core/exceptions.c: do not include handler code in exception backtrace

Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
open-power · Oct 2, 2019 · 1785745 · 1785745
1 parent 216433a
commit 1785745
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Showing 3 changed files with 31 additions and 6 deletions.
diff --git a/core/exceptions.c b/core/exceptions.c
@@ -112,7 +112,7 @@ void exception_entry(struct stack_frame *stack)
 		l += snprintf(buf + l, EXCEPTION_MAX_STR - l, "  MSR "REG, msr);
 		prerror("%s\n", buf);
 		dump_regs(stack);
-		backtrace();
+		backtrace_r1((uint64_t)stack);
 		if (platform.terminate)
 			platform.terminate(buf);
 		for (;;) ;
@@ -129,7 +129,7 @@ void exception_entry(struct stack_frame *stack)
 	l += snprintf(buf + l, EXCEPTION_MAX_STR - l, "  MSR "REG, msr);
 	prerror("%s\n", buf);
 	dump_regs(stack);
-	backtrace();
+	backtrace_r1((uint64_t)stack);
 	if (fatal) {
 		if (platform.terminate)
 			platform.terminate(buf);

diff --git a/core/stack.c b/core/stack.c
@@ -17,13 +17,13 @@
 static struct bt_entry bt_buf[STACK_BUF_ENTRIES];
 
 /* Dumps backtrace to buffer */
-void __nomcount backtrace_create(struct bt_entry *entries,
+static void __nomcount __backtrace_create(struct bt_entry *entries,
 				 unsigned int max_ents,
-				 struct bt_metadata *metadata)
+				 struct bt_metadata *metadata,
+				 struct stack_frame *eframe)
 {
-	unsigned long *fp = __builtin_frame_address(0);
+	unsigned long *fp = (unsigned long *)eframe;
 	unsigned long top_adj = top_of_ram;
-	struct stack_frame *eframe = (struct stack_frame *)fp;
 
 	/* Assume one stack for early backtraces */
 	if (top_of_ram == SKIBOOT_BASE + SKIBOOT_SIZE)
@@ -52,6 +52,16 @@ void __nomcount backtrace_create(struct bt_entry *entries,
 	metadata->pir = mfspr(SPR_PIR);
 }
 
+void __nomcount backtrace_create(struct bt_entry *entries,
+				 unsigned int max_ents,
+				 struct bt_metadata *metadata)
+{
+	unsigned long *fp = __builtin_frame_address(0);
+	struct stack_frame *eframe = (struct stack_frame *)fp;
+
+	__backtrace_create(entries, max_ents, metadata, eframe);
+}
+
 void backtrace_print(struct bt_entry *entries, struct bt_metadata *metadata,
 		     char *out_buf, unsigned int *len, bool symbols)
 {
@@ -124,6 +134,18 @@ void backtrace(void)
 	unlock(&bt_lock);
 }
 
+void backtrace_r1(uint64_t r1)
+{
+	struct bt_metadata metadata;
+
+	lock(&bt_lock);
+
+	__backtrace_create(bt_buf, STACK_BUF_ENTRIES, &metadata, (struct stack_frame *)r1);
+	backtrace_print(bt_buf, &metadata, NULL, NULL, true);
+
+	unlock(&bt_lock);
+}
+
 void __nomcount __stack_chk_fail(void);
 void __nomcount __stack_chk_fail(void)
 {

diff --git a/include/stack.h b/include/stack.h
@@ -123,6 +123,9 @@ extern void backtrace_print(struct bt_entry *entries,
 /* For use by debug code, create and print backtrace, uses a static buffer */
 extern void backtrace(void);
 
+/* For use by exception debug code, supply an r1 */
+extern void backtrace_r1(uint64_t r1);
+
 #ifdef STACK_CHECK_ENABLED
 extern void check_stacks(void);
 #else