![Adrian Hunter](/assets/img/avatar_default.png)
Now that the symbol filter is recorded on the machine there is no need to pass it to thread__find_addr_map(). So remove it. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1375961547-30267-9-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
572 lines
13 KiB
C
572 lines
13 KiB
C
/*
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* Post mortem Dwarf CFI based unwinding on top of regs and stack dumps.
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*
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* Lots of this code have been borrowed or heavily inspired from parts of
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* the libunwind 0.99 code which are (amongst other contributors I may have
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* forgotten):
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*
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* Copyright (C) 2002-2007 Hewlett-Packard Co
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* Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
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*
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* And the bugs have been added by:
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*
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* Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com>
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* Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com>
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*
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*/
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#include <elf.h>
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#include <gelf.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <linux/list.h>
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#include <libunwind.h>
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#include <libunwind-ptrace.h>
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#include "thread.h"
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#include "session.h"
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#include "perf_regs.h"
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#include "unwind.h"
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#include "util.h"
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extern int
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UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
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unw_word_t ip,
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unw_dyn_info_t *di,
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unw_proc_info_t *pi,
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int need_unwind_info, void *arg);
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#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
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#define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */
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#define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */
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/* Pointer-encoding formats: */
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#define DW_EH_PE_omit 0xff
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#define DW_EH_PE_ptr 0x00 /* pointer-sized unsigned value */
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#define DW_EH_PE_udata4 0x03 /* unsigned 32-bit value */
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#define DW_EH_PE_udata8 0x04 /* unsigned 64-bit value */
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#define DW_EH_PE_sdata4 0x0b /* signed 32-bit value */
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#define DW_EH_PE_sdata8 0x0c /* signed 64-bit value */
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/* Pointer-encoding application: */
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#define DW_EH_PE_absptr 0x00 /* absolute value */
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#define DW_EH_PE_pcrel 0x10 /* rel. to addr. of encoded value */
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/*
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* The following are not documented by LSB v1.3, yet they are used by
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* GCC, presumably they aren't documented by LSB since they aren't
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* used on Linux:
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*/
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#define DW_EH_PE_funcrel 0x40 /* start-of-procedure-relative */
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#define DW_EH_PE_aligned 0x50 /* aligned pointer */
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/* Flags intentionaly not handled, since they're not needed:
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* #define DW_EH_PE_indirect 0x80
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* #define DW_EH_PE_uleb128 0x01
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* #define DW_EH_PE_udata2 0x02
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* #define DW_EH_PE_sleb128 0x09
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* #define DW_EH_PE_sdata2 0x0a
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* #define DW_EH_PE_textrel 0x20
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* #define DW_EH_PE_datarel 0x30
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*/
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struct unwind_info {
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struct perf_sample *sample;
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struct machine *machine;
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struct thread *thread;
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u64 sample_uregs;
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};
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#define dw_read(ptr, type, end) ({ \
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type *__p = (type *) ptr; \
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type __v; \
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if ((__p + 1) > (type *) end) \
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return -EINVAL; \
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__v = *__p++; \
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ptr = (typeof(ptr)) __p; \
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__v; \
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})
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static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val,
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u8 encoding)
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{
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u8 *cur = *p;
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*val = 0;
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switch (encoding) {
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case DW_EH_PE_omit:
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*val = 0;
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goto out;
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case DW_EH_PE_ptr:
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*val = dw_read(cur, unsigned long, end);
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goto out;
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default:
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break;
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}
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switch (encoding & DW_EH_PE_APPL_MASK) {
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case DW_EH_PE_absptr:
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break;
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case DW_EH_PE_pcrel:
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*val = (unsigned long) cur;
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break;
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default:
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return -EINVAL;
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}
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if ((encoding & 0x07) == 0x00)
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encoding |= DW_EH_PE_udata4;
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switch (encoding & DW_EH_PE_FORMAT_MASK) {
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case DW_EH_PE_sdata4:
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*val += dw_read(cur, s32, end);
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break;
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case DW_EH_PE_udata4:
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*val += dw_read(cur, u32, end);
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break;
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case DW_EH_PE_sdata8:
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*val += dw_read(cur, s64, end);
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break;
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case DW_EH_PE_udata8:
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*val += dw_read(cur, u64, end);
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break;
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default:
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return -EINVAL;
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}
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out:
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*p = cur;
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return 0;
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}
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#define dw_read_encoded_value(ptr, end, enc) ({ \
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u64 __v; \
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if (__dw_read_encoded_value(&ptr, end, &__v, enc)) { \
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return -EINVAL; \
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} \
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__v; \
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})
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static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
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GElf_Shdr *shp, const char *name)
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{
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Elf_Scn *sec = NULL;
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while ((sec = elf_nextscn(elf, sec)) != NULL) {
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char *str;
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gelf_getshdr(sec, shp);
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str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
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if (!strcmp(name, str))
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break;
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}
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return sec;
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}
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static u64 elf_section_offset(int fd, const char *name)
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{
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Elf *elf;
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GElf_Ehdr ehdr;
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GElf_Shdr shdr;
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u64 offset = 0;
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elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
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if (elf == NULL)
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return 0;
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do {
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if (gelf_getehdr(elf, &ehdr) == NULL)
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break;
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if (!elf_section_by_name(elf, &ehdr, &shdr, name))
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break;
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offset = shdr.sh_offset;
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} while (0);
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elf_end(elf);
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return offset;
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}
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struct table_entry {
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u32 start_ip_offset;
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u32 fde_offset;
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};
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struct eh_frame_hdr {
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unsigned char version;
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unsigned char eh_frame_ptr_enc;
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unsigned char fde_count_enc;
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unsigned char table_enc;
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/*
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* The rest of the header is variable-length and consists of the
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* following members:
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*
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* encoded_t eh_frame_ptr;
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* encoded_t fde_count;
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*/
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/* A single encoded pointer should not be more than 8 bytes. */
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u64 enc[2];
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/*
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* struct {
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* encoded_t start_ip;
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* encoded_t fde_addr;
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* } binary_search_table[fde_count];
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*/
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char data[0];
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} __packed;
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static int unwind_spec_ehframe(struct dso *dso, struct machine *machine,
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u64 offset, u64 *table_data, u64 *segbase,
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u64 *fde_count)
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{
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struct eh_frame_hdr hdr;
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u8 *enc = (u8 *) &hdr.enc;
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u8 *end = (u8 *) &hdr.data;
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ssize_t r;
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r = dso__data_read_offset(dso, machine, offset,
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(u8 *) &hdr, sizeof(hdr));
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if (r != sizeof(hdr))
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return -EINVAL;
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/* We dont need eh_frame_ptr, just skip it. */
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dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc);
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*fde_count = dw_read_encoded_value(enc, end, hdr.fde_count_enc);
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*segbase = offset;
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*table_data = (enc - (u8 *) &hdr) + offset;
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return 0;
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}
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static int read_unwind_spec(struct dso *dso, struct machine *machine,
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u64 *table_data, u64 *segbase, u64 *fde_count)
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{
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int ret = -EINVAL, fd;
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u64 offset;
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fd = dso__data_fd(dso, machine);
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if (fd < 0)
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return -EINVAL;
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offset = elf_section_offset(fd, ".eh_frame_hdr");
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close(fd);
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if (offset)
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ret = unwind_spec_ehframe(dso, machine, offset,
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table_data, segbase,
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fde_count);
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/* TODO .debug_frame check if eh_frame_hdr fails */
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return ret;
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}
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static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
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{
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struct addr_location al;
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thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
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MAP__FUNCTION, ip, &al);
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return al.map;
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}
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static int
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find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi,
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int need_unwind_info, void *arg)
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{
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struct unwind_info *ui = arg;
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struct map *map;
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unw_dyn_info_t di;
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u64 table_data, segbase, fde_count;
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map = find_map(ip, ui);
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if (!map || !map->dso)
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return -EINVAL;
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pr_debug("unwind: find_proc_info dso %s\n", map->dso->name);
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if (read_unwind_spec(map->dso, ui->machine,
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&table_data, &segbase, &fde_count))
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return -EINVAL;
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memset(&di, 0, sizeof(di));
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di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
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di.start_ip = map->start;
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di.end_ip = map->end;
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di.u.rti.segbase = map->start + segbase;
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di.u.rti.table_data = map->start + table_data;
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di.u.rti.table_len = fde_count * sizeof(struct table_entry)
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/ sizeof(unw_word_t);
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return dwarf_search_unwind_table(as, ip, &di, pi,
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need_unwind_info, arg);
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}
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static int access_fpreg(unw_addr_space_t __maybe_unused as,
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unw_regnum_t __maybe_unused num,
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unw_fpreg_t __maybe_unused *val,
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int __maybe_unused __write,
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void __maybe_unused *arg)
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{
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pr_err("unwind: access_fpreg unsupported\n");
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return -UNW_EINVAL;
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}
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static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as,
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unw_word_t __maybe_unused *dil_addr,
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void __maybe_unused *arg)
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{
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return -UNW_ENOINFO;
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}
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static int resume(unw_addr_space_t __maybe_unused as,
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unw_cursor_t __maybe_unused *cu,
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void __maybe_unused *arg)
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{
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pr_err("unwind: resume unsupported\n");
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return -UNW_EINVAL;
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}
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static int
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get_proc_name(unw_addr_space_t __maybe_unused as,
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unw_word_t __maybe_unused addr,
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char __maybe_unused *bufp, size_t __maybe_unused buf_len,
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unw_word_t __maybe_unused *offp, void __maybe_unused *arg)
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{
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pr_err("unwind: get_proc_name unsupported\n");
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return -UNW_EINVAL;
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}
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static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
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unw_word_t *data)
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{
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struct addr_location al;
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ssize_t size;
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thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
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MAP__FUNCTION, addr, &al);
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if (!al.map) {
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pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
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return -1;
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}
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if (!al.map->dso)
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return -1;
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size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
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addr, (u8 *) data, sizeof(*data));
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return !(size == sizeof(*data));
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}
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static int reg_value(unw_word_t *valp, struct regs_dump *regs, int id,
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u64 sample_regs)
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{
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int i, idx = 0;
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if (!(sample_regs & (1 << id)))
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return -EINVAL;
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for (i = 0; i < id; i++) {
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if (sample_regs & (1 << i))
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idx++;
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}
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*valp = regs->regs[idx];
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return 0;
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}
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static int access_mem(unw_addr_space_t __maybe_unused as,
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unw_word_t addr, unw_word_t *valp,
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int __write, void *arg)
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{
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struct unwind_info *ui = arg;
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struct stack_dump *stack = &ui->sample->user_stack;
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unw_word_t start, end;
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int offset;
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int ret;
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/* Don't support write, probably not needed. */
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if (__write || !stack || !ui->sample->user_regs.regs) {
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*valp = 0;
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return 0;
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}
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ret = reg_value(&start, &ui->sample->user_regs, PERF_REG_SP,
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ui->sample_uregs);
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if (ret)
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return ret;
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end = start + stack->size;
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/* Check overflow. */
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if (addr + sizeof(unw_word_t) < addr)
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return -EINVAL;
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if (addr < start || addr + sizeof(unw_word_t) >= end) {
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ret = access_dso_mem(ui, addr, valp);
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if (ret) {
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pr_debug("unwind: access_mem %p not inside range %p-%p\n",
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(void *)addr, (void *)start, (void *)end);
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*valp = 0;
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return ret;
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}
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return 0;
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}
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offset = addr - start;
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*valp = *(unw_word_t *)&stack->data[offset];
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pr_debug("unwind: access_mem addr %p, val %lx, offset %d\n",
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(void *)addr, (unsigned long)*valp, offset);
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return 0;
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}
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static int access_reg(unw_addr_space_t __maybe_unused as,
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unw_regnum_t regnum, unw_word_t *valp,
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int __write, void *arg)
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{
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struct unwind_info *ui = arg;
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int id, ret;
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/* Don't support write, I suspect we don't need it. */
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if (__write) {
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pr_err("unwind: access_reg w %d\n", regnum);
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return 0;
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}
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if (!ui->sample->user_regs.regs) {
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*valp = 0;
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return 0;
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}
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id = unwind__arch_reg_id(regnum);
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if (id < 0)
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return -EINVAL;
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ret = reg_value(valp, &ui->sample->user_regs, id, ui->sample_uregs);
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if (ret) {
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pr_err("unwind: can't read reg %d\n", regnum);
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return ret;
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}
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pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp);
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return 0;
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}
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static void put_unwind_info(unw_addr_space_t __maybe_unused as,
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unw_proc_info_t *pi __maybe_unused,
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void *arg __maybe_unused)
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{
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pr_debug("unwind: put_unwind_info called\n");
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}
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static int entry(u64 ip, struct thread *thread, struct machine *machine,
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unwind_entry_cb_t cb, void *arg)
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{
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struct unwind_entry e;
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struct addr_location al;
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thread__find_addr_location(thread, machine,
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PERF_RECORD_MISC_USER,
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MAP__FUNCTION, ip, &al);
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e.ip = ip;
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e.map = al.map;
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e.sym = al.sym;
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pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
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al.sym ? al.sym->name : "''",
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ip,
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al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
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return cb(&e, arg);
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}
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static void display_error(int err)
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{
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switch (err) {
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case UNW_EINVAL:
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pr_err("unwind: Only supports local.\n");
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break;
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case UNW_EUNSPEC:
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pr_err("unwind: Unspecified error.\n");
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break;
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case UNW_EBADREG:
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pr_err("unwind: Register unavailable.\n");
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break;
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default:
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break;
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}
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}
|
|
|
|
static unw_accessors_t accessors = {
|
|
.find_proc_info = find_proc_info,
|
|
.put_unwind_info = put_unwind_info,
|
|
.get_dyn_info_list_addr = get_dyn_info_list_addr,
|
|
.access_mem = access_mem,
|
|
.access_reg = access_reg,
|
|
.access_fpreg = access_fpreg,
|
|
.resume = resume,
|
|
.get_proc_name = get_proc_name,
|
|
};
|
|
|
|
static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
|
|
void *arg)
|
|
{
|
|
unw_addr_space_t addr_space;
|
|
unw_cursor_t c;
|
|
int ret;
|
|
|
|
addr_space = unw_create_addr_space(&accessors, 0);
|
|
if (!addr_space) {
|
|
pr_err("unwind: Can't create unwind address space.\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ret = unw_init_remote(&c, addr_space, ui);
|
|
if (ret)
|
|
display_error(ret);
|
|
|
|
while (!ret && (unw_step(&c) > 0)) {
|
|
unw_word_t ip;
|
|
|
|
unw_get_reg(&c, UNW_REG_IP, &ip);
|
|
ret = entry(ip, ui->thread, ui->machine, cb, arg);
|
|
}
|
|
|
|
unw_destroy_addr_space(addr_space);
|
|
return ret;
|
|
}
|
|
|
|
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
|
|
struct machine *machine, struct thread *thread,
|
|
u64 sample_uregs, struct perf_sample *data)
|
|
{
|
|
unw_word_t ip;
|
|
struct unwind_info ui = {
|
|
.sample = data,
|
|
.sample_uregs = sample_uregs,
|
|
.thread = thread,
|
|
.machine = machine,
|
|
};
|
|
int ret;
|
|
|
|
if (!data->user_regs.regs)
|
|
return -EINVAL;
|
|
|
|
ret = reg_value(&ip, &data->user_regs, PERF_REG_IP, sample_uregs);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = entry(ip, thread, machine, cb, arg);
|
|
if (ret)
|
|
return -ENOMEM;
|
|
|
|
return get_entries(&ui, cb, arg);
|
|
}
|