uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive()

arch/x86 doesn't care (so far), but as Pratyush Anand pointed
out other architectures might want why arch_uretprobe_is_alive()
was called and use different checks depending on the context.
Add the new argument to distinguish 2 callers.

Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134026.GA4779@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 7e61c8ca27e0..df5661a44e35 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1514,7 +1514,9 @@ static unsigned long get_trampoline_vaddr(void)
 static void cleanup_return_instances(struct uprobe_task *utask, struct pt_regs *regs)
 {
         struct return_instance *ri = utask->return_instances;
-        while (ri && !arch_uretprobe_is_alive(ri, regs)) {
+        enum rp_check ctx = RP_CHECK_CALL;
+
+        while (ri && !arch_uretprobe_is_alive(ri, ctx, regs)) {
                 ri = free_ret_instance(ri);
                 utask->depth--;
         }
@@ -1805,7 +1807,7 @@ static void handle_trampoline(struct pt_regs *regs)
                  * could hit this trampoline on return. TODO: sigaltstack().
                  */
                 next = find_next_ret_chain(ri);
-                valid = !next || arch_uretprobe_is_alive(next, regs);
+                valid = !next || arch_uretprobe_is_alive(next, RP_CHECK_RET, regs);
 
                 instruction_pointer_set(regs, ri->orig_ret_vaddr);
                 do {
@@ -1830,7 +1832,8 @@ bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs)
         return false;
 }
 
-bool __weak arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs)
+bool __weak arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx,
+                                        struct pt_regs *regs)
 {
         return true;
 }