// SPDX-License-Identifier: GPL-2.0-or-later/* Kernel module help for PPC64. Copyright (C) 2001, 2003 Rusty Russell IBM Corporation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h>#include <linux/elf.h>#include <linux/moduleloader.h>#include <linux/err.h>#include <linux/vmalloc.h>#include <linux/ftrace.h>#include <linux/bug.h>#include <linux/uaccess.h>#include <asm/module.h>#include <asm/firmware.h>#include <asm/code-patching.h>#include <linux/sort.h>#include <asm/setup.h>#include <asm/sections.h> /* FIXME: We don't do .init separately. To do this, we'd need to have a separate r2 value in the init and core section, and stub between them, too. Using a magic allocator which places modules within 32MB solves this, and makes other things simpler. Anton? --RR. */ #ifdef PPC64_ELF_ABI_v2 /* An address is simply the address of the function. */typedef unsigned long func_desc_t; static func_desc_t func_desc(unsigned long addr){ return addr;}static unsigned long func_addr(unsigned long addr){ return addr;}static unsigned long stub_func_addr(func_desc_t func){ return func;} /* PowerPC64 specific values for the Elf64_Sym st_other field. */#define STO_PPC64_LOCAL_BIT 5#define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT)#define PPC64_LOCAL_ENTRY_OFFSET(other) \ (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2) static unsigned int local_entry_offset(const Elf64_Sym *sym){ /* sym->st_other indicates offset to local entry point * (otherwise it will assume r12 is the address of the start * of function and try to derive r2 from it). */ return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);}#else /* An address is address of the OPD entry, which contains address of fn. */typedef struct ppc64_opd_entry func_desc_t; static func_desc_t func_desc(unsigned long addr){ return *(struct ppc64_opd_entry *)addr;}static unsigned long func_addr(unsigned long addr){ return func_desc(addr).funcaddr;}static unsigned long stub_func_addr(func_desc_t func){ return func.funcaddr;}static unsigned int local_entry_offset(const Elf64_Sym *sym){ return 0;} void *dereference_module_function_descriptor(struct module *mod, void *ptr){ if (ptr < (void *)mod->arch.start_opd || ptr >= (void *)mod->arch.end_opd) return ptr; return dereference_function_descriptor(ptr);}#endif #define STUB_MAGIC 0x73747562 /* stub */ /* Like PPC32, we need little trampolines to do > 24-bit jumps (into the kernel itself). But on PPC64, these need to be used for every jump, actually, to reset r2 (TOC+0x8000). */struct ppc64_stub_entry{ /* 28 byte jump instruction sequence (7 instructions). We only * need 6 instructions on ABIv2 but we always allocate 7 so * so we don't have to modify the trampoline load instruction. */ u32 jump[7]; /* Used by ftrace to identify stubs */ u32 magic; /* Data for the above code */ func_desc_t funcdata;}; /* * PPC64 uses 24 bit jumps, but we need to jump into other modules or * the kernel which may be further. So we jump to a stub. * * For ELFv1 we need to use this to set up the new r2 value (aka TOC * pointer). For ELFv2 it's the callee's responsibility to set up the * new r2, but for both we need to save the old r2. * * We could simply patch the new r2 value and function pointer into * the stub, but it's significantly shorter to put these values at the * end of the stub code, and patch the stub address (32-bits relative * to the TOC ptr, r2) into the stub. * * addis r11,r2, <high> * addi r11,r11, <low> * std r2,R2_STACK_OFFSET(r1) * ld r12,32(r11) * ld r2,40(r11) * mtctr r12 * bctr */static u32 ppc64_stub_insns[] = { PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2), PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11), /* Save current r2 value in magic place on the stack. */ PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET, PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32,#ifdef PPC64_ELF_ABI_v1 /* Set up new r2 from function descriptor */ PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40,#endif PPC_INST_MTCTR | __PPC_RS(R12), PPC_INST_BCTR,}; #ifdef CONFIG_DYNAMIC_FTRACEint module_trampoline_target(struct module *mod, unsigned long addr, unsigned long *target){ struct ppc64_stub_entry *stub; func_desc_t funcdata; u32 magic; if (!within_module_core(addr, mod)) { pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); return -EFAULT; } stub = (struct ppc64_stub_entry *)addr; if (probe_kernel_read(&magic, &stub->magic, sizeof(magic))) { pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } if (magic != STUB_MAGIC) { pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } if (probe_kernel_read(&funcdata, &stub->funcdata, sizeof(funcdata))) { pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } *target = stub_func_addr(funcdata); return 0;}#endif /* Count how many different 24-bit relocations (different symbol, different addend) */static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num){ unsigned int i, r_info, r_addend, _count_relocs; /* FIXME: Only count external ones --RR */ _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 (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && (r_info != ELF64_R_SYM(rela[i].r_info) || r_addend != rela[i].r_addend)) { _count_relocs++; r_info = ELF64_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 Elf64_Rela *x, *y; y = (Elf64_Rela *)_x; x = (Elf64_Rela *)_y; /* Compare the entire r_info (as opposed to ELF64_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){ uint64_t *x, *y, tmp; int i; y = (uint64_t *)_x; x = (uint64_t *)_y; for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) { tmp = x[i]; x[i] = y[i]; y[i] = tmp; }} /* Get size of potential trampolines required. */static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs){ /* One extra reloc so it's always 0-funcaddr terminated */ unsigned long relocs = 1; unsigned i; /* Every relocated section... */ for (i = 1; i < hdr->e_shnum; i++) { if (sechdrs[i].sh_type == SHT_RELA) { pr_debug("Found relocations in section %u\n", i); pr_debug("Ptr: %p. Number: %Lu\n", (void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_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 *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), sizeof(Elf64_Rela), relacmp, relaswap); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela)); } } #ifdef CONFIG_DYNAMIC_FTRACE /* make the trampoline to the ftrace_caller */ relocs++;#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* an additional one for ftrace_regs_caller */ relocs++;#endif#endif pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry);} /* Still needed for ELFv2, for .TOC. */static void dedotify_versions(struct modversion_info *vers, unsigned long size){ struct modversion_info *end; for (end = (void *)vers + size; vers < end; vers++) if (vers->name[0] == '.') { memmove(vers->name, vers->name+1, strlen(vers->name)); }} /* * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. * seem to be defined (value set later). */static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab){ unsigned int i; for (i = 1; i < numsyms; i++) { if (syms[i].st_shndx == SHN_UNDEF) { char *name = strtab + syms[i].st_name; if (name[0] == '.') { if (strcmp(name+1, "TOC.") == 0) syms[i].st_shndx = SHN_ABS; syms[i].st_name++; } } }} static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex){ unsigned int i, numsyms; Elf64_Sym *syms; syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); for (i = 1; i < numsyms; i++) { if (syms[i].st_shndx == SHN_ABS && strcmp(strtab + syms[i].st_name, "TOC.") == 0) return &syms[i]; } return NULL;} int module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs, char *secstrings, struct module *me){ unsigned int i; /* Find .toc and .stubs sections, symtab and strtab */ for (i = 1; i < hdr->e_shnum; i++) { char *p; if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) me->arch.stubs_section = i; else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) { me->arch.toc_section = i; if (sechdrs[i].sh_addralign < 8) sechdrs[i].sh_addralign = 8; } else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0) dedotify_versions((void *)hdr + sechdrs[i].sh_offset, sechdrs[i].sh_size); /* We don't handle .init for the moment: rename to _init */ while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) p[0] = '_'; if (sechdrs[i].sh_type == SHT_SYMTAB) dedotify((void *)hdr + sechdrs[i].sh_offset, sechdrs[i].sh_size / sizeof(Elf64_Sym), (void *)hdr + sechdrs[sechdrs[i].sh_link].sh_offset); } if (!me->arch.stubs_section) { pr_err("%s: doesn't contain .stubs.\n", me->name); return -ENOEXEC; } /* If we don't have a .toc, just use .stubs. We need to set r2 to some reasonable value in case the module calls out to other functions via a stub, or if a function pointer escapes the module by some means. */ if (!me->arch.toc_section) me->arch.toc_section = me->arch.stubs_section; /* Override the stubs size */ sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); return 0;} /* * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the * value maximum span in an instruction which uses a signed offset). Round down * to a 256 byte boundary for the odd case where we are setting up r2 without a * .toc section. */static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me){ return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;} /* Patch stub to reference function and correct r2 value. */static inline int create_stub(const Elf64_Shdr *sechdrs, struct ppc64_stub_entry *entry, unsigned long addr, struct module *me){ long reladdr; memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns)); /* Stub uses address relative to r2. */ reladdr = (unsigned long)entry - my_r2(sechdrs, me); if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { pr_err("%s: Address %p of stub out of range of %p.\n", me->name, (void *)reladdr, (void *)my_r2); return 0; } pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); entry->jump[0] |= PPC_HA(reladdr); entry->jump[1] |= PPC_LO(reladdr); entry->funcdata = func_desc(addr); entry->magic = STUB_MAGIC; return 1;} /* Create stub to jump to function described in this OPD/ptr: we need the stub to set up the TOC ptr (r2) for the function. */static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me){ struct ppc64_stub_entry *stubs; unsigned int i, num_stubs; num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); /* Find this stub, or if that fails, the next avail. entry */ stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { if (WARN_ON(i >= num_stubs)) return 0; if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) return (unsigned long)&stubs[i]; } if (!create_stub(sechdrs, &stubs[i], addr, me)) return 0; return (unsigned long)&stubs[i];} #ifdef CONFIG_MPROFILE_KERNELstatic bool is_mprofile_mcount_callsite(const char *name, u32 *instruction){ if (strcmp("_mcount", name)) return false; /* * Check if this is one of the -mprofile-kernel sequences. */ if (instruction[-1] == PPC_INST_STD_LR && instruction[-2] == PPC_INST_MFLR) return true; if (instruction[-1] == PPC_INST_MFLR) return true; return false;} /* * In case of _mcount calls, do not save the current callee's TOC (in r2) into * the original caller's stack frame. If we did we would clobber the saved TOC * value of the original caller. */static void squash_toc_save_inst(const char *name, unsigned long addr){ struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr; /* Only for calls to _mcount */ if (strcmp("_mcount", name) != 0) return; stub->jump[2] = PPC_INST_NOP;}#elsestatic void squash_toc_save_inst(const char *name, unsigned long addr) { } static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction){ return false;}#endif /* We expect a noop next: if it is, replace it with instruction to restore r2. */static int restore_r2(const char *name, u32 *instruction, struct module *me){ u32 *prev_insn = instruction - 1; Lines 1–500 of 840. Load more
// SPDX-License-Identifier: GPL-2.0-or-later /* Kernel module help for PPC64. Copyright (C) 2001, 2003 Rusty Russell IBM Corporation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/elf.h> #include <linux/moduleloader.h> #include <linux/err.h> #include <linux/vmalloc.h> #include <linux/ftrace.h> #include <linux/bug.h> #include <linux/uaccess.h> #include <asm/module.h> #include <asm/firmware.h> #include <asm/code-patching.h> #include <linux/sort.h> #include <asm/setup.h> #include <asm/sections.h> /* FIXME: We don't do .init separately. To do this, we'd need to have a separate r2 value in the init and core section, and stub between them, too. Using a magic allocator which places modules within 32MB solves this, and makes other things simpler. Anton? --RR. */ #ifdef PPC64_ELF_ABI_v2 /* An address is simply the address of the function. */ typedef unsigned long func_desc_t; static func_desc_t func_desc(unsigned long addr) { return addr; } static unsigned long func_addr(unsigned long addr) { return addr; } static unsigned long stub_func_addr(func_desc_t func) { return func; } /* PowerPC64 specific values for the Elf64_Sym st_other field. */ #define STO_PPC64_LOCAL_BIT 5 #define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT) #define PPC64_LOCAL_ENTRY_OFFSET(other) \ (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2) static unsigned int local_entry_offset(const Elf64_Sym *sym) { /* sym->st_other indicates offset to local entry point * (otherwise it will assume r12 is the address of the start * of function and try to derive r2 from it). */ return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other); } #else /* An address is address of the OPD entry, which contains address of fn. */ typedef struct ppc64_opd_entry func_desc_t; static func_desc_t func_desc(unsigned long addr) { return *(struct ppc64_opd_entry *)addr; } static unsigned long func_addr(unsigned long addr) { return func_desc(addr).funcaddr; } static unsigned long stub_func_addr(func_desc_t func) { return func.funcaddr; } static unsigned int local_entry_offset(const Elf64_Sym *sym) { return 0; } void *dereference_module_function_descriptor(struct module *mod, void *ptr) { if (ptr < (void *)mod->arch.start_opd || ptr >= (void *)mod->arch.end_opd) return ptr; return dereference_function_descriptor(ptr); } #endif #define STUB_MAGIC 0x73747562 /* stub */ /* Like PPC32, we need little trampolines to do > 24-bit jumps (into the kernel itself). But on PPC64, these need to be used for every jump, actually, to reset r2 (TOC+0x8000). */ struct ppc64_stub_entry { /* 28 byte jump instruction sequence (7 instructions). We only * need 6 instructions on ABIv2 but we always allocate 7 so * so we don't have to modify the trampoline load instruction. */ u32 jump[7]; /* Used by ftrace to identify stubs */ u32 magic; /* Data for the above code */ func_desc_t funcdata; }; /* * PPC64 uses 24 bit jumps, but we need to jump into other modules or * the kernel which may be further. So we jump to a stub. * * For ELFv1 we need to use this to set up the new r2 value (aka TOC * pointer). For ELFv2 it's the callee's responsibility to set up the * new r2, but for both we need to save the old r2. * * We could simply patch the new r2 value and function pointer into * the stub, but it's significantly shorter to put these values at the * end of the stub code, and patch the stub address (32-bits relative * to the TOC ptr, r2) into the stub. * * addis r11,r2, <high> * addi r11,r11, <low> * std r2,R2_STACK_OFFSET(r1) * ld r12,32(r11) * ld r2,40(r11) * mtctr r12 * bctr */ static u32 ppc64_stub_insns[] = { PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2), PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11), /* Save current r2 value in magic place on the stack. */ PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET, PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32, #ifdef PPC64_ELF_ABI_v1 /* Set up new r2 from function descriptor */ PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40, #endif PPC_INST_MTCTR | __PPC_RS(R12), PPC_INST_BCTR, }; #ifdef CONFIG_DYNAMIC_FTRACE int module_trampoline_target(struct module *mod, unsigned long addr, unsigned long *target) { struct ppc64_stub_entry *stub; func_desc_t funcdata; u32 magic; if (!within_module_core(addr, mod)) { pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name); return -EFAULT; } stub = (struct ppc64_stub_entry *)addr; if (probe_kernel_read(&magic, &stub->magic, sizeof(magic))) { pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } if (magic != STUB_MAGIC) { pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } if (probe_kernel_read(&funcdata, &stub->funcdata, sizeof(funcdata))) { pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name); return -EFAULT; } *target = stub_func_addr(funcdata); return 0; } #endif /* Count how many different 24-bit relocations (different symbol, different addend) */ static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) { unsigned int i, r_info, r_addend, _count_relocs; /* FIXME: Only count external ones --RR */ _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 (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && (r_info != ELF64_R_SYM(rela[i].r_info) || r_addend != rela[i].r_addend)) { _count_relocs++; r_info = ELF64_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 Elf64_Rela *x, *y; y = (Elf64_Rela *)_x; x = (Elf64_Rela *)_y; /* Compare the entire r_info (as opposed to ELF64_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) { uint64_t *x, *y, tmp; int i; y = (uint64_t *)_x; x = (uint64_t *)_y; for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) { tmp = x[i]; x[i] = y[i]; y[i] = tmp; } } /* Get size of potential trampolines required. */ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs) { /* One extra reloc so it's always 0-funcaddr terminated */ unsigned long relocs = 1; unsigned i; /* Every relocated section... */ for (i = 1; i < hdr->e_shnum; i++) { if (sechdrs[i].sh_type == SHT_RELA) { pr_debug("Found relocations in section %u\n", i); pr_debug("Ptr: %p. Number: %Lu\n", (void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_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 *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), sizeof(Elf64_Rela), relacmp, relaswap); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela)); } } #ifdef CONFIG_DYNAMIC_FTRACE /* make the trampoline to the ftrace_caller */ relocs++; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* an additional one for ftrace_regs_caller */ relocs++; #endif #endif pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry); } /* Still needed for ELFv2, for .TOC. */ static void dedotify_versions(struct modversion_info *vers, unsigned long size) { struct modversion_info *end; for (end = (void *)vers + size; vers < end; vers++) if (vers->name[0] == '.') { memmove(vers->name, vers->name+1, strlen(vers->name)); } } /* * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC. * seem to be defined (value set later). */ static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) { unsigned int i; for (i = 1; i < numsyms; i++) { if (syms[i].st_shndx == SHN_UNDEF) { char *name = strtab + syms[i].st_name; if (name[0] == '.') { if (strcmp(name+1, "TOC.") == 0) syms[i].st_shndx = SHN_ABS; syms[i].st_name++; } } } } static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex) { unsigned int i, numsyms; Elf64_Sym *syms; syms = (Elf64_Sym *)sechdrs[symindex].sh_addr; numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym); for (i = 1; i < numsyms; i++) { if (syms[i].st_shndx == SHN_ABS && strcmp(strtab + syms[i].st_name, "TOC.") == 0) return &syms[i]; } return NULL; } int module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs, char *secstrings, struct module *me) { unsigned int i; /* Find .toc and .stubs sections, symtab and strtab */ for (i = 1; i < hdr->e_shnum; i++) { char *p; if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) me->arch.stubs_section = i; else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) { me->arch.toc_section = i; if (sechdrs[i].sh_addralign < 8) sechdrs[i].sh_addralign = 8; } else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0) dedotify_versions((void *)hdr + sechdrs[i].sh_offset, sechdrs[i].sh_size); /* We don't handle .init for the moment: rename to _init */ while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) p[0] = '_'; if (sechdrs[i].sh_type == SHT_SYMTAB) dedotify((void *)hdr + sechdrs[i].sh_offset, sechdrs[i].sh_size / sizeof(Elf64_Sym), (void *)hdr + sechdrs[sechdrs[i].sh_link].sh_offset); } if (!me->arch.stubs_section) { pr_err("%s: doesn't contain .stubs.\n", me->name); return -ENOEXEC; } /* If we don't have a .toc, just use .stubs. We need to set r2 to some reasonable value in case the module calls out to other functions via a stub, or if a function pointer escapes the module by some means. */ if (!me->arch.toc_section) me->arch.toc_section = me->arch.stubs_section; /* Override the stubs size */ sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); return 0; } /* * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the * value maximum span in an instruction which uses a signed offset). Round down * to a 256 byte boundary for the odd case where we are setting up r2 without a * .toc section. */ static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) { return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; } /* Patch stub to reference function and correct r2 value. */ static inline int create_stub(const Elf64_Shdr *sechdrs, struct ppc64_stub_entry *entry, unsigned long addr, struct module *me) { long reladdr; memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns)); /* Stub uses address relative to r2. */ reladdr = (unsigned long)entry - my_r2(sechdrs, me); if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { pr_err("%s: Address %p of stub out of range of %p.\n", me->name, (void *)reladdr, (void *)my_r2); return 0; } pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); entry->jump[0] |= PPC_HA(reladdr); entry->jump[1] |= PPC_LO(reladdr); entry->funcdata = func_desc(addr); entry->magic = STUB_MAGIC; return 1; } /* Create stub to jump to function described in this OPD/ptr: we need the stub to set up the TOC ptr (r2) for the function. */ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me) { struct ppc64_stub_entry *stubs; unsigned int i, num_stubs; num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); /* Find this stub, or if that fails, the next avail. entry */ stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; for (i = 0; stub_func_addr(stubs[i].funcdata); i++) { if (WARN_ON(i >= num_stubs)) return 0; if (stub_func_addr(stubs[i].funcdata) == func_addr(addr)) return (unsigned long)&stubs[i]; } if (!create_stub(sechdrs, &stubs[i], addr, me)) return 0; return (unsigned long)&stubs[i]; } #ifdef CONFIG_MPROFILE_KERNEL static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction) { if (strcmp("_mcount", name)) return false; /* * Check if this is one of the -mprofile-kernel sequences. */ if (instruction[-1] == PPC_INST_STD_LR && instruction[-2] == PPC_INST_MFLR) return true; if (instruction[-1] == PPC_INST_MFLR) return true; return false; } /* * In case of _mcount calls, do not save the current callee's TOC (in r2) into * the original caller's stack frame. If we did we would clobber the saved TOC * value of the original caller. */ static void squash_toc_save_inst(const char *name, unsigned long addr) { struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr; /* Only for calls to _mcount */ if (strcmp("_mcount", name) != 0) return; stub->jump[2] = PPC_INST_NOP; } #else static void squash_toc_save_inst(const char *name, unsigned long addr) { } static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction) { return false; } #endif /* We expect a noop next: if it is, replace it with instruction to restore r2. */ static int restore_r2(const char *name, u32 *instruction, struct module *me) { u32 *prev_insn = instruction - 1;