[PATCH v12 06/13] unwind_user/sframe: Wire up unwind_user to sframe

[Jens Remus <jremus@linux.ibm.com>]

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.

[ Jens Remus: Remove unused pt_regs from unwind_user_next_common() and
its callers.  Simplify unwind_user_next_sframe(). ]

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Cc: Kees Cook <kees@kernel.org>
Cc: "Carlos O'Donell" <codonell@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---

Notes (jremus):
    Changes in v12:
    - Remove unused pt_regs from unwind_user_next_common() and its
      callers. (Peter)
    - Simplify unwind_user_next_sframe(). (Peter)

 arch/Kconfig                      |  1 +
 include/linux/unwind_user_types.h |  4 +++-
 kernel/unwind/user.c              | 23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index cdb0e72773be..ab1941ef1411 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -491,6 +491,7 @@ config HAVE_UNWIND_USER_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 412729a269bc..43e4b160883f 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h
@@ -9,7 +9,8 @@
  * available.
  */
 enum unwind_user_type_bits {
-	UNWIND_USER_TYPE_FP_BIT =		0,
+	UNWIND_USER_TYPE_SFRAME_BIT =		0,
+	UNWIND_USER_TYPE_FP_BIT =		1,
 
 	NR_UNWIND_USER_TYPE_BITS,
 };
@@ -17,6 +18,7 @@ enum unwind_user_type_bits {
 enum unwind_user_type {
 	/* Type "none" for the start of stack walk iteration. */
 	UNWIND_USER_TYPE_NONE =			0,
+	UNWIND_USER_TYPE_SFRAME =		BIT(UNWIND_USER_TYPE_SFRAME_BIT),
 	UNWIND_USER_TYPE_FP =			BIT(UNWIND_USER_TYPE_FP_BIT),
 };
 
diff --git a/kernel/unwind/user.c b/kernel/unwind/user.c
index 39e270789444..7644ab9f6a61 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>
 
 #define for_each_user_frame(state) \
 	for (unwind_user_start(state); !(state)->done; unwind_user_next(state))
@@ -86,6 +87,16 @@ static int unwind_user_next_fp(struct unwind_user_state *state)
 #endif
 }
 
+static int unwind_user_next_sframe(struct unwind_user_state *state)
+{
+	struct unwind_user_frame frame;
+
+	/* sframe expects the frame to be local storage */
+	if (sframe_find(state->ip, &frame))
+		return -ENOENT;
+	return unwind_user_next_common(state, &frame);
+}
+
 static int unwind_user_next(struct unwind_user_state *state)
 {
 	unsigned long iter_mask = state->available_types;
@@ -99,6 +110,16 @@ static int unwind_user_next(struct unwind_user_state *state)
 
 		state->current_type = type;
 		switch (type) {
+		case UNWIND_USER_TYPE_SFRAME:
+			switch (unwind_user_next_sframe(state)) {
+			case 0:
+				return 0;
+			case -ENOENT:
+				continue;	/* Try next method. */
+			default:
+				state->done = true;
+			}
+			break;
 		case UNWIND_USER_TYPE_FP:
 			if (!unwind_user_next_fp(state))
 				return 0;
@@ -127,6 +148,8 @@ static int unwind_user_start(struct unwind_user_state *state)
 		return -EINVAL;
 	}
 
+	if (current_has_sframe())
+		state->available_types |= UNWIND_USER_TYPE_SFRAME;
 	if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
 		state->available_types |= UNWIND_USER_TYPE_FP;
 
-- 
2.48.1