[linux.git] / arch / arc / kernel / module.c

/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/moduleloader.h>
#include <linux/kernel.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <asm/unwind.h>

static inline void arc_write_me(unsigned short *addr, unsigned long value)
{
	*addr = (value & 0xffff0000) >> 16;
	*(addr + 1) = (value & 0xffff);
}

/* ARC specific section quirks - before relocation loop in generic loader
 *
 * For dwarf unwinding out of modules, this needs to
 * 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
 *    -fasynchronous-unwind-tables it doesn't).
 * 2. Since we are iterating thru sec hdr tbl anyways, make a note of
 *    the exact section index, for later use.
 */
int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
			      char *secstr, struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
	int i;

	mod->arch.unw_sec_idx = 0;
	mod->arch.unw_info = NULL;

	for (i = 1; i < hdr->e_shnum; i++) {
		if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
			sechdrs[i].sh_flags |= SHF_ALLOC;
			mod->arch.unw_sec_idx = i;
			break;
		}
	}
#endif
	return 0;
}

void module_arch_cleanup(struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
	if (mod->arch.unw_info)
		unwind_remove_table(mod->arch.unw_info, 0);
#endif
}

int apply_relocate_add(Elf32_Shdr *sechdrs,
		       const char *strtab,
		       unsigned int symindex,	/* sec index for sym tbl */
		       unsigned int relsec,	/* sec index for relo sec */
		       struct module *module)
{
	int i, n;
	Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr;
	Elf32_Sym *sym_entry, *sym_sec;
	Elf32_Addr relocation;
	Elf32_Addr location;
	Elf32_Addr sec_to_patch;
	int relo_type;

	sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
	sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
	n = sechdrs[relsec].sh_size / sizeof(*rel_entry);

	pr_debug("\n========== Module Sym reloc ===========================\n");
	pr_debug("Section to fixup %x\n", sec_to_patch);
	pr_debug("=========================================================\n");
	pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n");
	pr_debug("=========================================================\n");

	/* Loop thru entries in relocation section */
	for (i = 0; i < n; i++) {

		/* This is where to make the change */
		location = sec_to_patch + rel_entry[i].r_offset;

		/* This is the symbol it is referring to.  Note that all
		   undefined symbols have been resolved.  */
		sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);

		relocation = sym_entry->st_value + rel_entry[i].r_addend;

		pr_debug("\t%x\t\t%x\t\t%x  %x %x [%s]\n",
			rel_entry[i].r_offset, rel_entry[i].r_addend,
			sym_entry->st_value, location, relocation,
			strtab + sym_entry->st_name);

		/* This assumes modules are built with -mlong-calls
		 * so any branches/jumps are absolute 32 bit jmps
		 * global data access again is abs 32 bit.
		 * Both of these are handled by same relocation type
		 */
		relo_type = ELF32_R_TYPE(rel_entry[i].r_info);

		if (likely(R_ARC_32_ME == relo_type))
			arc_write_me((unsigned short *)location, relocation);
		else if (R_ARC_32 == relo_type)
			*((Elf32_Addr *) location) = relocation;
		else
			goto relo_err;

	}
	return 0;

relo_err:
	pr_err("%s: unknown relocation: %u\n",
		module->name, ELF32_R_TYPE(rel_entry[i].r_info));
	return -ENOEXEC;

}

/* Just before lift off: After sections have been relocated, we add the
 * dwarf section to unwinder table pool
 * This couldn't be done in module_frob_arch_sections() because
 * relocations had not been applied by then
 */
int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
		    struct module *mod)
{
#ifdef CONFIG_ARC_DW2_UNWIND
	void *unw;
	int unwsec = mod->arch.unw_sec_idx;

	if (unwsec) {
		unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
				       sechdrs[unwsec].sh_size);
		mod->arch.unw_info = unw;
	}
#endif
	return 0;
}
Commit	Line	Data
fa1c3ff9 VG	1	/*
	2	* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/module.h>
	10	#include <linux/moduleloader.h>
	11	#include <linux/kernel.h>
	12	#include <linux/elf.h>
	13	#include <linux/vmalloc.h>
	14	#include <linux/slab.h>
	15	#include <linux/fs.h>
	16	#include <linux/string.h>
854a0d95	17	#include <asm/unwind.h>
fa1c3ff9 VG	18
	19	static inline void arc_write_me(unsigned short *addr, unsigned long value)
	20	{
	21	*addr = (value & 0xffff0000) >> 16;
	22	*(addr + 1) = (value & 0xffff);
	23	}
	24
854a0d95 VG	25	/* ARC specific section quirks - before relocation loop in generic loader
	26	*
	27	* For dwarf unwinding out of modules, this needs to
	28	* 1. Ensure the .debug_frame is allocatable (ARC Linker bug: despite
	29	* -fasynchronous-unwind-tables it doesn't).
	30	* 2. Since we are iterating thru sec hdr tbl anyways, make a note of
	31	* the exact section index, for later use.
	32	*/
	33	int module_frob_arch_sections(Elf_Ehdr hdr, Elf_Shdr sechdrs,
	34	char secstr, struct module mod)
	35	{
	36	#ifdef CONFIG_ARC_DW2_UNWIND
	37	int i;
	38
	39	mod->arch.unw_sec_idx = 0;
	40	mod->arch.unw_info = NULL;
	41
	42	for (i = 1; i < hdr->e_shnum; i++) {
	43	if (strcmp(secstr+sechdrs[i].sh_name, ".debug_frame") == 0) {
	44	sechdrs[i].sh_flags \|= SHF_ALLOC;
	45	mod->arch.unw_sec_idx = i;
	46	break;
	47	}
	48	}
	49	#endif
955ad595	50	return 0;
854a0d95 VG	51	}
	52
	53	void module_arch_cleanup(struct module *mod)
	54	{
	55	#ifdef CONFIG_ARC_DW2_UNWIND
	56	if (mod->arch.unw_info)
	57	unwind_remove_table(mod->arch.unw_info, 0);
	58	#endif
	59	}
	60
fa1c3ff9 VG	61	int apply_relocate_add(Elf32_Shdr *sechdrs,
	62	const char *strtab,
	63	unsigned int symindex, /* sec index for sym tbl */
	64	unsigned int relsec, /* sec index for relo sec */
	65	struct module *module)
	66	{
	67	int i, n;
	68	Elf32_Rela rel_entry = (void )sechdrs[relsec].sh_addr;
	69	Elf32_Sym sym_entry, sym_sec;
	70	Elf32_Addr relocation;
	71	Elf32_Addr location;
	72	Elf32_Addr sec_to_patch;
	73	int relo_type;
	74
	75	sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr;
	76	sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr;
	77	n = sechdrs[relsec].sh_size / sizeof(*rel_entry);
	78
	79	pr_debug("\n========== Module Sym reloc ===========================\n");
	80	pr_debug("Section to fixup %x\n", sec_to_patch);
	81	pr_debug("=========================================================\n");
	82	pr_debug("rela->r_off \| rela->addend \| sym->st_value \| ADDR \| VALUE\n");
	83	pr_debug("=========================================================\n");
	84
	85	/* Loop thru entries in relocation section */
	86	for (i = 0; i < n; i++) {
	87
	88	/* This is where to make the change */
	89	location = sec_to_patch + rel_entry[i].r_offset;
	90
	91	/* This is the symbol it is referring to. Note that all
	92	undefined symbols have been resolved. */
	93	sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info);
	94
	95	relocation = sym_entry->st_value + rel_entry[i].r_addend;
	96
	97	pr_debug("\t%x\t\t%x\t\t%x %x %x [%s]\n",
	98	rel_entry[i].r_offset, rel_entry[i].r_addend,
	99	sym_entry->st_value, location, relocation,
	100	strtab + sym_entry->st_name);
	101
	102	/* This assumes modules are built with -mlong-calls
	103	* so any branches/jumps are absolute 32 bit jmps
	104	* global data access again is abs 32 bit.
	105	* Both of these are handled by same relocation type
	106	*/
	107	relo_type = ELF32_R_TYPE(rel_entry[i].r_info);
	108
	109	if (likely(R_ARC_32_ME == relo_type))
	110	arc_write_me((unsigned short *)location, relocation);
	111	else if (R_ARC_32 == relo_type)
	112	((Elf32_Addr ) location) = relocation;
	113	else
	114	goto relo_err;
	115
	116	}
	117	return 0;
	118
	119	relo_err:
	120	pr_err("%s: unknown relocation: %u\n",
	121	module->name, ELF32_R_TYPE(rel_entry[i].r_info));
	122	return -ENOEXEC;
	123
	124	}
854a0d95 VG	125
	126	/* Just before lift off: After sections have been relocated, we add the
	127	* dwarf section to unwinder table pool
	128	* This couldn't be done in module_frob_arch_sections() because
	129	* relocations had not been applied by then
	130	*/
	131	int module_finalize(const Elf32_Ehdr hdr, const Elf_Shdr sechdrs,
	132	struct module *mod)
	133	{
	134	#ifdef CONFIG_ARC_DW2_UNWIND
	135	void *unw;
	136	int unwsec = mod->arch.unw_sec_idx;
	137
	138	if (unwsec) {
	139	unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr,
	140	sechdrs[unwsec].sh_size);
	141	mod->arch.unw_info = unw;
	142	}
	143	#endif
955ad595	144	return 0;
854a0d95	145	}