1 #include <linux/compiler.h>
2 #include <elfutils/libdw.h>
3 #include <elfutils/libdwfl.h>
8 #include "unwind-libdw.h"
11 #include <linux/types.h>
13 #include "perf_regs.h"
14 #include "callchain.h"
17 static char *debuginfo_path
;
19 static const Dwfl_Callbacks offline_callbacks
= {
20 .find_debuginfo
= dwfl_standard_find_debuginfo
,
21 .debuginfo_path
= &debuginfo_path
,
22 .section_address
= dwfl_offline_section_address
,
25 static int __report_module(struct addr_location
*al
, u64 ip
,
26 struct unwind_info
*ui
)
29 struct dso
*dso
= NULL
;
31 thread__find_addr_location(ui
->thread
,
32 PERF_RECORD_MISC_USER
,
33 MAP__FUNCTION
, ip
, al
);
41 mod
= dwfl_addrmodule(ui
->dwfl
, ip
);
43 mod
= dwfl_report_elf(ui
->dwfl
, dso
->short_name
,
44 dso
->long_name
, -1, al
->map
->start
,
47 return mod
&& dwfl_addrmodule(ui
->dwfl
, ip
) == mod
? 0 : -1;
50 static int report_module(u64 ip
, struct unwind_info
*ui
)
52 struct addr_location al
;
54 return __report_module(&al
, ip
, ui
);
58 * Store all entries within entries array,
59 * we will process it after we finish unwind.
61 static int entry(u64 ip
, struct unwind_info
*ui
)
64 struct unwind_entry
*e
= &ui
->entries
[ui
->idx
++];
65 struct addr_location al
;
67 if (__report_module(&al
, ip
, ui
))
74 pr_debug("unwind: %s:ip = 0x%" PRIx64
" (0x%" PRIx64
")\n",
75 al
.sym
? al
.sym
->name
: "''",
77 al
.map
? al
.map
->map_ip(al
.map
, ip
) : (u64
) 0);
81 static pid_t
next_thread(Dwfl
*dwfl
, void *arg
, void **thread_argp
)
83 /* We want only single thread to be processed. */
84 if (*thread_argp
!= NULL
)
88 return dwfl_pid(dwfl
);
91 static int access_dso_mem(struct unwind_info
*ui
, Dwarf_Addr addr
,
94 struct addr_location al
;
97 thread__find_addr_map(ui
->thread
, PERF_RECORD_MISC_USER
,
98 MAP__FUNCTION
, addr
, &al
);
101 * We've seen cases (softice) where DWARF unwinder went
102 * through non executable mmaps, which we need to lookup
103 * in MAP__VARIABLE tree.
105 thread__find_addr_map(ui
->thread
, PERF_RECORD_MISC_USER
,
106 MAP__VARIABLE
, addr
, &al
);
110 pr_debug("unwind: no map for %lx\n", (unsigned long)addr
);
117 size
= dso__data_read_addr(al
.map
->dso
, al
.map
, ui
->machine
,
118 addr
, (u8
*) data
, sizeof(*data
));
120 return !(size
== sizeof(*data
));
123 static bool memory_read(Dwfl
*dwfl __maybe_unused
, Dwarf_Addr addr
, Dwarf_Word
*result
,
126 struct unwind_info
*ui
= arg
;
127 struct stack_dump
*stack
= &ui
->sample
->user_stack
;
132 ret
= perf_reg_value(&start
, &ui
->sample
->user_regs
, PERF_REG_SP
);
136 end
= start
+ stack
->size
;
138 /* Check overflow. */
139 if (addr
+ sizeof(Dwarf_Word
) < addr
)
142 if (addr
< start
|| addr
+ sizeof(Dwarf_Word
) > end
) {
143 ret
= access_dso_mem(ui
, addr
, result
);
145 pr_debug("unwind: access_mem 0x%" PRIx64
" not inside range"
146 " 0x%" PRIx64
"-0x%" PRIx64
"\n",
153 offset
= addr
- start
;
154 *result
= *(Dwarf_Word
*)&stack
->data
[offset
];
155 pr_debug("unwind: access_mem addr 0x%" PRIx64
", val %lx, offset %d\n",
156 addr
, (unsigned long)*result
, offset
);
160 static const Dwfl_Thread_Callbacks callbacks
= {
161 .next_thread
= next_thread
,
162 .memory_read
= memory_read
,
163 .set_initial_registers
= libdw__arch_set_initial_registers
,
167 frame_callback(Dwfl_Frame
*state
, void *arg
)
169 struct unwind_info
*ui
= arg
;
172 if (!dwfl_frame_pc(state
, &pc
, NULL
)) {
173 pr_err("%s", dwfl_errmsg(-1));
174 return DWARF_CB_ABORT
;
177 return entry(pc
, ui
) || !(--ui
->max_stack
) ?
178 DWARF_CB_ABORT
: DWARF_CB_OK
;
181 int unwind__get_entries(unwind_entry_cb_t cb
, void *arg
,
182 struct thread
*thread
,
183 struct perf_sample
*data
,
186 struct unwind_info
*ui
, ui_buf
= {
189 .machine
= thread
->mg
->machine
,
192 .max_stack
= max_stack
,
195 int err
= -EINVAL
, i
;
197 if (!data
->user_regs
.regs
)
200 ui
= zalloc(sizeof(ui_buf
) + sizeof(ui_buf
.entries
[0]) * max_stack
);
206 ui
->dwfl
= dwfl_begin(&offline_callbacks
);
210 err
= perf_reg_value(&ip
, &data
->user_regs
, PERF_REG_IP
);
214 err
= report_module(ip
, ui
);
218 if (!dwfl_attach_state(ui
->dwfl
, EM_NONE
, thread
->tid
, &callbacks
, ui
))
221 err
= dwfl_getthread_frames(ui
->dwfl
, thread
->tid
, frame_callback
, ui
);
223 if (err
&& !ui
->max_stack
)
227 * Display what we got based on the order setup.
229 for (i
= 0; i
< ui
->idx
&& !err
; i
++) {
232 if (callchain_param
.order
== ORDER_CALLER
)
235 err
= ui
->entries
[j
].ip
? ui
->cb(&ui
->entries
[j
], ui
->arg
) : 0;
240 pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));