forked from Minki/linux
6716dbbdef
So finally after almost 8 years of dealing with .debug_frame, we are
finally switching to .eh_frame. The reason being stripped kernel
binaries had non-functional unwinder as .debug_frame was gone.
Also, in general .eh_frame seems more common way of doing unwinding.
This also folds a revert of f52e126cc7 ("ARC: unwind: ensure that
.debug_frame is generated (vs. .eh_frame)") to ensure that we start
getting .eh_frame
Reported-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
143 lines
4.0 KiB
C
143 lines
4.0 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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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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#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/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/unwind.h>
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static inline void arc_write_me(unsigned short *addr, unsigned long value)
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{
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*addr = (value & 0xffff0000) >> 16;
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*(addr + 1) = (value & 0xffff);
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}
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/*
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* This gets called before relocation loop in generic loader
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* Make a note of the section index of unwinding section
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*/
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int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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char *secstr, struct module *mod)
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{
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#ifdef CONFIG_ARC_DW2_UNWIND
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int i;
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mod->arch.unw_sec_idx = 0;
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mod->arch.unw_info = NULL;
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for (i = 1; i < hdr->e_shnum; i++) {
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if (strcmp(secstr+sechdrs[i].sh_name, ".eh_frame") == 0) {
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mod->arch.unw_sec_idx = i;
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break;
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}
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}
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#endif
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return 0;
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}
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void module_arch_cleanup(struct module *mod)
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{
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#ifdef CONFIG_ARC_DW2_UNWIND
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if (mod->arch.unw_info)
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unwind_remove_table(mod->arch.unw_info, 0);
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#endif
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}
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int apply_relocate_add(Elf32_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex, /* sec index for sym tbl */
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unsigned int relsec, /* sec index for relo sec */
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struct module *module)
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{
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int i, n;
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Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
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Elf32_Sym *sym_entry, *sym_sec;
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Elf32_Addr relocation;
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Elf32_Addr location;
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Elf32_Addr sec_to_patch;
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int relo_type;
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sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
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sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
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n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
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pr_debug("\n========== Module Sym reloc ===========================\n");
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pr_debug("Section to fixup %x\n", sec_to_patch);
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pr_debug("=========================================================\n");
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pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n");
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pr_debug("=========================================================\n");
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/* Loop thru entries in relocation section */
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for (i = 0; i < n; i++) {
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/* This is where to make the change */
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location = sec_to_patch + rel_entry[i].r_offset;
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/* This is the symbol it is referring to. Note that all
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undefined symbols have been resolved. */
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sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
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relocation = sym_entry->st_value + rel_entry[i].r_addend;
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pr_debug("\t%x\t\t%x\t\t%x %x %x [%s]\n",
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rel_entry[i].r_offset, rel_entry[i].r_addend,
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sym_entry->st_value, location, relocation,
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strtab + sym_entry->st_name);
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/* This assumes modules are built with -mlong-calls
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* so any branches/jumps are absolute 32 bit jmps
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* global data access again is abs 32 bit.
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* Both of these are handled by same relocation type
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*/
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relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
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if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */
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arc_write_me((unsigned short *)location, relocation);
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else if (R_ARC_32 == relo_type) /* ( S + A ) */
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*((Elf32_Addr *) location) = relocation;
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else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */
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*((Elf32_Addr *) location) = relocation - location;
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else
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goto relo_err;
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}
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return 0;
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relo_err:
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pr_err("%s: unknown relocation: %u\n",
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module->name, ELF32_R_TYPE(rel_entry[i].r_info));
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return -ENOEXEC;
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}
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/* Just before lift off: After sections have been relocated, we add the
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* dwarf section to unwinder table pool
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* This couldn't be done in module_frob_arch_sections() because
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* relocations had not been applied by then
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*/
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int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
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struct module *mod)
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{
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#ifdef CONFIG_ARC_DW2_UNWIND
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void *unw;
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int unwsec = mod->arch.unw_sec_idx;
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if (unwsec) {
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unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
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sechdrs[unwsec].sh_size);
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mod->arch.unw_info = unw;
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}
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#endif
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return 0;
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}
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