Merge branch 'objtool/urgent' into objtool/core

Conflicts:
	tools/objtool/elf.c
	tools/objtool/elf.h
	tools/objtool/orc_gen.c
	tools/objtool/check.c

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Peter Zijlstra 2020-06-18 17:55:29 +02:00
commit d832c0051f
8 changed files with 120 additions and 9 deletions

View File

@ -67,7 +67,7 @@ config X86
select ARCH_HAS_FILTER_PGPROT
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

View File

@ -84,4 +84,6 @@ unsigned long arch_jump_destination(struct instruction *insn);
unsigned long arch_dest_reloc_offset(int addend);
const char *arch_nop_insn(int len);
#endif /* _ARCH_H */

View File

@ -565,3 +565,21 @@ void arch_initial_func_cfi_state(struct cfi_init_state *state)
state->regs[16].base = CFI_CFA;
state->regs[16].offset = -8;
}
const char *arch_nop_insn(int len)
{
static const char nops[5][5] = {
/* 1 */ { 0x90 },
/* 2 */ { 0x66, 0x90 },
/* 3 */ { 0x0f, 0x1f, 0x00 },
/* 4 */ { 0x0f, 0x1f, 0x40, 0x00 },
/* 5 */ { 0x0f, 0x1f, 0x44, 0x00, 0x00 },
};
if (len < 1 || len > 5) {
WARN("invalid NOP size: %d\n", len);
return NULL;
}
return nops[len-1];
}

View File

@ -0,0 +1,6 @@
#ifndef _OBJTOOL_ARCH_ELF
#define _OBJTOOL_ARCH_ELF
#define R_NONE R_X86_64_NONE
#endif /* _OBJTOOL_ARCH_ELF */

View File

@ -12,6 +12,7 @@
#include "check.h"
#include "special.h"
#include "warn.h"
#include "arch_elf.h"
#include <linux/hashtable.h>
#include <linux/kernel.h>
@ -765,6 +766,24 @@ static int add_call_destinations(struct objtool_file *file)
} else
insn->call_dest = reloc->sym;
/*
* Many compilers cannot disable KCOV with a function attribute
* so they need a little help, NOP out any KCOV calls from noinstr
* text.
*/
if (insn->sec->noinstr &&
!strncmp(insn->call_dest->name, "__sanitizer_cov_", 16)) {
if (reloc) {
reloc->type = R_NONE;
elf_write_reloc(file->elf, reloc);
}
elf_write_insn(file->elf, insn->sec,
insn->offset, insn->len,
arch_nop_insn(insn->len));
insn->type = INSN_NOP;
}
/*
* Whatever stack impact regular CALLs have, should be undone
* by the RETURN of the called function.
@ -2740,7 +2759,7 @@ int check(const char *_objname, bool orc)
objname = _objname;
file.elf = elf_open_read(objname, orc ? O_RDWR : O_RDONLY);
file.elf = elf_open_read(objname, O_RDWR);
if (!file.elf)
return 1;
@ -2801,7 +2820,9 @@ int check(const char *_objname, bool orc)
ret = create_orc_sections(&file);
if (ret < 0)
goto out;
}
if (file.elf->changed) {
ret = elf_write(file.elf);
if (ret < 0)
goto out;

View File

@ -563,8 +563,10 @@ static int read_relocs(struct elf *elf)
break;
default: return -1;
}
reloc->sym = find_symbol_by_index(elf, symndx);
reloc->sec = sec;
reloc->idx = i;
reloc->sym = find_symbol_by_index(elf, symndx);
if (!reloc->sym) {
WARN("can't find reloc entry symbol %d for %s",
symndx, sec->name);
@ -747,6 +749,8 @@ struct section *elf_create_section(struct elf *elf, const char *name,
elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));
elf->changed = true;
return sec;
}
@ -880,11 +884,14 @@ static int elf_rebuild_rela_reloc_section(struct section *sec, int nr)
return 0;
}
int elf_rebuild_reloc_section(struct section *sec)
int elf_rebuild_reloc_section(struct elf *elf, struct section *sec)
{
struct reloc *reloc;
int nr;
sec->changed = true;
elf->changed = true;
nr = 0;
list_for_each_entry(reloc, &sec->reloc_list, list)
nr++;
@ -896,7 +903,54 @@ int elf_rebuild_reloc_section(struct section *sec)
}
}
int elf_write(const struct elf *elf)
int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn)
{
Elf_Data *data = sec->data;
if (data->d_type != ELF_T_BYTE || data->d_off) {
WARN("write to unexpected data for section: %s", sec->name);
return -1;
}
memcpy(data->d_buf + offset, insn, len);
elf_flagdata(data, ELF_C_SET, ELF_F_DIRTY);
elf->changed = true;
return 0;
}
int elf_write_reloc(struct elf *elf, struct reloc *reloc)
{
struct section *sec = reloc->sec;
if (sec->sh.sh_type == SHT_REL) {
reloc->rel.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
reloc->rel.r_offset = reloc->offset;
if (!gelf_update_rel(sec->data, reloc->idx, &reloc->rel)) {
WARN_ELF("gelf_update_rel");
return -1;
}
} else {
reloc->rela.r_info = GELF_R_INFO(reloc->sym->idx, reloc->type);
reloc->rela.r_addend = reloc->addend;
reloc->rela.r_offset = reloc->offset;
if (!gelf_update_rela(sec->data, reloc->idx, &reloc->rela)) {
WARN_ELF("gelf_update_rela");
return -1;
}
}
elf->changed = true;
return 0;
}
int elf_write(struct elf *elf)
{
struct section *sec;
Elf_Scn *s;
@ -913,6 +967,8 @@ int elf_write(const struct elf *elf)
WARN_ELF("gelf_update_shdr");
return -1;
}
sec->changed = false;
}
}
@ -925,6 +981,8 @@ int elf_write(const struct elf *elf)
return -1;
}
elf->changed = false;
return 0;
}

View File

@ -67,9 +67,10 @@ struct reloc {
};
struct section *sec;
struct symbol *sym;
unsigned int type;
unsigned long offset;
unsigned int type;
int addend;
int idx;
bool jump_table_start;
};
@ -79,6 +80,7 @@ struct elf {
Elf *elf;
GElf_Ehdr ehdr;
int fd;
bool changed;
char *name;
struct list_head sections;
DECLARE_HASHTABLE(symbol_hash, ELF_HASH_BITS);
@ -121,7 +123,11 @@ struct elf *elf_open_read(const char *name, int flags);
struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr);
struct section *elf_create_reloc_section(struct elf *elf, struct section *base, int reltype);
void elf_add_reloc(struct elf *elf, struct reloc *reloc);
int elf_write(const struct elf *elf);
int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn);
int elf_write_reloc(struct elf *elf, struct reloc *reloc);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
struct section *find_section_by_name(const struct elf *elf, const char *name);
@ -133,7 +139,7 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len);
struct symbol *find_func_containing(struct section *sec, unsigned long offset);
int elf_rebuild_reloc_section(struct section *sec);
int elf_rebuild_reloc_section(struct elf *elf, struct section *sec);
#define for_each_sec(file, sec) \
list_for_each_entry(sec, &file->elf->sections, list)

View File

@ -222,7 +222,7 @@ int create_orc_sections(struct objtool_file *file)
}
}
if (elf_rebuild_reloc_section(ip_relocsec))
if (elf_rebuild_reloc_section(file->elf, ip_relocsec))
return -1;
return 0;