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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>
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Linas Vepstas
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Linus Torvalds
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Nov 1, 2011
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/* | ||
* Kernel module loader for Hexagon | ||
* | ||
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. | ||
* | ||
* This program is free software; you can redistribute it and/or modify | ||
* it under the terms of the GNU General Public License version 2 and | ||
* only version 2 as published by the Free Software Foundation. | ||
* | ||
* This program 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 this program; if not, write to the Free Software | ||
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | ||
* 02110-1301, USA. | ||
*/ | ||
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#include <asm/module.h> | ||
#include <linux/elf.h> | ||
#include <linux/module.h> | ||
#include <linux/moduleloader.h> | ||
#include <linux/vmalloc.h> | ||
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#if 0 | ||
#define DEBUGP printk | ||
#else | ||
#define DEBUGP(fmt , ...) | ||
#endif | ||
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/* | ||
* module_frob_arch_sections - tweak got/plt sections. | ||
* @hdr - pointer to elf header | ||
* @sechdrs - pointer to elf load section headers | ||
* @secstrings - symbol names | ||
* @mod - pointer to module | ||
*/ | ||
int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, | ||
char *secstrings, | ||
struct module *mod) | ||
{ | ||
unsigned int i; | ||
int found = 0; | ||
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/* Look for .plt and/or .got.plt and/or .init.plt sections */ | ||
for (i = 0; i < hdr->e_shnum; i++) { | ||
DEBUGP("Section %d is %s\n", i, | ||
secstrings + sechdrs[i].sh_name); | ||
if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) | ||
found = i+1; | ||
if (strcmp(secstrings + sechdrs[i].sh_name, ".got.plt") == 0) | ||
found = i+1; | ||
if (strcmp(secstrings + sechdrs[i].sh_name, ".rela.plt") == 0) | ||
found = i+1; | ||
} | ||
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/* At this time, we don't support modules comiled with -shared */ | ||
if (found) { | ||
printk(KERN_WARNING | ||
"Module '%s' contains unexpected .plt/.got sections.\n", | ||
mod->name); | ||
/* return -ENOEXEC; */ | ||
} | ||
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return 0; | ||
} | ||
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/* | ||
* apply_relocate_add - perform rela relocations. | ||
* @sechdrs - pointer to section headers | ||
* @strtab - some sort of start address? | ||
* @symindex - symbol index offset or something? | ||
* @relsec - address to relocate to? | ||
* @module - pointer to module | ||
* | ||
* Perform rela relocations. | ||
*/ | ||
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, | ||
unsigned int symindex, unsigned int relsec, | ||
struct module *module) | ||
{ | ||
unsigned int i; | ||
Elf32_Sym *sym; | ||
uint32_t *location; | ||
uint32_t value; | ||
unsigned int nrelocs = sechdrs[relsec].sh_size / sizeof(Elf32_Rela); | ||
Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; | ||
Elf32_Word sym_info = sechdrs[relsec].sh_info; | ||
Elf32_Sym *sym_base = (Elf32_Sym *) sechdrs[symindex].sh_addr; | ||
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", | ||
relsec, sym_info, loc_base); | ||
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for (i = 0; i < nrelocs; i++) { | ||
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/* Symbol to relocate */ | ||
sym = sym_base + ELF32_R_SYM(rela[i].r_info); | ||
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/* Where to make the change */ | ||
location = loc_base + rela[i].r_offset; | ||
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/* `Everything is relative'. */ | ||
value = sym->st_value + rela[i].r_addend; | ||
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DEBUGP("%d: value=%08x loc=%p reloc=%d symbol=%s\n", | ||
i, value, location, ELF32_R_TYPE(rela[i].r_info), | ||
sym->st_name ? | ||
&strtab[sym->st_name] : "(anonymous)"); | ||
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switch (ELF32_R_TYPE(rela[i].r_info)) { | ||
case R_HEXAGON_B22_PCREL: { | ||
int dist = (int)(value - (uint32_t)location); | ||
if ((dist < -0x00800000) || | ||
(dist >= 0x00800000)) { | ||
printk(KERN_ERR | ||
"%s: %s: %08x=%08x-%08x %s\n", | ||
module->name, | ||
"R_HEXAGON_B22_PCREL reloc out of range", | ||
dist, value, (uint32_t)location, | ||
sym->st_name ? | ||
&strtab[sym->st_name] : "(anonymous)"); | ||
return -ENOEXEC; | ||
} | ||
DEBUGP("B22_PCREL contents: %08X.\n", *location); | ||
*location &= ~0x01ff3fff; | ||
*location |= 0x00003fff & dist; | ||
*location |= 0x01ff0000 & (dist<<2); | ||
DEBUGP("Contents after reloc: %08x\n", *location); | ||
break; | ||
} | ||
case R_HEXAGON_HI16: | ||
value = (value>>16) & 0xffff; | ||
/* fallthrough */ | ||
case R_HEXAGON_LO16: | ||
*location &= ~0x00c03fff; | ||
*location |= value & 0x3fff; | ||
*location |= (value & 0xc000) << 8; | ||
break; | ||
case R_HEXAGON_32: | ||
*location = value; | ||
break; | ||
case R_HEXAGON_32_PCREL: | ||
*location = value - (uint32_t)location; | ||
break; | ||
case R_HEXAGON_PLT_B22_PCREL: | ||
case R_HEXAGON_GOTOFF_LO16: | ||
case R_HEXAGON_GOTOFF_HI16: | ||
printk(KERN_ERR "%s: GOT/PLT relocations unsupported\n", | ||
module->name); | ||
return -ENOEXEC; | ||
default: | ||
printk(KERN_ERR "%s: unknown relocation: %u\n", | ||
module->name, | ||
ELF32_R_TYPE(rela[i].r_info)); | ||
return -ENOEXEC; | ||
} | ||
} | ||
return 0; | ||
} |