Re: [PATCH v8 06/12] unwind_user/sframe: Wire up unwind_user to sframe

From: Josh Poimboeuf <jpoimboe@kernel.org>

Now that the sframe infrastructure is fully in place, make it work by
hooking it up to the unwind_user interface.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
  arch/Kconfig                      |  1 +
  include/linux/unwind_user_types.h |  1 +
  kernel/unwind/user.c              | 25 ++++++++++++++++++++++---
  3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index c54d35e2f860..0c6056ef13de 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig

@@ -448,6 +448,7 @@ config HAVE_UNWIND_USER_COMPAT_FP
  
  config HAVE_UNWIND_USER_SFRAME
  	bool
+	select UNWIND_USER
  
  config HAVE_PERF_REGS
  	bool

diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h
index 0b6563951ca4..4d50476e950e 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h

@@ -13,6 +13,7 @@ enum unwind_user_type {
  	UNWIND_USER_TYPE_NONE,
  	UNWIND_USER_TYPE_FP,
  	UNWIND_USER_TYPE_COMPAT_FP,
+	UNWIND_USER_TYPE_SFRAME,
  };
  
  struct unwind_stacktrace {

diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 249d9e32fad7..6e7ca9f1293a 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c

@@ -7,6 +7,7 @@
  #include <linux/sched/task_stack.h>
  #include <linux/unwind_user.h>
  #include <linux/uaccess.h>
+#include <linux/sframe.h>
  
  static struct unwind_user_frame fp_frame = {
  	ARCH_INIT_USER_FP_FRAME

@@ -31,6 +32,12 @@ static inline bool compat_fp_state(struct unwind_user_state *state)
  	       state->type == UNWIND_USER_TYPE_COMPAT_FP;
  }
  
+static inline bool sframe_state(struct unwind_user_state *state)
+{
+	return IS_ENABLED(CONFIG_HAVE_UNWIND_USER_SFRAME) &&
+	       state->type == UNWIND_USER_TYPE_SFRAME;
+}
+
  #define unwind_get_user_long(to, from, state)				\
  ({									\
  	int __ret;							\

@@ -44,18 +51,28 @@ static inline bool compat_fp_state(struct unwind_user_state *state)
  static int unwind_user_next(struct unwind_user_state *state)
  {
  	struct unwind_user_frame *frame;
+	struct unwind_user_frame _frame;
  	unsigned long cfa = 0, fp, ra = 0;
  	unsigned int shift;
  
  	if (state->done)
  		return -EINVAL;
  
-	if (compat_fp_state(state))
+	if (compat_fp_state(state)) {
  		frame = &compat_fp_frame;
-	else if (fp_state(state))
+	} else if (sframe_state(state)) {
+		/* sframe expects the frame to be local storage */
+		frame = &_frame;
+		if (sframe_find(state->ip, frame)) {
+			if (!IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
+				goto done;
+			frame = &fp_frame;
+		}
+	} else if (fp_state(state)) {
  		frame = &fp_frame;
-	else
+	} else {
  		goto done;
+	}
  
  	if (frame->use_fp) {
  		if (state->fp < state->sp)

@@ -111,6 +128,8 @@ static int unwind_user_start(struct unwind_user_state *state)
  
  	if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_COMPAT_FP) && in_compat_mode(regs))
  		state->type = UNWIND_USER_TYPE_COMPAT_FP;
+	else if (current_has_sframe())
+		state->type = UNWIND_USER_TYPE_SFRAME;