Merge branch 'x86/urgent' into x86/fpu, to resolve a conflict

Resolve the conflict between these commits:

   x86/fpu:      1193f408cd51 ("x86/fpu/signal: Change return type of __fpu_restore_sig() to boolean")

   x86/urgent:   d298b03506d3 ("x86/fpu: Restore the masking out of reserved MXCSR bits")
                 b2381acd3fd9 ("x86/fpu: Mask out the invalid MXCSR bits properly")

 Conflicts:
        arch/x86/kernel/fpu/signal.c

Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 32 insertions, 7 deletions

diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
index a288035eb362..c756284b3b13 100644
--- a/tools/perf/tests/dwarf-unwind.c
+++ b/tools/perf/tests/dwarf-unwind.c
@@ -20,6 +20,23 @@
 /* For bsearch. We try to unwind functions in shared object. */
 #include <stdlib.h>
 
+/*
+ * The test will assert frames are on the stack but tail call optimizations lose
+ * the frame of the caller. Clang can disable this optimization on a called
+ * function but GCC currently (11/2020) lacks this attribute. The barrier is
+ * used to inhibit tail calls in these cases.
+ */
+#ifdef __has_attribute
+#if __has_attribute(disable_tail_calls)
+#define NO_TAIL_CALL_ATTRIBUTE __attribute__((disable_tail_calls))
+#define NO_TAIL_CALL_BARRIER
+#endif
+#endif
+#ifndef NO_TAIL_CALL_ATTRIBUTE
+#define NO_TAIL_CALL_ATTRIBUTE
+#define NO_TAIL_CALL_BARRIER __asm__ __volatile__("" : : : "memory");
+#endif
+
 static int mmap_handler(struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct perf_sample *sample,
@@ -91,7 +108,7 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
 	return strcmp((const char *) symbol, funcs[idx]);
 }
 
-noinline int test_dwarf_unwind__thread(struct thread *thread)
+NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__thread(struct thread *thread)
 {
 	struct perf_sample sample;
 	unsigned long cnt = 0;
@@ -122,7 +139,7 @@ noinline int test_dwarf_unwind__thread(struct thread *thread)
 
 static int global_unwind_retval = -INT_MAX;
 
-noinline int test_dwarf_unwind__compare(void *p1, void *p2)
+NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__compare(void *p1, void *p2)
 {
 	/* Any possible value should be 'thread' */
 	struct thread *thread = *(struct thread **)p1;
@@ -141,7 +158,7 @@ noinline int test_dwarf_unwind__compare(void *p1, void *p2)
 	return p1 - p2;
 }
 
-noinline int test_dwarf_unwind__krava_3(struct thread *thread)
+NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_3(struct thread *thread)
 {
 	struct thread *array[2] = {thread, thread};
 	void *fp = &bsearch;
@@ -160,14 +177,22 @@ noinline int test_dwarf_unwind__krava_3(struct thread *thread)
 	return global_unwind_retval;
 }
 
-noinline int test_dwarf_unwind__krava_2(struct thread *thread)
+NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_2(struct thread *thread)
 {
-	return test_dwarf_unwind__krava_3(thread);
+	int ret;
+
+	ret =  test_dwarf_unwind__krava_3(thread);
+	NO_TAIL_CALL_BARRIER;
+	return ret;
 }
 
-noinline int test_dwarf_unwind__krava_1(struct thread *thread)
+NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_1(struct thread *thread)
 {
-	return test_dwarf_unwind__krava_2(thread);
+	int ret;
+
+	ret =  test_dwarf_unwind__krava_2(thread);
+	NO_TAIL_CALL_BARRIER;
+	return ret;
 }
 
 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused)