s390/test_unwind: add ftrace test

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/lib/test_unwind.c b/arch/s390/lib/test_unwind.c
index 8be9ca263127de994a66a5e318abedb2f8132ec7..2224694a0888138efb3076e5009ab71a3f33c6c5 100644 (file)
--- a/arch/s390/lib/test_unwind.c
+++ b/arch/s390/lib/test_unwind.c
@@ -8,6 +8,7 @@
 #include <linux/completion.h>
 #include <linux/kallsyms.h>
 #include <linux/kthread.h>
+#include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/timer.h>
 #include <linux/slab.h>
@@ -129,6 +130,7 @@ static struct unwindme *unwindme;
 #define UWM_SWITCH_STACK       0x10    /* Use call_on_stack. */
 #define UWM_IRQ                        0x20    /* Unwind from irq context. */
 #define UWM_PGM                        0x40    /* Unwind from program check handler. */
+#define UWM_FTRACE             0x80    /* Unwind from ftrace handler. */
 
 static __always_inline unsigned long get_psw_addr(void)
 {
@@ -149,6 +151,57 @@ static int pgm_pre_handler(struct kprobe *p, struct pt_regs *regs)
        return 0;
 }
 
+static void notrace __used test_unwind_ftrace_handler(unsigned long ip,
+                                                     unsigned long parent_ip,
+                                                     struct ftrace_ops *fops,
+                                                     struct ftrace_regs *fregs)
+{
+       struct unwindme *u = (struct unwindme *)fregs->regs.gprs[2];
+
+       u->ret = test_unwind(NULL, (u->flags & UWM_REGS) ? &fregs->regs : NULL,
+                            (u->flags & UWM_SP) ? u->sp : 0);
+}
+
+static noinline int test_unwind_ftraced_func(struct unwindme *u)
+{
+       return READ_ONCE(u)->ret;
+}
+
+static int test_unwind_ftrace(struct unwindme *u)
+{
+       struct ftrace_ops *fops;
+       int ret;
+
+#ifndef CONFIG_DYNAMIC_FTRACE
+       kunit_skip(current_test, "requires CONFIG_DYNAMIC_FTRACE");
+       fops = NULL; /* used */
+#else
+       fops = kunit_kzalloc(current_test, sizeof(*fops), GFP_KERNEL);
+       fops->func = test_unwind_ftrace_handler;
+       fops->flags = FTRACE_OPS_FL_DYNAMIC |
+                    FTRACE_OPS_FL_RECURSION |
+                    FTRACE_OPS_FL_SAVE_REGS |
+                    FTRACE_OPS_FL_PERMANENT;
+#endif
+
+       ret = ftrace_set_filter_ip(fops, (unsigned long)test_unwind_ftraced_func, 0, 0);
+       if (ret) {
+               kunit_err(current_test, "failed to set ftrace filter (%d)\n", ret);
+               return -1;
+       }
+
+       ret = register_ftrace_function(fops);
+       if (!ret) {
+               ret = test_unwind_ftraced_func(u);
+               unregister_ftrace_function(fops);
+       } else {
+               kunit_err(current_test, "failed to register ftrace handler (%d)\n", ret);
+       }
+
+       ftrace_set_filter_ip(fops, (unsigned long)test_unwind_ftraced_func, 1, 0);
+       return ret;
+}
+
 /* This function may or may not appear in the backtrace. */
 static noinline int unwindme_func4(struct unwindme *u)
 {
@@ -189,6 +242,8 @@ static noinline int unwindme_func4(struct unwindme *u)
                unregister_kprobe(&kp);
                unwindme = NULL;
                return u->ret;
+       } else if (u->flags & UWM_FTRACE) {
+               return test_unwind_ftrace(u);
        } else {
                struct pt_regs regs;
 
@@ -321,6 +376,10 @@ static const struct test_params param_list[] = {
        TEST_WITH_FLAGS(UWM_PGM | UWM_SP),
        TEST_WITH_FLAGS(UWM_PGM | UWM_REGS),
        TEST_WITH_FLAGS(UWM_PGM | UWM_SP | UWM_REGS),
+       TEST_WITH_FLAGS(UWM_FTRACE),
+       TEST_WITH_FLAGS(UWM_FTRACE | UWM_SP),
+       TEST_WITH_FLAGS(UWM_FTRACE | UWM_REGS),
+       TEST_WITH_FLAGS(UWM_FTRACE | UWM_SP | UWM_REGS),
 };
 
 /*