// 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 <linux/kernel.h>#include <asm/module.h>#include <asm/firmware.h>#include <asm/text-patching.h>#include <linux/sort.h>#include <asm/setup.h>#include <asm/sections.h>#include <asm/inst.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. */ bool module_elf_check_arch(Elf_Ehdr *hdr){ unsigned long abi_level = hdr->e_flags & 0x3; if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) return abi_level == 2; else return abi_level < 2;} #ifdef CONFIG_PPC64_ELF_ABI_V2 static func_desc_t func_desc(unsigned long addr){ func_desc_t desc = { .addr = addr, }; return desc;} /* 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 static func_desc_t func_desc(unsigned long addr){ return *(struct func_desc *)addr;}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 static unsigned long func_addr(unsigned long addr){ return func_desc(addr).addr;} static unsigned long stub_func_addr(func_desc_t func){ return func.addr;} #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) that can * hold ppc64_stub_insns or stub_insns. Must be 8-byte aligned * with PCREL kernels that use prefix instructions in the stub. */ u32 jump[7]; /* Used by ftrace to identify stubs */ u32 magic; /* Data for the above code */ func_desc_t funcdata;} __aligned(8); struct ppc64_got_entry { u64 addr;}; /* * 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. * * Target address and TOC are loaded from function descriptor in the * ppc64_stub_entry. * * r12 is used to generate the target address, which is required for the * ELFv2 global entry point calling convention. * * TOC handling: * - PCREL does not have a TOC. * - ELFv2 non-PCREL just has to save r2, the callee is responsible for * setting its own TOC pointer at the global entry address. * - ELFv1 must load the new TOC pointer from the function descriptor. */static u32 ppc64_stub_insns[] = {#ifdef CONFIG_PPC_KERNEL_PCREL /* pld r12,addr */ PPC_PREFIX_8LS | __PPC_PRFX_R(1), PPC_INST_PLD | ___PPC_RT(_R12),#else PPC_RAW_ADDIS(_R11, _R2, 0), PPC_RAW_ADDI(_R11, _R11, 0), /* Save current r2 value in magic place on the stack. */ PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET), PPC_RAW_LD(_R12, _R11, 32),#ifdef CONFIG_PPC64_ELF_ABI_V1 /* Set up new r2 from function descriptor */ PPC_RAW_LD(_R2, _R11, 40),#endif#endif PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(),}; /* * Count how many different r_type relocations (different symbol, * different addend). */static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num, unsigned long r_type){ 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 r_type relocs, others don't need stubs */ if (ELF64_R_TYPE(rela[i].r_info) == r_type && (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;} /* Get size of potential trampolines required. */static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs, char *secstrings, struct module *me){ /* One extra reloc so it's always 0-addr 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 * algorithm 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, NULL); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC_REL24);#ifdef CONFIG_PPC_KERNEL_PCREL relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC64_REL24_NOTOC);#endif } } /* stubs for ftrace_caller and ftrace_regs_caller */ relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS); #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE /* stubs for the function tracer */ for (i = 1; i < hdr->e_shnum; i++) { if (!strcmp(secstrings + sechdrs[i].sh_name, "__patchable_function_entries")) { me->arch.ool_stub_count = sechdrs[i].sh_size / sizeof(unsigned long); me->arch.ool_stub_index = 0; relocs += roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry); break; } } if (i == hdr->e_shnum) { pr_err("%s: doesn't contain __patchable_function_entries.\n", me->name); return -ENOEXEC; }#endif pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry);} #ifdef CONFIG_PPC_KERNEL_PCRELstatic int count_pcpu_relocs(const Elf64_Shdr *sechdrs, const Elf64_Rela *rela, unsigned int num, unsigned int symindex, unsigned int pcpu){ unsigned int i, r_info, r_addend, _count_relocs; _count_relocs = 0; r_info = 0; r_addend = 0; for (i = 0; i < num; i++) { Elf64_Sym *sym; /* This is the symbol it is referring to */ sym = (Elf64_Sym *)sechdrs[symindex].sh_addr + ELF64_R_SYM(rela[i].r_info); if (sym->st_shndx == pcpu && (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;} /* Get size of potential GOT required. */static unsigned long get_got_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs, struct module *me){ /* One extra reloc so it's always 0-addr terminated */ unsigned long relocs = 1; unsigned int i, symindex = 0; for (i = 1; i < hdr->e_shnum; i++) { if (sechdrs[i].sh_type == SHT_SYMTAB) { symindex = i; break; } } WARN_ON_ONCE(!symindex); /* 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: %llu\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 * algorithm 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, NULL); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC64_GOT_PCREL34); /* * Percpu data access typically gets linked with * REL34 relocations, but the percpu section gets * moved at load time and requires that to be * converted to GOT linkage. */ if (IS_ENABLED(CONFIG_SMP) && symindex) relocs += count_pcpu_relocs(sechdrs, (void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), symindex, me->arch.pcpu_section); } } pr_debug("Looks like a total of %lu GOT entries, max\n", relocs); return relocs * sizeof(struct ppc64_got_entry);}#else /* CONFIG_PPC_KERNEL_PCREL */ /* 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;}#endif /* CONFIG_PPC_KERNEL_PCREL */ bool module_init_section(const char *name){ /* We don't handle .init for the moment: always return false. */ return false;} 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++) { if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) me->arch.stubs_section = i;#ifdef CONFIG_PPC_KERNEL_PCREL else if (strcmp(secstrings + sechdrs[i].sh_name, ".data..percpu") == 0) me->arch.pcpu_section = i; else if (strcmp(secstrings + sechdrs[i].sh_name, ".mygot") == 0) { me->arch.got_section = i; if (sechdrs[i].sh_addralign < 8) sechdrs[i].sh_addralign = 8; }#else 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); 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);#endif } if (!me->arch.stubs_section) { pr_err("%s: doesn't contain .stubs.\n", me->name); return -ENOEXEC; } #ifdef CONFIG_PPC_KERNEL_PCREL if (!me->arch.got_section) { pr_err("%s: doesn't contain .mygot.\n", me->name); return -ENOEXEC; } /* Override the got size */ sechdrs[me->arch.got_section].sh_size = get_got_size(hdr, sechdrs, me);#else /* 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;#endif /* Override the stubs size */ sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs, secstrings, me); return 0;} #if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) static u32 stub_insns[] = {#ifdef CONFIG_PPC_KERNEL_PCREL PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)), PPC_RAW_NOP(), /* align the prefix insn */ /* paddi r12,r12,addr */ PPC_PREFIX_MLS | __PPC_PRFX_R(0), PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(),#else PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), PPC_RAW_ADDIS(_R12, _R12, 0), PPC_RAW_ADDI(_R12, _R12, 0), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(),#endif};Lines 1–500 of 1156. 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 <linux/kernel.h> #include <asm/module.h> #include <asm/firmware.h> #include <asm/text-patching.h> #include <linux/sort.h> #include <asm/setup.h> #include <asm/sections.h> #include <asm/inst.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. */ bool module_elf_check_arch(Elf_Ehdr *hdr) { unsigned long abi_level = hdr->e_flags & 0x3; if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) return abi_level == 2; else return abi_level < 2; } #ifdef CONFIG_PPC64_ELF_ABI_V2 static func_desc_t func_desc(unsigned long addr) { func_desc_t desc = { .addr = addr, }; return desc; } /* 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 static func_desc_t func_desc(unsigned long addr) { return *(struct func_desc *)addr; } 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 static unsigned long func_addr(unsigned long addr) { return func_desc(addr).addr; } static unsigned long stub_func_addr(func_desc_t func) { return func.addr; } #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) that can * hold ppc64_stub_insns or stub_insns. Must be 8-byte aligned * with PCREL kernels that use prefix instructions in the stub. */ u32 jump[7]; /* Used by ftrace to identify stubs */ u32 magic; /* Data for the above code */ func_desc_t funcdata; } __aligned(8); struct ppc64_got_entry { u64 addr; }; /* * 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. * * Target address and TOC are loaded from function descriptor in the * ppc64_stub_entry. * * r12 is used to generate the target address, which is required for the * ELFv2 global entry point calling convention. * * TOC handling: * - PCREL does not have a TOC. * - ELFv2 non-PCREL just has to save r2, the callee is responsible for * setting its own TOC pointer at the global entry address. * - ELFv1 must load the new TOC pointer from the function descriptor. */ static u32 ppc64_stub_insns[] = { #ifdef CONFIG_PPC_KERNEL_PCREL /* pld r12,addr */ PPC_PREFIX_8LS | __PPC_PRFX_R(1), PPC_INST_PLD | ___PPC_RT(_R12), #else PPC_RAW_ADDIS(_R11, _R2, 0), PPC_RAW_ADDI(_R11, _R11, 0), /* Save current r2 value in magic place on the stack. */ PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET), PPC_RAW_LD(_R12, _R11, 32), #ifdef CONFIG_PPC64_ELF_ABI_V1 /* Set up new r2 from function descriptor */ PPC_RAW_LD(_R2, _R11, 40), #endif #endif PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(), }; /* * Count how many different r_type relocations (different symbol, * different addend). */ static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num, unsigned long r_type) { 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 r_type relocs, others don't need stubs */ if (ELF64_R_TYPE(rela[i].r_info) == r_type && (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; } /* Get size of potential trampolines required. */ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs, char *secstrings, struct module *me) { /* One extra reloc so it's always 0-addr 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 * algorithm 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, NULL); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC_REL24); #ifdef CONFIG_PPC_KERNEL_PCREL relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC64_REL24_NOTOC); #endif } } /* stubs for ftrace_caller and ftrace_regs_caller */ relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS); #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE /* stubs for the function tracer */ for (i = 1; i < hdr->e_shnum; i++) { if (!strcmp(secstrings + sechdrs[i].sh_name, "__patchable_function_entries")) { me->arch.ool_stub_count = sechdrs[i].sh_size / sizeof(unsigned long); me->arch.ool_stub_index = 0; relocs += roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry); break; } } if (i == hdr->e_shnum) { pr_err("%s: doesn't contain __patchable_function_entries.\n", me->name); return -ENOEXEC; } #endif pr_debug("Looks like a total of %lu stubs, max\n", relocs); return relocs * sizeof(struct ppc64_stub_entry); } #ifdef CONFIG_PPC_KERNEL_PCREL static int count_pcpu_relocs(const Elf64_Shdr *sechdrs, const Elf64_Rela *rela, unsigned int num, unsigned int symindex, unsigned int pcpu) { unsigned int i, r_info, r_addend, _count_relocs; _count_relocs = 0; r_info = 0; r_addend = 0; for (i = 0; i < num; i++) { Elf64_Sym *sym; /* This is the symbol it is referring to */ sym = (Elf64_Sym *)sechdrs[symindex].sh_addr + ELF64_R_SYM(rela[i].r_info); if (sym->st_shndx == pcpu && (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; } /* Get size of potential GOT required. */ static unsigned long get_got_size(const Elf64_Ehdr *hdr, const Elf64_Shdr *sechdrs, struct module *me) { /* One extra reloc so it's always 0-addr terminated */ unsigned long relocs = 1; unsigned int i, symindex = 0; for (i = 1; i < hdr->e_shnum; i++) { if (sechdrs[i].sh_type == SHT_SYMTAB) { symindex = i; break; } } WARN_ON_ONCE(!symindex); /* 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: %llu\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 * algorithm 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, NULL); relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), R_PPC64_GOT_PCREL34); /* * Percpu data access typically gets linked with * REL34 relocations, but the percpu section gets * moved at load time and requires that to be * converted to GOT linkage. */ if (IS_ENABLED(CONFIG_SMP) && symindex) relocs += count_pcpu_relocs(sechdrs, (void *)sechdrs[i].sh_addr, sechdrs[i].sh_size / sizeof(Elf64_Rela), symindex, me->arch.pcpu_section); } } pr_debug("Looks like a total of %lu GOT entries, max\n", relocs); return relocs * sizeof(struct ppc64_got_entry); } #else /* CONFIG_PPC_KERNEL_PCREL */ /* 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; } #endif /* CONFIG_PPC_KERNEL_PCREL */ bool module_init_section(const char *name) { /* We don't handle .init for the moment: always return false. */ return false; } 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++) { if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) me->arch.stubs_section = i; #ifdef CONFIG_PPC_KERNEL_PCREL else if (strcmp(secstrings + sechdrs[i].sh_name, ".data..percpu") == 0) me->arch.pcpu_section = i; else if (strcmp(secstrings + sechdrs[i].sh_name, ".mygot") == 0) { me->arch.got_section = i; if (sechdrs[i].sh_addralign < 8) sechdrs[i].sh_addralign = 8; } #else 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); 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); #endif } if (!me->arch.stubs_section) { pr_err("%s: doesn't contain .stubs.\n", me->name); return -ENOEXEC; } #ifdef CONFIG_PPC_KERNEL_PCREL if (!me->arch.got_section) { pr_err("%s: doesn't contain .mygot.\n", me->name); return -ENOEXEC; } /* Override the got size */ sechdrs[me->arch.got_section].sh_size = get_got_size(hdr, sechdrs, me); #else /* 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; #endif /* Override the stubs size */ sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs, secstrings, me); return 0; } #if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY) static u32 stub_insns[] = { #ifdef CONFIG_PPC_KERNEL_PCREL PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)), PPC_RAW_NOP(), /* align the prefix insn */ /* paddi r12,r12,addr */ PPC_PREFIX_MLS | __PPC_PRFX_R(0), PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(), #else PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)), PPC_RAW_ADDIS(_R12, _R12, 0), PPC_RAW_ADDI(_R12, _R12, 0), PPC_RAW_MTCTR(_R12), PPC_RAW_BCTR(), #endif };