tinycc/arm64-link.c
Ole André Vadla Ravnås 263232e8cf Improve support for Apple's ABIs
- i386: Align first argument on a 16 byte boundary.
- arm64: Support Apple's version of the AArch64 ABI, including zero-
  extension of variadic arguments smaller than 32 bits.
- arm64e: Make all indirect branches authenticated, and sign function
  pointer values both from the perspective of the C code and when
  looking up symbols.
- arm64e: Support signing and stripping pointers.
- Query page size to support text segments larger than 4096 bytes on
  i/macOS systems with 16K pages.
- Avoid RWX page allocations on most platforms as they're off limits on
  modern Apple platforms.
- Split relocation and marking pages executable to avoid crashing when
  marking fails.

Co-authored-by: Francesco Tamagni <mrmacete@protonmail.ch>
2020-11-14 19:16:48 +01:00

296 lines
10 KiB
C

#ifdef TARGET_DEFS_ONLY
#define EM_TCC_TARGET EM_AARCH64
#define R_DATA_32 R_AARCH64_ABS32
#define R_DATA_PTR R_AARCH64_ABS64
#define R_JMP_SLOT R_AARCH64_JUMP_SLOT
#define R_GLOB_DAT R_AARCH64_GLOB_DAT
#define R_COPY R_AARCH64_COPY
#define R_RELATIVE R_AARCH64_RELATIVE
#define R_NUM R_AARCH64_NUM
#define ELF_START_ADDR 0x00400000
#define ELF_PAGE_SIZE 0x10000
#define PCRELATIVE_DLLPLT 1
#define RELOCATE_DLLPLT 1
#else /* !TARGET_DEFS_ONLY */
#include "tcc.h"
/* Returns 1 for a code relocation, 0 for a data relocation. For unknown
relocations, returns -1. */
int code_reloc (int reloc_type)
{
switch (reloc_type) {
case R_AARCH64_ABS32:
case R_AARCH64_ABS64:
case R_AARCH64_PREL32:
case R_AARCH64_MOVW_UABS_G0_NC:
case R_AARCH64_MOVW_UABS_G1_NC:
case R_AARCH64_MOVW_UABS_G2_NC:
case R_AARCH64_MOVW_UABS_G3:
case R_AARCH64_ADR_PREL_PG_HI21:
case R_AARCH64_ADD_ABS_LO12_NC:
case R_AARCH64_ADR_GOT_PAGE:
case R_AARCH64_LD64_GOT_LO12_NC:
case R_AARCH64_LDST64_ABS_LO12_NC:
case R_AARCH64_GLOB_DAT:
case R_AARCH64_COPY:
return 0;
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
case R_AARCH64_JUMP_SLOT:
return 1;
}
return -1;
}
/* Returns an enumerator to describe whether and when the relocation needs a
GOT and/or PLT entry to be created. See tcc.h for a description of the
different values. */
int gotplt_entry_type (int reloc_type)
{
switch (reloc_type) {
case R_AARCH64_PREL32:
case R_AARCH64_MOVW_UABS_G0_NC:
case R_AARCH64_MOVW_UABS_G1_NC:
case R_AARCH64_MOVW_UABS_G2_NC:
case R_AARCH64_MOVW_UABS_G3:
case R_AARCH64_ADR_PREL_PG_HI21:
case R_AARCH64_ADD_ABS_LO12_NC:
case R_AARCH64_LDST64_ABS_LO12_NC:
case R_AARCH64_GLOB_DAT:
case R_AARCH64_JUMP_SLOT:
case R_AARCH64_COPY:
return NO_GOTPLT_ENTRY;
case R_AARCH64_ABS32:
case R_AARCH64_ABS64:
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
return AUTO_GOTPLT_ENTRY;
case R_AARCH64_ADR_GOT_PAGE:
case R_AARCH64_LD64_GOT_LO12_NC:
return ALWAYS_GOTPLT_ENTRY;
}
return -1;
}
ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
{
Section *plt = s1->plt;
uint8_t *p;
unsigned plt_offset;
if (plt->data_offset == 0) {
section_ptr_add(plt, 32);
}
plt_offset = plt->data_offset;
p = section_ptr_add(plt, 16);
write32le(p, got_offset);
write32le(p + 4, (uint64_t) got_offset >> 32);
return plt_offset;
}
/* relocate the PLT: compute addresses and offsets in the PLT now that final
address for PLT and GOT are known (see fill_program_header) */
ST_FUNC void relocate_plt(TCCState *s1)
{
uint8_t *p, *p_end;
uint32_t br_flags;
if (!s1->plt)
return;
p = s1->plt->data;
p_end = p + s1->plt->data_offset;
#ifdef HAVE_PTRAUTH
br_flags = 0x81f; // br => braaz
#else
br_flags = 0;
#endif
if (p < p_end) {
uint64_t plt = s1->plt->sh_addr;
uint64_t got = s1->got->sh_addr;
uint64_t off = (got >> 12) - (plt >> 12);
if ((off + ((uint32_t)1 << 20)) >> 21)
tcc_error("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, plt);
write32le(p, 0xa9bf7bf0); // stp x16,x30,[sp,#-16]!
write32le(p + 4, (0x90000010 | // adrp x16,...
(off & 0x1ffffc) << 3 | (off & 3) << 29));
write32le(p + 8, (0xf9400211 | // ldr x17,[x16,#...]
(got & 0xff8) << 7));
write32le(p + 12, (0x91000210 | // add x16,x16,#...
(got & 0xfff) << 10));
write32le(p + 16, 0xd61f0220 | br_flags); // br x17
write32le(p + 20, 0xd503201f); // nop
write32le(p + 24, 0xd503201f); // nop
write32le(p + 28, 0xd503201f); // nop
p += 32;
while (p < p_end) {
uint64_t pc = plt + (p - s1->plt->data);
uint64_t addr = got + read64le(p);
uint64_t off = (addr >> 12) - (pc >> 12);
if ((off + ((uint32_t)1 << 20)) >> 21)
tcc_error("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, pc);
write32le(p, (0x90000010 | // adrp x16,...
(off & 0x1ffffc) << 3 | (off & 3) << 29));
write32le(p + 4, (0xf9400211 | // ldr x17,[x16,#...]
(addr & 0xff8) << 7));
write32le(p + 8, (0x91000210 | // add x16,x16,#...
(addr & 0xfff) << 10));
write32le(p + 12, 0xd61f0220 | br_flags); // br x17
p += 16;
}
}
}
void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
{
int sym_index = ELFW(R_SYM)(rel->r_info), esym_index;
#ifdef DEBUG_RELOC
ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
#endif
switch(type) {
case R_AARCH64_ABS64:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_AARCH64_ABS64);
qrel->r_addend = rel->r_addend;
qrel++;
break;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_AARCH64_RELATIVE);
qrel->r_addend = read64le(ptr) + val;
qrel++;
}
}
add64le(ptr, val);
return;
case R_AARCH64_ABS32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* XXX: this logic may depend on TCC's codegen
now TCC uses R_AARCH64_RELATIVE even for a 64bit pointer */
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(0, R_AARCH64_RELATIVE);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + val;
qrel++;
}
add32le(ptr, val);
return;
case R_AARCH64_PREL32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* DLL relocation */
esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
if (esym_index) {
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(esym_index, R_AARCH64_PREL32);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
qrel++;
break;
}
}
write32le(ptr, val - addr);
return;
case R_AARCH64_MOVW_UABS_G0_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val & 0xffff) << 5));
return;
case R_AARCH64_MOVW_UABS_G1_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 16 & 0xffff) << 5));
return;
case R_AARCH64_MOVW_UABS_G2_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 32 & 0xffff) << 5));
return;
case R_AARCH64_MOVW_UABS_G3:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 48 & 0xffff) << 5));
return;
case R_AARCH64_ADR_PREL_PG_HI21: {
uint64_t off = (val >> 12) - (addr >> 12);
if ((off + ((uint64_t)1 << 20)) >> 21)
tcc_error("R_AARCH64_ADR_PREL_PG_HI21 relocation failed");
write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
(off & 0x1ffffc) << 3 | (off & 3) << 29));
return;
}
case R_AARCH64_ADD_ABS_LO12_NC:
write32le(ptr, ((read32le(ptr) & 0xffc003ff) |
(val & 0xfff) << 10));
return;
case R_AARCH64_LDST64_ABS_LO12_NC:
write32le(ptr, ((read32le(ptr) & 0xffc003ff) |
(val & 0xff8) << 7));
return;
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
#ifdef DEBUG_RELOC
printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr, val,
(char *) symtab_section->link->data + sym->st_name);
#endif
if (((val - addr) + ((uint64_t)1 << 27)) & ~(uint64_t)0xffffffc)
tcc_error("R_AARCH64_(JUMP|CALL)26 relocation failed"
" (val=%lx, addr=%lx)", val, addr);
write32le(ptr, (0x14000000 |
(uint32_t)(type == R_AARCH64_CALL26) << 31 |
((val - addr) >> 2 & 0x3ffffff)));
return;
case R_AARCH64_ADR_GOT_PAGE: {
uint64_t off =
(((s1->got->sh_addr +
get_sym_attr(s1, sym_index, 0)->got_offset) >> 12) - (addr >> 12));
if ((off + ((uint64_t)1 << 20)) >> 21)
tcc_error("R_AARCH64_ADR_GOT_PAGE relocation failed");
write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
(off & 0x1ffffc) << 3 | (off & 3) << 29));
return;
}
case R_AARCH64_LD64_GOT_LO12_NC:
write32le(ptr,
((read32le(ptr) & 0xfff803ff) |
((s1->got->sh_addr +
get_sym_attr(s1, sym_index, 0)->got_offset) & 0xff8) << 7));
return;
case R_AARCH64_COPY:
return;
case R_AARCH64_GLOB_DAT:
case R_AARCH64_JUMP_SLOT:
/* They don't need addend */
#ifdef DEBUG_RELOC
printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr,
val - rel->r_addend,
(char *) symtab_section->link->data + sym->st_name);
#endif
write64le(ptr, val - rel->r_addend);
return;
case R_AARCH64_RELATIVE:
#ifdef TCC_TARGET_PE
add32le(ptr, val - s1->pe_imagebase);
#endif
/* do nothing */
return;
default:
fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
return;
}
}
#endif /* !TARGET_DEFS_ONLY */