Hexagon: Support dynamic module loading.
Modules should be compiled as ordinary .o's; shared objects are not supported. Signed-off-by: Linas Vepstas <linas@codeaurora.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Richard Kuo <rkuo@codeaurora.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linas Vepstas
Linus Torvalds
parent
b39e293e1d
commit
98fb103694
162
arch/hexagon/kernel/module.c
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162
arch/hexagon/kernel/module.c
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/*
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* Kernel module loader for Hexagon
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*
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* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
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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 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include <asm/module.h>
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#include <linux/elf.h>
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#include <linux/module.h>
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#include <linux/moduleloader.h>
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#include <linux/vmalloc.h>
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(fmt , ...)
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#endif
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/*
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* module_frob_arch_sections - tweak got/plt sections.
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* @hdr - pointer to elf header
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* @sechdrs - pointer to elf load section headers
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* @secstrings - symbol names
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* @mod - pointer to module
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*/
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int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
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char *secstrings,
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struct module *mod)
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{
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unsigned int i;
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int found = 0;
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/* Look for .plt and/or .got.plt and/or .init.plt sections */
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for (i = 0; i < hdr->e_shnum; i++) {
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DEBUGP("Section %d is %s\n", i,
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secstrings + sechdrs[i].sh_name);
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if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
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found = i+1;
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if (strcmp(secstrings + sechdrs[i].sh_name, ".got.plt") == 0)
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found = i+1;
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if (strcmp(secstrings + sechdrs[i].sh_name, ".rela.plt") == 0)
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found = i+1;
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}
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/* At this time, we don't support modules comiled with -shared */
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if (found) {
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printk(KERN_WARNING
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"Module '%s' contains unexpected .plt/.got sections.\n",
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mod->name);
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/* return -ENOEXEC; */
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}
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return 0;
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}
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/*
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* apply_relocate_add - perform rela relocations.
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* @sechdrs - pointer to section headers
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* @strtab - some sort of start address?
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* @symindex - symbol index offset or something?
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* @relsec - address to relocate to?
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* @module - pointer to module
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*
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* Perform rela relocations.
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*/
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int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relsec,
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struct module *module)
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{
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unsigned int i;
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Elf32_Sym *sym;
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uint32_t *location;
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uint32_t value;
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unsigned int nrelocs = sechdrs[relsec].sh_size / sizeof(Elf32_Rela);
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Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
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Elf32_Word sym_info = sechdrs[relsec].sh_info;
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Elf32_Sym *sym_base = (Elf32_Sym *) sechdrs[symindex].sh_addr;
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void *loc_base = (void *) sechdrs[sym_info].sh_addr;
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DEBUGP("Applying relocations in section %u to section %u base=%p\n",
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relsec, sym_info, loc_base);
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for (i = 0; i < nrelocs; i++) {
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/* Symbol to relocate */
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sym = sym_base + ELF32_R_SYM(rela[i].r_info);
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/* Where to make the change */
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location = loc_base + rela[i].r_offset;
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/* `Everything is relative'. */
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value = sym->st_value + rela[i].r_addend;
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DEBUGP("%d: value=%08x loc=%p reloc=%d symbol=%s\n",
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i, value, location, ELF32_R_TYPE(rela[i].r_info),
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sym->st_name ?
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&strtab[sym->st_name] : "(anonymous)");
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switch (ELF32_R_TYPE(rela[i].r_info)) {
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case R_HEXAGON_B22_PCREL: {
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int dist = (int)(value - (uint32_t)location);
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if ((dist < -0x00800000) ||
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(dist >= 0x00800000)) {
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printk(KERN_ERR
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"%s: %s: %08x=%08x-%08x %s\n",
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module->name,
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"R_HEXAGON_B22_PCREL reloc out of range",
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dist, value, (uint32_t)location,
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sym->st_name ?
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&strtab[sym->st_name] : "(anonymous)");
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return -ENOEXEC;
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}
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DEBUGP("B22_PCREL contents: %08X.\n", *location);
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*location &= ~0x01ff3fff;
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*location |= 0x00003fff & dist;
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*location |= 0x01ff0000 & (dist<<2);
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DEBUGP("Contents after reloc: %08x\n", *location);
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break;
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}
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case R_HEXAGON_HI16:
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value = (value>>16) & 0xffff;
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/* fallthrough */
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case R_HEXAGON_LO16:
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*location &= ~0x00c03fff;
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*location |= value & 0x3fff;
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*location |= (value & 0xc000) << 8;
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break;
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case R_HEXAGON_32:
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*location = value;
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break;
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case R_HEXAGON_32_PCREL:
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*location = value - (uint32_t)location;
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break;
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case R_HEXAGON_PLT_B22_PCREL:
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case R_HEXAGON_GOTOFF_LO16:
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case R_HEXAGON_GOTOFF_HI16:
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printk(KERN_ERR "%s: GOT/PLT relocations unsupported\n",
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module->name);
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return -ENOEXEC;
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default:
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printk(KERN_ERR "%s: unknown relocation: %u\n",
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module->name,
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ELF32_R_TYPE(rela[i].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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