123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137 |
- /*
- * Xtensa ELF code used by dl-startup.c.
- *
- * Copyright (C) 2007 Tensilica Inc.
- *
- * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
- * Parts taken from glibc/sysdeps/xtensa/dl-machine.h.
- */
- __asm__ (
- " .text\n"
- " .align 4\n"
- " .literal_position\n"
- " .global _start\n"
- " .type _start, @function\n"
- " .hidden _start\n"
- "_start:\n"
- " # Compute load offset in a2: the GOT has not yet been relocated\n"
- " # but the entries for local symbols contain the relative offsets\n"
- " # and we can explicitly add the load offset in this code.\n"
- " _call0 0f\n"
- " .align 4\n"
- "0: movi a3, _start+3\n"
- " sub a2, a0, a3\n"
- #if defined(__XTENSA_WINDOWED_ABI__)
- " # Make sure a0 is cleared to mark the top of stack.\n"
- " movi a0, 0\n"
- " # user_entry_point = _dl_start(pointer to argument block)\n"
- " movi a4, _dl_start\n"
- " mov a6, sp\n"
- " add a4, a4, a2\n"
- " callx4 a4\n"
- " # Save user_entry_point so we can jump to it.\n"
- " mov a3, a6\n"
- #elif defined(__XTENSA_CALL0_ABI__)
- " # user_entry_point = _dl_start(pointer to argument block)\n"
- " movi a0, _dl_start\n"
- " add a0, a0, a2\n"
- " mov a2, sp\n"
- " callx0 a0\n"
- " # Save user_entry_point so we can jump to it.\n"
- " mov a3, a2\n"
- #else
- #error Unsupported Xtensa ABI
- #endif
- " l32i a7, sp, 0 # load argc\n"
- " # Load _dl_skip_args into a4.\n"
- " movi a4, _dl_skip_args\n"
- " l32i a4, a4, 0\n"
- " bnez a4, .Lfixup_stack\n"
- ".Lfixup_stack_ret:\n"
- " # Pass finalizer (_dl_fini) in a2 to the user entry point.\n"
- " movi a2, _dl_fini\n"
- " # Jump to user's entry point (_start).\n"
- " jx a3\n"
- ".Lfixup_stack:\n"
- " # argc -= _dl_skip_args (with argc @ sp+0)\n"
- " sub a7, a7, a4\n"
- " s32i a7, sp, 0\n"
- " # Shift everything by _dl_skip_args.\n"
- " addi a5, sp, 4 # a5 = destination ptr = argv\n"
- " add a4, a5, a4 # a4 = source ptr = argv + _dl_skip_args\n"
- " # Shift argv.\n"
- "1: l32i a6, a4, 0\n"
- " addi a4, a4, 4\n"
- " s32i a6, a5, 0\n"
- " addi a5, a5, 4\n"
- " bnez a6, 1b\n"
- " # Shift envp.\n"
- "2: l32i a6, a4, 0\n"
- " addi a4, a4, 4\n"
- " s32i a6, a5, 0\n"
- " addi a5, a5, 4\n"
- " bnez a6, 2b\n"
- " # Shift auxiliary table.\n"
- "3: l32i a6, a4, 0\n"
- " l32i a8, a4, 4\n"
- " addi a4, a4, 8\n"
- " s32i a6, a5, 0\n"
- " s32i a8, a5, 4\n"
- " addi a5, a5, 8\n"
- " bnez a6, 3b\n"
- " j .Lfixup_stack_ret");
- /* Get a pointer to the argv value. */
- #define GET_ARGV(ARGVP, ARGS) ARGVP = (((unsigned long *) ARGS) + 1)
- /* Function calls are not safe until the GOT relocations have been done. */
- #define NO_FUNCS_BEFORE_BOOTSTRAP
- #define PERFORM_BOOTSTRAP_GOT(tpnt) \
- do { \
- xtensa_got_location *got_loc; \
- unsigned long l_addr = tpnt->loadaddr; \
- Elf32_Word relative_count; \
- unsigned long rel_addr; \
- Elf32_Addr prev_got_start = 0, prev_got_end = 0; \
- int x; \
- \
- got_loc = (xtensa_got_location *) \
- (tpnt->dynamic_info[DT_XTENSA (GOT_LOC_OFF)] + l_addr); \
- \
- for (x = 0; x < tpnt->dynamic_info[DT_XTENSA (GOT_LOC_SZ)]; x++) { \
- Elf32_Addr got_start, got_end; \
- got_start = got_loc[x].offset & ~(PAGE_SIZE - 1); \
- got_end = ((got_loc[x].offset + got_loc[x].length + PAGE_SIZE - 1) \
- & ~(PAGE_SIZE - 1)); \
- if (got_end >= prev_got_start && got_start <= prev_got_end) { \
- if (got_end > prev_got_end) \
- prev_got_end = got_end; \
- if (got_start < prev_got_start) \
- prev_got_start = got_start; \
- continue; \
- } else if (prev_got_start != prev_got_end) { \
- _dl_mprotect ((void *)(prev_got_start + l_addr), \
- prev_got_end - prev_got_start, \
- PROT_READ | PROT_WRITE | PROT_EXEC); \
- } \
- prev_got_start = got_start; \
- prev_got_end = got_end; \
- } \
- \
- if (prev_got_start != prev_got_end) { \
- _dl_mprotect ((void *)(prev_got_start + l_addr), \
- prev_got_end - prev_got_start, \
- PROT_READ | PROT_WRITE | PROT_EXEC); \
- } \
- \
- /* The following is a stripped down version of the code following \
- the invocation of PERFORM_BOOTSTRAP_GOT in dl-startup.c. That \
- code is skipped when PERFORM_BOOTSTRAP_GOT is defined, so it has \
- to be done here instead. */ \
- relative_count = tpnt->dynamic_info[DT_RELCONT_IDX]; \
- rel_addr = tpnt->dynamic_info[DT_RELOC_TABLE_ADDR]; \
- if (rel_addr) \
- elf_machine_relative(load_addr, rel_addr, relative_count); \
- } while (0)
|