diff options
Diffstat (limited to 'grub-core/kern/arm/dl_helper.c')
| -rw-r--r-- | grub-core/kern/arm/dl_helper.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/grub-core/kern/arm/dl_helper.c b/grub-core/kern/arm/dl_helper.c new file mode 100644 index 0000000..21d77f7 --- /dev/null +++ b/grub-core/kern/arm/dl_helper.c @@ -0,0 +1,245 @@ +/* dl.c - arch-dependent part of loadable module support */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2013 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/dl.h> +#include <grub/elf.h> +#include <grub/misc.h> +#include <grub/err.h> +#include <grub/mm.h> +#include <grub/i18n.h> +#include <grub/arm/reloc.h> + +static inline grub_uint32_t +thumb_get_instruction_word (grub_uint16_t *target) +{ + /* Extract instruction word in alignment-safe manner */ + return grub_le_to_cpu16 ((*target)) << 16 | grub_le_to_cpu16 (*(target + 1)); +} + +static inline void +thumb_set_instruction_word (grub_uint16_t *target, grub_uint32_t insword) +{ + *target = grub_cpu_to_le16 (insword >> 16); + *(target + 1) = grub_cpu_to_le16 (insword & 0xffff); +} + +/* + * R_ARM_ABS32 + * + * Simple relocation of 32-bit value (in literal pool) + */ +grub_err_t +grub_arm_reloc_abs32 (Elf32_Word *target, Elf32_Addr sym_addr) +{ + Elf32_Addr tmp; + + tmp = grub_le_to_cpu32 (*target); + tmp += sym_addr; + *target = grub_cpu_to_le32 (tmp); + + return GRUB_ERR_NONE; +} + +/******************************************************************** + * Thumb (T32) relocations: * + * * + * 32-bit Thumb instructions can be 16-bit aligned, and are fetched * + * little-endian, requiring some additional fiddling. * + ********************************************************************/ + +grub_int32_t +grub_arm_thm_call_get_offset (grub_uint16_t *target) +{ + grub_uint32_t sign, j1, j2; + grub_uint32_t insword; + grub_int32_t offset; + + insword = thumb_get_instruction_word (target); + + /* Extract bitfields from instruction words */ + sign = (insword >> 26) & 1; + j1 = (insword >> 13) & 1; + j2 = (insword >> 11) & 1; + offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | + ((~(j2 ^ sign) & 1) << 22) | + ((insword & 0x03ff0000) >> 4) | ((insword & 0x000007ff) << 1); + + /* Sign adjust and calculate offset */ + if (offset & (1 << 24)) + offset -= (1 << 25); + + return offset; +} + +grub_err_t +grub_arm_thm_call_set_offset (grub_uint16_t *target, grub_int32_t offset) +{ + grub_uint32_t sign, j1, j2; + const grub_uint32_t insmask = 0xf800d000; + grub_uint32_t insword; + int is_blx; + + insword = thumb_get_instruction_word (target); + + if (((insword >> 12) & 0xd) == 0xc) + is_blx = 1; + else + is_blx = 0; + + if (!is_blx && !(offset & 1)) + return grub_error (GRUB_ERR_BAD_MODULE, "bl/b.w targettting ARM"); + + /* Transform blx into bl if necessarry. */ + if (is_blx && (offset & 1)) + insword |= (1 << 12); + + /* Reassemble instruction word */ + sign = (offset >> 24) & 1; + j1 = sign ^ (~(offset >> 23) & 1); + j2 = sign ^ (~(offset >> 22) & 1); + insword = (insword & insmask) | + (sign << 26) | + (((offset >> 12) & 0x03ff) << 16) | + (j1 << 13) | (j2 << 11) | ((offset >> 1) & 0x07ff); + + thumb_set_instruction_word (target, insword); + + grub_dprintf ("dl", " *insword = 0x%08x", insword); + + return GRUB_ERR_NONE; +} + +grub_int32_t +grub_arm_thm_jump19_get_offset (grub_uint16_t *target) +{ + grub_int32_t offset; + grub_uint32_t insword; + + insword = thumb_get_instruction_word (target); + + /* Extract and sign extend offset */ + offset = ((insword >> 26) & 1) << 19 + | ((insword >> 11) & 1) << 18 + | ((insword >> 13) & 1) << 17 + | ((insword >> 16) & 0x3f) << 11 + | (insword & 0x7ff); + offset <<= 1; + if (offset & (1 << 20)) + offset -= (1 << 21); + + return offset; +} + +void +grub_arm_thm_jump19_set_offset (grub_uint16_t *target, grub_int32_t offset) +{ + grub_uint32_t insword; + const grub_uint32_t insmask = 0xfbc0d000; + + offset >>= 1; + offset &= 0xfffff; + + insword = thumb_get_instruction_word (target); + + /* Reassemble instruction word and write back */ + insword &= insmask; + insword |= ((offset >> 19) & 1) << 26 + | ((offset >> 18) & 1) << 11 + | ((offset >> 17) & 1) << 13 + | ((offset >> 11) & 0x3f) << 16 + | (offset & 0x7ff); + thumb_set_instruction_word (target, insword); +} + +int +grub_arm_thm_jump19_check_offset (grub_int32_t offset) +{ + if ((offset > 1048574) || (offset < -1048576)) + return 0; + return 1; +} + +grub_uint16_t +grub_arm_thm_movw_movt_get_value (grub_uint16_t *target) +{ + grub_uint32_t insword; + + insword = thumb_get_instruction_word (target); + + return ((insword & 0xf0000) >> 4) | ((insword & 0x04000000) >> 15) | \ + ((insword & 0x7000) >> 4) | (insword & 0xff); +} + +void +grub_arm_thm_movw_movt_set_value (grub_uint16_t *target, grub_uint16_t value) +{ + grub_uint32_t insword; + const grub_uint32_t insmask = 0xfbf08f00; + + insword = thumb_get_instruction_word (target); + insword &= insmask; + + insword |= ((value & 0xf000) << 4) | ((value & 0x0800) << 15) | \ + ((value & 0x0700) << 4) | (value & 0xff); + + thumb_set_instruction_word (target, insword); +} + + +/*********************************************************** + * ARM (A32) relocations: * + * * + * ARM instructions are 32-bit in size and 32-bit aligned. * + ***********************************************************/ + +grub_int32_t +grub_arm_jump24_get_offset (grub_uint32_t *target) +{ + grub_int32_t offset; + grub_uint32_t insword; + + insword = grub_le_to_cpu32 (*target); + + offset = (insword & 0x00ffffff) << 2; + if (offset & 0x02000000) + offset -= 0x04000000; + return offset; +} + +int +grub_arm_jump24_check_offset (grub_int32_t offset) +{ + if (offset >= 0x02000000 || offset < -0x02000000) + return 0; + return 1; +} + +void +grub_arm_jump24_set_offset (grub_uint32_t *target, + grub_int32_t offset) +{ + grub_uint32_t insword; + + insword = grub_le_to_cpu32 (*target); + + insword &= 0xff000000; + insword |= (offset >> 2) & 0x00ffffff; + + *target = grub_cpu_to_le32 (insword); +} |