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-rw-r--r--grub-core/kern/arm/dl.c280
1 files changed, 280 insertions, 0 deletions
diff --git a/grub-core/kern/arm/dl.c b/grub-core/kern/arm/dl.c
new file mode 100644
index 0000000..eab9d17
--- /dev/null
+++ b/grub-core/kern/arm/dl.c
@@ -0,0 +1,280 @@
+/* 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>
+
+struct trampoline_arm
+{
+#define ARM_LOAD_IP 0xe59fc000
+#define ARM_BX 0xe12fff1c
+#define ARM_MOV_PC 0xe1a0f00c
+ grub_uint32_t load_ip; /* ldr ip, [pc] */
+ grub_uint32_t bx; /* bx ip or mov pc, ip*/
+ grub_uint32_t addr;
+};
+
+static grub_uint16_t thumb_template[8] =
+ {
+ 0x468c, /* mov ip, r1 */
+ 0x4903, /* ldr r1, [pc, #12] ; (10 <.text+0x10>) */
+ /* Exchange R1 and IP in limited Thumb instruction set.
+ IP gets negated but we compensate it by C code. */
+ /* R1 IP */
+ /* -A R1 */
+ 0x4461, /* add r1, ip */ /* R1-A R1 */
+ 0x4249, /* negs r1, r1 */ /* A-R1 R1 */
+ 0x448c, /* add ip, r1 */ /* A-R1 A */
+ 0x4249, /* negs r1, r1 */ /* R1-A A */
+ 0x4461, /* add r1, ip */ /* R1 A */
+ 0x4760 /* bx ip */
+ };
+
+struct trampoline_thumb
+{
+ grub_uint16_t template[8];
+ grub_uint32_t neg_addr;
+};
+
+#pragma GCC diagnostic ignored "-Wcast-align"
+
+grub_err_t
+grub_arch_dl_get_tramp_got_size (const void *ehdr, grub_size_t *tramp,
+ grub_size_t *got)
+{
+ const Elf_Ehdr *e = ehdr;
+ const Elf_Shdr *s;
+ unsigned i;
+
+ *tramp = 0;
+ *got = 0;
+
+ for (i = 0, s = (const Elf_Shdr *) ((grub_addr_t) e + e->e_shoff);
+ i < e->e_shnum;
+ i++, s = (const Elf_Shdr *) ((grub_addr_t) s + e->e_shentsize))
+ if (s->sh_type == SHT_REL)
+ {
+ const Elf_Rel *rel, *max;
+
+ for (rel = (const Elf_Rel *) ((grub_addr_t) e + s->sh_offset),
+ max = (const Elf_Rel *) ((grub_addr_t) rel + s->sh_size);
+ rel + 1 <= max;
+ rel = (const Elf_Rel *) ((grub_addr_t) rel + s->sh_entsize))
+ switch (ELF_R_TYPE (rel->r_info))
+ {
+ case R_ARM_CALL:
+ case R_ARM_JUMP24:
+ {
+ *tramp += sizeof (struct trampoline_arm);
+ break;
+ }
+ case R_ARM_THM_CALL:
+ case R_ARM_THM_JUMP24:
+ case R_ARM_THM_JUMP19:
+ {
+ *tramp += sizeof (struct trampoline_thumb);
+ break;
+ }
+ }
+ }
+
+ grub_dprintf ("dl", "trampoline size %x\n", *tramp);
+
+ return GRUB_ERR_NONE;
+}
+
+/*************************************************
+ * Runtime dynamic linker with helper functions. *
+ *************************************************/
+grub_err_t
+grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr,
+ Elf_Shdr *s, grub_dl_segment_t seg)
+{
+ Elf_Rel *rel, *max;
+
+ for (rel = (Elf_Rel *) ((char *) ehdr + s->sh_offset),
+ max = (Elf_Rel *) ((char *) rel + s->sh_size);
+ rel < max;
+ rel = (Elf_Rel *) ((char *) rel + s->sh_entsize))
+ {
+ Elf_Addr *target, sym_addr;
+ grub_err_t retval;
+ Elf_Sym *sym;
+
+ if (seg->size < rel->r_offset)
+ return grub_error (GRUB_ERR_BAD_MODULE,
+ "reloc offset is out of the segment");
+ target = (void *) ((char *) seg->addr + rel->r_offset);
+ sym = (Elf_Sym *) ((char *) mod->symtab
+ + mod->symsize * ELF_R_SYM (rel->r_info));
+
+ sym_addr = sym->st_value;
+
+ switch (ELF_R_TYPE (rel->r_info))
+ {
+ case R_ARM_ABS32:
+ {
+ /* Data will be naturally aligned */
+ retval = grub_arm_reloc_abs32 (target, sym_addr);
+ if (retval != GRUB_ERR_NONE)
+ return retval;
+ }
+ break;
+ case R_ARM_CALL:
+ case R_ARM_JUMP24:
+ {
+ grub_int32_t offset;
+
+ sym_addr += grub_arm_jump24_get_offset (target);
+ offset = sym_addr - (grub_uint32_t) target;
+
+ if ((sym_addr & 1) || !grub_arm_jump24_check_offset (offset))
+ {
+ struct trampoline_arm *tp = mod->trampptr;
+ mod->trampptr = tp + 1;
+ tp->load_ip = ARM_LOAD_IP;
+ tp->bx = (sym_addr & 1) ? ARM_BX : ARM_MOV_PC;
+ tp->addr = sym_addr + 8;
+ offset = (grub_uint8_t *) tp - (grub_uint8_t *) target - 8;
+ }
+ if (!grub_arm_jump24_check_offset (offset))
+ return grub_error (GRUB_ERR_BAD_MODULE,
+ "trampoline out of range");
+ grub_arm_jump24_set_offset (target, offset);
+ }
+ break;
+ case R_ARM_THM_CALL:
+ case R_ARM_THM_JUMP24:
+ {
+ /* Thumb instructions can be 16-bit aligned */
+ grub_int32_t offset;
+
+ sym_addr += grub_arm_thm_call_get_offset ((grub_uint16_t *) target);
+
+ grub_dprintf ("dl", " sym_addr = 0x%08x\n", sym_addr);
+ if (ELF_ST_TYPE (sym->st_info) != STT_FUNC)
+ sym_addr |= 1;
+
+ offset = sym_addr - (grub_uint32_t) target;
+
+ grub_dprintf("dl", " BL*: target=%p, sym_addr=0x%08x, offset=%d\n",
+ target, sym_addr, offset);
+
+ if (!(sym_addr & 1) || (offset < -0x200000 || offset >= 0x200000))
+ {
+ struct trampoline_thumb *tp = mod->trampptr;
+ mod->trampptr = tp + 1;
+ grub_memcpy (tp->template, thumb_template, sizeof (tp->template));
+ tp->neg_addr = -sym_addr - 4;
+ offset = ((grub_uint8_t *) tp - (grub_uint8_t *) target - 4) | 1;
+ }
+
+ if (offset < -0x200000 || offset >= 0x200000)
+ return grub_error (GRUB_ERR_BAD_MODULE,
+ "trampoline out of range");
+
+ grub_dprintf ("dl", " relative destination = %p\n",
+ (char *) target + offset);
+
+ retval = grub_arm_thm_call_set_offset ((grub_uint16_t *) target, offset);
+ if (retval != GRUB_ERR_NONE)
+ return retval;
+ }
+ break;
+ /* Happens when compiled with -march=armv4. Since currently we need
+ at least armv5, keep bx as-is.
+ */
+ case R_ARM_V4BX:
+ break;
+ case R_ARM_THM_MOVW_ABS_NC:
+ case R_ARM_THM_MOVT_ABS:
+ {
+ grub_uint32_t offset;
+ offset = grub_arm_thm_movw_movt_get_value((grub_uint16_t *) target);
+ offset += sym_addr;
+
+ if (ELF_R_TYPE (rel->r_info) == R_ARM_THM_MOVT_ABS)
+ offset >>= 16;
+ else
+ offset &= 0xffff;
+
+ grub_arm_thm_movw_movt_set_value((grub_uint16_t *) target, offset);
+ }
+ break;
+ case R_ARM_THM_JUMP19:
+ {
+ /* Thumb instructions can be 16-bit aligned */
+ grub_int32_t offset;
+
+ sym_addr += grub_arm_thm_jump19_get_offset ((grub_uint16_t *) target);
+
+ if (ELF_ST_TYPE (sym->st_info) != STT_FUNC)
+ sym_addr |= 1;
+
+ offset = sym_addr - (grub_uint32_t) target;
+
+ if (!grub_arm_thm_jump19_check_offset (offset)
+ || !(sym_addr & 1))
+ {
+ struct trampoline_thumb *tp = mod->trampptr;
+ mod->trampptr = tp + 1;
+ grub_memcpy (tp->template, thumb_template, sizeof (tp->template));
+ tp->neg_addr = -sym_addr - 4;
+ offset = ((grub_uint8_t *) tp - (grub_uint8_t *) target - 4) | 1;
+ }
+
+ if (!grub_arm_thm_jump19_check_offset (offset))
+ return grub_error (GRUB_ERR_BAD_MODULE,
+ "trampoline out of range");
+
+ grub_arm_thm_jump19_set_offset ((grub_uint16_t *) target, offset);
+ }
+ break;
+ default:
+ return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+ N_("relocation 0x%x is not implemented yet"),
+ ELF_R_TYPE (rel->r_info));
+ }
+ }
+
+ return GRUB_ERR_NONE;
+}
+
+
+/*
+ * Check if EHDR is a valid ELF header.
+ */
+grub_err_t
+grub_arch_dl_check_header (void *ehdr)
+{
+ Elf_Ehdr *e = ehdr;
+
+ /* Check the magic numbers. */
+ if (e->e_ident[EI_CLASS] != ELFCLASS32
+ || e->e_ident[EI_DATA] != ELFDATA2LSB || e->e_machine != EM_ARM)
+ return grub_error (GRUB_ERR_BAD_OS,
+ N_("invalid arch-dependent ELF magic"));
+
+ return GRUB_ERR_NONE;
+}
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