orig.disp = KPROBE_ON_FTRACE_NOP;
- new.disp = KPROBE_ON_FTRACE_CALL;
+ ftrace_generate_kprobe_nop_insn(&orig);
+ ftrace_generate_kprobe_call_insn(&new);
} else {
/* Replace nop with an ftrace call. */
ftrace_generate_nop_insn(&orig);