arm64: kgdb_step_brk_fn: ignore other's exception

ARM64 step exception does not have any syndrome information. So, it is
responsibility of exception handler to take care that they handle it
only if exception was raised for them.

Since kgdb_step_brk_fn() always returns 0, therefore we might have problem
when we will have other step handler registered as well.

This patch fixes kgdb_step_brk_fn() to return error in case of step handler
was not meant for kgdb.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
index e017a9493b92e907235cc19e7df7e53397c3f56e..d217c9e95b06cc10726dafddd6a169ec2394cc6d 100644 (file)
--- a/arch/arm64/kernel/kgdb.c
+++ b/arch/arm64/kernel/kgdb.c
@@ -247,6 +247,9 @@ NOKPROBE_SYMBOL(kgdb_compiled_brk_fn);
 
 static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
 {
+       if (!kgdb_single_step)
+               return DBG_HOOK_ERROR;
+
        kgdb_handle_exception(1, SIGTRAP, 0, regs);
        return 0;
 }