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linux-next/tools/objtool/orc_dump.c
Matt Helsley 0decf1f8de objtool: Enable compilation of objtool for all architectures
Objtool currently only compiles for x86 architectures. This is
fine as it presently does not support tooling for other
architectures. However, we would like to be able to convert other
kernel tools to run as objtool sub commands because they too
process ELF object files. This will allow us to convert tools
such as recordmcount to use objtool's ELF code.

Since much of recordmcount's ELF code is copy-paste code to/from
a variety of other kernel tools (look at modpost for example) this
means that if we can convert recordmcount we can convert more.

We define weak definitions for subcommand entry functions and other weak
definitions for shared functions critical to building existing
subcommands. These return 127 when the command is missing which signify
tools that do not exist on all architectures.  In this case the "check"
and "orc" tools do not exist on all architectures so we only add them
for x86. Future changes adding support for "check", to arm64 for
example, can then modify the SUBCMD_CHECK variable when building for
arm64.

Objtool is not currently wired in to KConfig to be built for other
architectures because it's not needed for those architectures and
there are no commands it supports other than those for x86. As more
command support is enabled on various architectures the necessary
KConfig changes can be made (e.g. adding "STACK_VALIDATION") to
trigger building objtool.

[ jpoimboe: remove aliases, add __weak macro, add error messages ]

Cc: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Matt Helsley <mhelsley@vmware.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-05-20 09:17:28 -05:00

214 lines
4.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
#include <unistd.h>
#include <asm/orc_types.h>
#include "objtool.h"
#include "warn.h"
static const char *reg_name(unsigned int reg)
{
switch (reg) {
case ORC_REG_PREV_SP:
return "prevsp";
case ORC_REG_DX:
return "dx";
case ORC_REG_DI:
return "di";
case ORC_REG_BP:
return "bp";
case ORC_REG_SP:
return "sp";
case ORC_REG_R10:
return "r10";
case ORC_REG_R13:
return "r13";
case ORC_REG_BP_INDIRECT:
return "bp(ind)";
case ORC_REG_SP_INDIRECT:
return "sp(ind)";
default:
return "?";
}
}
static const char *orc_type_name(unsigned int type)
{
switch (type) {
case ORC_TYPE_CALL:
return "call";
case ORC_TYPE_REGS:
return "regs";
case ORC_TYPE_REGS_IRET:
return "iret";
default:
return "?";
}
}
static void print_reg(unsigned int reg, int offset)
{
if (reg == ORC_REG_BP_INDIRECT)
printf("(bp%+d)", offset);
else if (reg == ORC_REG_SP_INDIRECT)
printf("(sp%+d)", offset);
else if (reg == ORC_REG_UNDEFINED)
printf("(und)");
else
printf("%s%+d", reg_name(reg), offset);
}
int orc_dump(const char *_objname)
{
int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
struct orc_entry *orc = NULL;
char *name;
size_t nr_sections;
Elf64_Addr orc_ip_addr = 0;
size_t shstrtab_idx, strtab_idx = 0;
Elf *elf;
Elf_Scn *scn;
GElf_Shdr sh;
GElf_Rela rela;
GElf_Sym sym;
Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
objname = _objname;
elf_version(EV_CURRENT);
fd = open(objname, O_RDONLY);
if (fd == -1) {
perror("open");
return -1;
}
elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
if (!elf) {
WARN_ELF("elf_begin");
return -1;
}
if (elf_getshdrnum(elf, &nr_sections)) {
WARN_ELF("elf_getshdrnum");
return -1;
}
if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
WARN_ELF("elf_getshdrstrndx");
return -1;
}
for (i = 0; i < nr_sections; i++) {
scn = elf_getscn(elf, i);
if (!scn) {
WARN_ELF("elf_getscn");
return -1;
}
if (!gelf_getshdr(scn, &sh)) {
WARN_ELF("gelf_getshdr");
return -1;
}
name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
if (!name) {
WARN_ELF("elf_strptr");
return -1;
}
data = elf_getdata(scn, NULL);
if (!data) {
WARN_ELF("elf_getdata");
return -1;
}
if (!strcmp(name, ".symtab")) {
symtab = data;
} else if (!strcmp(name, ".strtab")) {
strtab_idx = i;
} else if (!strcmp(name, ".orc_unwind")) {
orc = data->d_buf;
orc_size = sh.sh_size;
} else if (!strcmp(name, ".orc_unwind_ip")) {
orc_ip = data->d_buf;
orc_ip_addr = sh.sh_addr;
} else if (!strcmp(name, ".rela.orc_unwind_ip")) {
rela_orc_ip = data;
}
}
if (!symtab || !strtab_idx || !orc || !orc_ip)
return 0;
if (orc_size % sizeof(*orc) != 0) {
WARN("bad .orc_unwind section size");
return -1;
}
nr_entries = orc_size / sizeof(*orc);
for (i = 0; i < nr_entries; i++) {
if (rela_orc_ip) {
if (!gelf_getrela(rela_orc_ip, i, &rela)) {
WARN_ELF("gelf_getrela");
return -1;
}
if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
WARN_ELF("gelf_getsym");
return -1;
}
if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
scn = elf_getscn(elf, sym.st_shndx);
if (!scn) {
WARN_ELF("elf_getscn");
return -1;
}
if (!gelf_getshdr(scn, &sh)) {
WARN_ELF("gelf_getshdr");
return -1;
}
name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
if (!name) {
WARN_ELF("elf_strptr");
return -1;
}
} else {
name = elf_strptr(elf, strtab_idx, sym.st_name);
if (!name) {
WARN_ELF("elf_strptr");
return -1;
}
}
printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
} else {
printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
}
printf(" sp:");
print_reg(orc[i].sp_reg, orc[i].sp_offset);
printf(" bp:");
print_reg(orc[i].bp_reg, orc[i].bp_offset);
printf(" type:%s end:%d\n",
orc_type_name(orc[i].type), orc[i].end);
}
elf_end(elf);
close(fd);
return 0;
}