arch/powerpc/kernel/module_32.c - third_party/linux - Git at Google

 /*  Kernel module help for PPC.
     Copyright (C) 2001 Rusty Russell.

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 #include <linux/module.h>
 #include <linux/moduleloader.h>
 #include <linux/elf.h>
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/cache.h>
 #include <linux/bug.h>

 #include "setup.h"

 #if 0
 #define DEBUGP printk
 #else
 #define DEBUGP(fmt , ...)
 #endif

 LIST_HEAD(module_bug_list);

 void *module_alloc(unsigned long size)
 {
 	if (size == 0)
 		return NULL;
 	return vmalloc(size);
 }

 /* Free memory returned from module_alloc */
 void module_free(struct module *mod, void *module_region)
 {
 	vfree(module_region);
 	/* FIXME: If module_region == mod->init_region, trim exception
            table entries. */
 }

 /* Count how many different relocations (different symbol, different
    addend) */
 static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
 {
 	unsigned int i, j, ret = 0;

 	/* Sure, this is order(n^2), but it's usually short, and not
            time critical */
 	for (i = 0; i < num; i++) {
 		for (j = 0; j < i; j++) {
 			/* If this addend appeared before, it's
                            already been counted */
 			if (ELF32_R_SYM(rela[i].r_info)
 			    == ELF32_R_SYM(rela[j].r_info)
 			    && rela[i].r_addend == rela[j].r_addend)
 				break;
 		}
 		if (j == i) ret++;
 	}
 	return ret;
 }

 /* Get the potential trampolines size required of the init and
    non-init sections */
 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
 				  const Elf32_Shdr *sechdrs,
 				  const char *secstrings,
 				  int is_init)
 {
 	unsigned long ret = 0;
 	unsigned i;

 	/* Everything marked ALLOC (this includes the exported
            symbols) */
 	for (i = 1; i < hdr->e_shnum; i++) {
 		/* If it's called *.init*, and we're not init, we're
                    not interested */
 		if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
 		    != is_init)
 			continue;

 		/* We don't want to look at debug sections. */
 		if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
 			continue;

 		if (sechdrs[i].sh_type == SHT_RELA) {
 			DEBUGP("Found relocations in section %u\n", i);
 			DEBUGP("Ptr: %p.  Number: %u\n",
 			       (void *)hdr + sechdrs[i].sh_offset,
 			       sechdrs[i].sh_size / sizeof(Elf32_Rela));
 			ret += count_relocs((void *)hdr
 					     + sechdrs[i].sh_offset,
 					     sechdrs[i].sh_size
 					     / sizeof(Elf32_Rela))
 				* sizeof(struct ppc_plt_entry);
 		}
 	}

 	return ret;
 }

 int module_frob_arch_sections(Elf32_Ehdr *hdr,
 			      Elf32_Shdr *sechdrs,
 			      char *secstrings,
 			      struct module *me)
 {
 	unsigned int i;

 	/* Find .plt and .init.plt sections */
 	for (i = 0; i < hdr->e_shnum; i++) {
 		if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
 			me->arch.init_plt_section = i;
 		else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
 			me->arch.core_plt_section = i;
 	}
 	if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
 		printk("Module doesn't contain .plt or .init.plt sections.\n");
 		return -ENOEXEC;
 	}

 	/* Override their sizes */
 	sechdrs[me->arch.core_plt_section].sh_size
 		= get_plt_size(hdr, sechdrs, secstrings, 0);
 	sechdrs[me->arch.init_plt_section].sh_size
 		= get_plt_size(hdr, sechdrs, secstrings, 1);
 	return 0;
 }

 int apply_relocate(Elf32_Shdr *sechdrs,
 		   const char *strtab,
 		   unsigned int symindex,
 		   unsigned int relsec,
 		   struct module *module)
 {
 	printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
 	       module->name);
 	return -ENOEXEC;
 }

 static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
 {
 	if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
 	    && entry->jump[1] == 0x396b0000 + (val & 0xffff))
 		return 1;
 	return 0;
 }

 /* Set up a trampoline in the PLT to bounce us to the distant function */
 static uint32_t do_plt_call(void *location,
 			    Elf32_Addr val,
 			    Elf32_Shdr *sechdrs,
 			    struct module *mod)
 {
 	struct ppc_plt_entry *entry;

 	DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
 	/* Init, or core PLT? */
 	if (location >= mod->module_core
 	    && location < mod->module_core + mod->core_size)
 		entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
 	else
 		entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;

 	/* Find this entry, or if that fails, the next avail. entry */
 	while (entry->jump[0]) {
 		if (entry_matches(entry, val)) return (uint32_t)entry;
 		entry++;
 	}

 	/* Stolen from Paul Mackerras as well... */
 	entry->jump[0] = 0x3d600000+((val+0x8000)>>16);	/* lis r11,sym@ha */
 	entry->jump[1] = 0x396b0000 + (val&0xffff);	/* addi r11,r11,sym@l*/
 	entry->jump[2] = 0x7d6903a6;			/* mtctr r11 */
 	entry->jump[3] = 0x4e800420;			/* bctr */

 	DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
 	return (uint32_t)entry;
 }

 int apply_relocate_add(Elf32_Shdr *sechdrs,
 		       const char *strtab,
 		       unsigned int symindex,
 		       unsigned int relsec,
 		       struct module *module)
 {
 	unsigned int i;
 	Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
 	Elf32_Sym *sym;
 	uint32_t *location;
 	uint32_t value;

 	DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
 	       sechdrs[relsec].sh_info);
 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
 		/* This is where to make the change */
 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rela[i].r_offset;
 		/* This is the symbol it is referring to.  Note that all
 		   undefined symbols have been resolved.  */
 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 			+ ELF32_R_SYM(rela[i].r_info);
 		/* `Everything is relative'. */
 		value = sym->st_value + rela[i].r_addend;

 		switch (ELF32_R_TYPE(rela[i].r_info)) {
 		case R_PPC_ADDR32:
 			/* Simply set it */
 			*(uint32_t *)location = value;
 			break;

 		case R_PPC_ADDR16_LO:
 			/* Low half of the symbol */
 			*(uint16_t *)location = value;
 			break;

 		case R_PPC_ADDR16_HI:
 			/* Higher half of the symbol */
 			*(uint16_t *)location = (value >> 16);
 			break;

 		case R_PPC_ADDR16_HA:
 			/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
 			   (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
 			   This is the same, only sane.
 			 */
 			*(uint16_t *)location = (value + 0x8000) >> 16;
 			break;

 		case R_PPC_REL24:
 			if ((int)(value - (uint32_t)location) < -0x02000000
 			    || (int)(value - (uint32_t)location) >= 0x02000000)
 				value = do_plt_call(location, value,
 						    sechdrs, module);

 			/* Only replace bits 2 through 26 */
 			DEBUGP("REL24 value = %08X. location = %08X\n",
 			       value, (uint32_t)location);
 			DEBUGP("Location before: %08X.\n",
 			       *(uint32_t *)location);
 			*(uint32_t *)location
 				= (*(uint32_t *)location & ~0x03fffffc)
 				| ((value - (uint32_t)location)
 				   & 0x03fffffc);
 			DEBUGP("Location after: %08X.\n",
 			       *(uint32_t *)location);
 			DEBUGP("ie. jump to %08X+%08X = %08X\n",
 			       *(uint32_t *)location & 0x03fffffc,
 			       (uint32_t)location,
 			       (*(uint32_t *)location & 0x03fffffc)
 			       + (uint32_t)location);
 			break;

 		case R_PPC_REL32:
 			/* 32-bit relative jump. */
 			*(uint32_t *)location = value - (uint32_t)location;
 			break;

 		default:
 			printk("%s: unknown ADD relocation: %u\n",
 			       module->name,
 			       ELF32_R_TYPE(rela[i].r_info));
 			return -ENOEXEC;
 		}
 	}
 	return 0;
 }

 static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
 				    const Elf_Shdr *sechdrs,
 				    const char *name)
 {
 	char *secstrings;
 	unsigned int i;

 	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 	for (i = 1; i < hdr->e_shnum; i++)
 		if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
 			return &sechdrs[i];
 	return NULL;
 }

 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
 		    struct module *me)
 {
 	const Elf_Shdr *sect;
 	int err;

 	err = module_bug_finalize(hdr, sechdrs, me);
 	if (err)		/* never true, currently */
 		return err;

 	/* Apply feature fixups */
 	sect = find_section(hdr, sechdrs, "__ftr_fixup");
 	if (sect != NULL)
 		do_feature_fixups(cur_cpu_spec->cpu_features,
 				  (void *)sect->sh_addr,
 				  (void *)sect->sh_addr + sect->sh_size);

 	return 0;
 }

 void module_arch_cleanup(struct module *mod)
 {
 	module_bug_cleanup(mod);
 }

 struct bug_entry *module_find_bug(unsigned long bugaddr)
 {
 	struct mod_arch_specific *mod;
 	unsigned int i;
 	struct bug_entry *bug;

 	list_for_each_entry(mod, &module_bug_list, bug_list) {
 		bug = mod->bug_table;
 		for (i = 0; i < mod->num_bugs; ++i, ++bug)
 			if (bugaddr == bug->bug_addr)
 				return bug;
 	}
 	return NULL;
 }
	/* Kernel module help for PPC.
	Copyright (C) 2001 Rusty Russell.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/
	#include <linux/module.h>
	#include <linux/moduleloader.h>
	#include <linux/elf.h>
	#include <linux/vmalloc.h>
	#include <linux/fs.h>
	#include <linux/string.h>
	#include <linux/kernel.h>
	#include <linux/cache.h>
	#include <linux/bug.h>

	#include "setup.h"

	#if 0
	#define DEBUGP printk
	#else
	#define DEBUGP(fmt , ...)
	#endif

	LIST_HEAD(module_bug_list);

	void *module_alloc(unsigned long size)
	{
	if (size == 0)
	return NULL;
	return vmalloc(size);
	}

	/* Free memory returned from module_alloc */
	void module_free(struct module mod, void module_region)
	{
	vfree(module_region);
	/* FIXME: If module_region == mod->init_region, trim exception
	table entries. */
	}

	/* Count how many different relocations (different symbol, different
	addend) */
	static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
	{
	unsigned int i, j, ret = 0;

	/* Sure, this is order(n^2), but it's usually short, and not
	time critical */
	for (i = 0; i < num; i++) {
	for (j = 0; j < i; j++) {
	/* If this addend appeared before, it's
	already been counted */
	if (ELF32_R_SYM(rela[i].r_info)
	== ELF32_R_SYM(rela[j].r_info)
	&& rela[i].r_addend == rela[j].r_addend)
	break;
	}
	if (j == i) ret++;
	}
	return ret;
	}

	/* Get the potential trampolines size required of the init and
	non-init sections */
	static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
	const Elf32_Shdr *sechdrs,
	const char *secstrings,
	int is_init)
	{
	unsigned long ret = 0;
	unsigned i;

	/* Everything marked ALLOC (this includes the exported
	symbols) */
	for (i = 1; i < hdr->e_shnum; i++) {
	/* If it's called .init, and we're not init, we're
	not interested */
	if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
	!= is_init)
	continue;

	/* We don't want to look at debug sections. */
	if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
	continue;

	if (sechdrs[i].sh_type == SHT_RELA) {
	DEBUGP("Found relocations in section %u\n", i);
	DEBUGP("Ptr: %p. Number: %u\n",
	(void *)hdr + sechdrs[i].sh_offset,
	sechdrs[i].sh_size / sizeof(Elf32_Rela));
	ret += count_relocs((void *)hdr
	+ sechdrs[i].sh_offset,
	sechdrs[i].sh_size
	/ sizeof(Elf32_Rela))
	* sizeof(struct ppc_plt_entry);
	}
	}

	return ret;
	}

	int module_frob_arch_sections(Elf32_Ehdr *hdr,
	Elf32_Shdr *sechdrs,
	char *secstrings,
	struct module *me)
	{
	unsigned int i;

	/* Find .plt and .init.plt sections */
	for (i = 0; i < hdr->e_shnum; i++) {
	if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
	me->arch.init_plt_section = i;
	else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
	me->arch.core_plt_section = i;
	}
	if (!me->arch.core_plt_section \|\| !me->arch.init_plt_section) {
	printk("Module doesn't contain .plt or .init.plt sections.\n");
	return -ENOEXEC;
	}

	/* Override their sizes */
	sechdrs[me->arch.core_plt_section].sh_size
	= get_plt_size(hdr, sechdrs, secstrings, 0);
	sechdrs[me->arch.init_plt_section].sh_size
	= get_plt_size(hdr, sechdrs, secstrings, 1);
	return 0;
	}

	int apply_relocate(Elf32_Shdr *sechdrs,
	const char *strtab,
	unsigned int symindex,
	unsigned int relsec,
	struct module *module)
	{
	printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
	module->name);
	return -ENOEXEC;
	}

	static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
	{
	if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
	&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
	return 1;
	return 0;
	}

	/* Set up a trampoline in the PLT to bounce us to the distant function */
	static uint32_t do_plt_call(void *location,
	Elf32_Addr val,
	Elf32_Shdr *sechdrs,
	struct module *mod)
	{
	struct ppc_plt_entry *entry;

	DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
	/* Init, or core PLT? */
	if (location >= mod->module_core
	&& location < mod->module_core + mod->core_size)
	entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
	else
	entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;

	/* Find this entry, or if that fails, the next avail. entry */
	while (entry->jump[0]) {
	if (entry_matches(entry, val)) return (uint32_t)entry;
	entry++;
	}

	/* Stolen from Paul Mackerras as well... */
	entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
	entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
	entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
	entry->jump[3] = 0x4e800420; /* bctr */

	DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
	return (uint32_t)entry;
	}

	int apply_relocate_add(Elf32_Shdr *sechdrs,
	const char *strtab,
	unsigned int symindex,
	unsigned int relsec,
	struct module *module)
	{
	unsigned int i;
	Elf32_Rela rela = (void )sechdrs[relsec].sh_addr;
	Elf32_Sym *sym;
	uint32_t *location;
	uint32_t value;

	DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
	sechdrs[relsec].sh_info);
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
	/* This is where to make the change */
	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	+ rela[i].r_offset;
	/* This is the symbol it is referring to. Note that all
	undefined symbols have been resolved. */
	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	+ ELF32_R_SYM(rela[i].r_info);
	/* `Everything is relative'. */
	value = sym->st_value + rela[i].r_addend;

	switch (ELF32_R_TYPE(rela[i].r_info)) {
	case R_PPC_ADDR32:
	/* Simply set it */
	(uint32_t )location = value;
	break;

	case R_PPC_ADDR16_LO:
	/* Low half of the symbol */
	(uint16_t )location = value;
	break;

	case R_PPC_ADDR16_HI:
	/* Higher half of the symbol */
	(uint16_t )location = (value >> 16);
	break;

	case R_PPC_ADDR16_HA:
	/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
	(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
	This is the same, only sane.
	*/
	(uint16_t )location = (value + 0x8000) >> 16;
	break;

	case R_PPC_REL24:
	if ((int)(value - (uint32_t)location) < -0x02000000
	\|\| (int)(value - (uint32_t)location) >= 0x02000000)
	value = do_plt_call(location, value,
	sechdrs, module);

	/* Only replace bits 2 through 26 */
	DEBUGP("REL24 value = %08X. location = %08X\n",
	value, (uint32_t)location);
	DEBUGP("Location before: %08X.\n",
	(uint32_t )location);
	(uint32_t )location
	= ((uint32_t )location & ~0x03fffffc)
	\| ((value - (uint32_t)location)
	& 0x03fffffc);
	DEBUGP("Location after: %08X.\n",
	(uint32_t )location);
	DEBUGP("ie. jump to %08X+%08X = %08X\n",
	(uint32_t )location & 0x03fffffc,
	(uint32_t)location,
	((uint32_t )location & 0x03fffffc)
	+ (uint32_t)location);
	break;

	case R_PPC_REL32:
	/* 32-bit relative jump. */
	(uint32_t )location = value - (uint32_t)location;
	break;

	default:
	printk("%s: unknown ADD relocation: %u\n",
	module->name,
	ELF32_R_TYPE(rela[i].r_info));
	return -ENOEXEC;
	}
	}
	return 0;
	}

	static const Elf_Shdr find_section(const Elf_Ehdr hdr,
	const Elf_Shdr *sechdrs,
	const char *name)
	{
	char *secstrings;
	unsigned int i;

	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	for (i = 1; i < hdr->e_shnum; i++)
	if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
	return &sechdrs[i];
	return NULL;
	}

	int module_finalize(const Elf_Ehdr *hdr,
	const Elf_Shdr *sechdrs,
	struct module *me)
	{
	const Elf_Shdr *sect;
	int err;

	err = module_bug_finalize(hdr, sechdrs, me);
	if (err) /* never true, currently */
	return err;

	/* Apply feature fixups */
	sect = find_section(hdr, sechdrs, "__ftr_fixup");
	if (sect != NULL)
	do_feature_fixups(cur_cpu_spec->cpu_features,
	(void *)sect->sh_addr,
	(void *)sect->sh_addr + sect->sh_size);

	return 0;
	}

	void module_arch_cleanup(struct module *mod)
	{
	module_bug_cleanup(mod);
	}

	struct bug_entry *module_find_bug(unsigned long bugaddr)
	{
	struct mod_arch_specific *mod;
	unsigned int i;
	struct bug_entry *bug;

	list_for_each_entry(mod, &module_bug_list, bug_list) {
	bug = mod->bug_table;
	for (i = 0; i < mod->num_bugs; ++i, ++bug)
	if (bugaddr == bug->bug_addr)
	return bug;
	}
	return NULL;
	}