[PATCH v4 22/39] unwind_user/sframe: Wire up unwind_user to sframe

Josh Poimboeuf
2025-01-22T02:32:15Z

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>
---
arch/Kconfig | 1 +
include/linux/unwind_user_types.h | 1 +
kernel/unwind/user.c | 22 +++++++++++++++++++---
3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 23edd0e4e16a..12a3b73cbe66 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 AS_SFRAME
def_bool $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc)
diff --git a/include/linux/unwind_user_types.h b/include/linux/unwind_user_types.h
index 3ec4a097a3dd..5558558948b7 100644
--- a/include/linux/unwind_user_types.h
+++ b/include/linux/unwind_user_types.h
@@ -9,6 +9,7 @@ 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 92963f129c6a..fc0c75da81f6 100644
--- a/kernel/unwind/user.c
+++ b/kernel/unwind/user.c
@@ -6,6 +6,7 @@
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/unwind_user.h>
+#include <linux/sframe.h>
#include <linux/uaccess.h>
#include <asm/unwind_user.h>

@@ -29,6 +30,12 @@ static inline bool compat_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; \
@@ -48,12 +55,19 @@ int unwind_user_next(struct unwind_user_state *state)
if (state->done)
return -EINVAL;

- if (compat_state(state))
+ if (compat_state(state)) {
frame = &compat_fp_frame;
- else if (fp_state(state))
+ } else if (sframe_state(state)) {
+ if (sframe_find(state->ip, frame)) {
+ if (!IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
+ goto the_end;
+ frame = &fp_frame;
+ }
+ } else if (fp_state(state)) {
frame = &fp_frame;
- else
+ } else {
goto the_end;
+ }

cfa = (frame->use_fp ? state->fp : state->sp) + frame->cfa_off;

@@ -94,6 +108,8 @@ 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;
else if (IS_ENABLED(CONFIG_HAVE_UNWIND_USER_FP))
state->type = UNWIND_USER_TYPE_FP;
else
--
2.48.1