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-rw-r--r--arch/x86/include/asm/unwind.h73
-rw-r--r--arch/x86/kernel/Makefile6
-rw-r--r--arch/x86/kernel/unwind_frame.c93
-rw-r--r--arch/x86/kernel/unwind_guess.c43
4 files changed, 215 insertions, 0 deletions
diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h
new file mode 100644
index 000000000000..c4b6d1cafa46
--- /dev/null
+++ b/arch/x86/include/asm/unwind.h
@@ -0,0 +1,73 @@
1#ifndef _ASM_X86_UNWIND_H
2#define _ASM_X86_UNWIND_H
3
4#include <linux/sched.h>
5#include <linux/ftrace.h>
6#include <asm/ptrace.h>
7#include <asm/stacktrace.h>
8
9struct unwind_state {
10 struct stack_info stack_info;
11 unsigned long stack_mask;
12 struct task_struct *task;
13 int graph_idx;
14#ifdef CONFIG_FRAME_POINTER
15 unsigned long *bp;
16#else
17 unsigned long *sp;
18#endif
19};
20
21void __unwind_start(struct unwind_state *state, struct task_struct *task,
22 struct pt_regs *regs, unsigned long *first_frame);
23
24bool unwind_next_frame(struct unwind_state *state);
25
26static inline bool unwind_done(struct unwind_state *state)
27{
28 return state->stack_info.type == STACK_TYPE_UNKNOWN;
29}
30
31static inline
32void unwind_start(struct unwind_state *state, struct task_struct *task,
33 struct pt_regs *regs, unsigned long *first_frame)
34{
35 first_frame = first_frame ? : get_stack_pointer(task, regs);
36
37 __unwind_start(state, task, regs, first_frame);
38}
39
40#ifdef CONFIG_FRAME_POINTER
41
42static inline
43unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
44{
45 if (unwind_done(state))
46 return NULL;
47
48 return state->bp + 1;
49}
50
51unsigned long unwind_get_return_address(struct unwind_state *state);
52
53#else /* !CONFIG_FRAME_POINTER */
54
55static inline
56unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
57{
58 return NULL;
59}
60
61static inline
62unsigned long unwind_get_return_address(struct unwind_state *state)
63{
64 if (unwind_done(state))
65 return 0;
66
67 return ftrace_graph_ret_addr(state->task, &state->graph_idx,
68 *state->sp, state->sp);
69}
70
71#endif /* CONFIG_FRAME_POINTER */
72
73#endif /* _ASM_X86_UNWIND_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 0503f5bfb18d..45257cf84370 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -125,6 +125,12 @@ obj-$(CONFIG_EFI) += sysfb_efi.o
125obj-$(CONFIG_PERF_EVENTS) += perf_regs.o 125obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
126obj-$(CONFIG_TRACING) += tracepoint.o 126obj-$(CONFIG_TRACING) += tracepoint.o
127 127
128ifdef CONFIG_FRAME_POINTER
129obj-y += unwind_frame.o
130else
131obj-y += unwind_guess.o
132endif
133
128### 134###
129# 64 bit specific files 135# 64 bit specific files
130ifeq ($(CONFIG_X86_64),y) 136ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
new file mode 100644
index 000000000000..a2456d4d286a
--- /dev/null
+++ b/arch/x86/kernel/unwind_frame.c
@@ -0,0 +1,93 @@
1#include <linux/sched.h>
2#include <asm/ptrace.h>
3#include <asm/bitops.h>
4#include <asm/stacktrace.h>
5#include <asm/unwind.h>
6
7#define FRAME_HEADER_SIZE (sizeof(long) * 2)
8
9unsigned long unwind_get_return_address(struct unwind_state *state)
10{
11 unsigned long addr;
12 unsigned long *addr_p = unwind_get_return_address_ptr(state);
13
14 if (unwind_done(state))
15 return 0;
16
17 addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p,
18 addr_p);
19
20 return __kernel_text_address(addr) ? addr : 0;
21}
22EXPORT_SYMBOL_GPL(unwind_get_return_address);
23
24static bool update_stack_state(struct unwind_state *state, void *addr,
25 size_t len)
26{
27 struct stack_info *info = &state->stack_info;
28
29 /*
30 * If addr isn't on the current stack, switch to the next one.
31 *
32 * We may have to traverse multiple stacks to deal with the possibility
33 * that 'info->next_sp' could point to an empty stack and 'addr' could
34 * be on a subsequent stack.
35 */
36 while (!on_stack(info, addr, len))
37 if (get_stack_info(info->next_sp, state->task, info,
38 &state->stack_mask))
39 return false;
40
41 return true;
42}
43
44bool unwind_next_frame(struct unwind_state *state)
45{
46 unsigned long *next_bp;
47
48 if (unwind_done(state))
49 return false;
50
51 next_bp = (unsigned long *)*state->bp;
52
53 /* make sure the next frame's data is accessible */
54 if (!update_stack_state(state, next_bp, FRAME_HEADER_SIZE))
55 return false;
56
57 /* move to the next frame */
58 state->bp = next_bp;
59 return true;
60}
61EXPORT_SYMBOL_GPL(unwind_next_frame);
62
63void __unwind_start(struct unwind_state *state, struct task_struct *task,
64 struct pt_regs *regs, unsigned long *first_frame)
65{
66 memset(state, 0, sizeof(*state));
67 state->task = task;
68
69 /* don't even attempt to start from user mode regs */
70 if (regs && user_mode(regs)) {
71 state->stack_info.type = STACK_TYPE_UNKNOWN;
72 return;
73 }
74
75 /* set up the starting stack frame */
76 state->bp = get_frame_pointer(task, regs);
77
78 /* initialize stack info and make sure the frame data is accessible */
79 get_stack_info(state->bp, state->task, &state->stack_info,
80 &state->stack_mask);
81 update_stack_state(state, state->bp, FRAME_HEADER_SIZE);
82
83 /*
84 * The caller can provide the address of the first frame directly
85 * (first_frame) or indirectly (regs->sp) to indicate which stack frame
86 * to start unwinding at. Skip ahead until we reach it.
87 */
88 while (!unwind_done(state) &&
89 (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
90 state->bp < first_frame))
91 unwind_next_frame(state);
92}
93EXPORT_SYMBOL_GPL(__unwind_start);
diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
new file mode 100644
index 000000000000..b5a834c93065
--- /dev/null
+++ b/arch/x86/kernel/unwind_guess.c
@@ -0,0 +1,43 @@
1#include <linux/sched.h>
2#include <linux/ftrace.h>
3#include <asm/ptrace.h>
4#include <asm/bitops.h>
5#include <asm/stacktrace.h>
6#include <asm/unwind.h>
7
8bool unwind_next_frame(struct unwind_state *state)
9{
10 struct stack_info *info = &state->stack_info;
11
12 if (unwind_done(state))
13 return false;
14
15 do {
16 for (state->sp++; state->sp < info->end; state->sp++)
17 if (__kernel_text_address(*state->sp))
18 return true;
19
20 state->sp = info->next_sp;
21
22 } while (!get_stack_info(state->sp, state->task, info,
23 &state->stack_mask));
24
25 return false;
26}
27EXPORT_SYMBOL_GPL(unwind_next_frame);
28
29void __unwind_start(struct unwind_state *state, struct task_struct *task,
30 struct pt_regs *regs, unsigned long *first_frame)
31{
32 memset(state, 0, sizeof(*state));
33
34 state->task = task;
35 state->sp = first_frame;
36
37 get_stack_info(first_frame, state->task, &state->stack_info,
38 &state->stack_mask);
39
40 if (!__kernel_text_address(*first_frame))
41 unwind_next_frame(state);
42}
43EXPORT_SYMBOL_GPL(__unwind_start);
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