[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / powerpc / kernel / module_32.c

/*  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 <linux/sort.h>

#include "setup.h"

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

/* Count how many different relocations (different symbol, different
   addend) */
static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
{
	unsigned int i, r_info, r_addend, _count_relocs;

	_count_relocs = 0;
	r_info = 0;
	r_addend = 0;
	for (i = 0; i < num; i++)
		/* Only count 24-bit relocs, others don't need stubs */
		if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
		    (r_info != ELF32_R_SYM(rela[i].r_info) ||
		     r_addend != rela[i].r_addend)) {
			_count_relocs++;
			r_info = ELF32_R_SYM(rela[i].r_info);
			r_addend = rela[i].r_addend;
		}

	return _count_relocs;
}

static int relacmp(const void *_x, const void *_y)
{
	const Elf32_Rela *x, *y;

	y = (Elf32_Rela *)_x;
	x = (Elf32_Rela *)_y;

	/* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
	 * make the comparison cheaper/faster. It won't affect the sorting or
	 * the counting algorithms' performance
	 */
	if (x->r_info < y->r_info)
		return -1;
	else if (x->r_info > y->r_info)
		return 1;
	else if (x->r_addend < y->r_addend)
		return -1;
	else if (x->r_addend > y->r_addend)
		return 1;
	else
		return 0;
}

static void relaswap(void *_x, void *_y, int size)
{
	uint32_t *x, *y, tmp;
	int i;

	y = (uint32_t *)_x;
	x = (uint32_t *)_y;

	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
		tmp = x[i];
		x[i] = y[i];
		y[i] = tmp;
	}
}

/* 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));

			/* Sort the relocation information based on a symbol and
			 * addend key. This is a stable O(n*log n) complexity
			 * alogrithm but it will reduce the complexity of
			 * count_relocs() to linear complexity O(n)
			 */
			sort((void *)hdr + sechdrs[i].sh_offset,
			     sechdrs[i].sh_size / sizeof(Elf32_Rela),
			     sizeof(Elf32_Rela), relacmp, relaswap);

			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;
}
Commit	Line	Data
1da177e4 LT	1	/* Kernel module help for PPC.
	2	Copyright (C) 2001 Rusty Russell.
	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 as published by
	6	the Free Software Foundation; either version 2 of the License, or
	7	(at your option) any later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	GNU General Public License for more details.
	13
	14	You should have received a copy of the GNU General Public License
	15	along with this program; if not, write to the Free Software
	16	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17	*/
	18	#include <linux/module.h>
	19	#include <linux/moduleloader.h>
	20	#include <linux/elf.h>
	21	#include <linux/vmalloc.h>
	22	#include <linux/fs.h>
	23	#include <linux/string.h>
	24	#include <linux/kernel.h>
	25	#include <linux/cache.h>
73c9ceab	26	#include <linux/bug.h>
eda09fbd	27	#include <linux/sort.h>
1da177e4	28
21c4ff80 BH	29	#include "setup.h"
21c4ff80 BH	30
1da177e4 LT	31	#if 0
	32	#define DEBUGP printk
	33	#else
	34	#define DEBUGP(fmt , ...)
	35	#endif
	36
1da177e4 LT	37	/* Count how many different relocations (different symbol, different
	38	addend) */
	39	static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
	40	{
eda09fbd EM	41	unsigned int i, r_info, r_addend, _count_relocs;
	42
	43	_count_relocs = 0;
	44	r_info = 0;
	45	r_addend = 0;
	46	for (i = 0; i < num; i++)
	47	/* Only count 24-bit relocs, others don't need stubs */
	48	if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
	49	(r_info != ELF32_R_SYM(rela[i].r_info) \|\|
	50	r_addend != rela[i].r_addend)) {
	51	_count_relocs++;
	52	r_info = ELF32_R_SYM(rela[i].r_info);
	53	r_addend = rela[i].r_addend;
1da177e4	54	}
eda09fbd EM	55
	56	return _count_relocs;
	57	}
	58
	59	static int relacmp(const void _x, const void _y)
	60	{
	61	const Elf32_Rela x, y;
	62
	63	y = (Elf32_Rela *)_x;
	64	x = (Elf32_Rela *)_y;
	65
	66	/* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
	67	* make the comparison cheaper/faster. It won't affect the sorting or
	68	* the counting algorithms' performance
	69	*/
	70	if (x->r_info < y->r_info)
	71	return -1;
	72	else if (x->r_info > y->r_info)
	73	return 1;
	74	else if (x->r_addend < y->r_addend)
	75	return -1;
	76	else if (x->r_addend > y->r_addend)
	77	return 1;
	78	else
	79	return 0;
	80	}
	81
	82	static void relaswap(void _x, void _y, int size)
	83	{
	84	uint32_t x, y, tmp;
	85	int i;
	86
	87	y = (uint32_t *)_x;
	88	x = (uint32_t *)_y;
	89
	90	for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
	91	tmp = x[i];
	92	x[i] = y[i];
	93	y[i] = tmp;
1da177e4	94	}
1da177e4 LT	95	}
	96
	97	/* Get the potential trampolines size required of the init and
	98	non-init sections */
	99	static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
	100	const Elf32_Shdr *sechdrs,
	101	const char *secstrings,
	102	int is_init)
	103	{
	104	unsigned long ret = 0;
	105	unsigned i;
	106
	107	/* Everything marked ALLOC (this includes the exported
	108	symbols) */
	109	for (i = 1; i < hdr->e_shnum; i++) {
	110	/* If it's called .init, and we're not init, we're
	111	not interested */
	112	if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
	113	!= is_init)
	114	continue;
	115
	116	/* We don't want to look at debug sections. */
	117	if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
	118	continue;
	119
	120	if (sechdrs[i].sh_type == SHT_RELA) {
	121	DEBUGP("Found relocations in section %u\n", i);
	122	DEBUGP("Ptr: %p. Number: %u\n",
	123	(void *)hdr + sechdrs[i].sh_offset,
	124	sechdrs[i].sh_size / sizeof(Elf32_Rela));
eda09fbd EM	125
	126	/* Sort the relocation information based on a symbol and
	127	* addend key. This is a stable O(n*log n) complexity
	128	* alogrithm but it will reduce the complexity of
	129	* count_relocs() to linear complexity O(n)
	130	*/
	131	sort((void *)hdr + sechdrs[i].sh_offset,
	132	sechdrs[i].sh_size / sizeof(Elf32_Rela),
	133	sizeof(Elf32_Rela), relacmp, relaswap);
	134
1da177e4 LT	135	ret += count_relocs((void *)hdr
	136	+ sechdrs[i].sh_offset,
	137	sechdrs[i].sh_size
	138	/ sizeof(Elf32_Rela))
	139	* sizeof(struct ppc_plt_entry);
	140	}
	141	}
	142
	143	return ret;
	144	}
	145
	146	int module_frob_arch_sections(Elf32_Ehdr *hdr,
	147	Elf32_Shdr *sechdrs,
	148	char *secstrings,
	149	struct module *me)
	150	{
	151	unsigned int i;
	152
	153	/* Find .plt and .init.plt sections */
	154	for (i = 0; i < hdr->e_shnum; i++) {
	155	if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
	156	me->arch.init_plt_section = i;
	157	else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
	158	me->arch.core_plt_section = i;
	159	}
	160	if (!me->arch.core_plt_section \|\| !me->arch.init_plt_section) {
	161	printk("Module doesn't contain .plt or .init.plt sections.\n");
	162	return -ENOEXEC;
	163	}
	164
	165	/* Override their sizes */
	166	sechdrs[me->arch.core_plt_section].sh_size
	167	= get_plt_size(hdr, sechdrs, secstrings, 0);
	168	sechdrs[me->arch.init_plt_section].sh_size
	169	= get_plt_size(hdr, sechdrs, secstrings, 1);
	170	return 0;
	171	}
	172
	173	int apply_relocate(Elf32_Shdr *sechdrs,
	174	const char *strtab,
	175	unsigned int symindex,
	176	unsigned int relsec,
	177	struct module *module)
	178	{
	179	printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
	180	module->name);
	181	return -ENOEXEC;
	182	}
	183
	184	static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
	185	{
	186	if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
	187	&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
	188	return 1;
	189	return 0;
	190	}
	191
	192	/* Set up a trampoline in the PLT to bounce us to the distant function */
	193	static uint32_t do_plt_call(void *location,
	194	Elf32_Addr val,
	195	Elf32_Shdr *sechdrs,
	196	struct module *mod)
	197	{
	198	struct ppc_plt_entry *entry;
199
200	DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
201	/* Init, or core PLT? */
202	if (location >= mod->module_core
203	&& location < mod->module_core + mod->core_size)
204	entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
205	else
206	entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
207
208	/* Find this entry, or if that fails, the next avail. entry */
209	while (entry->jump[0]) {
210	if (entry_matches(entry, val)) return (uint32_t)entry;
211	entry++;
212	}
213
214	/* Stolen from Paul Mackerras as well... */
215	entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
216	entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
217	entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
218	entry->jump[3] = 0x4e800420; /* bctr */
219
220	DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
221	return (uint32_t)entry;
222	}
223
224	int apply_relocate_add(Elf32_Shdr *sechdrs,
225	const char *strtab,
226	unsigned int symindex,
227	unsigned int relsec,
228	struct module *module)
229	{
230	unsigned int i;
231	Elf32_Rela rela = (void )sechdrs[relsec].sh_addr;
232	Elf32_Sym *sym;
233	uint32_t *location;
234	uint32_t value;
235
236	DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
237	sechdrs[relsec].sh_info);
238	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
239	/* This is where to make the change */
240	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
241	+ rela[i].r_offset;
242	/* This is the symbol it is referring to. Note that all
243	undefined symbols have been resolved. */
244	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
245	+ ELF32_R_SYM(rela[i].r_info);
246	/* `Everything is relative'. */
247	value = sym->st_value + rela[i].r_addend;
248
249	switch (ELF32_R_TYPE(rela[i].r_info)) {
250	case R_PPC_ADDR32:
251	/* Simply set it */
252	(uint32_t )location = value;
253	break;
254
255	case R_PPC_ADDR16_LO:
256	/* Low half of the symbol */
257	(uint16_t )location = value;
258	break;
9a3d6458 SV	259
	260	case R_PPC_ADDR16_HI:
	261	/* Higher half of the symbol */
	262	(uint16_t )location = (value >> 16);
	263	break;
	264
1da177e4 LT	265	case R_PPC_ADDR16_HA:
	266	/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
	267	(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
	268	This is the same, only sane.
	269	*/
	270	(uint16_t )location = (value + 0x8000) >> 16;
	271	break;
	272
	273	case R_PPC_REL24:
	274	if ((int)(value - (uint32_t)location) < -0x02000000
	275	\|\| (int)(value - (uint32_t)location) >= 0x02000000)
	276	value = do_plt_call(location, value,
	277	sechdrs, module);
	278
	279	/* Only replace bits 2 through 26 */
	280	DEBUGP("REL24 value = %08X. location = %08X\n",
	281	value, (uint32_t)location);
	282	DEBUGP("Location before: %08X.\n",
	283	(uint32_t )location);
	284	(uint32_t )location
	285	= ((uint32_t )location & ~0x03fffffc)
	286	\| ((value - (uint32_t)location)
	287	& 0x03fffffc);
	288	DEBUGP("Location after: %08X.\n",
	289	(uint32_t )location);
	290	DEBUGP("ie. jump to %08X+%08X = %08X\n",
	291	(uint32_t )location & 0x03fffffc,
	292	(uint32_t)location,
	293	((uint32_t )location & 0x03fffffc)
	294	+ (uint32_t)location);
	295	break;
	296
	297	case R_PPC_REL32:
	298	/* 32-bit relative jump. */
	299	(uint32_t )location = value - (uint32_t)location;
	300	break;
	301
	302	default:
	303	printk("%s: unknown ADD relocation: %u\n",
	304	module->name,
	305	ELF32_R_TYPE(rela[i].r_info));
	306	return -ENOEXEC;
	307	}
	308	}
	309	return 0;
	310	}