arch/powerpc/kernel/module_32.c - SHIFTPHONES/mainline/linux - Gitiles

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*  Kernel module help for PPC.
     Copyright (C) 2001 Rusty Russell.

 */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #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/ftrace.h>
 #include <linux/cache.h>
 #include <linux/bug.h>
 #include <linux/sort.h>
 #include <asm/setup.h>

 /* 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;
 		}

 #ifdef CONFIG_DYNAMIC_FTRACE
 	_count_relocs++;	/* add one for ftrace_caller */
 #endif
 	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;
 }

 /* 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") != NULL)
 		    != is_init)
 			continue;

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

 		if (sechdrs[i].sh_type == SHT_RELA) {
 			pr_debug("Found relocations in section %u\n", i);
 			pr_debug("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, NULL);

 			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) {
 		pr_err("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;
 }

 static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
 {
 	if (entry->jump[0] != PPC_RAW_LIS(_R12, PPC_HA(val)))
 		return 0;
 	if (entry->jump[1] != PPC_RAW_ADDI(_R12, _R12, PPC_LO(val)))
 		return 0;
 	return 1;
 }

 /* 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,
 			    const Elf32_Shdr *sechdrs,
 			    struct module *mod)
 {
 	struct ppc_plt_entry *entry;

 	pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
 	/* Init, or core PLT? */
 	if (location >= mod->core_layout.base
 	    && location < mod->core_layout.base + mod->core_layout.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++;
 	}

 	entry->jump[0] = PPC_RAW_LIS(_R12, PPC_HA(val));
 	entry->jump[1] = PPC_RAW_ADDI(_R12, _R12, PPC_LO(val));
 	entry->jump[2] = PPC_RAW_MTCTR(_R12);
 	entry->jump[3] = PPC_RAW_BCTR();

 	pr_debug("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;

 	pr_debug("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 */
 			pr_debug("REL24 value = %08X. location = %08X\n",
 			       value, (uint32_t)location);
 			pr_debug("Location before: %08X.\n",
 			       *(uint32_t *)location);
 			*(uint32_t *)location
 				= (*(uint32_t *)location & ~0x03fffffc)
 				| ((value - (uint32_t)location)
 				   & 0x03fffffc);
 			pr_debug("Location after: %08X.\n",
 			       *(uint32_t *)location);
 			pr_debug("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:
 			pr_err("%s: unknown ADD relocation: %u\n",
 			       module->name,
 			       ELF32_R_TYPE(rela[i].r_info));
 			return -ENOEXEC;
 		}
 	}

 	return 0;
 }

 #ifdef CONFIG_DYNAMIC_FTRACE
 int module_trampoline_target(struct module *mod, unsigned long addr,
 			     unsigned long *target)
 {
 	unsigned int jmp[4];

 	/* Find where the trampoline jumps to */
 	if (copy_from_kernel_nofault(jmp, (void *)addr, sizeof(jmp)))
 		return -EFAULT;

 	/* verify that this is what we expect it to be */
 	if ((jmp[0] & 0xffff0000) != PPC_RAW_LIS(_R12, 0) ||
 	    (jmp[1] & 0xffff0000) != PPC_RAW_ADDI(_R12, _R12, 0) ||
 	    jmp[2] != PPC_RAW_MTCTR(_R12) ||
 	    jmp[3] != PPC_RAW_BCTR())
 		return -EINVAL;

 	addr = (jmp[1] & 0xffff) | ((jmp[0] & 0xffff) << 16);
 	if (addr & 0x8000)
 		addr -= 0x10000;

 	*target = addr;

 	return 0;
 }

 int module_finalize_ftrace(struct module *module, const Elf_Shdr *sechdrs)
 {
 	module->arch.tramp = do_plt_call(module->core_layout.base,
 					 (unsigned long)ftrace_caller,
 					 sechdrs, module);
 	if (!module->arch.tramp)
 		return -ENOENT;

 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 	module->arch.tramp_regs = do_plt_call(module->core_layout.base,
 					      (unsigned long)ftrace_regs_caller,
 					      sechdrs, module);
 	if (!module->arch.tramp_regs)
 		return -ENOENT;
 #endif

 	return 0;
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0-or-later
	/* Kernel module help for PPC.
	Copyright (C) 2001 Rusty Russell.

	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#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/ftrace.h>
	#include <linux/cache.h>
	#include <linux/bug.h>
	#include <linux/sort.h>
	#include <asm/setup.h>

	/* 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;
	}

	#ifdef CONFIG_DYNAMIC_FTRACE
	_count_relocs++; /* add one for ftrace_caller */
	#endif
	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;
	}

	/* 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") != NULL)
	!= is_init)
	continue;

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

	if (sechdrs[i].sh_type == SHT_RELA) {
	pr_debug("Found relocations in section %u\n", i);
	pr_debug("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, NULL);

	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) {
	pr_err("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;
	}

	static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
	{
	if (entry->jump[0] != PPC_RAW_LIS(_R12, PPC_HA(val)))
	return 0;
	if (entry->jump[1] != PPC_RAW_ADDI(_R12, _R12, PPC_LO(val)))
	return 0;
	return 1;
	}

	/* 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,
	const Elf32_Shdr *sechdrs,
	struct module *mod)
	{
	struct ppc_plt_entry *entry;

	pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
	/* Init, or core PLT? */
	if (location >= mod->core_layout.base
	&& location < mod->core_layout.base + mod->core_layout.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++;
	}

	entry->jump[0] = PPC_RAW_LIS(_R12, PPC_HA(val));
	entry->jump[1] = PPC_RAW_ADDI(_R12, _R12, PPC_LO(val));
	entry->jump[2] = PPC_RAW_MTCTR(_R12);
	entry->jump[3] = PPC_RAW_BCTR();

	pr_debug("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;

	pr_debug("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 */
	pr_debug("REL24 value = %08X. location = %08X\n",
	value, (uint32_t)location);
	pr_debug("Location before: %08X.\n",
	(uint32_t )location);
	(uint32_t )location
	= ((uint32_t )location & ~0x03fffffc)
	\| ((value - (uint32_t)location)
	& 0x03fffffc);
	pr_debug("Location after: %08X.\n",
	(uint32_t )location);
	pr_debug("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:
	pr_err("%s: unknown ADD relocation: %u\n",
	module->name,
	ELF32_R_TYPE(rela[i].r_info));
	return -ENOEXEC;
	}
	}

	return 0;
	}

	#ifdef CONFIG_DYNAMIC_FTRACE
	int module_trampoline_target(struct module *mod, unsigned long addr,
	unsigned long *target)
	{
	unsigned int jmp[4];

	/* Find where the trampoline jumps to */
	if (copy_from_kernel_nofault(jmp, (void *)addr, sizeof(jmp)))
	return -EFAULT;

	/* verify that this is what we expect it to be */
	if ((jmp[0] & 0xffff0000) != PPC_RAW_LIS(_R12, 0) \|\|
	(jmp[1] & 0xffff0000) != PPC_RAW_ADDI(_R12, _R12, 0) \|\|
	jmp[2] != PPC_RAW_MTCTR(_R12) \|\|
	jmp[3] != PPC_RAW_BCTR())
	return -EINVAL;

	addr = (jmp[1] & 0xffff) \| ((jmp[0] & 0xffff) << 16);
	if (addr & 0x8000)
	addr -= 0x10000;

	*target = addr;

	return 0;
	}

	int module_finalize_ftrace(struct module module, const Elf_Shdr sechdrs)
	{
	module->arch.tramp = do_plt_call(module->core_layout.base,
	(unsigned long)ftrace_caller,
	sechdrs, module);
	if (!module->arch.tramp)
	return -ENOENT;

	#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
	module->arch.tramp_regs = do_plt_call(module->core_layout.base,
	(unsigned long)ftrace_regs_caller,
	sechdrs, module);
	if (!module->arch.tramp_regs)
	return -ENOENT;
	#endif

	return 0;
	}
	#endif