442 lines
14 KiB
C
442 lines
14 KiB
C
#ifdef TARGET_DEFS_ONLY
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#define EM_TCC_TARGET EM_ARM
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/* relocation type for 32 bit data relocation */
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#define R_DATA_32 R_ARM_ABS32
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#define R_DATA_PTR R_ARM_ABS32
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#define R_JMP_SLOT R_ARM_JUMP_SLOT
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#define R_GLOB_DAT R_ARM_GLOB_DAT
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#define R_COPY R_ARM_COPY
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#define R_RELATIVE R_ARM_RELATIVE
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#define R_NUM R_ARM_NUM
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#define ELF_START_ADDR 0x00010000
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#define ELF_PAGE_SIZE 0x10000
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#define PCRELATIVE_DLLPLT 1
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#define RELOCATE_DLLPLT 1
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enum float_abi {
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ARM_SOFTFP_FLOAT,
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ARM_HARD_FLOAT,
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};
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#else /* !TARGET_DEFS_ONLY */
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#include "tcc.h"
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/* Returns 1 for a code relocation, 0 for a data relocation. For unknown
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relocations, returns -1. */
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int code_reloc (int reloc_type)
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{
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switch (reloc_type) {
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case R_ARM_MOVT_ABS:
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case R_ARM_MOVW_ABS_NC:
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case R_ARM_THM_MOVT_ABS:
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case R_ARM_THM_MOVW_ABS_NC:
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case R_ARM_ABS32:
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case R_ARM_REL32:
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case R_ARM_GOTPC:
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case R_ARM_GOTOFF:
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case R_ARM_GOT32:
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case R_ARM_GOT_PREL:
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case R_ARM_COPY:
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case R_ARM_GLOB_DAT:
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case R_ARM_NONE:
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case R_ARM_TARGET1:
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case R_ARM_MOVT_PREL:
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case R_ARM_MOVW_PREL_NC:
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return 0;
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case R_ARM_PC24:
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case R_ARM_CALL:
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case R_ARM_JUMP24:
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case R_ARM_PLT32:
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case R_ARM_THM_PC22:
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case R_ARM_THM_JUMP24:
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case R_ARM_PREL31:
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case R_ARM_V4BX:
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case R_ARM_JUMP_SLOT:
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return 1;
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}
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return -1;
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}
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/* Returns an enumerator to describe whether and when the relocation needs a
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GOT and/or PLT entry to be created. See tcc.h for a description of the
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different values. */
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int gotplt_entry_type (int reloc_type)
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{
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switch (reloc_type) {
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case R_ARM_NONE:
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case R_ARM_COPY:
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case R_ARM_GLOB_DAT:
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case R_ARM_JUMP_SLOT:
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return NO_GOTPLT_ENTRY;
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case R_ARM_PC24:
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case R_ARM_CALL:
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case R_ARM_JUMP24:
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case R_ARM_PLT32:
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case R_ARM_THM_PC22:
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case R_ARM_THM_JUMP24:
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case R_ARM_MOVT_ABS:
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case R_ARM_MOVW_ABS_NC:
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case R_ARM_THM_MOVT_ABS:
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case R_ARM_THM_MOVW_ABS_NC:
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case R_ARM_PREL31:
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case R_ARM_ABS32:
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case R_ARM_REL32:
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case R_ARM_V4BX:
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case R_ARM_TARGET1:
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case R_ARM_MOVT_PREL:
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case R_ARM_MOVW_PREL_NC:
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return AUTO_GOTPLT_ENTRY;
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case R_ARM_GOTPC:
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case R_ARM_GOTOFF:
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return BUILD_GOT_ONLY;
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case R_ARM_GOT32:
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case R_ARM_GOT_PREL:
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return ALWAYS_GOTPLT_ENTRY;
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}
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return -1;
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}
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#ifndef TCC_TARGET_PE
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ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
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{
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Section *plt = s1->plt;
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uint8_t *p;
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unsigned plt_offset;
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/* when building a DLL, GOT entry accesses must be done relative to
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start of GOT (see x86_64 example above) */
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/* empty PLT: create PLT0 entry that push address of call site and
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jump to ld.so resolution routine (GOT + 8) */
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if (plt->data_offset == 0) {
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p = section_ptr_add(plt, 20);
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write32le(p, 0xe52de004); /* push {lr} */
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write32le(p+4, 0xe59fe004); /* ldr lr, [pc, #4] */
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write32le(p+8, 0xe08fe00e); /* add lr, pc, lr */
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write32le(p+12, 0xe5bef008); /* ldr pc, [lr, #8]! */
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/* p+16 is set in relocate_plt */
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}
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plt_offset = plt->data_offset;
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if (attr->plt_thumb_stub) {
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p = section_ptr_add(plt, 4);
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write32le(p, 0x4778); /* bx pc */
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write32le(p+2, 0x46c0); /* nop */
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}
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p = section_ptr_add(plt, 16);
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/* save GOT offset for relocate_plt */
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write32le(p + 4, got_offset);
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return plt_offset;
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}
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/* relocate the PLT: compute addresses and offsets in the PLT now that final
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address for PLT and GOT are known (see fill_program_header) */
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ST_FUNC void relocate_plt(TCCState *s1)
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{
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uint8_t *p, *p_end;
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if (!s1->plt)
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return;
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p = s1->plt->data;
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p_end = p + s1->plt->data_offset;
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if (p < p_end) {
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int x = s1->got->sh_addr - s1->plt->sh_addr - 12;
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write32le(s1->plt->data + 16, x - 4);
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p += 20;
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while (p < p_end) {
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unsigned off = x + read32le(p + 4) + (s1->plt->data - p) + 4;
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if (read32le(p) == 0x46c04778) /* PLT Thumb stub present */
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p += 4;
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write32le(p, 0xe28fc200 | ((off >> 28) & 0xf)); // add ip, pc, #0xN0000000
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write32le(p + 4, 0xe28cc600 | ((off >> 20) & 0xff)); // add ip, pc, #0xNN00000
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write32le(p + 8, 0xe28cca00 | ((off >> 12) & 0xff)); // add ip, ip, #0xNN000
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write32le(p + 12, 0xe5bcf000 | (off & 0xfff)); // ldr pc, [ip, #0xNNN]!
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p += 16;
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}
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}
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if (s1->plt->reloc) {
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ElfW_Rel *rel;
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p = s1->got->data;
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for_each_elem(s1->plt->reloc, 0, rel, ElfW_Rel) {
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write32le(p + rel->r_offset, s1->plt->sh_addr);
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}
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}
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}
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#endif
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void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
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{
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ElfW(Sym) *sym;
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int sym_index, esym_index;
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sym_index = ELFW(R_SYM)(rel->r_info);
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sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
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switch(type) {
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case R_ARM_PC24:
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case R_ARM_CALL:
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case R_ARM_JUMP24:
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case R_ARM_PLT32:
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{
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int x, is_thumb, is_call, h, blx_avail, is_bl, th_ko;
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x = (*(int *) ptr) & 0xffffff;
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#ifdef DEBUG_RELOC
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printf ("reloc %d: x=0x%x val=0x%x ", type, x, val);
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#endif
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(*(int *)ptr) &= 0xff000000;
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if (x & 0x800000)
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x -= 0x1000000;
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x <<= 2;
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blx_avail = (TCC_CPU_VERSION >= 5);
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is_thumb = val & 1;
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is_bl = (*(unsigned *) ptr) >> 24 == 0xeb;
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is_call = (type == R_ARM_CALL || (type == R_ARM_PC24 && is_bl));
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x += val - addr;
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#ifdef DEBUG_RELOC
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printf (" newx=0x%x name=%s\n", x,
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(char *) symtab_section->link->data + sym->st_name);
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#endif
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h = x & 2;
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th_ko = (x & 3) && (!blx_avail || !is_call);
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if (th_ko || x >= 0x2000000 || x < -0x2000000)
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tcc_error("can't relocate value at %x,%d",addr, type);
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x >>= 2;
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x &= 0xffffff;
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/* Only reached if blx is avail and it is a call */
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if (is_thumb) {
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x |= h << 24;
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(*(int *)ptr) = 0xfa << 24; /* bl -> blx */
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}
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(*(int *) ptr) |= x;
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}
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return;
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/* Since these relocations only concern Thumb-2 and blx instruction was
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introduced before Thumb-2, we can assume blx is available and not
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guard its use */
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case R_ARM_THM_PC22:
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case R_ARM_THM_JUMP24:
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{
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int x, hi, lo, s, j1, j2, i1, i2, imm10, imm11;
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int to_thumb, is_call, to_plt, blx_bit = 1 << 12;
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Section *plt;
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/* weak reference */
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if (sym->st_shndx == SHN_UNDEF &&
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ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
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return;
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/* Get initial offset */
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hi = (*(uint16_t *)ptr);
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lo = (*(uint16_t *)(ptr+2));
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s = (hi >> 10) & 1;
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j1 = (lo >> 13) & 1;
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j2 = (lo >> 11) & 1;
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i1 = (j1 ^ s) ^ 1;
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i2 = (j2 ^ s) ^ 1;
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imm10 = hi & 0x3ff;
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imm11 = lo & 0x7ff;
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x = (s << 24) | (i1 << 23) | (i2 << 22) |
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(imm10 << 12) | (imm11 << 1);
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if (x & 0x01000000)
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x -= 0x02000000;
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/* Relocation infos */
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to_thumb = val & 1;
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plt = s1->plt;
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to_plt = (val >= plt->sh_addr) &&
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(val < plt->sh_addr + plt->data_offset);
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is_call = (type == R_ARM_THM_PC22);
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if (!to_thumb && !to_plt && !is_call) {
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int index;
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uint8_t *p;
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char *name, buf[1024];
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Section *text;
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name = (char *) symtab_section->link->data + sym->st_name;
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text = s1->sections[sym->st_shndx];
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/* Modify reloc to target a thumb stub to switch to ARM */
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snprintf(buf, sizeof(buf), "%s_from_thumb", name);
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index = put_elf_sym(symtab_section,
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text->data_offset + 1,
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sym->st_size, sym->st_info, 0,
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sym->st_shndx, buf);
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to_thumb = 1;
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val = text->data_offset + 1;
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rel->r_info = ELFW(R_INFO)(index, type);
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/* Create a thumb stub function to switch to ARM mode */
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put_elf_reloc(symtab_section, text,
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text->data_offset + 4, R_ARM_JUMP24,
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sym_index);
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p = section_ptr_add(text, 8);
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write32le(p, 0x4778); /* bx pc */
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write32le(p+2, 0x46c0); /* nop */
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write32le(p+4, 0xeafffffe); /* b $sym */
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}
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/* Compute final offset */
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x += val - addr;
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if (!to_thumb && is_call) {
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blx_bit = 0; /* bl -> blx */
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x = (x + 3) & -4; /* Compute offset from aligned PC */
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}
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/* Check that relocation is possible
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* offset must not be out of range
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* if target is to be entered in arm mode:
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- bit 1 must not set
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- instruction must be a call (bl) or a jump to PLT */
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if (!to_thumb || x >= 0x1000000 || x < -0x1000000)
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if (to_thumb || (val & 2) || (!is_call && !to_plt))
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tcc_error("can't relocate value at %x,%d",addr, type);
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/* Compute and store final offset */
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s = (x >> 24) & 1;
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i1 = (x >> 23) & 1;
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i2 = (x >> 22) & 1;
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j1 = s ^ (i1 ^ 1);
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j2 = s ^ (i2 ^ 1);
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imm10 = (x >> 12) & 0x3ff;
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imm11 = (x >> 1) & 0x7ff;
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(*(uint16_t *)ptr) = (uint16_t) ((hi & 0xf800) |
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(s << 10) | imm10);
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(*(uint16_t *)(ptr+2)) = (uint16_t) ((lo & 0xc000) |
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(j1 << 13) | blx_bit | (j2 << 11) |
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imm11);
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}
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return;
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case R_ARM_MOVT_ABS:
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case R_ARM_MOVW_ABS_NC:
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{
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int x, imm4, imm12;
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if (type == R_ARM_MOVT_ABS)
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val >>= 16;
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imm12 = val & 0xfff;
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imm4 = (val >> 12) & 0xf;
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x = (imm4 << 16) | imm12;
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if (type == R_ARM_THM_MOVT_ABS)
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*(int *)ptr |= x;
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else
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*(int *)ptr += x;
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}
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return;
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case R_ARM_MOVT_PREL:
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case R_ARM_MOVW_PREL_NC:
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{
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int insn = *(int *)ptr;
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int addend = ((insn >> 4) & 0xf000) | (insn & 0xfff);
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addend = (addend ^ 0x8000) - 0x8000;
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val += addend - addr;
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if (type == R_ARM_MOVT_PREL)
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val >>= 16;
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*(int *)ptr = (insn & 0xfff0f000) |
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((val & 0xf000) << 4) | (val & 0xfff);
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}
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return;
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case R_ARM_THM_MOVT_ABS:
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case R_ARM_THM_MOVW_ABS_NC:
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{
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int x, i, imm4, imm3, imm8;
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if (type == R_ARM_THM_MOVT_ABS)
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val >>= 16;
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imm8 = val & 0xff;
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imm3 = (val >> 8) & 0x7;
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i = (val >> 11) & 1;
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imm4 = (val >> 12) & 0xf;
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x = (imm3 << 28) | (imm8 << 16) | (i << 10) | imm4;
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if (type == R_ARM_THM_MOVT_ABS)
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*(int *)ptr |= x;
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else
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*(int *)ptr += x;
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}
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return;
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case R_ARM_PREL31:
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{
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int x;
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x = (*(int *)ptr) & 0x7fffffff;
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(*(int *)ptr) &= 0x80000000;
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x = (x * 2) / 2;
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x += val - addr;
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if((x^(x>>1))&0x40000000)
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tcc_error("can't relocate value at %x,%d",addr, type);
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(*(int *)ptr) |= x & 0x7fffffff;
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}
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return;
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case R_ARM_ABS32:
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case R_ARM_TARGET1:
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if (s1->output_type == TCC_OUTPUT_DLL) {
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esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
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qrel->r_offset = rel->r_offset;
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if (esym_index) {
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qrel->r_info = ELFW(R_INFO)(esym_index, R_ARM_ABS32);
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qrel++;
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return;
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} else {
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qrel->r_info = ELFW(R_INFO)(0, R_ARM_RELATIVE);
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qrel++;
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}
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}
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*(int *)ptr += val;
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return;
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case R_ARM_REL32:
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*(int *)ptr += val - addr;
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return;
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case R_ARM_GOTPC:
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*(int *)ptr += s1->got->sh_addr - addr;
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return;
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case R_ARM_GOTOFF:
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*(int *)ptr += val - s1->got->sh_addr;
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return;
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case R_ARM_GOT32:
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/* we load the got offset */
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*(int *)ptr += get_sym_attr(s1, sym_index, 0)->got_offset;
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return;
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case R_ARM_GOT_PREL:
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/* we load the pc relative got offset */
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*(int *)ptr += s1->got->sh_addr +
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get_sym_attr(s1, sym_index, 0)->got_offset -
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addr;
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return;
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case R_ARM_COPY:
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return;
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case R_ARM_V4BX:
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/* trade Thumb support for ARMv4 support */
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if ((0x0ffffff0 & *(int*)ptr) == 0x012FFF10)
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*(int*)ptr ^= 0xE12FFF10 ^ 0xE1A0F000; /* BX Rm -> MOV PC, Rm */
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return;
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case R_ARM_GLOB_DAT:
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case R_ARM_JUMP_SLOT:
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*(addr_t *)ptr = val;
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return;
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case R_ARM_NONE:
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/* Nothing to do. Normally used to indicate a dependency
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on a certain symbol (like for exception handling under EABI). */
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return;
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case R_ARM_RELATIVE:
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#ifdef TCC_TARGET_PE
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add32le(ptr, val - s1->pe_imagebase);
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#endif
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/* do nothing */
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return;
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default:
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fprintf(stderr,"FIXME: handle reloc type %d at %x [%p] to %x\n",
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type, (unsigned)addr, ptr, (unsigned)val);
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return;
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}
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}
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#endif /* !TARGET_DEFS_ONLY */
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