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Subject[PATCH v3 1/2] kprobes: introduce weak arch_check_ftrace_location() helper function
Date
Introduce weak arch_check_ftrace_location() helper function which
architectures can override in order to implement handling of kprobes
on function tracer call sites on their own, without depending on
common code or implementing the KPROBES_ON_FTRACE feature.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---
include/linux/kprobes.h | 1 +
kernel/kprobes.c | 18 +++++++++++-------
2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index f7296e57d614..5297f9fa0ef2 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -335,6 +335,7 @@ extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
#endif

+int arch_check_ftrace_location(struct kprobe *p);

/* Get the kprobe at this addr (if any) - called with preemption disabled */
struct kprobe *get_kprobe(void *addr);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3995f546d0f3..317eb8ad28dd 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1410,16 +1410,10 @@ static inline int check_kprobe_rereg(struct kprobe *p)
return ret;
}

-static int check_kprobe_address_safe(struct kprobe *p,
- struct module **probed_mod)
+int __weak arch_check_ftrace_location(struct kprobe *p)
{
- int ret = 0;
unsigned long ftrace_addr;

- /*
- * If the address is located on a ftrace nop, set the
- * breakpoint to the following instruction.
- */
ftrace_addr = ftrace_location((unsigned long)p->addr);
if (ftrace_addr) {
#ifdef CONFIG_KPROBES_ON_FTRACE
@@ -1431,7 +1425,17 @@ static int check_kprobe_address_safe(struct kprobe *p,
return -EINVAL;
#endif
}
+ return 0;
+}

+static int check_kprobe_address_safe(struct kprobe *p,
+ struct module **probed_mod)
+{
+ int ret;
+
+ ret = arch_check_ftrace_location(p);
+ if (ret)
+ return ret;
jump_label_lock();
preempt_disable();

--
1.8.5.5


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