For previously detected early kprobes on ftrace, retrieve old
instruction using kprobe_on_ftrace_get_old_insn() instead of
ftrace_nop_replace(). Which will enable convertion an early kprobed
ftrace entry directly to 'call' instrustion without turnning off
kprobe.
Signed-off-by: Wang Nan <wangn...@huawei.com>
---
arch/x86/kernel/ftrace.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 7bdba65..f200cd4 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -21,6 +21,7 @@
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/kprobes.h>
#include <trace/syscall.h>
@@ -164,7 +165,17 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long
addr)
unsigned const char *new, *old;
unsigned long ip = rec->ip;
- old = ftrace_nop_replace();
+#if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES)
+ unsigned char kprobes_old_insn[MCOUNT_INSN_SIZE];
+
+ if (unlikely(rec->flags & FTRACE_FL_EARLY_KPROBES))
+ old = kprobe_on_ftrace_get_old_insn(rec,
+ ftrace_nop_replace(),
+ kprobes_old_insn,
+ MCOUNT_INSN_SIZE);
+ else
+#endif
+ old = ftrace_nop_replace();
new = ftrace_call_replace(ip, addr);
/* Should only be called when module is loaded */
@@ -335,8 +346,16 @@ static int add_brk_on_call(struct dyn_ftrace *rec,
unsigned long addr)
static int add_brk_on_nop(struct dyn_ftrace *rec)
{
unsigned const char *old;
+#if defined(CONFIG_KPROBES_ON_FTRACE) && defined(CONFIG_EARLY_KPROBES)
+ unsigned char kprobes_old_insn[MCOUNT_INSN_SIZE];
- old = ftrace_nop_replace();
+ if (unlikely(rec->flags & FTRACE_FL_EARLY_KPROBES))
+ old = kprobe_on_ftrace_get_old_insn(rec, ftrace_nop_replace(),
+ kprobes_old_insn,
+ MCOUNT_INSN_SIZE);
+ else
+#endif
+ old = ftrace_nop_replace();
return add_break(rec->ip, old);
}
--
1.8.4
--
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