Contributors: 25
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Mark Rutland |
450 |
28.09% |
16 |
24.62% |
| Madhavan T. Venkataraman |
203 |
12.67% |
6 |
9.23% |
| Will Deacon |
197 |
12.30% |
4 |
6.15% |
| Catalin Marinas |
155 |
9.68% |
1 |
1.54% |
| Jean Pihet |
109 |
6.80% |
1 |
1.54% |
| Puranjay Mohan |
91 |
5.68% |
3 |
4.62% |
| Qiwu Chen |
85 |
5.31% |
1 |
1.54% |
| Marc Zyngier |
68 |
4.24% |
2 |
3.08% |
| Mark Brown |
51 |
3.18% |
4 |
6.15% |
| Masami Hiramatsu |
44 |
2.75% |
4 |
6.15% |
| AKASHI Takahiro |
39 |
2.43% |
4 |
6.15% |
| Ard Biesheuvel |
25 |
1.56% |
2 |
3.08% |
| Dmitry Safonov |
18 |
1.12% |
3 |
4.62% |
| Pratyush Anand |
17 |
1.06% |
2 |
3.08% |
| Mark Salter |
11 |
0.69% |
1 |
1.54% |
| Kalesh Singh |
8 |
0.50% |
1 |
1.54% |
| Steven Rostedt |
8 |
0.50% |
1 |
1.54% |
| Dave P Martin |
7 |
0.44% |
1 |
1.54% |
| Ingo Molnar |
6 |
0.37% |
2 |
3.08% |
| Rohit Thapliyal |
3 |
0.19% |
1 |
1.54% |
| Yang Shi |
2 |
0.12% |
1 |
1.54% |
| Thomas Gleixner |
2 |
0.12% |
1 |
1.54% |
| Prakash Gupta |
1 |
0.06% |
1 |
1.54% |
| Peter Collingbourne |
1 |
0.06% |
1 |
1.54% |
| Stephen Boyd |
1 |
0.06% |
1 |
1.54% |
| Total |
1602 |
|
65 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Stack tracing support
*
* Copyright (C) 2012 ARM Ltd.
*/
#include <linux/kernel.h>
#include <linux/efi.h>
#include <linux/export.h>
#include <linux/filter.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/efi.h>
#include <asm/irq.h>
#include <asm/stack_pointer.h>
#include <asm/stacktrace.h>
/*
* Kernel unwind state
*
* @common: Common unwind state.
* @task: The task being unwound.
* @graph_idx: Used by ftrace_graph_ret_addr() for optimized stack unwinding.
* @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;
int graph_idx;
#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.
*
* The unwind will begin at the PC within the regs.
*
* The regs must be on a stack currently owned by the calling task.
*/
static __always_inline void
kunwind_init_from_regs(struct kunwind_state *state,
struct pt_regs *regs)
{
kunwind_init(state, current);
state->common.fp = regs->regs[29];
state->common.pc = regs->pc;
}
/*
* Start an unwind from a caller.
*
* The unwind will begin at the caller of whichever function this is inlined
* into.
*
* The function which invokes this must be noinline.
*/
static __always_inline void
kunwind_init_from_caller(struct kunwind_state *state)
{
kunwind_init(state, current);
state->common.fp = (unsigned long)__builtin_frame_address(1);
state->common.pc = (unsigned long)__builtin_return_address(0);
}
/*
* Start an unwind from a blocked task.
*
* The unwind will begin at the blocked tasks saved PC (i.e. the caller of
* cpu_switch_to()).
*
* The caller should ensure the task is blocked in cpu_switch_to() for the
* duration of the unwind, or the unwind will be bogus. It is never valid to
* call this for the current task.
*/
static __always_inline void
kunwind_init_from_task(struct kunwind_state *state,
struct task_struct *task)
{
kunwind_init(state, task);
state->common.fp = thread_saved_fp(task);
state->common.pc = thread_saved_pc(task);
}
static __always_inline int
kunwind_recover_return_address(struct kunwind_state *state)
{
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (state->task->ret_stack &&
(state->common.pc == (unsigned long)return_to_handler)) {
unsigned long orig_pc;
orig_pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
state->common.pc,
(void *)state->common.fp);
if (WARN_ON_ONCE(state->common.pc == orig_pc))
return -EINVAL;
state->common.pc = orig_pc;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef CONFIG_KRETPROBES
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 */
return 0;
}
/*
* 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 __always_inline int
kunwind_next(struct kunwind_state *state)
{
struct task_struct *tsk = state->task;
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->common);
if (err)
return err;
state->common.pc = ptrauth_strip_kernel_insn_pac(state->common.pc);
return kunwind_recover_return_address(state);
}
typedef bool (*kunwind_consume_fn)(const struct kunwind_state *state, void *cookie);
static __always_inline void
do_kunwind(struct kunwind_state *state, kunwind_consume_fn consume_state,
void *cookie)
{
if (kunwind_recover_return_address(state))
return;
while (1) {
int ret;
if (!consume_state(state, cookie))
break;
ret = kunwind_next(state);
if (ret < 0)
break;
}
}
/*
* Per-cpu stacks are only accessible when unwinding the current task in a
* non-preemptible context.
*/
#define STACKINFO_CPU(name) \
({ \
((task == current) && !preemptible()) \
? stackinfo_get_##name() \
: stackinfo_get_unknown(); \
})
/*
* SDEI stacks are only accessible when unwinding the current task in an NMI
* context.
*/
#define STACKINFO_SDEI(name) \
({ \
((task == current) && in_nmi()) \
? stackinfo_get_sdei_##name() \
: stackinfo_get_unknown(); \
})
#define STACKINFO_EFI \
({ \
((task == current) && current_in_efi()) \
? stackinfo_get_efi() \
: stackinfo_get_unknown(); \
})
static __always_inline void
kunwind_stack_walk(kunwind_consume_fn consume_state,
void *cookie, struct task_struct *task,
struct pt_regs *regs)
{
struct stack_info stacks[] = {
stackinfo_get_task(task),
STACKINFO_CPU(irq),
#if defined(CONFIG_VMAP_STACK)
STACKINFO_CPU(overflow),
#endif
#if defined(CONFIG_VMAP_STACK) && defined(CONFIG_ARM_SDE_INTERFACE)
STACKINFO_SDEI(normal),
STACKINFO_SDEI(critical),
#endif
#ifdef CONFIG_EFI
STACKINFO_EFI,
#endif
};
struct kunwind_state state = {
.common = {
.stacks = stacks,
.nr_stacks = ARRAY_SIZE(stacks),
},
};
if (regs) {
if (task != current)
return;
kunwind_init_from_regs(&state, regs);
} else if (task == current) {
kunwind_init_from_caller(&state);
} else {
kunwind_init_from_task(&state, task);
}
do_kunwind(&state, consume_state, cookie);
}
struct kunwind_consume_entry_data {
stack_trace_consume_fn consume_entry;
void *cookie;
};
static __always_inline 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);
}
struct bpf_unwind_consume_entry_data {
bool (*consume_entry)(void *cookie, u64 ip, u64 sp, u64 fp);
void *cookie;
};
static bool
arch_bpf_unwind_consume_entry(const struct kunwind_state *state, void *cookie)
{
struct bpf_unwind_consume_entry_data *data = cookie;
return data->consume_entry(data->cookie, state->common.pc, 0,
state->common.fp);
}
noinline noinstr void arch_bpf_stack_walk(bool (*consume_entry)(void *cookie, u64 ip, u64 sp,
u64 fp), void *cookie)
{
struct bpf_unwind_consume_entry_data data = {
.consume_entry = consume_entry,
.cookie = cookie,
};
kunwind_stack_walk(arch_bpf_unwind_consume_entry, &data, current, NULL);
}
static bool dump_backtrace_entry(void *arg, unsigned long where)
{
char *loglvl = arg;
printk("%s %pSb\n", loglvl, (void *)where);
return true;
}
void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
const char *loglvl)
{
pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
if (regs && user_mode(regs))
return;
if (!tsk)
tsk = current;
if (!try_get_task_stack(tsk))
return;
printk("%sCall trace:\n", loglvl);
arch_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs);
put_task_stack(tsk);
}
void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
{
dump_backtrace(NULL, tsk, loglvl);
barrier();
}
/*
* The struct defined for userspace stack frame in AARCH64 mode.
*/
struct frame_tail {
struct frame_tail __user *fp;
unsigned long lr;
} __attribute__((packed));
/*
* Get the return address for a single stackframe and return a pointer to the
* next frame tail.
*/
static struct frame_tail __user *
unwind_user_frame(struct frame_tail __user *tail, void *cookie,
stack_trace_consume_fn consume_entry)
{
struct frame_tail buftail;
unsigned long err;
unsigned long lr;
/* Also check accessibility of one struct frame_tail beyond */
if (!access_ok(tail, sizeof(buftail)))
return NULL;
pagefault_disable();
err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
pagefault_enable();
if (err)
return NULL;
lr = ptrauth_strip_user_insn_pac(buftail.lr);
if (!consume_entry(cookie, lr))
return NULL;
/*
* Frame pointers should strictly progress back up the stack
* (towards higher addresses).
*/
if (tail >= buftail.fp)
return NULL;
return buftail.fp;
}
#ifdef CONFIG_COMPAT
/*
* The registers we're interested in are at the end of the variable
* length saved register structure. The fp points at the end of this
* structure so the address of this struct is:
* (struct compat_frame_tail *)(xxx->fp)-1
*
* This code has been adapted from the ARM OProfile support.
*/
struct compat_frame_tail {
compat_uptr_t fp; /* a (struct compat_frame_tail *) in compat mode */
u32 sp;
u32 lr;
} __attribute__((packed));
static struct compat_frame_tail __user *
unwind_compat_user_frame(struct compat_frame_tail __user *tail, void *cookie,
stack_trace_consume_fn consume_entry)
{
struct compat_frame_tail buftail;
unsigned long err;
/* Also check accessibility of one struct frame_tail beyond */
if (!access_ok(tail, sizeof(buftail)))
return NULL;
pagefault_disable();
err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
pagefault_enable();
if (err)
return NULL;
if (!consume_entry(cookie, buftail.lr))
return NULL;
/*
* Frame pointers should strictly progress back up the stack
* (towards higher addresses).
*/
if (tail + 1 >= (struct compat_frame_tail __user *)
compat_ptr(buftail.fp))
return NULL;
return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1;
}
#endif /* CONFIG_COMPAT */
void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
const struct pt_regs *regs)
{
if (!consume_entry(cookie, regs->pc))
return;
if (!compat_user_mode(regs)) {
/* AARCH64 mode */
struct frame_tail __user *tail;
tail = (struct frame_tail __user *)regs->regs[29];
while (tail && !((unsigned long)tail & 0x7))
tail = unwind_user_frame(tail, cookie, consume_entry);
} else {
#ifdef CONFIG_COMPAT
/* AARCH32 compat mode */
struct compat_frame_tail __user *tail;
tail = (struct compat_frame_tail __user *)regs->compat_fp - 1;
while (tail && !((unsigned long)tail & 0x3))
tail = unwind_compat_user_frame(tail, cookie, consume_entry);
#endif
}
}