diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/riscv/kernel/module.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c new file mode 100644 index 000000000..a331001e3 --- /dev/null +++ b/arch/riscv/kernel/module.c @@ -0,0 +1,459 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) 2017 Zihao Yu + */ + +#include <linux/elf.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/moduleloader.h> +#include <linux/vmalloc.h> +#include <linux/sizes.h> +#include <linux/pgtable.h> +#include <asm/alternative.h> +#include <asm/sections.h> + +/* + * The auipc+jalr instruction pair can reach any PC-relative offset + * in the range [-2^31 - 2^11, 2^31 - 2^11) + */ +static bool riscv_insn_valid_32bit_offset(ptrdiff_t val) +{ +#ifdef CONFIG_32BIT + return true; +#else + return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11)); +#endif +} + +static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v) +{ + if (v != (u32)v) { + pr_err("%s: value %016llx out of range for 32-bit field\n", + me->name, (long long)v); + return -EINVAL; + } + *location = v; + return 0; +} + +static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v) +{ + *(u64 *)location = v; + return 0; +} + +static int apply_r_riscv_branch_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u32 imm12 = (offset & 0x1000) << (31 - 12); + u32 imm11 = (offset & 0x800) >> (11 - 7); + u32 imm10_5 = (offset & 0x7e0) << (30 - 10); + u32 imm4_1 = (offset & 0x1e) << (11 - 4); + + *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1; + return 0; +} + +static int apply_r_riscv_jal_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u32 imm20 = (offset & 0x100000) << (31 - 20); + u32 imm19_12 = (offset & 0xff000); + u32 imm11 = (offset & 0x800) << (20 - 11); + u32 imm10_1 = (offset & 0x7fe) << (30 - 10); + + *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1; + return 0; +} + +static int apply_r_riscv_rvc_branch_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u16 imm8 = (offset & 0x100) << (12 - 8); + u16 imm7_6 = (offset & 0xc0) >> (6 - 5); + u16 imm5 = (offset & 0x20) >> (5 - 2); + u16 imm4_3 = (offset & 0x18) << (12 - 5); + u16 imm2_1 = (offset & 0x6) << (12 - 10); + + *(u16 *)location = (*(u16 *)location & 0xe383) | + imm8 | imm7_6 | imm5 | imm4_3 | imm2_1; + return 0; +} + +static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u16 imm11 = (offset & 0x800) << (12 - 11); + u16 imm10 = (offset & 0x400) >> (10 - 8); + u16 imm9_8 = (offset & 0x300) << (12 - 11); + u16 imm7 = (offset & 0x80) >> (7 - 6); + u16 imm6 = (offset & 0x40) << (12 - 11); + u16 imm5 = (offset & 0x20) >> (5 - 2); + u16 imm4 = (offset & 0x10) << (12 - 5); + u16 imm3_1 = (offset & 0xe) << (12 - 10); + + *(u16 *)location = (*(u16 *)location & 0xe003) | + imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1; + return 0; +} + +static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + s32 hi20; + + if (!riscv_insn_valid_32bit_offset(offset)) { + pr_err( + "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + + hi20 = (offset + 0x800) & 0xfffff000; + *location = (*location & 0xfff) | hi20; + return 0; +} + +static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + /* + * v is the lo12 value to fill. It is calculated before calling this + * handler. + */ + *location = (*location & 0xfffff) | ((v & 0xfff) << 20); + return 0; +} + +static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + /* + * v is the lo12 value to fill. It is calculated before calling this + * handler. + */ + u32 imm11_5 = (v & 0xfe0) << (31 - 11); + u32 imm4_0 = (v & 0x1f) << (11 - 4); + + *location = (*location & 0x1fff07f) | imm11_5 | imm4_0; + return 0; +} + +static int apply_r_riscv_hi20_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + s32 hi20; + + if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) { + pr_err( + "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + + hi20 = ((s32)v + 0x800) & 0xfffff000; + *location = (*location & 0xfff) | hi20; + return 0; +} + +static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + /* Skip medlow checking because of filtering by HI20 already */ + s32 hi20 = ((s32)v + 0x800) & 0xfffff000; + s32 lo12 = ((s32)v - hi20); + *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20); + return 0; +} + +static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + /* Skip medlow checking because of filtering by HI20 already */ + s32 hi20 = ((s32)v + 0x800) & 0xfffff000; + s32 lo12 = ((s32)v - hi20); + u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11); + u32 imm4_0 = (lo12 & 0x1f) << (11 - 4); + *location = (*location & 0x1fff07f) | imm11_5 | imm4_0; + return 0; +} + +static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + s32 hi20; + + /* Always emit the got entry */ + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { + offset = module_emit_got_entry(me, v); + offset = (void *)offset - (void *)location; + } else { + pr_err( + "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + + hi20 = (offset + 0x800) & 0xfffff000; + *location = (*location & 0xfff) | hi20; + return 0; +} + +static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u32 hi20, lo12; + + if (!riscv_insn_valid_32bit_offset(offset)) { + /* Only emit the plt entry if offset over 32-bit range */ + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { + offset = module_emit_plt_entry(me, v); + offset = (void *)offset - (void *)location; + } else { + pr_err( + "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + } + + hi20 = (offset + 0x800) & 0xfffff000; + lo12 = (offset - hi20) & 0xfff; + *location = (*location & 0xfff) | hi20; + *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20); + return 0; +} + +static int apply_r_riscv_call_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - (void *)location; + u32 hi20, lo12; + + if (!riscv_insn_valid_32bit_offset(offset)) { + pr_err( + "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", + me->name, (long long)v, location); + return -EINVAL; + } + + hi20 = (offset + 0x800) & 0xfffff000; + lo12 = (offset - hi20) & 0xfff; + *location = (*location & 0xfff) | hi20; + *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20); + return 0; +} + +static int apply_r_riscv_relax_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + return 0; +} + +static int apply_r_riscv_align_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + pr_err( + "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n", + me->name, location); + return -EINVAL; +} + +static int apply_r_riscv_add32_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + *(u32 *)location += (u32)v; + return 0; +} + +static int apply_r_riscv_add64_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + *(u64 *)location += (u64)v; + return 0; +} + +static int apply_r_riscv_sub32_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + *(u32 *)location -= (u32)v; + return 0; +} + +static int apply_r_riscv_sub64_rela(struct module *me, u32 *location, + Elf_Addr v) +{ + *(u64 *)location -= (u64)v; + return 0; +} + +static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, + Elf_Addr v) = { + [R_RISCV_32] = apply_r_riscv_32_rela, + [R_RISCV_64] = apply_r_riscv_64_rela, + [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, + [R_RISCV_JAL] = apply_r_riscv_jal_rela, + [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, + [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, + [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, + [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, + [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, + [R_RISCV_HI20] = apply_r_riscv_hi20_rela, + [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, + [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, + [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, + [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, + [R_RISCV_CALL] = apply_r_riscv_call_rela, + [R_RISCV_RELAX] = apply_r_riscv_relax_rela, + [R_RISCV_ALIGN] = apply_r_riscv_align_rela, + [R_RISCV_ADD32] = apply_r_riscv_add32_rela, + [R_RISCV_ADD64] = apply_r_riscv_add64_rela, + [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, + [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, +}; + +int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, + unsigned int symindex, unsigned int relsec, + struct module *me) +{ + Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr; + int (*handler)(struct module *me, u32 *location, Elf_Addr v); + Elf_Sym *sym; + u32 *location; + unsigned int i, type; + Elf_Addr v; + int res; + + pr_debug("Applying relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + + for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { + /* This is where to make the change */ + location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr + + rel[i].r_offset; + /* This is the symbol it is referring to */ + sym = (Elf_Sym *)sechdrs[symindex].sh_addr + + ELF_RISCV_R_SYM(rel[i].r_info); + if (IS_ERR_VALUE(sym->st_value)) { + /* Ignore unresolved weak symbol */ + if (ELF_ST_BIND(sym->st_info) == STB_WEAK) + continue; + pr_warn("%s: Unknown symbol %s\n", + me->name, strtab + sym->st_name); + return -ENOENT; + } + + type = ELF_RISCV_R_TYPE(rel[i].r_info); + + if (type < ARRAY_SIZE(reloc_handlers_rela)) + handler = reloc_handlers_rela[type]; + else + handler = NULL; + + if (!handler) { + pr_err("%s: Unknown relocation type %u\n", + me->name, type); + return -EINVAL; + } + + v = sym->st_value + rel[i].r_addend; + + if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { + unsigned int j; + + for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { + unsigned long hi20_loc = + sechdrs[sechdrs[relsec].sh_info].sh_addr + + rel[j].r_offset; + u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); + + /* Find the corresponding HI20 relocation entry */ + if (hi20_loc == sym->st_value + && (hi20_type == R_RISCV_PCREL_HI20 + || hi20_type == R_RISCV_GOT_HI20)) { + s32 hi20, lo12; + Elf_Sym *hi20_sym = + (Elf_Sym *)sechdrs[symindex].sh_addr + + ELF_RISCV_R_SYM(rel[j].r_info); + unsigned long hi20_sym_val = + hi20_sym->st_value + + rel[j].r_addend; + + /* Calculate lo12 */ + size_t offset = hi20_sym_val - hi20_loc; + if (IS_ENABLED(CONFIG_MODULE_SECTIONS) + && hi20_type == R_RISCV_GOT_HI20) { + offset = module_emit_got_entry( + me, hi20_sym_val); + offset = offset - hi20_loc; + } + hi20 = (offset + 0x800) & 0xfffff000; + lo12 = offset - hi20; + v = lo12; + + break; + } + } + if (j == sechdrs[relsec].sh_size / sizeof(*rel)) { + pr_err( + "%s: Can not find HI20 relocation information\n", + me->name); + return -EINVAL; + } + } + + res = handler(me, location, v); + if (res) + return res; + } + + return 0; +} + +#if defined(CONFIG_MMU) && defined(CONFIG_64BIT) +void *module_alloc(unsigned long size) +{ + return __vmalloc_node_range(size, 1, MODULES_VADDR, + MODULES_END, GFP_KERNEL, + PAGE_KERNEL, VM_FLUSH_RESET_PERMS, + NUMA_NO_NODE, + __builtin_return_address(0)); +} +#endif + +static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + const char *name) +{ + const Elf_Shdr *s, *se; + const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { + if (strcmp(name, secstrs + s->sh_name) == 0) + return s; + } + + return NULL; +} + +int module_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *me) +{ + const Elf_Shdr *s; + + s = find_section(hdr, sechdrs, ".alternative"); + if (s) + apply_module_alternatives((void *)s->sh_addr, s->sh_size); + + return 0; +} |