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arm64: stacktrace: Factor out common unwind()

Browse source 
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
This commit is contained in:
Kalesh Singh 2022-07-26 00:37:38 -07:00 committed by Marc Zyngier
parent 5b1b08619f
commit f51e714674
3 changed files with 70 additions and 67 deletions
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51
arch/arm64/include/asm/stacktrace.h
View file

@ -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 */

19
arch/arm64/include/asm/stacktrace/common.h
View file

@ -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 */

67
arch/arm64/kernel/stacktrace.c
View file

@ -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;