arm64: stacktrace: Factor out common unwind()

Move unwind() to stacktrace/common.h, and as a result
the kernel unwind_next() to asm/stacktrace.h. This allow
reusing unwind() in the implementation of the nVHE HYP
stack unwinder, later in the series.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-6-kaleshsingh@google.com

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 43f4b4a6d38377c84893e9adfdb84eda6cec6b71..ea828579a98b699ac1f4d85fd78db9ee13103591 100644 (file)
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -11,6 +11,7 @@
 #include <linux/llist.h>
 
 #include <asm/memory.h>
+#include <asm/pointer_auth.h>
 #include <asm/ptrace.h>
 #include <asm/sdei.h>
 
@@ -80,4 +81,54 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
        return false;
 }
 
+/*
+ * Unwind from one frame record (A) to the next frame record (B).
+ *
+ * We terminate early if the location of B indicates a malformed chain of frame
+ * records (e.g. a cycle), determined based on the location and fp value of A
+ * and the location (but not the fp value) of B.
+ */
+static inline int notrace unwind_next(struct unwind_state *state)
+{
+       struct task_struct *tsk = state->task;
+       unsigned long fp = state->fp;
+       struct stack_info info;
+       int err;
+
+       /* Final frame; nothing to unwind */
+       if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
+               return -ENOENT;
+
+       err = unwind_next_common(state, &info, NULL);
+       if (err)
+               return err;
+
+       state->pc = ptrauth_strip_insn_pac(state->pc);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+       if (tsk->ret_stack &&
+               (state->pc == (unsigned long)return_to_handler)) {
+               unsigned long orig_pc;
+               /*
+                * This is a case where function graph tracer has
+                * modified a return address (LR) in a stack frame
+                * to hook a function return.
+                * So replace it to an original value.
+                */
+               orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc,
+                                               (void *)state->fp);
+               if (WARN_ON_ONCE(state->pc == orig_pc))
+                       return -EINVAL;
+               state->pc = orig_pc;
+       }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+#ifdef CONFIG_KRETPROBES
+       if (is_kretprobe_trampoline(state->pc))
+               state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur);
+#endif
+
+       return 0;
+}
+NOKPROBE_SYMBOL(unwind_next);
+
 #endif /* __ASM_STACKTRACE_H */

diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
index b241edba5c76931e123cbf3a0a7bb1faf866f72c..4b632141d91cfdd042539eb07de7ac29be4d0fa2 100644 (file)
--- a/arch/arm64/include/asm/stacktrace/common.h
+++ b/arch/arm64/include/asm/stacktrace/common.h
@@ -9,6 +9,7 @@
 
 #include <linux/bitmap.h>
 #include <linux/bitops.h>
+#include <linux/kprobes.h>
 #include <linux/types.h>
 
 enum stack_type {
@@ -69,6 +70,8 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
                                       unsigned long sp, unsigned long size,
                                       struct stack_info *info);
 
+static inline int unwind_next(struct unwind_state *state);
+
 static inline bool on_stack(unsigned long sp, unsigned long size,
                            unsigned long low, unsigned long high,
                            enum stack_type type, struct stack_info *info)
@@ -191,4 +194,20 @@ static inline int unwind_next_common(struct unwind_state *state,
 
        return 0;
 }
+
+static inline void notrace unwind(struct unwind_state *state,
+                                 stack_trace_consume_fn consume_entry,
+                                 void *cookie)
+{
+       while (1) {
+               int ret;
+
+               if (!consume_entry(cookie, state->pc))
+                       break;
+               ret = unwind_next(state);
+               if (ret < 0)
+                       break;
+       }
+}
+NOKPROBE_SYMBOL(unwind);
 #endif /* __ASM_STACKTRACE_COMMON_H */

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index eef3cf6bf2d7af9ca6df13d3fbfe3a9bb3c35ed2..9fa60ee48499f126e4fa658402d787d348eeac8b 100644 (file)
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -7,14 +7,12 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/ftrace.h>
-#include <linux/kprobes.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
 #include <linux/stacktrace.h>
 
 #include <asm/irq.h>
-#include <asm/pointer_auth.h>
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
@@ -69,71 +67,6 @@ static inline void unwind_init_from_task(struct unwind_state *state,
        state->pc = thread_saved_pc(task);
 }
 
-/*
- * Unwind from one frame record (A) to the next frame record (B).
- *
- * We terminate early if the location of B indicates a malformed chain of frame
- * records (e.g. a cycle), determined based on the location and fp value of A
- * and the location (but not the fp value) of B.
- */
-static int notrace unwind_next(struct unwind_state *state)
-{
-       struct task_struct *tsk = state->task;
-       unsigned long fp = state->fp;
-       struct stack_info info;
-       int err;
-
-       /* Final frame; nothing to unwind */
-       if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
-               return -ENOENT;
-
-       err = unwind_next_common(state, &info, NULL);
-       if (err)
-               return err;
-
-       state->pc = ptrauth_strip_insn_pac(state->pc);
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-       if (tsk->ret_stack &&
-               (state->pc == (unsigned long)return_to_handler)) {
-               unsigned long orig_pc;
-               /*
-                * This is a case where function graph tracer has
-                * modified a return address (LR) in a stack frame
-                * to hook a function return.
-                * So replace it to an original value.
-                */
-               orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc,
-                                               (void *)state->fp);
-               if (WARN_ON_ONCE(state->pc == orig_pc))
-                       return -EINVAL;
-               state->pc = orig_pc;
-       }
-#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-#ifdef CONFIG_KRETPROBES
-       if (is_kretprobe_trampoline(state->pc))
-               state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur);
-#endif
-
-       return 0;
-}
-NOKPROBE_SYMBOL(unwind_next);
-
-static void notrace unwind(struct unwind_state *state,
-                          stack_trace_consume_fn consume_entry, void *cookie)
-{
-       while (1) {
-               int ret;
-
-               if (!consume_entry(cookie, state->pc))
-                       break;
-               ret = unwind_next(state);
-               if (ret < 0)
-                       break;
-       }
-}
-NOKPROBE_SYMBOL(unwind);
-
 static bool dump_backtrace_entry(void *arg, unsigned long where)
 {
        char *loglvl = arg;