2 * arm64 callchain support
4 * Copyright (C) 2015 ARM Limited
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 #include <linux/perf_event.h>
19 #include <linux/uaccess.h>
21 #include <asm/stacktrace.h>
24 struct frame_tail __user *fp;
26 } __attribute__((packed));
29 * Get the return address for a single stackframe and return a pointer to the
32 static struct frame_tail __user *
33 user_backtrace(struct frame_tail __user *tail,
34 struct perf_callchain_entry_ctx *entry)
36 struct frame_tail buftail;
39 /* Also check accessibility of one struct frame_tail beyond */
40 if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
44 err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
50 perf_callchain_store(entry, buftail.lr);
53 * Frame pointers should strictly progress back up the stack
54 * (towards higher addresses).
56 if (tail >= buftail.fp)
64 * The registers we're interested in are at the end of the variable
65 * length saved register structure. The fp points at the end of this
66 * structure so the address of this struct is:
67 * (struct compat_frame_tail *)(xxx->fp)-1
69 * This code has been adapted from the ARM OProfile support.
71 struct compat_frame_tail {
72 compat_uptr_t fp; /* a (struct compat_frame_tail *) in compat mode */
75 } __attribute__((packed));
77 static struct compat_frame_tail __user *
78 compat_user_backtrace(struct compat_frame_tail __user *tail,
79 struct perf_callchain_entry_ctx *entry)
81 struct compat_frame_tail buftail;
84 /* Also check accessibility of one struct frame_tail beyond */
85 if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
89 err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
95 perf_callchain_store(entry, buftail.lr);
98 * Frame pointers should strictly progress back up the stack
99 * (towards higher addresses).
101 if (tail + 1 >= (struct compat_frame_tail __user *)
102 compat_ptr(buftail.fp))
105 return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1;
107 #endif /* CONFIG_COMPAT */
109 void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
110 struct pt_regs *regs)
112 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
113 /* We don't support guest os callchain now */
117 perf_callchain_store(entry, regs->pc);
119 if (!compat_user_mode(regs)) {
121 struct frame_tail __user *tail;
123 tail = (struct frame_tail __user *)regs->regs[29];
125 while (entry->nr < entry->max_stack &&
126 tail && !((unsigned long)tail & 0xf))
127 tail = user_backtrace(tail, entry);
130 /* AARCH32 compat mode */
131 struct compat_frame_tail __user *tail;
133 tail = (struct compat_frame_tail __user *)regs->compat_fp - 1;
135 while ((entry->nr < entry->max_stack) &&
136 tail && !((unsigned long)tail & 0x3))
137 tail = compat_user_backtrace(tail, entry);
143 * Gets called by walk_stackframe() for every stackframe. This will be called
144 * whist unwinding the stackframe and is like a subroutine return so we use
147 static int callchain_trace(struct stackframe *frame, void *data)
149 struct perf_callchain_entry_ctx *entry = data;
150 perf_callchain_store(entry, frame->pc);
154 void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
155 struct pt_regs *regs)
157 struct stackframe frame;
159 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
160 /* We don't support guest os callchain now */
164 frame.fp = regs->regs[29];
167 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
168 frame.graph = current->curr_ret_stack;
171 walk_stackframe(current, &frame, callchain_trace, entry);
174 unsigned long perf_instruction_pointer(struct pt_regs *regs)
176 if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
177 return perf_guest_cbs->get_guest_ip();
179 return instruction_pointer(regs);
182 unsigned long perf_misc_flags(struct pt_regs *regs)
186 if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
187 if (perf_guest_cbs->is_user_mode())
188 misc |= PERF_RECORD_MISC_GUEST_USER;
190 misc |= PERF_RECORD_MISC_GUEST_KERNEL;
193 misc |= PERF_RECORD_MISC_USER;
195 misc |= PERF_RECORD_MISC_KERNEL;