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Diffstat (limited to 'arch/arm64/include/asm/stacktrace.h')
-rw-r--r--arch/arm64/include/asm/stacktrace.h78
1 files changed, 65 insertions, 13 deletions
diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index df45af931459..4d9b1f48dc39 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -8,19 +8,12 @@
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
+#include <linux/types.h>
#include <asm/memory.h>
#include <asm/ptrace.h>
#include <asm/sdei.h>
-struct stackframe {
- unsigned long fp;
- unsigned long pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- int graph;
-#endif
-};
-
enum stack_type {
STACK_TYPE_UNKNOWN,
STACK_TYPE_TASK,
@@ -28,6 +21,7 @@ enum stack_type {
STACK_TYPE_OVERFLOW,
STACK_TYPE_SDEI_NORMAL,
STACK_TYPE_SDEI_CRITICAL,
+ __NR_STACK_TYPES
};
struct stack_info {
@@ -36,6 +30,37 @@ struct stack_info {
enum stack_type type;
};
+/*
+ * A snapshot of a frame record or fp/lr register values, along with some
+ * accounting information necessary for robust unwinding.
+ *
+ * @fp: The fp value in the frame record (or the real fp)
+ * @pc: The fp value in the frame record (or the real lr)
+ *
+ * @stacks_done: Stacks which have been entirely unwound, for which it is no
+ * longer valid to unwind to.
+ *
+ * @prev_fp: The fp that pointed to this frame record, or a synthetic value
+ * of 0. This is used to ensure that within a stack, each
+ * subsequent frame record is at an increasing address.
+ * @prev_type: The type of stack this frame record was on, or a synthetic
+ * value of STACK_TYPE_UNKNOWN. This is used to detect a
+ * transition from one stack to another.
+ *
+ * @graph: When FUNCTION_GRAPH_TRACER is selected, holds the index of a
+ * replacement lr value in the ftrace graph stack.
+ */
+struct stackframe {
+ unsigned long fp;
+ unsigned long pc;
+ DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
+ unsigned long prev_fp;
+ enum stack_type prev_type;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ int graph;
+#endif
+};
+
extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
int (*fn)(struct stackframe *, void *), void *data);
@@ -64,8 +89,9 @@ static inline bool on_irq_stack(unsigned long sp,
return true;
}
-static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp,
- struct stack_info *info)
+static inline bool on_task_stack(const struct task_struct *tsk,
+ unsigned long sp,
+ struct stack_info *info)
{
unsigned long low = (unsigned long)task_stack_page(tsk);
unsigned long high = low + THREAD_SIZE;
@@ -112,10 +138,13 @@ static inline bool on_overflow_stack(unsigned long sp,
* We can only safely access per-cpu stacks from current in a non-preemptible
* context.
*/
-static inline bool on_accessible_stack(struct task_struct *tsk,
- unsigned long sp,
- struct stack_info *info)
+static inline bool on_accessible_stack(const struct task_struct *tsk,
+ unsigned long sp,
+ struct stack_info *info)
{
+ if (info)
+ info->type = STACK_TYPE_UNKNOWN;
+
if (on_task_stack(tsk, sp, info))
return true;
if (tsk != current || preemptible())
@@ -130,4 +159,27 @@ static inline bool on_accessible_stack(struct task_struct *tsk,
return false;
}
+static inline void start_backtrace(struct stackframe *frame,
+ unsigned long fp, unsigned long pc)
+{
+ frame->fp = fp;
+ frame->pc = pc;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ frame->graph = 0;
+#endif
+
+ /*
+ * Prime the first unwind.
+ *
+ * In unwind_frame() we'll check that the FP points to a valid stack,
+ * which can't be STACK_TYPE_UNKNOWN, and the first unwind will be
+ * treated as a transition to whichever stack that happens to be. The
+ * prev_fp value won't be used, but we set it to 0 such that it is
+ * definitely not an accessible stack address.
+ */
+ bitmap_zero(frame->stacks_done, __NR_STACK_TYPES);
+ frame->prev_fp = 0;
+ frame->prev_type = STACK_TYPE_UNKNOWN;
+}
+
#endif /* __ASM_STACKTRACE_H */