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linux_dsm_epyc7002/tools/perf/util/symbol-elf.c
Adrian Hunter 61f82e3fb6 perf kcore_copy: Fix module map when there are no modules loaded 
In the absence of any modules, no "modules" map is created, but there
are other executable pages to map, due to eBPF JIT, kprobe or ftrace.
Map them by recognizing that the first "module" symbol is not
necessarily from a module, and adjust the map accordingly.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20200512121922.8997-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-05-28 10:03:28 -03:00

2311 lines
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// SPDX-License-Identifier: GPL-2.0
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>
#include "dso.h"
#include "map.h"
#include "maps.h"
#include "symbol.h"
#include "symsrc.h"
#include "demangle-java.h"
#include "demangle-rust.h"
#include "machine.h"
#include "vdso.h"
#include "debug.h"
#include "util/copyfile.h"
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <symbol/kallsyms.h>
#include <internal/lib.h>
#ifndef EM_AARCH64
#define EM_AARCH64 183 /* ARM 64 bit */
#endif
#ifndef ELF32_ST_VISIBILITY
#define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
#endif
/* For ELF64 the definitions are the same. */
#ifndef ELF64_ST_VISIBILITY
#define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
#endif
/* How to extract information held in the st_other field. */
#ifndef GELF_ST_VISIBILITY
#define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
#endif
typedef Elf64_Nhdr GElf_Nhdr;
#ifndef DMGL_PARAMS
#define DMGL_NO_OPTS 0 /* For readability... */
#define DMGL_PARAMS (1 << 0) /* Include function args */
#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
#endif
#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
extern char *cplus_demangle(const char *, int);
static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
{
return cplus_demangle(c, i);
}
#else
#ifdef NO_DEMANGLE
static inline char *bfd_demangle(void __maybe_unused *v,
const char __maybe_unused *c,
int __maybe_unused i)
{
return NULL;
}
#else
#define PACKAGE 'perf'
#include <bfd.h>
#endif
#endif
#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
static int elf_getphdrnum(Elf *elf, size_t *dst)
{
GElf_Ehdr gehdr;
GElf_Ehdr *ehdr;
ehdr = gelf_getehdr(elf, &gehdr);
if (!ehdr)
return -1;
*dst = ehdr->e_phnum;
return 0;
}
#endif
#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
{
pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
return -1;
}
#endif
#ifndef NT_GNU_BUILD_ID
#define NT_GNU_BUILD_ID 3
#endif
/**
* elf_symtab__for_each_symbol - iterate thru all the symbols
*
* @syms: struct elf_symtab instance to iterate
* @idx: uint32_t idx
* @sym: GElf_Sym iterator
*/
#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
for (idx = 0, gelf_getsym(syms, idx, &sym);\
idx < nr_syms; \
idx++, gelf_getsym(syms, idx, &sym))
static inline uint8_t elf_sym__type(const GElf_Sym *sym)
{
return GELF_ST_TYPE(sym->st_info);
}
static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
{
return GELF_ST_VISIBILITY(sym->st_other);
}
#ifndef STT_GNU_IFUNC
#define STT_GNU_IFUNC 10
#endif
static inline int elf_sym__is_function(const GElf_Sym *sym)
{
return (elf_sym__type(sym) == STT_FUNC ||
elf_sym__type(sym) == STT_GNU_IFUNC) &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF;
}
static inline bool elf_sym__is_object(const GElf_Sym *sym)
{
return elf_sym__type(sym) == STT_OBJECT &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF;
}
static inline int elf_sym__is_label(const GElf_Sym *sym)
{
return elf_sym__type(sym) == STT_NOTYPE &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF &&
sym->st_shndx != SHN_ABS &&
elf_sym__visibility(sym) != STV_HIDDEN &&
elf_sym__visibility(sym) != STV_INTERNAL;
}
static bool elf_sym__filter(GElf_Sym *sym)
{
return elf_sym__is_function(sym) || elf_sym__is_object(sym);
}
static inline const char *elf_sym__name(const GElf_Sym *sym,
const Elf_Data *symstrs)
{
return symstrs->d_buf + sym->st_name;
}
static inline const char *elf_sec__name(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return secstrs->d_buf + shdr->sh_name;
}
static inline int elf_sec__is_text(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
}
static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
}
static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
{
return elf_sec__is_text(shdr, secstrs) ||
elf_sec__is_data(shdr, secstrs);
}
static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
{
Elf_Scn *sec = NULL;
GElf_Shdr shdr;
size_t cnt = 1;
while ((sec = elf_nextscn(elf, sec)) != NULL) {
gelf_getshdr(sec, &shdr);
if ((addr >= shdr.sh_addr) &&
(addr < (shdr.sh_addr + shdr.sh_size)))
return cnt;
++cnt;
}
return -1;
}
Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
GElf_Shdr *shp, const char *name, size_t *idx)
{
Elf_Scn *sec = NULL;
size_t cnt = 1;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
return NULL;
while ((sec = elf_nextscn(elf, sec)) != NULL) {
char *str;
gelf_getshdr(sec, shp);
str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
if (str && !strcmp(name, str)) {
if (idx)
*idx = cnt;
return sec;
}
++cnt;
}
return NULL;
}
static bool want_demangle(bool is_kernel_sym)
{
return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
}
static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
{
int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
char *demangled = NULL;
/*
* We need to figure out if the object was created from C++ sources
* DWARF DW_compile_unit has this, but we don't always have access
* to it...
*/
if (!want_demangle(dso->kernel || kmodule))
return demangled;
demangled = bfd_demangle(NULL, elf_name, demangle_flags);
if (demangled == NULL)
demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
else if (rust_is_mangled(demangled))
/*
* Input to Rust demangling is the BFD-demangled
* name which it Rust-demangles in place.
*/
rust_demangle_sym(demangled);
return demangled;
}
#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
idx < nr_entries; \
++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
idx < nr_entries; \
++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
/*
* We need to check if we have a .dynsym, so that we can handle the
* .plt, synthesizing its symbols, that aren't on the symtabs (be it
* .dynsym or .symtab).
* And always look at the original dso, not at debuginfo packages, that
* have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
*/
int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
{
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
u64 plt_offset, plt_header_size, plt_entry_size;
GElf_Shdr shdr_plt;
struct symbol *f;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
Elf_Data *reldata, *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
Elf *elf;
int nr = 0, symidx, err = 0;
if (!ss->dynsym)
return 0;
elf = ss->elf;
ehdr = ss->ehdr;
scn_dynsym = ss->dynsym;
shdr_dynsym = ss->dynshdr;
dynsym_idx = ss->dynsym_idx;
if (scn_dynsym == NULL)
goto out_elf_end;
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rela.plt", NULL);
if (scn_plt_rel == NULL) {
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rel.plt", NULL);
if (scn_plt_rel == NULL)
goto out_elf_end;
}
err = -1;
if (shdr_rel_plt.sh_link != dynsym_idx)
goto out_elf_end;
if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
goto out_elf_end;
/*
* Fetch the relocation section to find the idxes to the GOT
* and the symbols in the .dynsym they refer to.
*/
reldata = elf_getdata(scn_plt_rel, NULL);
if (reldata == NULL)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
if (syms == NULL)
goto out_elf_end;
scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
if (scn_symstrs == NULL)
goto out_elf_end;
symstrs = elf_getdata(scn_symstrs, NULL);
if (symstrs == NULL)
goto out_elf_end;
if (symstrs->d_size == 0)
goto out_elf_end;
nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
switch (ehdr.e_machine) {
case EM_ARM:
plt_header_size = 20;
plt_entry_size = 12;
break;
case EM_AARCH64:
plt_header_size = 32;
plt_entry_size = 16;
break;
case EM_SPARC:
plt_header_size = 48;
plt_entry_size = 12;
break;
case EM_SPARCV9:
plt_header_size = 128;
plt_entry_size = 32;
break;
default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
plt_header_size = shdr_plt.sh_entsize;
plt_entry_size = shdr_plt.sh_entsize;
break;
}
plt_offset += plt_header_size;
if (shdr_rel_plt.sh_type == SHT_RELA) {
GElf_Rela pos_mem, *pos;
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
const char *elf_name = NULL;
char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
gelf_getsym(syms, symidx, &sym);
elf_name = elf_sym__name(&sym, symstrs);
demangled = demangle_sym(dso, 0, elf_name);
if (demangled != NULL)
elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_name);
free(demangled);
f = symbol__new(plt_offset, plt_entry_size,
STB_GLOBAL, STT_FUNC, sympltname);
if (!f)
goto out_elf_end;
plt_offset += plt_entry_size;
symbols__insert(&dso->symbols, f);
++nr;
}
} else if (shdr_rel_plt.sh_type == SHT_REL) {
GElf_Rel pos_mem, *pos;
elf_section__for_each_rel(reldata, pos, pos_mem, idx,
nr_rel_entries) {
const char *elf_name = NULL;
char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
gelf_getsym(syms, symidx, &sym);
elf_name = elf_sym__name(&sym, symstrs);
demangled = demangle_sym(dso, 0, elf_name);
if (demangled != NULL)
elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_name);
free(demangled);
f = symbol__new(plt_offset, plt_entry_size,
STB_GLOBAL, STT_FUNC, sympltname);
if (!f)
goto out_elf_end;
plt_offset += plt_entry_size;
symbols__insert(&dso->symbols, f);
++nr;
}
}
err = 0;
out_elf_end:
if (err == 0)
return nr;
pr_debug("%s: problems reading %s PLT info.\n",
__func__, dso->long_name);
return 0;
}
char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
{
return demangle_sym(dso, kmodule, elf_name);
}
/*
* Align offset to 4 bytes as needed for note name and descriptor data.
*/
#define NOTE_ALIGN(n) (((n) + 3) & -4U)
static int elf_read_build_id(Elf *elf, void *bf, size_t size)
{
int err = -1;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Data *data;
Elf_Scn *sec;
Elf_Kind ek;
void *ptr;
if (size < BUILD_ID_SIZE)
goto out;
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out;
if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
goto out;
}
/*
* Check following sections for notes:
* '.note.gnu.build-id'
* '.notes'
* '.note' (VDSO specific)
*/
do {
sec = elf_section_by_name(elf, &ehdr, &shdr,
".note.gnu.build-id", NULL);
if (sec)
break;
sec = elf_section_by_name(elf, &ehdr, &shdr,
".notes", NULL);
if (sec)
break;
sec = elf_section_by_name(elf, &ehdr, &shdr,
".note", NULL);
if (sec)
break;
return err;
} while (0);
data = elf_getdata(sec, NULL);
if (data == NULL)
goto out;
ptr = data->d_buf;
while (ptr < (data->d_buf + data->d_size)) {
GElf_Nhdr *nhdr = ptr;
size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
descsz = NOTE_ALIGN(nhdr->n_descsz);
const char *name;
ptr += sizeof(*nhdr);
name = ptr;
ptr += namesz;
if (nhdr->n_type == NT_GNU_BUILD_ID &&
nhdr->n_namesz == sizeof("GNU")) {
if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
size_t sz = min(size, descsz);
memcpy(bf, ptr, sz);
memset(bf + sz, 0, size - sz);
err = descsz;
break;
}
}
ptr += descsz;
}
out:
return err;
}
int filename__read_build_id(const char *filename, void *bf, size_t size)
{
int fd, err = -1;
Elf *elf;
if (size < BUILD_ID_SIZE)
goto out;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
goto out_close;
}
err = elf_read_build_id(elf, bf, size);
elf_end(elf);
out_close:
close(fd);
out:
return err;
}
int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
{
int fd, err = -1;
if (size < BUILD_ID_SIZE)
goto out;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
while (1) {
char bf[BUFSIZ];
GElf_Nhdr nhdr;
size_t namesz, descsz;
if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
break;
namesz = NOTE_ALIGN(nhdr.n_namesz);
descsz = NOTE_ALIGN(nhdr.n_descsz);
if (nhdr.n_type == NT_GNU_BUILD_ID &&
nhdr.n_namesz == sizeof("GNU")) {
if (read(fd, bf, namesz) != (ssize_t)namesz)
break;
if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
size_t sz = min(descsz, size);
if (read(fd, build_id, sz) == (ssize_t)sz) {
memset(build_id + sz, 0, size - sz);
err = 0;
break;
}
} else if (read(fd, bf, descsz) != (ssize_t)descsz)
break;
} else {
int n = namesz + descsz;
if (n > (int)sizeof(bf)) {
n = sizeof(bf);
pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
__func__, filename, nhdr.n_namesz, nhdr.n_descsz);
}
if (read(fd, bf, n) != n)
break;
}
}
close(fd);
out:
return err;
}
int filename__read_debuglink(const char *filename, char *debuglink,
size_t size)
{
int fd, err = -1;
Elf *elf;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Data *data;
Elf_Scn *sec;
Elf_Kind ek;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
goto out_close;
}
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out_elf_end;
if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
sec = elf_section_by_name(elf, &ehdr, &shdr,
".gnu_debuglink", NULL);
if (sec == NULL)
goto out_elf_end;
data = elf_getdata(sec, NULL);
if (data == NULL)
goto out_elf_end;
/* the start of this section is a zero-terminated string */
strncpy(debuglink, data->d_buf, size);
err = 0;
out_elf_end:
elf_end(elf);
out_close:
close(fd);
out:
return err;
}
static int dso__swap_init(struct dso *dso, unsigned char eidata)
{
static unsigned int const endian = 1;
dso->needs_swap = DSO_SWAP__NO;
switch (eidata) {
case ELFDATA2LSB:
/* We are big endian, DSO is little endian. */
if (*(unsigned char const *)&endian != 1)
dso->needs_swap = DSO_SWAP__YES;
break;
case ELFDATA2MSB:
/* We are little endian, DSO is big endian. */
if (*(unsigned char const *)&endian != 0)
dso->needs_swap = DSO_SWAP__YES;
break;
default:
pr_err("unrecognized DSO data encoding %d\n", eidata);
return -EINVAL;
}
return 0;
}
bool symsrc__possibly_runtime(struct symsrc *ss)
{
return ss->dynsym || ss->opdsec;
}
bool symsrc__has_symtab(struct symsrc *ss)
{
return ss->symtab != NULL;
}
void symsrc__destroy(struct symsrc *ss)
{
zfree(&ss->name);
elf_end(ss->elf);
close(ss->fd);
}
bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
{
/*
* Usually vmlinux is an ELF file with type ET_EXEC for most
* architectures; except Arm64 kernel is linked with option
* '-share', so need to check type ET_DYN.
*/
return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||
ehdr.e_type == ET_DYN;
}
int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
enum dso_binary_type type)
{
GElf_Ehdr ehdr;
Elf *elf;
int fd;
if (dso__needs_decompress(dso)) {
fd = dso__decompress_kmodule_fd(dso, name);
if (fd < 0)
return -1;
type = dso->symtab_type;
} else {
fd = open(name, O_RDONLY);
if (fd < 0) {
dso->load_errno = errno;
return -1;
}
}
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
goto out_close;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
pr_debug("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
goto out_elf_end;
}
/* Always reject images with a mismatched build-id: */
if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
u8 build_id[BUILD_ID_SIZE];
if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
goto out_elf_end;
}
if (!dso__build_id_equal(dso, build_id)) {
pr_debug("%s: build id mismatch for %s.\n", __func__, name);
dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
goto out_elf_end;
}
}
ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
NULL);
if (ss->symshdr.sh_type != SHT_SYMTAB)
ss->symtab = NULL;
ss->dynsym_idx = 0;
ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
&ss->dynsym_idx);
if (ss->dynshdr.sh_type != SHT_DYNSYM)
ss->dynsym = NULL;
ss->opdidx = 0;
ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
&ss->opdidx);
if (ss->opdshdr.sh_type != SHT_PROGBITS)
ss->opdsec = NULL;
if (dso->kernel == DSO_TYPE_USER)
ss->adjust_symbols = true;
else
ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
ss->name = strdup(name);
if (!ss->name) {
dso->load_errno = errno;
goto out_elf_end;
}
ss->elf = elf;
ss->fd = fd;
ss->ehdr = ehdr;
ss->type = type;
return 0;
out_elf_end:
elf_end(elf);
out_close:
close(fd);
return -1;
}
/**
* ref_reloc_sym_not_found - has kernel relocation symbol been found.
* @kmap: kernel maps and relocation reference symbol
*
* This function returns %true if we are dealing with the kernel maps and the
* relocation reference symbol has not yet been found. Otherwise %false is
* returned.
*/
static bool ref_reloc_sym_not_found(struct kmap *kmap)
{
return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
!kmap->ref_reloc_sym->unrelocated_addr;
}
/**
* ref_reloc - kernel relocation offset.
* @kmap: kernel maps and relocation reference symbol
*
* This function returns the offset of kernel addresses as determined by using
* the relocation reference symbol i.e. if the kernel has not been relocated
* then the return value is zero.
*/
static u64 ref_reloc(struct kmap *kmap)
{
if (kmap && kmap->ref_reloc_sym &&
kmap->ref_reloc_sym->unrelocated_addr)
return kmap->ref_reloc_sym->addr -
kmap->ref_reloc_sym->unrelocated_addr;
return 0;
}
void __weak arch__sym_update(struct symbol *s __maybe_unused,
GElf_Sym *sym __maybe_unused) { }
static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
GElf_Sym *sym, GElf_Shdr *shdr,
struct maps *kmaps, struct kmap *kmap,
struct dso **curr_dsop, struct map **curr_mapp,
const char *section_name,
bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
{
struct dso *curr_dso = *curr_dsop;
struct map *curr_map;
char dso_name[PATH_MAX];
/* Adjust symbol to map to file offset */
if (adjust_kernel_syms)
sym->st_value -= shdr->sh_addr - shdr->sh_offset;
if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
return 0;
if (strcmp(section_name, ".text") == 0) {
/*
* The initial kernel mapping is based on
* kallsyms and identity maps. Overwrite it to
* map to the kernel dso.
*/
if (*remap_kernel && dso->kernel) {
*remap_kernel = false;
map->start = shdr->sh_addr + ref_reloc(kmap);
map->end = map->start + shdr->sh_size;
map->pgoff = shdr->sh_offset;
map->map_ip = map__map_ip;
map->unmap_ip = map__unmap_ip;
/* Ensure maps are correctly ordered */
if (kmaps) {
map__get(map);
maps__remove(kmaps, map);
maps__insert(kmaps, map);
map__put(map);
}
}
/*
* The initial module mapping is based on
* /proc/modules mapped to offset zero.
* Overwrite it to map to the module dso.
*/
if (*remap_kernel && kmodule) {
*remap_kernel = false;
map->pgoff = shdr->sh_offset;
}
*curr_mapp = map;
*curr_dsop = dso;
return 0;
}
if (!kmap)
return 0;
snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
curr_map = maps__find_by_name(kmaps, dso_name);
if (curr_map == NULL) {
u64 start = sym->st_value;
if (kmodule)
start += map->start + shdr->sh_offset;
curr_dso = dso__new(dso_name);
if (curr_dso == NULL)
return -1;
curr_dso->kernel = dso->kernel;
curr_dso->long_name = dso->long_name;
curr_dso->long_name_len = dso->long_name_len;
curr_map = map__new2(start, curr_dso);
dso__put(curr_dso);
if (curr_map == NULL)
return -1;
if (curr_dso->kernel)
map__kmap(curr_map)->kmaps = kmaps;
if (adjust_kernel_syms) {
curr_map->start = shdr->sh_addr + ref_reloc(kmap);
curr_map->end = curr_map->start + shdr->sh_size;
curr_map->pgoff = shdr->sh_offset;
} else {
curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
}
curr_dso->symtab_type = dso->symtab_type;
maps__insert(kmaps, curr_map);
/*
* Add it before we drop the referece to curr_map, i.e. while
* we still are sure to have a reference to this DSO via
* *curr_map->dso.
*/
dsos__add(&kmaps->machine->dsos, curr_dso);
/* kmaps already got it */
map__put(curr_map);
dso__set_loaded(curr_dso);
*curr_mapp = curr_map;
*curr_dsop = curr_dso;
} else
*curr_dsop = curr_map->dso;
return 0;
}
int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
struct symsrc *runtime_ss, int kmodule)
{
struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
struct map *curr_map = map;
struct dso *curr_dso = dso;
Elf_Data *symstrs, *secstrs;
uint32_t nr_syms;
int err = -1;
uint32_t idx;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
GElf_Shdr tshdr;
Elf_Data *syms, *opddata = NULL;
GElf_Sym sym;
Elf_Scn *sec, *sec_strndx;
Elf *elf;
int nr = 0;
bool remap_kernel = false, adjust_kernel_syms = false;
if (kmap && !kmaps)
return -1;
dso->symtab_type = syms_ss->type;
dso->is_64_bit = syms_ss->is_64_bit;
dso->rel = syms_ss->ehdr.e_type == ET_REL;
/*
* Modules may already have symbols from kallsyms, but those symbols
* have the wrong values for the dso maps, so remove them.
*/
if (kmodule && syms_ss->symtab)
symbols__delete(&dso->symbols);
if (!syms_ss->symtab) {
/*
* If the vmlinux is stripped, fail so we will fall back
* to using kallsyms. The vmlinux runtime symbols aren't
* of much use.
*/
if (dso->kernel)
goto out_elf_end;
syms_ss->symtab = syms_ss->dynsym;
syms_ss->symshdr = syms_ss->dynshdr;
}
elf = syms_ss->elf;
ehdr = syms_ss->ehdr;
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
if (runtime_ss->opdsec)
opddata = elf_rawdata(runtime_ss->opdsec, NULL);
syms = elf_getdata(sec, NULL);
if (syms == NULL)
goto out_elf_end;
sec = elf_getscn(elf, shdr.sh_link);
if (sec == NULL)
goto out_elf_end;
symstrs = elf_getdata(sec, NULL);
if (symstrs == NULL)
goto out_elf_end;
sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
if (sec_strndx == NULL)
goto out_elf_end;
secstrs = elf_getdata(sec_strndx, NULL);
if (secstrs == NULL)
goto out_elf_end;
nr_syms = shdr.sh_size / shdr.sh_entsize;
memset(&sym, 0, sizeof(sym));
/*
* The kernel relocation symbol is needed in advance in order to adjust
* kernel maps correctly.
*/
if (ref_reloc_sym_not_found(kmap)) {
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
const char *elf_name = elf_sym__name(&sym, symstrs);
if (strcmp(elf_name, kmap->ref_reloc_sym->name))
continue;
kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
map->reloc = kmap->ref_reloc_sym->addr -
kmap->ref_reloc_sym->unrelocated_addr;
break;
}
}
/*
* Handle any relocation of vdso necessary because older kernels
* attempted to prelink vdso to its virtual address.
*/
if (dso__is_vdso(dso))
map->reloc = map->start - dso->text_offset;
dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
/*
* Initial kernel and module mappings do not map to the dso.
* Flag the fixups.
*/
if (dso->kernel || kmodule) {
remap_kernel = true;
adjust_kernel_syms = dso->adjust_symbols;
}
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
struct symbol *f;
const char *elf_name = elf_sym__name(&sym, symstrs);
char *demangled = NULL;
int is_label = elf_sym__is_label(&sym);
const char *section_name;
bool used_opd = false;
if (!is_label && !elf_sym__filter(&sym))
continue;
/* Reject ARM ELF "mapping symbols": these aren't unique and
* don't identify functions, so will confuse the profile
* output: */
if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
&& (elf_name[2] == '\0' || elf_name[2] == '.'))
continue;
}
if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
u64 *opd = opddata->d_buf + offset;
sym.st_value = DSO__SWAP(dso, u64, *opd);
sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
sym.st_value);
used_opd = true;
}
/*
* When loading symbols in a data mapping, ABS symbols (which
* has a value of SHN_ABS in its st_shndx) failed at
* elf_getscn(). And it marks the loading as a failure so
* already loaded symbols cannot be fixed up.
*
* I'm not sure what should be done. Just ignore them for now.
* - Namhyung Kim
*/
if (sym.st_shndx == SHN_ABS)
continue;
sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
if (!sec)
goto out_elf_end;
gelf_getshdr(sec, &shdr);
if (is_label && !elf_sec__filter(&shdr, secstrs))
continue;
section_name = elf_sec__name(&shdr, secstrs);
/* On ARM, symbols for thumb functions have 1 added to
* the symbol address as a flag - remove it */
if ((ehdr.e_machine == EM_ARM) &&
(GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
(sym.st_value & 1))
--sym.st_value;
if (dso->kernel || kmodule) {
if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
section_name, adjust_kernel_syms, kmodule, &remap_kernel))
goto out_elf_end;
} else if ((used_opd && runtime_ss->adjust_symbols) ||
(!used_opd && syms_ss->adjust_symbols)) {
pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
"sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
(u64)sym.st_value, (u64)shdr.sh_addr,
(u64)shdr.sh_offset);
sym.st_value -= shdr.sh_addr - shdr.sh_offset;
}
demangled = demangle_sym(dso, kmodule, elf_name);
if (demangled != NULL)
elf_name = demangled;
f = symbol__new(sym.st_value, sym.st_size,
GELF_ST_BIND(sym.st_info),
GELF_ST_TYPE(sym.st_info), elf_name);
free(demangled);
if (!f)
goto out_elf_end;
arch__sym_update(f, &sym);
__symbols__insert(&curr_dso->symbols, f, dso->kernel);
nr++;
}
/*
* For misannotated, zeroed, ASM function sizes.
*/
if (nr > 0) {
symbols__fixup_end(&dso->symbols);
symbols__fixup_duplicate(&dso->symbols);
if (kmap) {
/*
* We need to fixup this here too because we create new
* maps here, for things like vsyscall sections.
*/
maps__fixup_end(kmaps);
}
}
err = nr;
out_elf_end:
return err;
}
static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
{
GElf_Phdr phdr;
size_t i, phdrnum;
int err;
u64 sz;
if (elf_getphdrnum(elf, &phdrnum))
return -1;
for (i = 0; i < phdrnum; i++) {
if (gelf_getphdr(elf, i, &phdr) == NULL)
return -1;
if (phdr.p_type != PT_LOAD)
continue;
if (exe) {
if (!(phdr.p_flags & PF_X))
continue;
} else {
if (!(phdr.p_flags & PF_R))
continue;
}
sz = min(phdr.p_memsz, phdr.p_filesz);
if (!sz)
continue;
err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
if (err)
return err;
}
return 0;
}
int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
bool *is_64_bit)
{
int err;
Elf *elf;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL)
return -1;
if (is_64_bit)
*is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
err = elf_read_maps(elf, exe, mapfn, data);
elf_end(elf);
return err;
}
enum dso_type dso__type_fd(int fd)
{
enum dso_type dso_type = DSO__TYPE_UNKNOWN;
GElf_Ehdr ehdr;
Elf_Kind ek;
Elf *elf;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL)
goto out;
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out_end;
if (gelf_getclass(elf) == ELFCLASS64) {
dso_type = DSO__TYPE_64BIT;
goto out_end;
}
if (gelf_getehdr(elf, &ehdr) == NULL)
goto out_end;
if (ehdr.e_machine == EM_X86_64)
dso_type = DSO__TYPE_X32BIT;
else
dso_type = DSO__TYPE_32BIT;
out_end:
elf_end(elf);
out:
return dso_type;
}
static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
{
ssize_t r;
size_t n;
int err = -1;
char *buf = malloc(page_size);
if (buf == NULL)
return -1;
if (lseek(to, to_offs, SEEK_SET) != to_offs)
goto out;
if (lseek(from, from_offs, SEEK_SET) != from_offs)
goto out;
while (len) {
n = page_size;
if (len < n)
n = len;
/* Use read because mmap won't work on proc files */
r = read(from, buf, n);
if (r < 0)
goto out;
if (!r)
break;
n = r;
r = write(to, buf, n);
if (r < 0)
goto out;
if ((size_t)r != n)
goto out;
len -= n;
}
err = 0;
out:
free(buf);
return err;
}
struct kcore {
int fd;
int elfclass;
Elf *elf;
GElf_Ehdr ehdr;
};
static int kcore__open(struct kcore *kcore, const char *filename)
{
GElf_Ehdr *ehdr;
kcore->fd = open(filename, O_RDONLY);
if (kcore->fd == -1)
return -1;
kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
if (!kcore->elf)
goto out_close;
kcore->elfclass = gelf_getclass(kcore->elf);
if (kcore->elfclass == ELFCLASSNONE)
goto out_end;
ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
if (!ehdr)
goto out_end;
return 0;
out_end:
elf_end(kcore->elf);
out_close:
close(kcore->fd);
return -1;
}
static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
bool temp)
{
kcore->elfclass = elfclass;
if (temp)
kcore->fd = mkstemp(filename);
else
kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
if (kcore->fd == -1)
return -1;
kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
if (!kcore->elf)
goto out_close;
if (!gelf_newehdr(kcore->elf, elfclass))
goto out_end;
memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
return 0;
out_end:
elf_end(kcore->elf);
out_close:
close(kcore->fd);
unlink(filename);
return -1;
}
static void kcore__close(struct kcore *kcore)
{
elf_end(kcore->elf);
close(kcore->fd);
}
static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
{
GElf_Ehdr *ehdr = &to->ehdr;
GElf_Ehdr *kehdr = &from->ehdr;
memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
ehdr->e_type = kehdr->e_type;
ehdr->e_machine = kehdr->e_machine;
ehdr->e_version = kehdr->e_version;
ehdr->e_entry = 0;
ehdr->e_shoff = 0;
ehdr->e_flags = kehdr->e_flags;
ehdr->e_phnum = count;
ehdr->e_shentsize = 0;
ehdr->e_shnum = 0;
ehdr->e_shstrndx = 0;
if (from->elfclass == ELFCLASS32) {
ehdr->e_phoff = sizeof(Elf32_Ehdr);
ehdr->e_ehsize = sizeof(Elf32_Ehdr);
ehdr->e_phentsize = sizeof(Elf32_Phdr);
} else {
ehdr->e_phoff = sizeof(Elf64_Ehdr);
ehdr->e_ehsize = sizeof(Elf64_Ehdr);
ehdr->e_phentsize = sizeof(Elf64_Phdr);
}
if (!gelf_update_ehdr(to->elf, ehdr))
return -1;
if (!gelf_newphdr(to->elf, count))
return -1;
return 0;
}
static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
u64 addr, u64 len)
{
GElf_Phdr phdr = {
.p_type = PT_LOAD,
.p_flags = PF_R | PF_W | PF_X,
.p_offset = offset,
.p_vaddr = addr,
.p_paddr = 0,
.p_filesz = len,
.p_memsz = len,
.p_align = page_size,
};
if (!gelf_update_phdr(kcore->elf, idx, &phdr))
return -1;
return 0;
}
static off_t kcore__write(struct kcore *kcore)
{
return elf_update(kcore->elf, ELF_C_WRITE);
}
struct phdr_data {
off_t offset;
off_t rel;
u64 addr;
u64 len;
struct list_head node;
struct phdr_data *remaps;
};
struct sym_data {
u64 addr;
struct list_head node;
};
struct kcore_copy_info {
u64 stext;
u64 etext;
u64 first_symbol;
u64 last_symbol;
u64 first_module;
u64 first_module_symbol;
u64 last_module_symbol;
size_t phnum;
struct list_head phdrs;
struct list_head syms;
};
#define kcore_copy__for_each_phdr(k, p) \
list_for_each_entry((p), &(k)->phdrs, node)
static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
{
struct phdr_data *p = zalloc(sizeof(*p));
if (p) {
p->addr = addr;
p->len = len;
p->offset = offset;
}
return p;
}
static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
u64 addr, u64 len,
off_t offset)
{
struct phdr_data *p = phdr_data__new(addr, len, offset);
if (p)
list_add_tail(&p->node, &kci->phdrs);
return p;
}
static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
{
struct phdr_data *p, *tmp;
list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
list_del_init(&p->node);
free(p);
}
}
static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
u64 addr)
{
struct sym_data *s = zalloc(sizeof(*s));
if (s) {
s->addr = addr;
list_add_tail(&s->node, &kci->syms);
}
return s;
}
static void kcore_copy__free_syms(struct kcore_copy_info *kci)
{
struct sym_data *s, *tmp;
list_for_each_entry_safe(s, tmp, &kci->syms, node) {
list_del_init(&s->node);
free(s);
}
}
static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
u64 start)
{
struct kcore_copy_info *kci = arg;
if (!kallsyms__is_function(type))
return 0;
if (strchr(name, '[')) {
if (!kci->first_module_symbol || start < kci->first_module_symbol)
kci->first_module_symbol = start;
if (start > kci->last_module_symbol)
kci->last_module_symbol = start;
return 0;
}
if (!kci->first_symbol || start < kci->first_symbol)
kci->first_symbol = start;
if (!kci->last_symbol || start > kci->last_symbol)
kci->last_symbol = start;
if (!strcmp(name, "_stext")) {
kci->stext = start;
return 0;
}
if (!strcmp(name, "_etext")) {
kci->etext = start;
return 0;
}
if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
return -1;
return 0;
}
static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
const char *dir)
{
char kallsyms_filename[PATH_MAX];
scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
return -1;
if (kallsyms__parse(kallsyms_filename, kci,
kcore_copy__process_kallsyms) < 0)
return -1;
return 0;
}
static int kcore_copy__process_modules(void *arg,
const char *name __maybe_unused,
u64 start, u64 size __maybe_unused)
{
struct kcore_copy_info *kci = arg;
if (!kci->first_module || start < kci->first_module)
kci->first_module = start;
return 0;
}
static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
const char *dir)
{
char modules_filename[PATH_MAX];
scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
if (symbol__restricted_filename(modules_filename, "/proc/modules"))
return -1;
if (modules__parse(modules_filename, kci,
kcore_copy__process_modules) < 0)
return -1;
return 0;
}
static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
u64 pgoff, u64 s, u64 e)
{
u64 len, offset;
if (s < start || s >= end)
return 0;
offset = (s - start) + pgoff;
len = e < end ? e - s : end - s;
return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
}
static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
{
struct kcore_copy_info *kci = data;
u64 end = start + len;
struct sym_data *sdat;
if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
return -1;
if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
kci->last_module_symbol))
return -1;
list_for_each_entry(sdat, &kci->syms, node) {
u64 s = round_down(sdat->addr, page_size);
if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
return -1;
}
return 0;
}
static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
{
if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
return -1;
return 0;
}
static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
{
struct phdr_data *p, *k = NULL;
u64 kend;
if (!kci->stext)
return;
/* Find phdr that corresponds to the kernel map (contains stext) */
kcore_copy__for_each_phdr(kci, p) {
u64 pend = p->addr + p->len - 1;
if (p->addr <= kci->stext && pend >= kci->stext) {
k = p;
break;
}
}
if (!k)
return;
kend = k->offset + k->len;
/* Find phdrs that remap the kernel */
kcore_copy__for_each_phdr(kci, p) {
u64 pend = p->offset + p->len;
if (p == k)
continue;
if (p->offset >= k->offset && pend <= kend)
p->remaps = k;
}
}
static void kcore_copy__layout(struct kcore_copy_info *kci)
{
struct phdr_data *p;
off_t rel = 0;
kcore_copy__find_remaps(kci);
kcore_copy__for_each_phdr(kci, p) {
if (!p->remaps) {
p->rel = rel;
rel += p->len;
}
kci->phnum += 1;
}
kcore_copy__for_each_phdr(kci, p) {
struct phdr_data *k = p->remaps;
if (k)
p->rel = p->offset - k->offset + k->rel;
}
}
static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
Elf *elf)
{
if (kcore_copy__parse_kallsyms(kci, dir))
return -1;
if (kcore_copy__parse_modules(kci, dir))
return -1;
if (kci->stext)
kci->stext = round_down(kci->stext, page_size);
else
kci->stext = round_down(kci->first_symbol, page_size);
if (kci->etext) {
kci->etext = round_up(kci->etext, page_size);
} else if (kci->last_symbol) {
kci->etext = round_up(kci->last_symbol, page_size);
kci->etext += page_size;
}
if (kci->first_module_symbol &&
(!kci->first_module || kci->first_module_symbol < kci->first_module))
kci->first_module = kci->first_module_symbol;
kci->first_module = round_down(kci->first_module, page_size);
if (kci->last_module_symbol) {
kci->last_module_symbol = round_up(kci->last_module_symbol,
page_size);
kci->last_module_symbol += page_size;
}
if (!kci->stext || !kci->etext)
return -1;
if (kci->first_module && !kci->last_module_symbol)
return -1;
if (kcore_copy__read_maps(kci, elf))
return -1;
kcore_copy__layout(kci);
return 0;
}
static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
const char *name)
{
char from_filename[PATH_MAX];
char to_filename[PATH_MAX];
scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
return copyfile_mode(from_filename, to_filename, 0400);
}
static int kcore_copy__unlink(const char *dir, const char *name)
{
char filename[PATH_MAX];
scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
return unlink(filename);
}
static int kcore_copy__compare_fds(int from, int to)
{
char *buf_from;
char *buf_to;
ssize_t ret;
size_t len;
int err = -1;
buf_from = malloc(page_size);
buf_to = malloc(page_size);
if (!buf_from || !buf_to)
goto out;
while (1) {
/* Use read because mmap won't work on proc files */
ret = read(from, buf_from, page_size);
if (ret < 0)
goto out;
if (!ret)
break;
len = ret;
if (readn(to, buf_to, len) != (int)len)
goto out;
if (memcmp(buf_from, buf_to, len))
goto out;
}
err = 0;
out:
free(buf_to);
free(buf_from);
return err;
}
static int kcore_copy__compare_files(const char *from_filename,
const char *to_filename)
{
int from, to, err = -1;
from = open(from_filename, O_RDONLY);
if (from < 0)
return -1;
to = open(to_filename, O_RDONLY);
if (to < 0)
goto out_close_from;
err = kcore_copy__compare_fds(from, to);
close(to);
out_close_from:
close(from);
return err;
}
static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
const char *name)
{
char from_filename[PATH_MAX];
char to_filename[PATH_MAX];
scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
return kcore_copy__compare_files(from_filename, to_filename);
}
/**
* kcore_copy - copy kallsyms, modules and kcore from one directory to another.
* @from_dir: from directory
* @to_dir: to directory
*
* This function copies kallsyms, modules and kcore files from one directory to
* another. kallsyms and modules are copied entirely. Only code segments are
* copied from kcore. It is assumed that two segments suffice: one for the
* kernel proper and one for all the modules. The code segments are determined
* from kallsyms and modules files. The kernel map starts at _stext or the
* lowest function symbol, and ends at _etext or the highest function symbol.
* The module map starts at the lowest module address and ends at the highest
* module symbol. Start addresses are rounded down to the nearest page. End
* addresses are rounded up to the nearest page. An extra page is added to the
* highest kernel symbol and highest module symbol to, hopefully, encompass that
* symbol too. Because it contains only code sections, the resulting kcore is
* unusual. One significant peculiarity is that the mapping (start -> pgoff)
* is not the same for the kernel map and the modules map. That happens because
* the data is copied adjacently whereas the original kcore has gaps. Finally,
* kallsyms and modules files are compared with their copies to check that
* modules have not been loaded or unloaded while the copies were taking place.
*
* Return: %0 on success, %-1 on failure.
*/
int kcore_copy(const char *from_dir, const char *to_dir)
{
struct kcore kcore;
struct kcore extract;
int idx = 0, err = -1;
off_t offset, sz;
struct kcore_copy_info kci = { .stext = 0, };
char kcore_filename[PATH_MAX];
char extract_filename[PATH_MAX];
struct phdr_data *p;
INIT_LIST_HEAD(&kci.phdrs);
INIT_LIST_HEAD(&kci.syms);
if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
return -1;
if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
goto out_unlink_kallsyms;
scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
if (kcore__open(&kcore, kcore_filename))
goto out_unlink_modules;
if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
goto out_kcore_close;
if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
goto out_kcore_close;
if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
goto out_extract_close;
offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
offset = round_up(offset, page_size);
kcore_copy__for_each_phdr(&kci, p) {
off_t offs = p->rel + offset;
if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
goto out_extract_close;
}
sz = kcore__write(&extract);
if (sz < 0 || sz > offset)
goto out_extract_close;
kcore_copy__for_each_phdr(&kci, p) {
off_t offs = p->rel + offset;
if (p->remaps)
continue;
if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
goto out_extract_close;
}
if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
goto out_extract_close;
if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
goto out_extract_close;
err = 0;
out_extract_close:
kcore__close(&extract);
if (err)
unlink(extract_filename);
out_kcore_close:
kcore__close(&kcore);
out_unlink_modules:
if (err)
kcore_copy__unlink(to_dir, "modules");
out_unlink_kallsyms:
if (err)
kcore_copy__unlink(to_dir, "kallsyms");
kcore_copy__free_phdrs(&kci);
kcore_copy__free_syms(&kci);
return err;
}
int kcore_extract__create(struct kcore_extract *kce)
{
struct kcore kcore;
struct kcore extract;
size_t count = 1;
int idx = 0, err = -1;
off_t offset = page_size, sz;
if (kcore__open(&kcore, kce->kcore_filename))
return -1;
strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
goto out_kcore_close;
if (kcore__copy_hdr(&kcore, &extract, count))
goto out_extract_close;
if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
goto out_extract_close;
sz = kcore__write(&extract);
if (sz < 0 || sz > offset)
goto out_extract_close;
if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
goto out_extract_close;
err = 0;
out_extract_close:
kcore__close(&extract);
if (err)
unlink(kce->extract_filename);
out_kcore_close:
kcore__close(&kcore);
return err;
}
void kcore_extract__delete(struct kcore_extract *kce)
{
unlink(kce->extract_filename);
}
#ifdef HAVE_GELF_GETNOTE_SUPPORT
static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
{
if (!base_off)
return;
if (tmp->bit32)
tmp->addr.a32[SDT_NOTE_IDX_LOC] =
tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
tmp->addr.a32[SDT_NOTE_IDX_BASE];
else
tmp->addr.a64[SDT_NOTE_IDX_LOC] =
tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
tmp->addr.a64[SDT_NOTE_IDX_BASE];
}
static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
GElf_Addr base_off)
{
if (!base_off)
return;
if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
}
/**
* populate_sdt_note : Parse raw data and identify SDT note
* @elf: elf of the opened file
* @data: raw data of a section with description offset applied
* @len: note description size
* @type: type of the note
* @sdt_notes: List to add the SDT note
*
* Responsible for parsing the @data in section .note.stapsdt in @elf and
* if its an SDT note, it appends to @sdt_notes list.
*/
static int populate_sdt_note(Elf **elf, const char *data, size_t len,
struct list_head *sdt_notes)
{
const char *provider, *name, *args;
struct sdt_note *tmp = NULL;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
int ret = -EINVAL;
union {
Elf64_Addr a64[NR_ADDR];
Elf32_Addr a32[NR_ADDR];
} buf;
Elf_Data dst = {
.d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
.d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
.d_off = 0, .d_align = 0
};
Elf_Data src = {
.d_buf = (void *) data, .d_type = ELF_T_ADDR,
.d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
.d_align = 0
};
tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
if (!tmp) {
ret = -ENOMEM;
goto out_err;
}
INIT_LIST_HEAD(&tmp->note_list);
if (len < dst.d_size + 3)
goto out_free_note;
/* Translation from file representation to memory representation */
if (gelf_xlatetom(*elf, &dst, &src,
elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
goto out_free_note;
}
/* Populate the fields of sdt_note */
provider = data + dst.d_size;
name = (const char *)memchr(provider, '\0', data + len - provider);
if (name++ == NULL)
goto out_free_note;
tmp->provider = strdup(provider);
if (!tmp->provider) {
ret = -ENOMEM;
goto out_free_note;
}
tmp->name = strdup(name);
if (!tmp->name) {
ret = -ENOMEM;
goto out_free_prov;
}
args = memchr(name, '\0', data + len - name);
/*
* There is no argument if:
* - We reached the end of the note;
* - There is not enough room to hold a potential string;
* - The argument string is empty or just contains ':'.
*/
if (args == NULL || data + len - args < 2 ||
args[1] == ':' || args[1] == '\0')
tmp->args = NULL;
else {
tmp->args = strdup(++args);
if (!tmp->args) {
ret = -ENOMEM;
goto out_free_name;
}
}
if (gelf_getclass(*elf) == ELFCLASS32) {
memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
tmp->bit32 = true;
} else {
memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
tmp->bit32 = false;
}
if (!gelf_getehdr(*elf, &ehdr)) {
pr_debug("%s : cannot get elf header.\n", __func__);
ret = -EBADF;
goto out_free_args;
}
/* Adjust the prelink effect :
* Find out the .stapsdt.base section.
* This scn will help us to handle prelinking (if present).
* Compare the retrieved file offset of the base section with the
* base address in the description of the SDT note. If its different,
* then accordingly, adjust the note location.
*/
if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
sdt_adjust_loc(tmp, shdr.sh_offset);
/* Adjust reference counter offset */
if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
list_add_tail(&tmp->note_list, sdt_notes);
return 0;
out_free_args:
zfree(&tmp->args);
out_free_name:
zfree(&tmp->name);
out_free_prov:
zfree(&tmp->provider);
out_free_note:
free(tmp);
out_err:
return ret;
}
/**
* construct_sdt_notes_list : constructs a list of SDT notes
* @elf : elf to look into
* @sdt_notes : empty list_head
*
* Scans the sections in 'elf' for the section
* .note.stapsdt. It, then calls populate_sdt_note to find
* out the SDT events and populates the 'sdt_notes'.
*/
static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
{
GElf_Ehdr ehdr;
Elf_Scn *scn = NULL;
Elf_Data *data;
GElf_Shdr shdr;
size_t shstrndx, next;
GElf_Nhdr nhdr;
size_t name_off, desc_off, offset;
int ret = 0;
if (gelf_getehdr(elf, &ehdr) == NULL) {
ret = -EBADF;
goto out_ret;
}
if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
ret = -EBADF;
goto out_ret;
}
/* Look for the required section */
scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
if (!scn) {
ret = -ENOENT;
goto out_ret;
}
if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
ret = -ENOENT;
goto out_ret;
}
data = elf_getdata(scn, NULL);
/* Get the SDT notes */
for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
&desc_off)) > 0; offset = next) {
if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
!memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
sizeof(SDT_NOTE_NAME))) {
/* Check the type of the note */
if (nhdr.n_type != SDT_NOTE_TYPE)
goto out_ret;
ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
nhdr.n_descsz, sdt_notes);
if (ret < 0)
goto out_ret;
}
}
if (list_empty(sdt_notes))
ret = -ENOENT;
out_ret:
return ret;
}
/**
* get_sdt_note_list : Wrapper to construct a list of sdt notes
* @head : empty list_head
* @target : file to find SDT notes from
*
* This opens the file, initializes
* the ELF and then calls construct_sdt_notes_list.
*/
int get_sdt_note_list(struct list_head *head, const char *target)
{
Elf *elf;
int fd, ret;
fd = open(target, O_RDONLY);
if (fd < 0)
return -EBADF;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (!elf) {
ret = -EBADF;
goto out_close;
}
ret = construct_sdt_notes_list(elf, head);
elf_end(elf);
out_close:
close(fd);
return ret;
}
/**
* cleanup_sdt_note_list : free the sdt notes' list
* @sdt_notes: sdt notes' list
*
* Free up the SDT notes in @sdt_notes.
* Returns the number of SDT notes free'd.
*/
int cleanup_sdt_note_list(struct list_head *sdt_notes)
{
struct sdt_note *tmp, *pos;
int nr_free = 0;
list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
list_del_init(&pos->note_list);
zfree(&pos->name);
zfree(&pos->provider);
free(pos);
nr_free++;
}
return nr_free;
}
/**
* sdt_notes__get_count: Counts the number of sdt events
* @start: list_head to sdt_notes list
*
* Returns the number of SDT notes in a list
*/
int sdt_notes__get_count(struct list_head *start)
{
struct sdt_note *sdt_ptr;
int count = 0;
list_for_each_entry(sdt_ptr, start, note_list)
count++;
return count;
}
#endif
void symbol__elf_init(void)
{
elf_version(EV_CURRENT);
}
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