add user stack walk

yhnu · Sep 17, 2021 · c9af4cd · c9af4cd
1 parent 5c7c982
commit c9af4cd
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diff --git a/blu7t/op7-r70/arch/arm64/configs/blu_spark_defconfig b/blu7t/op7-r70/arch/arm64/configs/blu_spark_defconfig
@@ -5621,6 +5621,7 @@ CONFIG_SCHEDSTATS=y
 # CONFIG_LOCK_TORTURE_TEST is not set
 # CONFIG_WW_MUTEX_SELFTEST is not set
 CONFIG_STACKTRACE=y
+CONFIG_USER_STACKTRACE_SUPPORT=y
 # CONFIG_WARN_ALL_UNSEEDED_RANDOM is not set
 # CONFIG_DEBUG_KOBJECT is not set
 CONFIG_HAVE_DEBUG_BUGVERBOSE=y

diff --git a/blu7t/op7-r70/arch/arm64/kernel/stacktrace.c b/blu7t/op7-r70/arch/arm64/kernel/stacktrace.c
@@ -194,3 +194,53 @@ void save_stack_trace(struct stack_trace *trace)
 
 EXPORT_SYMBOL_GPL(save_stack_trace);
 #endif
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+#include <linux/uaccess.h>
+struct stack_frame_user {
+	const void __user *next_fp;
+	unsigned long		lr;
+};
+static int
+copy_stack_frame_user(const void __user *fp, struct stack_frame_user *frame)
+{
+	int ret;
+	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+		return 0;
+	ret = 1;
+	pagefault_disable();
+	if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+		ret = 0;
+	pagefault_enable();
+	return ret;
+}
+static inline void __save_stack_trace_user(struct stack_trace *trace)
+{
+	const struct pt_regs *regs = task_pt_regs(current);
+	const void __user *fp = (const void __user *)regs->regs[29];
+	if (trace->nr_entries < trace->max_entries)
+		trace->entries[trace->nr_entries++] = regs->pc;
+	while (trace->nr_entries < trace->max_entries) {
+		struct stack_frame_user frame;
+		frame.next_fp = NULL;
+		frame.lr = 0;
+		if (!copy_stack_frame_user(fp, &frame))
+			break;
+		if ((unsigned long)fp < regs->sp)
+			break;
+		if (frame.lr) {
+			trace->entries[trace->nr_entries++] = frame.lr;
+		}
+		fp = frame.next_fp;
+	}
+}
+void save_stack_trace_user(struct stack_trace *trace)
+{
+	if (current->mm) {
+		__save_stack_trace_user(trace);
+		if (trace->nr_entries < trace->max_entries)
+			trace->entries[trace->nr_entries++] = ULONG_MAX;
+	}
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_user);
+#endif