diff options
Diffstat (limited to 'arch/powerpc/kernel/module_64.c')
| -rw-r--r-- | arch/powerpc/kernel/module_64.c | 1109 |
1 files changed, 1109 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c new file mode 100644 index 000000000..7112adc59 --- /dev/null +++ b/arch/powerpc/kernel/module_64.c @@ -0,0 +1,1109 @@ +// 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/code-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) +{ + /* 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 + } + } + +#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); +} + +#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); + + 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 +}; + +/* + * For mprofile-kernel we use a special stub for ftrace_caller() because we + * can't rely on r2 containing this module's TOC when we enter the stub. + * + * That can happen if the function calling us didn't need to use the toc. In + * that case it won't have setup r2, and the r2 value will be either the + * kernel's toc, or possibly another modules toc. + * + * To deal with that this stub uses the kernel toc, which is always accessible + * via the paca (in r13). The target (ftrace_caller()) is responsible for + * saving and restoring the toc before returning. + */ +static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, + unsigned long addr, + struct module *me) +{ + long reladdr; + + 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(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); + entry->magic = STUB_MAGIC; + + return 1; +} + +static bool is_mprofile_ftrace_call(const char *name) +{ + if (!strcmp("_mcount", name)) + return true; +#ifdef CONFIG_DYNAMIC_FTRACE + if (!strcmp("ftrace_caller", name)) + return true; +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + if (!strcmp("ftrace_regs_caller", name)) + return true; +#endif +#endif + + return false; +} +#else +static inline int create_ftrace_stub(struct ppc64_stub_entry *entry, + unsigned long addr, + struct module *me) +{ + return 0; +} + +static bool is_mprofile_ftrace_call(const char *name) +{ + return false; +} +#endif + +/* + * 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) +{ +#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. */ +static inline int create_stub(const Elf64_Shdr *sechdrs, + struct ppc64_stub_entry *entry, + unsigned long addr, + struct module *me, + const char *name) +{ + long reladdr; + func_desc_t desc; + int i; + + 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; + } + + 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); + + /* 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; + + } 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); + for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) { + if (patch_instruction(((u32 *)&entry->funcdata) + i, + ppc_inst(((u32 *)(&desc))[i]))) + return 0; + } + + if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC))) + return 0; + + 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, + const char *name) +{ + 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, name)) + return 0; + + 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) +{ + 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; + + /* + * Make sure the branch isn't a sibling call. Sibling calls aren't + * "link" branches and they don't return, so they don't need the r2 + * restore afterwards. + */ + if (!instr_is_relative_link_branch(ppc_inst(*prev_insn))) + return 0; + + /* + * For livepatch, the restore r2 instruction might have already been + * written previously, if the referenced symbol is in a previously + * unloaded module which is now being loaded again. In that case, skip + * the warning and the instruction write. + */ + if (insn_val == PPC_INST_LD_TOC) + return 0; + + if (insn_val != PPC_RAW_NOP()) { + pr_err("%s: Expected nop after call, got %08x at %pS\n", + me->name, insn_val, instruction); + return -ENOEXEC; + } + + /* ld r2,R2_STACK_OFFSET(r1) */ + return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC)); +} + +int apply_relocate_add(Elf64_Shdr *sechdrs, + const char *strtab, + unsigned int symindex, + unsigned int relsec, + struct module *me) +{ + unsigned int i; + Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; + Elf64_Sym *sym; + unsigned long *location; + unsigned long value; + + 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); + /* It's theoretically possible that a module doesn't want a + * .TOC. so don't fail it just for that. */ + if (sym) + 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 + + rela[i].r_offset; + /* This is the symbol it is referring to */ + sym = (Elf64_Sym *)sechdrs[symindex].sh_addr + + ELF64_R_SYM(rela[i].r_info); + + pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", + location, (long)ELF64_R_TYPE(rela[i].r_info), + strtab + sym->st_name, (unsigned long)sym->st_value, + (long)rela[i].r_addend); + + /* `Everything is relative'. */ + value = sym->st_value + rela[i].r_addend; + + switch (ELF64_R_TYPE(rela[i].r_info)) { + case R_PPC64_ADDR32: + /* Simply set it */ + *(u32 *)location = value; + break; + + case R_PPC64_ADDR64: + /* Simply set it */ + *(unsigned long *)location = value; + break; + +#ifndef CONFIG_PPC_KERNEL_PCREL + case R_PPC64_TOC: + *(unsigned long *)location = my_r2(sechdrs, me); + break; + + case R_PPC64_TOC16: + /* Subtract TOC pointer */ + value -= my_r2(sechdrs, me); + if (value + 0x8000 > 0xffff) { + pr_err("%s: bad TOC16 relocation (0x%lx)\n", + me->name, value); + return -ENOEXEC; + } + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xffff) + | (value & 0xffff); + break; + + case R_PPC64_TOC16_LO: + /* Subtract TOC pointer */ + value -= my_r2(sechdrs, me); + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xffff) + | (value & 0xffff); + break; + + case R_PPC64_TOC16_DS: + /* Subtract TOC pointer */ + value -= my_r2(sechdrs, me); + if ((value & 3) != 0 || value + 0x8000 > 0xffff) { + pr_err("%s: bad TOC16_DS relocation (0x%lx)\n", + me->name, value); + return -ENOEXEC; + } + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xfffc) + | (value & 0xfffc); + break; + + case R_PPC64_TOC16_LO_DS: + /* Subtract TOC pointer */ + value -= my_r2(sechdrs, me); + if ((value & 3) != 0) { + pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n", + me->name, value); + return -ENOEXEC; + } + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xfffc) + | (value & 0xfffc); + break; + + case R_PPC64_TOC16_HA: + /* Subtract TOC pointer */ + value -= my_r2(sechdrs, me); + value = ((value + 0x8000) >> 16); + *((uint16_t *) location) + = (*((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) { + /* External: go via stub */ + value = stub_for_addr(sechdrs, value, me, + strtab + sym->st_name); + if (!value) + return -ENOENT; + if (restore_r2(strtab + sym->st_name, + (u32 *)location + 1, me)) + return -ENOEXEC; + } else + value += local_entry_offset(sym); + + /* Convert value to relative */ + value -= (unsigned long)location; + if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ + pr_err("%s: REL24 %li out of range!\n", + me->name, (long int)value); + return -ENOEXEC; + } + + /* Only replace bits 2 through 26 */ + value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value); + + if (patch_instruction((u32 *)location, ppc_inst(value))) + return -EFAULT; + + break; + + case R_PPC64_REL64: + /* 64 bits relative (used by features fixups) */ + *location = value - (unsigned long)location; + break; + + case R_PPC64_REL32: + /* 32 bits relative (used by relative exception tables) */ + /* Convert value to relative */ + value -= (unsigned long)location; + if (value + 0x80000000 > 0xffffffff) { + pr_err("%s: REL32 %li out of range!\n", + me->name, (long int)value); + return -ENOEXEC; + } + *(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. + * That would only save us one instruction, so ignore + * 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. + */ + value = my_r2(sechdrs, me) - (unsigned long)location; + if (value + 0x80008000 > 0xffffffff) + break; + /* + * Check for the large code model prolog sequence: + * ld r2, ...(r12) + * add r2, r2, r12 + */ + if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0)) + break; + if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12)) + break; + /* + * If found, replace it with: + * addis r2, r12, (.TOC.-func)@ha + * addi r2, r2, (.TOC.-func)@l + */ + ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value)); + ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value)); + break; + + case R_PPC64_REL16_HA: + /* Subtract location pointer */ + value -= (unsigned long)location; + value = ((value + 0x8000) >> 16); + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xffff) + | (value & 0xffff); + break; + + case R_PPC64_REL16_LO: + /* Subtract location pointer */ + value -= (unsigned long)location; + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xffff) + | (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, + (unsigned long)ELF64_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) +{ + 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 (copy_from_kernel_nofault(&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 (copy_from_kernel_nofault(&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; +} + +int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs) +{ + mod->arch.tramp = stub_for_addr(sechdrs, + (unsigned long)ftrace_caller, + mod, + "ftrace_caller"); +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + mod->arch.tramp_regs = stub_for_addr(sechdrs, + (unsigned long)ftrace_regs_caller, + mod, + "ftrace_regs_caller"); + if (!mod->arch.tramp_regs) + return -ENOENT; +#endif + + if (!mod->arch.tramp) + return -ENOENT; + + return 0; +} +#endif |