diff options
Diffstat (limited to 'arch/powerpc/kernel/module_64.c')
| -rw-r--r-- | arch/powerpc/kernel/module_64.c | 377 |
1 files changed, 335 insertions, 42 deletions
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 2ac78d207f77..92570289ce08 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -101,32 +101,45 @@ static unsigned long stub_func_addr(func_desc_t func) /* 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. */ +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. * - * 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. + * 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. * - * 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. + * 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. */ @@ -136,13 +149,17 @@ static u32 ppc64_stub_insns[] = { /* 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 24-bit relocations (different symbol, - different addend) */ -static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) +/* + * 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; @@ -151,8 +168,8 @@ static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) 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 && + /* 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++; @@ -213,7 +230,14 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, relocs += count_relocs((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size - / sizeof(Elf64_Rela)); + / 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 } } @@ -230,6 +254,95 @@ static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, 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) @@ -279,6 +392,7 @@ static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs, } return NULL; } +#endif /* CONFIG_PPC_KERNEL_PCREL */ bool module_init_section(const char *name) { @@ -297,6 +411,15 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, 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) @@ -311,6 +434,7 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, sechdrs[i].sh_size / sizeof(Elf64_Sym), (void *)hdr + sechdrs[sechdrs[i].sh_link].sh_offset); +#endif } if (!me->arch.stubs_section) { @@ -318,26 +442,47 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, 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); + return 0; } #ifdef CONFIG_MPROFILE_KERNEL 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 }; /* @@ -358,18 +503,37 @@ static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, { long reladdr; - memcpy(entry->jump, stub_insns, sizeof(stub_insns)); - - /* Stub uses address relative to kernel toc (from the paca) */ - reladdr = addr - kernel_toc_addr(); - if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { - pr_err("%s: Address of %ps out of range of kernel_toc.\n", - me->name, (void *)addr); + if ((unsigned long)entry->jump % 8 != 0) { + pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name); return 0; } - entry->jump[1] |= PPC_HA(reladdr); - entry->jump[2] |= PPC_LO(reladdr); + BUILD_BUG_ON(sizeof(stub_insns) > sizeof(entry->jump)); + memcpy(entry->jump, stub_insns, sizeof(stub_insns)); + + if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { + /* Stub uses address relative to kernel base (from the paca) */ + reladdr = addr - local_paca->kernelbase; + if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) { + pr_err("%s: Address of %ps out of range of 34-bit relative address.\n", + me->name, (void *)addr); + return 0; + } + + entry->jump[2] |= IMM_H18(reladdr); + entry->jump[3] |= IMM_L(reladdr); + } else { + /* Stub uses address relative to kernel toc (from the paca) */ + reladdr = addr - kernel_toc_addr(); + if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { + pr_err("%s: Address of %ps out of range of kernel_toc.\n", + me->name, (void *)addr); + return 0; + } + + entry->jump[1] |= PPC_HA(reladdr); + entry->jump[2] |= PPC_LO(reladdr); + } /* Even though we don't use funcdata in the stub, it's needed elsewhere. */ entry->funcdata = func_desc(addr); @@ -415,7 +579,11 @@ static bool is_mprofile_ftrace_call(const char *name) */ static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me) { +#ifndef CONFIG_PPC_KERNEL_PCREL return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000; +#else + return -1; +#endif } /* Patch stub to reference function and correct r2 value. */ @@ -432,28 +600,53 @@ static inline int create_stub(const Elf64_Shdr *sechdrs, if (is_mprofile_ftrace_call(name)) return create_ftrace_stub(entry, addr, me); + if ((unsigned long)entry->jump % 8 != 0) { + pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name); + return 0; + } + + BUILD_BUG_ON(sizeof(ppc64_stub_insns) > sizeof(entry->jump)); for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) { if (patch_instruction(&entry->jump[i], ppc_inst(ppc64_stub_insns[i]))) return 0; } - /* 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); + if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { + /* Stub uses address relative to itself! */ + reladdr = 0 + offsetof(struct ppc64_stub_entry, funcdata); + BUILD_BUG_ON(reladdr != 32); + if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) { + pr_err("%s: Address of %p out of range of 34-bit relative address.\n", + me->name, (void *)reladdr); + return 0; + } + pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr); - if (patch_instruction(&entry->jump[0], - ppc_inst(entry->jump[0] | PPC_HA(reladdr)))) - return 0; + /* May not even need this if we're relative to 0 */ + if (patch_instruction(&entry->jump[0], + ppc_inst_prefix(entry->jump[0] | IMM_H18(reladdr), + entry->jump[1] | IMM_L(reladdr)))) + return 0; - if (patch_instruction(&entry->jump[1], - ppc_inst(entry->jump[1] | PPC_LO(reladdr)))) - return 0; + } else { + /* 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); + + if (patch_instruction(&entry->jump[0], + ppc_inst(entry->jump[0] | PPC_HA(reladdr)))) + return 0; + + if (patch_instruction(&entry->jump[1], + ppc_inst(entry->jump[1] | PPC_LO(reladdr)))) + return 0; + } // func_desc_t is 8 bytes if ABIv2, else 16 bytes desc = func_desc(addr); @@ -497,6 +690,37 @@ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs, return (unsigned long)&stubs[i]; } +#ifdef CONFIG_PPC_KERNEL_PCREL +/* Create GOT to load the location described in this ptr */ +static unsigned long got_for_addr(const Elf64_Shdr *sechdrs, + unsigned long addr, + struct module *me, + const char *name) +{ + struct ppc64_got_entry *got; + unsigned int i, num_got; + + if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return addr; + + num_got = sechdrs[me->arch.got_section].sh_size / sizeof(*got); + + /* Find this stub, or if that fails, the next avail. entry */ + got = (void *)sechdrs[me->arch.got_section].sh_addr; + for (i = 0; got[i].addr; i++) { + if (WARN_ON(i >= num_got)) + return 0; + + if (got[i].addr == addr) + return (unsigned long)&got[i]; + } + + got[i].addr = addr; + + return (unsigned long)&got[i]; +} +#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) @@ -504,6 +728,9 @@ static int restore_r2(const char *name, u32 *instruction, struct module *me) u32 *prev_insn = instruction - 1; u32 insn_val = *instruction; + if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return 0; + if (is_mprofile_ftrace_call(name)) return 0; @@ -549,6 +776,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, pr_debug("Applying ADD relocate section %u to %u\n", relsec, sechdrs[relsec].sh_info); +#ifndef CONFIG_PPC_KERNEL_PCREL /* First time we're called, we can fix up .TOC. */ if (!me->arch.toc_fixed) { sym = find_dot_toc(sechdrs, strtab, symindex); @@ -558,7 +786,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, sym->st_value = my_r2(sechdrs, me); me->arch.toc_fixed = true; } - +#endif 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 @@ -586,6 +814,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, *(unsigned long *)location = value; break; +#ifndef CONFIG_PPC_KERNEL_PCREL case R_PPC64_TOC: *(unsigned long *)location = my_r2(sechdrs, me); break; @@ -645,8 +874,13 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, = (*((uint16_t *) location) & ~0xffff) | (value & 0xffff); break; +#endif case R_PPC_REL24: +#ifdef CONFIG_PPC_KERNEL_PCREL + /* PCREL still generates REL24 for mcount */ + case R_PPC64_REL24_NOTOC: +#endif /* FIXME: Handle weak symbols here --RR */ if (sym->st_shndx == SHN_UNDEF || sym->st_shndx == SHN_LIVEPATCH) { @@ -694,6 +928,47 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, *(u32 *)location = value; break; +#ifdef CONFIG_PPC_KERNEL_PCREL + case R_PPC64_PCREL34: { + unsigned long absvalue = value; + + /* Convert value to relative */ + value -= (unsigned long)location; + + if (value + 0x200000000 > 0x3ffffffff) { + if (sym->st_shndx != me->arch.pcpu_section) { + pr_err("%s: REL34 %li out of range!\n", + me->name, (long)value); + return -ENOEXEC; + } + + /* + * per-cpu section is special cased because + * it is moved during loading, so has to be + * converted to use GOT. + */ + value = got_for_addr(sechdrs, absvalue, me, + strtab + sym->st_name); + if (!value) + return -ENOENT; + value -= (unsigned long)location; + + /* Turn pla into pld */ + if (patch_instruction((u32 *)location, + ppc_inst_prefix((*(u32 *)location & ~0x02000000), + (*((u32 *)location + 1) & ~0xf8000000) | 0xe4000000))) + return -EFAULT; + } + + if (patch_instruction((u32 *)location, + ppc_inst_prefix((*(u32 *)location & ~0x3ffff) | IMM_H18(value), + (*((u32 *)location + 1) & ~0xffff) | IMM_L(value)))) + return -EFAULT; + + break; + } + +#else case R_PPC64_TOCSAVE: /* * Marker reloc indicates we don't have to save r2. @@ -701,8 +976,12 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, * it. */ break; +#endif case R_PPC64_ENTRY: + if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + break; + /* * Optimize ELFv2 large code model entry point if * the TOC is within 2GB range of current location. @@ -745,6 +1024,20 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, | (value & 0xffff); break; +#ifdef CONFIG_PPC_KERNEL_PCREL + case R_PPC64_GOT_PCREL34: + value = got_for_addr(sechdrs, value, me, + strtab + sym->st_name); + if (!value) + return -ENOENT; + value -= (unsigned long)location; + ((uint32_t *)location)[0] = (((uint32_t *)location)[0] & ~0x3ffff) | + ((value >> 16) & 0x3ffff); + ((uint32_t *)location)[1] = (((uint32_t *)location)[1] & ~0xffff) | + (value & 0xffff); + break; +#endif + default: pr_err("%s: Unknown ADD relocation: %lu\n", me->name, |