![Catalin Marinas](/assets/img/avatar_default.png)
Modules compiled to Thumb-2 have two additional relocations needing to be resolved at load time, R_ARM_THM_CALL and R_ARM_THM_JUMP24, for BL and B.W instructions. The maximum Thumb-2 addressing range is +/-2^24 (+/-16MB) therefore the MODULES_VADDR macro in asm/memory.h is set to (MODULES_END - 8MB) for the Thumb-2 compiled kernel. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
305 lines
8.2 KiB
C
305 lines
8.2 KiB
C
/*
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* linux/arch/arm/kernel/module.c
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*
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* Copyright (C) 2002 Russell King.
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* Modified for nommu by Hyok S. Choi
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Module allocation method suggested by Andi Kleen.
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*/
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#include <linux/module.h>
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#include <linux/moduleloader.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/elf.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <asm/pgtable.h>
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#include <asm/sections.h>
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#include <asm/unwind.h>
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#ifdef CONFIG_XIP_KERNEL
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/*
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* The XIP kernel text is mapped in the module area for modules and
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* some other stuff to work without any indirect relocations.
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* MODULES_VADDR is redefined here and not in asm/memory.h to avoid
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* recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
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*/
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#undef MODULES_VADDR
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#define MODULES_VADDR (((unsigned long)_etext + ~PGDIR_MASK) & PGDIR_MASK)
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#endif
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#ifdef CONFIG_MMU
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void *module_alloc(unsigned long size)
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{
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struct vm_struct *area;
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size = PAGE_ALIGN(size);
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if (!size)
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return NULL;
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area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
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if (!area)
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return NULL;
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return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
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}
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#else /* CONFIG_MMU */
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void *module_alloc(unsigned long size)
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{
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return size == 0 ? NULL : vmalloc(size);
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}
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#endif /* !CONFIG_MMU */
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void module_free(struct module *module, void *region)
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{
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vfree(region);
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}
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int module_frob_arch_sections(Elf_Ehdr *hdr,
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Elf_Shdr *sechdrs,
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char *secstrings,
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struct module *mod)
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{
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#ifdef CONFIG_ARM_UNWIND
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Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
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for (s = sechdrs; s < sechdrs_end; s++) {
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if (strcmp(".ARM.exidx.init.text", secstrings + s->sh_name) == 0)
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mod->arch.unw_sec_init = s;
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else if (strcmp(".ARM.exidx.devinit.text", secstrings + s->sh_name) == 0)
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mod->arch.unw_sec_devinit = s;
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else if (strcmp(".ARM.exidx", secstrings + s->sh_name) == 0)
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mod->arch.unw_sec_core = s;
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else if (strcmp(".init.text", secstrings + s->sh_name) == 0)
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mod->arch.sec_init_text = s;
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else if (strcmp(".devinit.text", secstrings + s->sh_name) == 0)
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mod->arch.sec_devinit_text = s;
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else if (strcmp(".text", secstrings + s->sh_name) == 0)
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mod->arch.sec_core_text = s;
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}
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#endif
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return 0;
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}
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int
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apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
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unsigned int relindex, struct module *module)
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{
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Elf32_Shdr *symsec = sechdrs + symindex;
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Elf32_Shdr *relsec = sechdrs + relindex;
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Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
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Elf32_Rel *rel = (void *)relsec->sh_addr;
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unsigned int i;
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for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
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unsigned long loc;
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Elf32_Sym *sym;
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s32 offset;
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u32 upper, lower, sign, j1, j2;
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offset = ELF32_R_SYM(rel->r_info);
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if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
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printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
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module->name, relindex, i);
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return -ENOEXEC;
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}
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sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
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if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
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printk(KERN_ERR "%s: out of bounds relocation, "
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"section %d reloc %d offset %d size %d\n",
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module->name, relindex, i, rel->r_offset,
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dstsec->sh_size);
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return -ENOEXEC;
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}
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loc = dstsec->sh_addr + rel->r_offset;
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switch (ELF32_R_TYPE(rel->r_info)) {
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case R_ARM_NONE:
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/* ignore */
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break;
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case R_ARM_ABS32:
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*(u32 *)loc += sym->st_value;
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break;
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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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offset = (*(u32 *)loc & 0x00ffffff) << 2;
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if (offset & 0x02000000)
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offset -= 0x04000000;
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offset += sym->st_value - loc;
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if (offset & 3 ||
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offset <= (s32)0xfe000000 ||
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offset >= (s32)0x02000000) {
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printk(KERN_ERR
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"%s: relocation out of range, section "
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"%d reloc %d sym '%s'\n", module->name,
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relindex, i, strtab + sym->st_name);
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return -ENOEXEC;
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}
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offset >>= 2;
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*(u32 *)loc &= 0xff000000;
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*(u32 *)loc |= offset & 0x00ffffff;
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break;
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case R_ARM_V4BX:
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/* Preserve Rm and the condition code. Alter
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* other bits to re-code instruction as
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* MOV PC,Rm.
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*/
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*(u32 *)loc &= 0xf000000f;
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*(u32 *)loc |= 0x01a0f000;
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break;
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case R_ARM_PREL31:
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offset = *(u32 *)loc + sym->st_value - loc;
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*(u32 *)loc = offset & 0x7fffffff;
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break;
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case R_ARM_MOVW_ABS_NC:
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case R_ARM_MOVT_ABS:
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offset = *(u32 *)loc;
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offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
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offset = (offset ^ 0x8000) - 0x8000;
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offset += sym->st_value;
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if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
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offset >>= 16;
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*(u32 *)loc &= 0xfff0f000;
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*(u32 *)loc |= ((offset & 0xf000) << 4) |
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(offset & 0x0fff);
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break;
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case R_ARM_THM_CALL:
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case R_ARM_THM_JUMP24:
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upper = *(u16 *)loc;
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lower = *(u16 *)(loc + 2);
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/*
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* 25 bit signed address range (Thumb-2 BL and B.W
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* instructions):
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* S:I1:I2:imm10:imm11:0
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* where:
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* S = upper[10] = offset[24]
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* I1 = ~(J1 ^ S) = offset[23]
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* I2 = ~(J2 ^ S) = offset[22]
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* imm10 = upper[9:0] = offset[21:12]
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* imm11 = lower[10:0] = offset[11:1]
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* J1 = lower[13]
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* J2 = lower[11]
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*/
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sign = (upper >> 10) & 1;
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j1 = (lower >> 13) & 1;
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j2 = (lower >> 11) & 1;
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offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
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((~(j2 ^ sign) & 1) << 22) |
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((upper & 0x03ff) << 12) |
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((lower & 0x07ff) << 1);
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if (offset & 0x01000000)
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offset -= 0x02000000;
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offset += sym->st_value - loc;
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/* only Thumb addresses allowed (no interworking) */
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if (!(offset & 1) ||
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offset <= (s32)0xff000000 ||
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offset >= (s32)0x01000000) {
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printk(KERN_ERR
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"%s: relocation out of range, section "
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"%d reloc %d sym '%s'\n", module->name,
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relindex, i, strtab + sym->st_name);
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return -ENOEXEC;
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}
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sign = (offset >> 24) & 1;
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j1 = sign ^ (~(offset >> 23) & 1);
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j2 = sign ^ (~(offset >> 22) & 1);
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*(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) |
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((offset >> 12) & 0x03ff));
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*(u16 *)(loc + 2) = (u16)((lower & 0xd000) |
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(j1 << 13) | (j2 << 11) |
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((offset >> 1) & 0x07ff));
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upper = *(u16 *)loc;
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lower = *(u16 *)(loc + 2);
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break;
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default:
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printk(KERN_ERR "%s: unknown relocation: %u\n",
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module->name, ELF32_R_TYPE(rel->r_info));
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return -ENOEXEC;
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}
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}
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return 0;
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}
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int
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apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relsec, struct module *module)
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{
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printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
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module->name);
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return -ENOEXEC;
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}
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#ifdef CONFIG_ARM_UNWIND
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static void register_unwind_tables(struct module *mod)
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{
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if (mod->arch.unw_sec_init && mod->arch.sec_init_text)
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mod->arch.unwind_init =
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unwind_table_add(mod->arch.unw_sec_init->sh_addr,
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mod->arch.unw_sec_init->sh_size,
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mod->arch.sec_init_text->sh_addr,
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mod->arch.sec_init_text->sh_size);
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if (mod->arch.unw_sec_devinit && mod->arch.sec_devinit_text)
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mod->arch.unwind_devinit =
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unwind_table_add(mod->arch.unw_sec_devinit->sh_addr,
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mod->arch.unw_sec_devinit->sh_size,
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mod->arch.sec_devinit_text->sh_addr,
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mod->arch.sec_devinit_text->sh_size);
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if (mod->arch.unw_sec_core && mod->arch.sec_core_text)
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mod->arch.unwind_core =
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unwind_table_add(mod->arch.unw_sec_core->sh_addr,
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mod->arch.unw_sec_core->sh_size,
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mod->arch.sec_core_text->sh_addr,
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mod->arch.sec_core_text->sh_size);
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}
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static void unregister_unwind_tables(struct module *mod)
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{
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unwind_table_del(mod->arch.unwind_init);
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unwind_table_del(mod->arch.unwind_devinit);
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unwind_table_del(mod->arch.unwind_core);
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}
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#else
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static inline void register_unwind_tables(struct module *mod) { }
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static inline void unregister_unwind_tables(struct module *mod) { }
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#endif
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int
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module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
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struct module *module)
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{
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register_unwind_tables(module);
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return 0;
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}
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void
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module_arch_cleanup(struct module *mod)
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{
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unregister_unwind_tables(mod);
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}
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