arm64: Handle TRAP_TRACE for user mode as well

uprobe registers a handler at step_hook. So, single_step_handler now
checks for user mode as well if there is a valid hook.

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

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 73ae90e..a8f8de0 100644 (file)
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -226,6 +226,8 @@ static void send_user_sigtrap(int si_code)
 static int single_step_handler(unsigned long addr, unsigned int esr,
                               struct pt_regs *regs)
 {
+       bool handler_found = false;
+
        /*
         * If we are stepping a pending breakpoint, call the hw_breakpoint
         * handler first.
@@ -233,7 +235,14 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
        if (!reinstall_suspended_bps(regs))
                return 0;
 
-       if (user_mode(regs)) {
+#ifdef CONFIG_KPROBES
+       if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED)
+               handler_found = true;
+#endif
+       if (!handler_found && call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
+               handler_found = true;
+
+       if (!handler_found && user_mode(regs)) {
                send_user_sigtrap(TRAP_TRACE);
 
                /*
@@ -243,15 +252,8 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
                 * to the active-not-pending state).
                 */
                user_rewind_single_step(current);
-       } else {
-#ifdef CONFIG_KPROBES
-               if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED)
-                       return 0;
-#endif
-               if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
-                       return 0;
-
-               pr_warning("Unexpected kernel single-step exception at EL1\n");
+       } else if (!handler_found) {
+               pr_warn("Unexpected kernel single-step exception at EL1\n");
                /*
                 * Re-enable stepping since we know that we will be
                 * returning to regs.