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Merge branch 'for-next/stacktrace' into for-next/core

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* for-next/stacktrace:
  arm64: stacktrace: factor out kunwind_stack_walk()
  arm64: stacktrace: factor out kernel unwind state
This commit is contained in:
Will Deacon 2024-01-04 12:28:31 +00:00
commit 41cff14b03
3 changed files with 104 additions and 63 deletions
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19
arch/arm64/include/asm/stacktrace/common.h
View File

@ -9,7 +9,6 @@
#ifndef __ASM_STACKTRACE_COMMON_H
#define __ASM_STACKTRACE_COMMON_H
#include <linux/kprobes.h>
#include <linux/types.h>
struct stack_info {
@ -23,12 +22,6 @@ struct stack_info {
* @fp: The fp value in the frame record (or the real fp)
* @pc: The lr value in the frame record (or the real lr)
*
* @kr_cur: When KRETPROBES is selected, holds the kretprobe instance
* associated with the most recently encountered replacement lr
* value.
*
* @task: The task being unwound.
*
* @stack: The stack currently being unwound.
* @stacks: An array of stacks which can be unwound.
* @nr_stacks: The number of stacks in @stacks.
@ -36,10 +29,6 @@ struct stack_info {
struct unwind_state {
unsigned long fp;
unsigned long pc;
#ifdef CONFIG_KRETPROBES
struct llist_node *kr_cur;
#endif
struct task_struct *task;
struct stack_info stack;
struct stack_info *stacks;
@ -66,14 +55,8 @@ static inline bool stackinfo_on_stack(const struct stack_info *info,
return true;
}
static inline void unwind_init_common(struct unwind_state *state,
struct task_struct *task)
static inline void unwind_init_common(struct unwind_state *state)
{
state->task = task;
#ifdef CONFIG_KRETPROBES
state->kr_cur = NULL;
#endif
state->stack = stackinfo_get_unknown();
}

2
arch/arm64/include/asm/stacktrace/nvhe.h
View File

@ -31,7 +31,7 @@ static inline void kvm_nvhe_unwind_init(struct unwind_state *state,
unsigned long fp,
unsigned long pc)
{
unwind_init_common(state, NULL);
unwind_init_common(state);
state->fp = fp;
state->pc = pc;

130
arch/arm64/kernel/stacktrace.c
View File

@ -8,6 +8,7 @@
#include <linux/efi.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>
@ -18,6 +19,31 @@
#include <asm/stack_pointer.h>
#include <asm/stacktrace.h>
/*
* Kernel unwind state
*
* @common: Common unwind state.
* @task: The task being unwound.
* @kr_cur: When KRETPROBES is selected, holds the kretprobe instance
* associated with the most recently encountered replacement lr
* value.
*/
struct kunwind_state {
struct unwind_state common;
struct task_struct *task;
#ifdef CONFIG_KRETPROBES
struct llist_node *kr_cur;
#endif
};
static __always_inline void
kunwind_init(struct kunwind_state *state,
struct task_struct *task)
{
unwind_init_common(&state->common);
state->task = task;
}
/*
* Start an unwind from a pt_regs.
*
@ -26,13 +52,13 @@
* The regs must be on a stack currently owned by the calling task.
*/
static __always_inline void
unwind_init_from_regs(struct unwind_state *state,
kunwind_init_from_regs(struct kunwind_state *state,
struct pt_regs *regs)
{
unwind_init_common(state, current);
kunwind_init(state, current);
state->fp = regs->regs[29];
state->pc = regs->pc;
state->common.fp = regs->regs[29];
state->common.pc = regs->pc;
}
/*
@ -44,12 +70,12 @@ unwind_init_from_regs(struct unwind_state *state,
* The function which invokes this must be noinline.
*/
static __always_inline void
unwind_init_from_caller(struct unwind_state *state)
kunwind_init_from_caller(struct kunwind_state *state)
{
unwind_init_common(state, current);
kunwind_init(state, current);
state->fp = (unsigned long)__builtin_frame_address(1);
state->pc = (unsigned long)__builtin_return_address(0);
state->common.fp = (unsigned long)__builtin_frame_address(1);
state->common.pc = (unsigned long)__builtin_return_address(0);
}
/*
@ -63,35 +89,38 @@ unwind_init_from_caller(struct unwind_state *state)
* call this for the current task.
*/
static __always_inline void
unwind_init_from_task(struct unwind_state *state,
kunwind_init_from_task(struct kunwind_state *state,
struct task_struct *task)
{
unwind_init_common(state, task);
kunwind_init(state, task);
state->fp = thread_saved_fp(task);
state->pc = thread_saved_pc(task);
state->common.fp = thread_saved_fp(task);
state->common.pc = thread_saved_pc(task);
}
static __always_inline int
unwind_recover_return_address(struct unwind_state *state)
kunwind_recover_return_address(struct kunwind_state *state)
{
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (state->task->ret_stack &&
(state->pc == (unsigned long)return_to_handler)) {
(state->common.pc == (unsigned long)return_to_handler)) {
unsigned long orig_pc;
orig_pc = ftrace_graph_ret_addr(state->task, NULL, state->pc,
(void *)state->fp);
if (WARN_ON_ONCE(state->pc == orig_pc))
orig_pc = ftrace_graph_ret_addr(state->task, NULL,
state->common.pc,
(void *)state->common.fp);
if (WARN_ON_ONCE(state->common.pc == orig_pc))
return -EINVAL;
state->pc = orig_pc;
state->common.pc = orig_pc;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef CONFIG_KRETPROBES
if (is_kretprobe_trampoline(state->pc)) {
state->pc = kretprobe_find_ret_addr(state->task,
(void *)state->fp,
if (is_kretprobe_trampoline(state->common.pc)) {
unsigned long orig_pc;
orig_pc = kretprobe_find_ret_addr(state->task,
(void *)state->common.fp,
&state->kr_cur);
state->common.pc = orig_pc;
}
#endif /* CONFIG_KRETPROBES */
@ -106,38 +135,40 @@ unwind_recover_return_address(struct unwind_state *state)
* and the location (but not the fp value) of B.
*/
static __always_inline int
unwind_next(struct unwind_state *state)
kunwind_next(struct kunwind_state *state)
{
struct task_struct *tsk = state->task;
unsigned long fp = state->fp;
unsigned long fp = state->common.fp;
int err;
/* Final frame; nothing to unwind */
if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
return -ENOENT;
err = unwind_next_frame_record(state);
err = unwind_next_frame_record(&state->common);
if (err)
return err;
state->pc = ptrauth_strip_kernel_insn_pac(state->pc);
state->common.pc = ptrauth_strip_kernel_insn_pac(state->common.pc);
return unwind_recover_return_address(state);
return kunwind_recover_return_address(state);
}
typedef bool (*kunwind_consume_fn)(const struct kunwind_state *state, void *cookie);
static __always_inline void
unwind(struct unwind_state *state, stack_trace_consume_fn consume_entry,
do_kunwind(struct kunwind_state *state, kunwind_consume_fn consume_state,
void *cookie)
{
if (unwind_recover_return_address(state))
if (kunwind_recover_return_address(state))
return;
while (1) {
int ret;
if (!consume_entry(cookie, state->pc))
if (!consume_state(state, cookie))
break;
ret = unwind_next(state);
ret = kunwind_next(state);
if (ret < 0)
break;
}
@ -172,7 +203,8 @@ unwind(struct unwind_state *state, stack_trace_consume_fn consume_entry,
: stackinfo_get_unknown(); \
})
noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
static __always_inline void
kunwind_stack_walk(kunwind_consume_fn consume_state,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{
@ -190,22 +222,48 @@ noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
STACKINFO_EFI,
#endif
};
struct unwind_state state = {
struct kunwind_state state = {
.common = {
.stacks = stacks,
.nr_stacks = ARRAY_SIZE(stacks),
},
};
if (regs) {
if (task != current)
return;
unwind_init_from_regs(&state, regs);
kunwind_init_from_regs(&state, regs);
} else if (task == current) {
unwind_init_from_caller(&state);
kunwind_init_from_caller(&state);
} else {
unwind_init_from_task(&state, task);
kunwind_init_from_task(&state, task);
}
unwind(&state, consume_entry, cookie);
do_kunwind(&state, consume_state, cookie);
}
struct kunwind_consume_entry_data {
stack_trace_consume_fn consume_entry;
void *cookie;
};
static bool
arch_kunwind_consume_entry(const struct kunwind_state *state, void *cookie)
{
struct kunwind_consume_entry_data *data = cookie;
return data->consume_entry(data->cookie, state->common.pc);
}
noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{
struct kunwind_consume_entry_data data = {
.consume_entry = consume_entry,
.cookie = cookie,
};
kunwind_stack_walk(arch_kunwind_consume_entry, &data, task, regs);
}
static bool dump_backtrace_entry(void *arg, unsigned long where)