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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ARM callchain support
4 *
5 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
6 * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
7 *
8 * This code is based on the ARM OProfile backtrace code.
9 */
10#include <linux/perf_event.h>
11#include <linux/uaccess.h>
12
13#include <asm/stacktrace.h>
14
15/*
16 * The registers we're interested in are at the end of the variable
17 * length saved register structure. The fp points at the end of this
18 * structure so the address of this struct is:
19 * (struct frame_tail *)(xxx->fp)-1
20 *
21 * This code has been adapted from the ARM OProfile support.
22 */
23struct frame_tail {
24 struct frame_tail __user *fp;
25 unsigned long sp;
26 unsigned long lr;
27} __attribute__((packed));
28
29/*
30 * Get the return address for a single stackframe and return a pointer to the
31 * next frame tail.
32 */
33static struct frame_tail __user *
34user_backtrace(struct frame_tail __user *tail,
35 struct perf_callchain_entry_ctx *entry)
36{
37 struct frame_tail buftail;
38 unsigned long err;
39
40 if (!access_ok(tail, sizeof(buftail)))
41 return NULL;
42
43 pagefault_disable();
44 err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
45 pagefault_enable();
46
47 if (err)
48 return NULL;
49
50 perf_callchain_store(entry, buftail.lr);
51
52 /*
53 * Frame pointers should strictly progress back up the stack
54 * (towards higher addresses).
55 */
56 if (tail + 1 >= buftail.fp)
57 return NULL;
58
59 return buftail.fp - 1;
60}
61
62void
63perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
64{
65 struct frame_tail __user *tail;
66
67 perf_callchain_store(entry, regs->ARM_pc);
68
69 if (!current->mm)
70 return;
71
72 tail = (struct frame_tail __user *)regs->ARM_fp - 1;
73
74 while ((entry->nr < entry->max_stack) &&
75 tail && !((unsigned long)tail & 0x3))
76 tail = user_backtrace(tail, entry);
77}
78
79/*
80 * Gets called by walk_stackframe() for every stackframe. This will be called
81 * whist unwinding the stackframe and is like a subroutine return so we use
82 * the PC.
83 */
84static bool
85callchain_trace(void *data, unsigned long pc)
86{
87 struct perf_callchain_entry_ctx *entry = data;
88 return perf_callchain_store(entry, pc) == 0;
89}
90
91void
92perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
93{
94 struct stackframe fr;
95
96 arm_get_current_stackframe(regs, &fr);
97 walk_stackframe(&fr, callchain_trace, entry);
98}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ARM callchain support
4 *
5 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
6 * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
7 *
8 * This code is based on the ARM OProfile backtrace code.
9 */
10#include <linux/perf_event.h>
11#include <linux/uaccess.h>
12
13#include <asm/stacktrace.h>
14
15/*
16 * The registers we're interested in are at the end of the variable
17 * length saved register structure. The fp points at the end of this
18 * structure so the address of this struct is:
19 * (struct frame_tail *)(xxx->fp)-1
20 *
21 * This code has been adapted from the ARM OProfile support.
22 */
23struct frame_tail {
24 struct frame_tail __user *fp;
25 unsigned long sp;
26 unsigned long lr;
27} __attribute__((packed));
28
29/*
30 * Get the return address for a single stackframe and return a pointer to the
31 * next frame tail.
32 */
33static struct frame_tail __user *
34user_backtrace(struct frame_tail __user *tail,
35 struct perf_callchain_entry_ctx *entry)
36{
37 struct frame_tail buftail;
38 unsigned long err;
39
40 if (!access_ok(tail, sizeof(buftail)))
41 return NULL;
42
43 pagefault_disable();
44 err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
45 pagefault_enable();
46
47 if (err)
48 return NULL;
49
50 perf_callchain_store(entry, buftail.lr);
51
52 /*
53 * Frame pointers should strictly progress back up the stack
54 * (towards higher addresses).
55 */
56 if (tail + 1 >= buftail.fp)
57 return NULL;
58
59 return buftail.fp - 1;
60}
61
62void
63perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
64{
65 struct frame_tail __user *tail;
66
67 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
68 /* We don't support guest os callchain now */
69 return;
70 }
71
72 perf_callchain_store(entry, regs->ARM_pc);
73
74 if (!current->mm)
75 return;
76
77 tail = (struct frame_tail __user *)regs->ARM_fp - 1;
78
79 while ((entry->nr < entry->max_stack) &&
80 tail && !((unsigned long)tail & 0x3))
81 tail = user_backtrace(tail, entry);
82}
83
84/*
85 * Gets called by walk_stackframe() for every stackframe. This will be called
86 * whist unwinding the stackframe and is like a subroutine return so we use
87 * the PC.
88 */
89static int
90callchain_trace(struct stackframe *fr,
91 void *data)
92{
93 struct perf_callchain_entry_ctx *entry = data;
94 perf_callchain_store(entry, fr->pc);
95 return 0;
96}
97
98void
99perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
100{
101 struct stackframe fr;
102
103 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
104 /* We don't support guest os callchain now */
105 return;
106 }
107
108 arm_get_current_stackframe(regs, &fr);
109 walk_stackframe(&fr, callchain_trace, entry);
110}
111
112unsigned long perf_instruction_pointer(struct pt_regs *regs)
113{
114 if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
115 return perf_guest_cbs->get_guest_ip();
116
117 return instruction_pointer(regs);
118}
119
120unsigned long perf_misc_flags(struct pt_regs *regs)
121{
122 int misc = 0;
123
124 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
125 if (perf_guest_cbs->is_user_mode())
126 misc |= PERF_RECORD_MISC_GUEST_USER;
127 else
128 misc |= PERF_RECORD_MISC_GUEST_KERNEL;
129 } else {
130 if (user_mode(regs))
131 misc |= PERF_RECORD_MISC_USER;
132 else
133 misc |= PERF_RECORD_MISC_KERNEL;
134 }
135
136 return misc;
137}