From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/powerpc/kernel/module_32.c | 341 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 341 insertions(+) create mode 100644 arch/powerpc/kernel/module_32.c (limited to 'arch/powerpc/kernel/module_32.c') diff --git a/arch/powerpc/kernel/module_32.c b/arch/powerpc/kernel/module_32.c new file mode 100644 index 000000000..ea6536171 --- /dev/null +++ b/arch/powerpc/kernel/module_32.c @@ -0,0 +1,341 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Kernel module help for PPC. + Copyright (C) 2001 Rusty Russell. + +*/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Count how many different relocations (different symbol, different + addend) */ +static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num) +{ + unsigned int i, r_info, r_addend, _count_relocs; + + _count_relocs = 0; + r_info = 0; + r_addend = 0; + for (i = 0; i < num; i++) + /* Only count 24-bit relocs, others don't need stubs */ + if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 && + (r_info != ELF32_R_SYM(rela[i].r_info) || + r_addend != rela[i].r_addend)) { + _count_relocs++; + r_info = ELF32_R_SYM(rela[i].r_info); + r_addend = rela[i].r_addend; + } + +#ifdef CONFIG_DYNAMIC_FTRACE + _count_relocs++; /* add one for ftrace_caller */ +#endif + return _count_relocs; +} + +static int relacmp(const void *_x, const void *_y) +{ + const Elf32_Rela *x, *y; + + y = (Elf32_Rela *)_x; + x = (Elf32_Rela *)_y; + + /* Compare the entire r_info (as opposed to ELF32_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 the potential trampolines size required of the init and + non-init sections */ +static unsigned long get_plt_size(const Elf32_Ehdr *hdr, + const Elf32_Shdr *sechdrs, + const char *secstrings, + int is_init) +{ + unsigned long ret = 0; + unsigned i; + + /* Everything marked ALLOC (this includes the exported + symbols) */ + for (i = 1; i < hdr->e_shnum; i++) { + /* If it's called *.init*, and we're not init, we're + not interested */ + if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != NULL) + != is_init) + continue; + + /* We don't want to look at debug sections. */ + if (strstr(secstrings + sechdrs[i].sh_name, ".debug")) + continue; + + if (sechdrs[i].sh_type == SHT_RELA) { + pr_debug("Found relocations in section %u\n", i); + pr_debug("Ptr: %p. Number: %u\n", + (void *)hdr + sechdrs[i].sh_offset, + sechdrs[i].sh_size / sizeof(Elf32_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 *)hdr + sechdrs[i].sh_offset, + sechdrs[i].sh_size / sizeof(Elf32_Rela), + sizeof(Elf32_Rela), relacmp, NULL); + + ret += count_relocs((void *)hdr + + sechdrs[i].sh_offset, + sechdrs[i].sh_size + / sizeof(Elf32_Rela)) + * sizeof(struct ppc_plt_entry); + } + } + + return ret; +} + +int module_frob_arch_sections(Elf32_Ehdr *hdr, + Elf32_Shdr *sechdrs, + char *secstrings, + struct module *me) +{ + unsigned int i; + + /* Find .plt and .init.plt sections */ + for (i = 0; i < hdr->e_shnum; i++) { + if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0) + me->arch.init_plt_section = i; + else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) + me->arch.core_plt_section = i; + } + if (!me->arch.core_plt_section || !me->arch.init_plt_section) { + pr_err("Module doesn't contain .plt or .init.plt sections.\n"); + return -ENOEXEC; + } + + /* Override their sizes */ + sechdrs[me->arch.core_plt_section].sh_size + = get_plt_size(hdr, sechdrs, secstrings, 0); + sechdrs[me->arch.init_plt_section].sh_size + = get_plt_size(hdr, sechdrs, secstrings, 1); + return 0; +} + +static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val) +{ + if (entry->jump[0] != PPC_RAW_LIS(_R12, PPC_HA(val))) + return 0; + if (entry->jump[1] != PPC_RAW_ADDI(_R12, _R12, PPC_LO(val))) + return 0; + return 1; +} + +/* Set up a trampoline in the PLT to bounce us to the distant function */ +static uint32_t do_plt_call(void *location, + Elf32_Addr val, + const Elf32_Shdr *sechdrs, + struct module *mod) +{ + struct ppc_plt_entry *entry; + + pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location); + /* Init, or core PLT? */ + if (location >= mod->core_layout.base + && location < mod->core_layout.base + mod->core_layout.size) + entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr; + else + entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr; + + /* Find this entry, or if that fails, the next avail. entry */ + while (entry->jump[0]) { + if (entry_matches(entry, val)) return (uint32_t)entry; + entry++; + } + + if (patch_instruction(&entry->jump[0], ppc_inst(PPC_RAW_LIS(_R12, PPC_HA(val))))) + return 0; + if (patch_instruction(&entry->jump[1], ppc_inst(PPC_RAW_ADDI(_R12, _R12, PPC_LO(val))))) + return 0; + if (patch_instruction(&entry->jump[2], ppc_inst(PPC_RAW_MTCTR(_R12)))) + return 0; + if (patch_instruction(&entry->jump[3], ppc_inst(PPC_RAW_BCTR()))) + return 0; + + pr_debug("Initialized plt for 0x%x at %p\n", val, entry); + return (uint32_t)entry; +} + +static int patch_location_16(uint32_t *loc, u16 value) +{ + loc = PTR_ALIGN_DOWN(loc, sizeof(u32)); + return patch_instruction(loc, ppc_inst((*loc & 0xffff0000) | value)); +} + +int apply_relocate_add(Elf32_Shdr *sechdrs, + const char *strtab, + unsigned int symindex, + unsigned int relsec, + struct module *module) +{ + unsigned int i; + Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; + Elf32_Sym *sym; + uint32_t *location; + uint32_t value; + + pr_debug("Applying ADD relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + 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. Note that all + undefined symbols have been resolved. */ + sym = (Elf32_Sym *)sechdrs[symindex].sh_addr + + ELF32_R_SYM(rela[i].r_info); + /* `Everything is relative'. */ + value = sym->st_value + rela[i].r_addend; + + switch (ELF32_R_TYPE(rela[i].r_info)) { + case R_PPC_ADDR32: + /* Simply set it */ + *(uint32_t *)location = value; + break; + + case R_PPC_ADDR16_LO: + /* Low half of the symbol */ + if (patch_location_16(location, PPC_LO(value))) + return -EFAULT; + break; + + case R_PPC_ADDR16_HI: + /* Higher half of the symbol */ + if (patch_location_16(location, PPC_HI(value))) + return -EFAULT; + break; + + case R_PPC_ADDR16_HA: + if (patch_location_16(location, PPC_HA(value))) + return -EFAULT; + break; + + case R_PPC_REL24: + if ((int)(value - (uint32_t)location) < -0x02000000 + || (int)(value - (uint32_t)location) >= 0x02000000) { + value = do_plt_call(location, value, + sechdrs, module); + if (!value) + return -EFAULT; + } + + /* Only replace bits 2 through 26 */ + pr_debug("REL24 value = %08X. location = %08X\n", + value, (uint32_t)location); + pr_debug("Location before: %08X.\n", + *(uint32_t *)location); + value = (*(uint32_t *)location & ~PPC_LI_MASK) | + PPC_LI(value - (uint32_t)location); + + if (patch_instruction(location, ppc_inst(value))) + return -EFAULT; + + pr_debug("Location after: %08X.\n", + *(uint32_t *)location); + pr_debug("ie. jump to %08X+%08X = %08X\n", + *(uint32_t *)PPC_LI((uint32_t)location), (uint32_t)location, + (*(uint32_t *)PPC_LI((uint32_t)location)) + (uint32_t)location); + break; + + case R_PPC_REL32: + /* 32-bit relative jump. */ + *(uint32_t *)location = value - (uint32_t)location; + break; + + default: + pr_err("%s: unknown ADD relocation: %u\n", + module->name, + ELF32_R_TYPE(rela[i].r_info)); + return -ENOEXEC; + } + } + + return 0; +} + +#ifdef CONFIG_DYNAMIC_FTRACE +notrace int module_trampoline_target(struct module *mod, unsigned long addr, + unsigned long *target) +{ + ppc_inst_t jmp[4]; + + /* Find where the trampoline jumps to */ + if (copy_inst_from_kernel_nofault(jmp, (void *)addr)) + return -EFAULT; + if (__copy_inst_from_kernel_nofault(jmp + 1, (void *)addr + 4)) + return -EFAULT; + if (__copy_inst_from_kernel_nofault(jmp + 2, (void *)addr + 8)) + return -EFAULT; + if (__copy_inst_from_kernel_nofault(jmp + 3, (void *)addr + 12)) + return -EFAULT; + + /* verify that this is what we expect it to be */ + if ((ppc_inst_val(jmp[0]) & 0xffff0000) != PPC_RAW_LIS(_R12, 0)) + return -EINVAL; + if ((ppc_inst_val(jmp[1]) & 0xffff0000) != PPC_RAW_ADDI(_R12, _R12, 0)) + return -EINVAL; + if (ppc_inst_val(jmp[2]) != PPC_RAW_MTCTR(_R12)) + return -EINVAL; + if (ppc_inst_val(jmp[3]) != PPC_RAW_BCTR()) + return -EINVAL; + + addr = (ppc_inst_val(jmp[1]) & 0xffff) | ((ppc_inst_val(jmp[0]) & 0xffff) << 16); + if (addr & 0x8000) + addr -= 0x10000; + + *target = addr; + + return 0; +} + +int module_finalize_ftrace(struct module *module, const Elf_Shdr *sechdrs) +{ + module->arch.tramp = do_plt_call(module->core_layout.base, + (unsigned long)ftrace_caller, + sechdrs, module); + if (!module->arch.tramp) + return -ENOENT; + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS + module->arch.tramp_regs = do_plt_call(module->core_layout.base, + (unsigned long)ftrace_regs_caller, + sechdrs, module); + if (!module->arch.tramp_regs) + return -ENOENT; +#endif + + return 0; +} +#endif -- cgit v1.2.3