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text relocation for netbsd

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netbsd does not allow text relocations in text segment.

tcc.h:
- Add data_ro_section
- Fix typo rela.plt

tccelf.c:
- Add data_ro_section
- Make bounds_section/lbounds_section rw
- Add GNU_RELRO section for data_ro_section/bounds_section/lbounds_section
- Fix relocation for __dso_handle in atexit()

tccgen.c:
- Use data_ro_section

x86_64-gen.c:
- Use R_X86_64_PC32 instead of R_X86_64_64 for bounds checking

tests/Makefile, tests/tests2/Makefile
- Enable dll tests for netbsd
This commit is contained in:
herman ten brugge 2020-12-30 14:08:06 +01:00
parent c13c434383
commit 0821940e26
6 changed files with 101 additions and 44 deletions
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5
tcc.h
View file

@ -409,7 +409,7 @@ extern long double strtold (const char *__nptr, char **__endptr);
# define ElfW_Rel ElfW(Rela)
# define SHT_RELX SHT_RELA
# define REL_SECTION_FMT ".rela%s"
# define RELPLT_SECTION_FMT ".rel.plt"
# define RELPLT_SECTION_FMT ".rela.plt"
#else
# define ELFCLASSW ELFCLASS32
# define ElfW(type) Elf##32##_##type
@ -872,7 +872,7 @@ struct TCCState {
Section *plt;
/* predefined sections */
Section *text_section, *data_section, *bss_section;
Section *text_section, *data_section, *data_ro_section, *bss_section;
Section *common_section;
Section *cur_text_section; /* current section where function code is generated */
#ifdef CONFIG_TCC_BCHECK
@ -1817,6 +1817,7 @@ ST_FUNC void gen_makedeps(TCCState *s, const char *target, const char *filename)
#define text_section TCC_STATE_VAR(text_section)
#define data_section TCC_STATE_VAR(data_section)
#define data_ro_section TCC_STATE_VAR(data_ro_section)
#define bss_section TCC_STATE_VAR(bss_section)
#define common_section TCC_STATE_VAR(common_section)
#define cur_text_section TCC_STATE_VAR(cur_text_section)

109
tccelf.c
View file

@ -58,6 +58,8 @@ ST_FUNC void tccelf_new(TCCState *s)
/* create standard sections */
text_section = new_section(s, ".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR);
data_section = new_section(s, ".data", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
/* create ro data section (make ro after relocation done with GNU_RELRO) */
data_ro_section = new_section(s, ".data.ro", SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
bss_section = new_section(s, ".bss", SHT_NOBITS, SHF_ALLOC | SHF_WRITE);
common_section = new_section(s, ".common", SHT_NOBITS, SHF_PRIVATE);
common_section->sh_num = SHN_COMMON;
@ -79,11 +81,11 @@ ST_FUNC void tccelf_new(TCCState *s)
ST_FUNC void tccelf_bounds_new(TCCState *s)
{
TCCState *s1 = s;
/* create bounds sections */
/* create bounds sections (make ro after relocation done with GNU_RELRO) */
bounds_section = new_section(s, ".bounds",
SHT_PROGBITS, SHF_ALLOC);
SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
lbounds_section = new_section(s, ".lbounds",
SHT_PROGBITS, SHF_ALLOC);
SHT_PROGBITS, SHF_ALLOC | SHF_WRITE);
}
#endif
@ -1043,6 +1045,16 @@ static int prepare_dynamic_rel(TCCState *s1, Section *sr)
case R_386_PC32:
#elif defined(TCC_TARGET_X86_64)
case R_X86_64_PC32:
{
ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
/* support __dso_handle in atexit() */
if (sym->st_shndx != SHN_UNDEF &&
ELFW(ST_VISIBILITY)(sym->st_other) == STV_HIDDEN) {
rel->r_info = ELFW(R_INFO)(sym_index, R_X86_64_PLT32);
break;
}
}
#elif defined(TCC_TARGET_ARM64)
case R_AARCH64_PREL32:
#endif
@ -1828,11 +1840,20 @@ struct dyn_inf {
addr_t rel_size;
};
/* Info for GNU_RELRO */
struct ro_inf {
addr_t sh_offset;
addr_t sh_addr;
addr_t sh_size;
};
/* Assign sections to segments and decide how are sections laid out when loaded
in memory. This function also fills corresponding program headers. */
static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr,
int phnum, int phfill,
Section *interp, Section* strsec,
struct dyn_inf *dyninf, int *sec_order)
struct dyn_inf *dyninf, struct ro_inf *roinf,
int *sec_order)
{
int i, sh_order_index, file_offset;
Section *s;
@ -1883,7 +1904,10 @@ static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
/* dynamic relocation table information, for .dynamic section */
dyninf->rel_addr = dyninf->rel_size = 0;
for(j = 0; j < (phnum == 6 ? 3 : 2); j++) {
/* read only segment mapping for GNU_RELRO */
roinf->sh_offset = roinf->sh_addr = roinf->sh_size = 0;
for(j = 0; j < phfill; j++) {
Section *relocplt = s1->got ? s1->got->relocplt : NULL;
ph->p_type = j == 2 ? PT_TLS : PT_LOAD;
@ -1898,7 +1922,7 @@ static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
info about the layout. We do the following ordering: interp,
symbol tables, relocations, progbits, nobits */
/* XXX: do faster and simpler sorting */
for(k = 0; k < 6; k++) {
for(k = 0; k < 7; k++) {
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
/* compute if section should be included */
@ -1930,12 +1954,17 @@ static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
else if (k != 3 && s == relocplt)
continue;
} else if (s->sh_type == SHT_NOBITS) {
if (k != 5)
if (k != 6)
continue;
} else {
} else if (s == data_ro_section ||
s == bounds_section ||
s == lbounds_section) {
if (k != 4)
continue;
}
} else {
if (k != 5)
continue;
}
sec_order[sh_order_index++] = i;
/* section matches: we align it and add its size */
@ -1956,8 +1985,17 @@ static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
if (s->sh_type == SHT_RELX && s != relocplt) {
if (dyninf->rel_size == 0)
dyninf->rel_addr = addr;
dyninf->rel_size += s->sh_size;
dyninf->rel_size = (addr - dyninf->rel_addr) + s->sh_size;
}
if (s == data_ro_section ||
s == bounds_section ||
s == lbounds_section) {
if (roinf->sh_size == 0) {
roinf->sh_offset = s->sh_offset;
roinf->sh_addr = s->sh_addr;
}
roinf->sh_size = (addr - roinf->sh_addr) + s->sh_size;
}
addr += s->sh_size;
if (s->sh_type != SHT_NOBITS)
file_offset += s->sh_size;
@ -2018,7 +2056,7 @@ static void put_dt(Section *dynamic, int dt, addr_t val)
}
static void fill_unloadable_phdr(ElfW(Phdr) *phdr, int phnum, Section *interp,
Section *dynamic, Section *note)
Section *dynamic, Section *note, struct ro_inf *roinf)
{
ElfW(Phdr) *ph;
@ -2046,7 +2084,7 @@ static void fill_unloadable_phdr(ElfW(Phdr) *phdr, int phnum, Section *interp,
}
if (note) {
ph = &phdr[phnum - 2];
ph = &phdr[phnum - 2 - (roinf != NULL)];
ph->p_type = PT_NOTE;
ph->p_offset = note->sh_offset;
@ -2060,7 +2098,7 @@ static void fill_unloadable_phdr(ElfW(Phdr) *phdr, int phnum, Section *interp,
/* if dynamic section, then add corresponding program header */
if (dynamic) {
ph = &phdr[phnum - 1];
ph = &phdr[phnum - 1 - (roinf != NULL)];
ph->p_type = PT_DYNAMIC;
ph->p_offset = dynamic->sh_offset;
@ -2071,6 +2109,19 @@ static void fill_unloadable_phdr(ElfW(Phdr) *phdr, int phnum, Section *interp,
ph->p_flags = PF_R | PF_W;
ph->p_align = dynamic->sh_addralign;
}
if (roinf) {
ph = &phdr[phnum - 1];
ph->p_type = PT_GNU_RELRO;
ph->p_offset = roinf->sh_offset;
ph->p_vaddr = roinf->sh_addr;
ph->p_paddr = ph->p_vaddr;
ph->p_filesz = roinf->sh_size;
ph->p_memsz = roinf->sh_size;
ph->p_flags = PF_R;
ph->p_align = 1;
}
}
/* Fill the dynamic section with tags describing the address and size of
@ -2440,8 +2491,9 @@ static Section *create_bsd_note_section(TCCState *s1,
/* XXX: suppress unneeded sections */
static int elf_output_file(TCCState *s1, const char *filename)
{
int ret, phnum, shnum, file_type, file_offset, *sec_order;
int i, ret, phnum, phfill, shnum, file_type, file_offset, *sec_order;
struct dyn_inf dyninf = {0};
struct ro_inf roinf, *roinf_use = NULL;
ElfW(Phdr) *phdr;
Section *strsec, *interp, *dynamic, *dynstr, *note = NULL;
@ -2489,6 +2541,8 @@ static int elf_output_file(TCCState *s1, const char *filename)
s1->dynsym = new_symtab(s1, ".dynsym", SHT_DYNSYM, SHF_ALLOC,
".dynstr",
".hash", SHF_ALLOC);
/* Number of local symbols (readelf complains if not set) */
s1->dynsym->sh_info = 1;
dynstr = s1->dynsym->link;
/* add dynamic section */
dynamic = new_section(s1, ".dynamic", SHT_DYNAMIC,
@ -2556,22 +2610,31 @@ static int elf_output_file(TCCState *s1, const char *filename)
}
#endif
for (i = 1; i < s1->nb_sections &&
!(s1->sections[i]->sh_flags & SHF_TLS); i++);
phfill = 2 + (i < s1->nb_sections);
/* compute number of program headers */
if (file_type == TCC_OUTPUT_OBJ)
phnum = 0;
phnum = phfill = 0;
else if (file_type == TCC_OUTPUT_DLL)
phnum = 3;
else if (s1->static_link)
phnum = 2;
else {
int i;
for (i = 1; i < s1->nb_sections &&
!(s1->sections[i]->sh_flags & SHF_TLS); i++);
phnum = i < s1->nb_sections ? 6 : 5;
phnum = 5 + (i < s1->nb_sections);
}
phnum += note != NULL;
#if !TARGETOS_FreeBSD && !TARGETOS_NetBSD && !defined(__APPLE__) && !defined(_WIN32)
/* GNU_RELRO */
if (file_type != TCC_OUTPUT_OBJ) {
phnum++;
roinf_use = &roinf;
}
#endif
/* allocate program segment headers */
phdr = tcc_mallocz(phnum * sizeof(ElfW(Phdr)));
@ -2583,14 +2646,14 @@ static int elf_output_file(TCCState *s1, const char *filename)
sec_order[0] = 0;
/* compute section to program header mapping */
file_offset = layout_sections(s1, phdr, phnum, interp, strsec, &dyninf,
sec_order);
file_offset = layout_sections(s1, phdr, phnum, phfill, interp, strsec,
&dyninf, &roinf, sec_order);
#ifndef ELF_OBJ_ONLY
/* Fill remaining program header and finalize relocation related to dynamic
linking. */
if (file_type != TCC_OUTPUT_OBJ) {
fill_unloadable_phdr(phdr, phnum, interp, dynamic, note);
fill_unloadable_phdr(phdr, phnum, interp, dynamic, note, roinf_use);
if (dynamic) {
ElfW(Sym) *sym;
dynamic->data_offset = dyninf.data_offset;

6
tccgen.c
View file

@ -8120,8 +8120,10 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
/* allocate symbol in corresponding section */
sec = ad->section;
if (!sec) {
if (has_init)
sec = data_section;
if (type->t & VT_CONSTANT)
sec = data_ro_section;
else if (has_init)
sec = data_section;
else if (tcc_state->nocommon)
sec = bss_section;
}

8
tests/Makefile
View file

@ -64,17 +64,11 @@ endif
ifeq ($(TARGETOS),OpenBSD)
dlltest: CFLAGS+=-fno-stack-protector
endif
ifeq ($(TARGETOS),FreeBSD)
ifneq (,$(filter FreeBSD NetBSD,$(TARGETOS)))
# test3 has dlsym problems
TESTS := $(filter-out test3,$(TESTS))
TESTS += test1
endif
ifeq ($(TARGETOS),NetBSD)
# test3 has dlsym problems
# dlltest does not allow text relocations
TESTS := $(filter-out test3 dlltest,$(TESTS))
TESTS += test1
endif
RUN_TCC = $(NATIVE_DEFINES) -run $(TOPSRC)/tcc.c $(TCCFLAGS)
DISAS = objdump -d

3
tests/tests2/Makefile
View file

@ -53,9 +53,6 @@ ifneq (,$(filter OpenBSD FreeBSD NetBSD,$(TARGETOS)))
SKIP += 114_bound_signal.test # libc problem signal/fork
SKIP += 116_bound_setjmp2.test # No TLS_FUNC/TLS_VAR in bcheck.c
endif
ifeq ($(TARGETOS),NetBSD)
SKIP += 113_btdll.test # text relocations
endif
# Some tests might need arguments
ARGS =

14
x86_64-gen.c
View file

@ -674,8 +674,8 @@ static void gen_bounds_prolog(void)
func_bound_offset = lbounds_section->data_offset;
func_bound_ind = ind;
func_bound_add_epilog = 0;
o(0xb848 + TREG_FASTCALL_1 * 0x100); /*lbound section pointer */
gen_le64 (0);
o(0x0d8d48 + ((TREG_FASTCALL_1 == TREG_RDI) * 0x300000)); /*lbound section pointer */
gen_le32 (0);
oad(0xb8, 0); /* call to function */
}
@ -700,17 +700,17 @@ static void gen_bounds_epilog(void)
if (offset_modified) {
saved_ind = ind;
ind = func_bound_ind;
greloca(cur_text_section, sym_data, ind + 2, R_X86_64_64, 0);
ind = ind + 10;
greloca(cur_text_section, sym_data, ind + 3, R_X86_64_PC32, -4);
ind = ind + 7;
gen_bounds_call(TOK___bound_local_new);
ind = saved_ind;
}
/* generate bound check local freeing */
o(0x5250); /* save returned value, if any */
greloca(cur_text_section, sym_data, ind + 2, R_X86_64_64, 0);
o(0xb848 + TREG_FASTCALL_1 * 0x100); /* mov xxx, %rcx/di */
gen_le64 (0);
greloca(cur_text_section, sym_data, ind + 3, R_X86_64_PC32, -4);
o(0x0d8d48 + ((TREG_FASTCALL_1 == TREG_RDI) * 0x300000)); /* lea xxx(%rip), %rcx/rdi */
gen_le32 (0);
gen_bounds_call(TOK___bound_local_delete);
o(0x585a); /* restore returned value, if any */
}