[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 "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_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;

	me->arch.bug_table = NULL;
	me->arch.num_bugs = 0;

	/* Find the __bug_table section, if present */
	sect = find_section(hdr, sechdrs, "__bug_table");
	if (sect != NULL) {
		me->arch.bug_table = (void *) sect->sh_addr;
		me->arch.num_bugs = sect->sh_size / sizeof(struct bug_entry);
	}

 	/*
	 * Strictly speaking this should have a spinlock to protect against
	 * traversals, but since we only traverse on BUG()s, a spinlock
	 * could potentially lead to deadlock and thus be counter-productive.
	 */
	list_add(&me->arch.bug_list, &module_bug_list);

	/* 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)
{
	list_del(&mod->arch.bug_list);
}

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;
}
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>
	26
21c4ff80 BH	27	#include "setup.h"
21c4ff80 BH	28
1da177e4 LT	29	#if 0
	30	#define DEBUGP printk
	31	#else
	32	#define DEBUGP(fmt , ...)
	33	#endif
	34
	35	LIST_HEAD(module_bug_list);
	36
	37	void *module_alloc(unsigned long size)
	38	{
	39	if (size == 0)
	40	return NULL;
	41	return vmalloc(size);
	42	}
	43
	44	/* Free memory returned from module_alloc */
	45	void module_free(struct module mod, void module_region)
	46	{
	47	vfree(module_region);
	48	/* FIXME: If module_region == mod->init_region, trim exception
	49	table entries. */
	50	}
	51
	52	/* Count how many different relocations (different symbol, different
	53	addend) */
	54	static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
	55	{
	56	unsigned int i, j, ret = 0;
	57
	58	/* Sure, this is order(n^2), but it's usually short, and not
	59	time critical */
	60	for (i = 0; i < num; i++) {
	61	for (j = 0; j < i; j++) {
	62	/* If this addend appeared before, it's
	63	already been counted */
	64	if (ELF32_R_SYM(rela[i].r_info)
	65	== ELF32_R_SYM(rela[j].r_info)
	66	&& rela[i].r_addend == rela[j].r_addend)
	67	break;
	68	}
	69	if (j == i) ret++;
	70	}
	71	return ret;
	72	}
	73
	74	/* Get the potential trampolines size required of the init and
	75	non-init sections */
	76	static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
	77	const Elf32_Shdr *sechdrs,
	78	const char *secstrings,
	79	int is_init)
	80	{
	81	unsigned long ret = 0;
	82	unsigned i;
	83
	84	/* Everything marked ALLOC (this includes the exported
	85	symbols) */
	86	for (i = 1; i < hdr->e_shnum; i++) {
	87	/* If it's called .init, and we're not init, we're
	88	not interested */
	89	if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
	90	!= is_init)
	91	continue;
	92
93	/* We don't want to look at debug sections. */
94	if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
95	continue;
96
97	if (sechdrs[i].sh_type == SHT_RELA) {
98	DEBUGP("Found relocations in section %u\n", i);
99	DEBUGP("Ptr: %p. Number: %u\n",
100	(void *)hdr + sechdrs[i].sh_offset,
101	sechdrs[i].sh_size / sizeof(Elf32_Rela));
102	ret += count_relocs((void *)hdr
103	+ sechdrs[i].sh_offset,
104	sechdrs[i].sh_size
105	/ sizeof(Elf32_Rela))
106	* sizeof(struct ppc_plt_entry);
107	}
108	}
109
110	return ret;
111	}
112
113	int module_frob_arch_sections(Elf32_Ehdr *hdr,
114	Elf32_Shdr *sechdrs,
115	char *secstrings,
116	struct module *me)
117	{
118	unsigned int i;
119
120	/* Find .plt and .init.plt sections */
121	for (i = 0; i < hdr->e_shnum; i++) {
122	if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
123	me->arch.init_plt_section = i;
124	else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
125	me->arch.core_plt_section = i;
126	}
127	if (!me->arch.core_plt_section \|\| !me->arch.init_plt_section) {
128	printk("Module doesn't contain .plt or .init.plt sections.\n");
129	return -ENOEXEC;
130	}
131
132	/* Override their sizes */
133	sechdrs[me->arch.core_plt_section].sh_size
134	= get_plt_size(hdr, sechdrs, secstrings, 0);
135	sechdrs[me->arch.init_plt_section].sh_size
136	= get_plt_size(hdr, sechdrs, secstrings, 1);
137	return 0;
138	}
139
140	int apply_relocate(Elf32_Shdr *sechdrs,
141	const char *strtab,
142	unsigned int symindex,
143	unsigned int relsec,
144	struct module *module)
145	{
146	printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
147	module->name);
148	return -ENOEXEC;
149	}
150
151	static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
152	{
153	if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
154	&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
155	return 1;
156	return 0;
157	}
158
159	/* Set up a trampoline in the PLT to bounce us to the distant function */
160	static uint32_t do_plt_call(void *location,
161	Elf32_Addr val,
162	Elf32_Shdr *sechdrs,
163	struct module *mod)
164	{
165	struct ppc_plt_entry *entry;
166
167	DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
168	/* Init, or core PLT? */
169	if (location >= mod->module_core
170	&& location < mod->module_core + mod->core_size)
171	entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
172	else
173	entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
174
175	/* Find this entry, or if that fails, the next avail. entry */
176	while (entry->jump[0]) {
177	if (entry_matches(entry, val)) return (uint32_t)entry;
178	entry++;
179	}
180
181	/* Stolen from Paul Mackerras as well... */
182	entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
183	entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
184	entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
185	entry->jump[3] = 0x4e800420; /* bctr */
186
187	DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
188	return (uint32_t)entry;
189	}
190
191	int apply_relocate_add(Elf32_Shdr *sechdrs,
192	const char *strtab,
193	unsigned int symindex,
194	unsigned int relsec,
195	struct module *module)
196	{
197	unsigned int i;
198	Elf32_Rela rela = (void )sechdrs[relsec].sh_addr;
199	Elf32_Sym *sym;
200	uint32_t *location;
201	uint32_t value;
202
203	DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
204	sechdrs[relsec].sh_info);
205	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
206	/* This is where to make the change */
207	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
208	+ rela[i].r_offset;
209	/* This is the symbol it is referring to. Note that all
210	undefined symbols have been resolved. */
211	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
212	+ ELF32_R_SYM(rela[i].r_info);
213	/* `Everything is relative'. */
214	value = sym->st_value + rela[i].r_addend;
215
216	switch (ELF32_R_TYPE(rela[i].r_info)) {
217	case R_PPC_ADDR32:
218	/* Simply set it */
219	(uint32_t )location = value;
220	break;
221
222	case R_PPC_ADDR16_LO:
223	/* Low half of the symbol */
224	(uint16_t )location = value;
225	break;
226
227	case R_PPC_ADDR16_HA:
228	/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
229	(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
230	This is the same, only sane.
231	*/
232	(uint16_t )location = (value + 0x8000) >> 16;
233	break;
234
235	case R_PPC_REL24:
236	if ((int)(value - (uint32_t)location) < -0x02000000
237	\|\| (int)(value - (uint32_t)location) >= 0x02000000)
238	value = do_plt_call(location, value,
239	sechdrs, module);
240
241	/* Only replace bits 2 through 26 */
242	DEBUGP("REL24 value = %08X. location = %08X\n",
243	value, (uint32_t)location);
244	DEBUGP("Location before: %08X.\n",
245	(uint32_t )location);
246	(uint32_t )location
247	= ((uint32_t )location & ~0x03fffffc)
248	\| ((value - (uint32_t)location)
249	& 0x03fffffc);
250	DEBUGP("Location after: %08X.\n",
251	(uint32_t )location);
252	DEBUGP("ie. jump to %08X+%08X = %08X\n",
253	(uint32_t )location & 0x03fffffc,
254	(uint32_t)location,
255	((uint32_t )location & 0x03fffffc)
256	+ (uint32_t)location);
257	break;
258
259	case R_PPC_REL32:
260	/* 32-bit relative jump. */
261	(uint32_t )location = value - (uint32_t)location;
262	break;
263
264	default:
265	printk("%s: unknown ADD relocation: %u\n",
266	module->name,
267	ELF32_R_TYPE(rela[i].r_info));
268	return -ENOEXEC;
269	}
270	}
271	return 0;
272	}
273
21c4ff80 BH	274	static const Elf_Shdr find_section(const Elf_Ehdr hdr,
	275	const Elf_Shdr *sechdrs,
	276	const char *name)
	277	{
	278	char *secstrings;
	279	unsigned int i;
	280
	281	secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	282	for (i = 1; i < hdr->e_shnum; i++)
	283	if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0)
	284	return &sechdrs[i];
	285	return NULL;
	286	}
	287
1da177e4 LT	288	int module_finalize(const Elf_Ehdr *hdr,
	289	const Elf_Shdr *sechdrs,
	290	struct module *me)
	291	{
21c4ff80	292	const Elf_Shdr *sect;
1da177e4 LT	293
	294	me->arch.bug_table = NULL;
	295	me->arch.num_bugs = 0;
	296
	297	/* Find the __bug_table section, if present */
21c4ff80 BH	298	sect = find_section(hdr, sechdrs, "__bug_table");
	299	if (sect != NULL) {
	300	me->arch.bug_table = (void *) sect->sh_addr;
	301	me->arch.num_bugs = sect->sh_size / sizeof(struct bug_entry);
1da177e4 LT	302	}
1da177e4 LT	303
21c4ff80	304	/*
1da177e4 LT	305	* Strictly speaking this should have a spinlock to protect against
	306	* traversals, but since we only traverse on BUG()s, a spinlock
	307	* could potentially lead to deadlock and thus be counter-productive.
	308	*/
	309	list_add(&me->arch.bug_list, &module_bug_list);
	310
21c4ff80 BH	311	/* Apply feature fixups */
	312	sect = find_section(hdr, sechdrs, "__ftr_fixup");
	313	if (sect != NULL)
	314	do_feature_fixups(cur_cpu_spec->cpu_features,
	315	(void *)sect->sh_addr,
	316	(void *)sect->sh_addr + sect->sh_size);
	317
1da177e4 LT	318	return 0;
	319	}
	320
	321	void module_arch_cleanup(struct module *mod)
	322	{
	323	list_del(&mod->arch.bug_list);
	324	}
	325
	326	struct bug_entry *module_find_bug(unsigned long bugaddr)
	327	{
	328	struct mod_arch_specific *mod;
	329	unsigned int i;
	330	struct bug_entry *bug;
	331
	332	list_for_each_entry(mod, &module_bug_list, bug_list) {
	333	bug = mod->bug_table;
	334	for (i = 0; i < mod->num_bugs; ++i, ++bug)
	335	if (bugaddr == bug->bug_addr)
	336	return bug;
	337	}
	338	return NULL;
	339	}