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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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*/
#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){ unsigned long relocs = 0; 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; } }#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)); }}
/* Same as normal versions, remove a leading dot if present. */static void dedotify_ext_version_names(char *str_seq, unsigned long size){ unsigned long out = 0; unsigned long in; char last = '\0';
for (in = 0; in < size; in++) { /* Skip one leading dot */ if (last == '\0' && str_seq[in] == '.') in++; last = str_seq[in]; str_seq[out++] = last; } /* Zero the trailing portion of the names table for robustness */ memset(&str_seq[out], 0, size - out);}
/* * 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); else if (strcmp(secstrings + sechdrs[i].sh_name, "__version_ext_names") == 0) dedotify_ext_version_names((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};
/* * 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;}#elsestatic 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_u32(((u32 *)&entry->funcdata) + i, ((u32 *)&desc)[i])) return 0; }
if (patch_u32(&entry->magic, 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; i < me->arch.stub_count; 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;
me->arch.stub_count++; 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_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 (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;}
static int setup_ftrace_ool_stubs(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me){#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE unsigned int total_stubs, num_stubs; struct ppc64_stub_entry *stub;
total_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stub); num_stubs = roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub), sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry);
if (WARN_ON(me->arch.stub_count + num_stubs > total_stubs)) return -1;
stub = (void *)sechdrs[me->arch.stubs_section].sh_addr; me->arch.ool_stubs = (struct ftrace_ool_stub *)(stub + me->arch.stub_count); me->arch.stub_count += num_stubs;#endif
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;
if (setup_ftrace_ool_stubs(sechdrs, mod->arch.tramp, mod)) return -ENOENT;
return 0;}#endif