diff options
Diffstat (limited to 'arch/riscv/kernel/module.c')
| -rw-r--r-- | arch/riscv/kernel/module.c | 907 |
1 files changed, 907 insertions, 0 deletions
diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c new file mode 100644 index 000000000000..7f6147c18033 --- /dev/null +++ b/arch/riscv/kernel/module.c @@ -0,0 +1,907 @@ +// 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/hashtable.h> +#include <linux/kernel.h> +#include <linux/log2.h> +#include <linux/moduleloader.h> +#include <linux/sizes.h> +#include <linux/pgtable.h> +#include <asm/alternative.h> +#include <asm/sections.h> + +struct used_bucket { + struct list_head head; + struct hlist_head *bucket; +}; + +struct relocation_head { + struct hlist_node node; + struct list_head rel_entry; + void *location; +}; + +struct relocation_entry { + struct list_head head; + Elf_Addr value; + unsigned int type; +}; + +struct relocation_handlers { + int (*reloc_handler)(struct module *me, void *location, Elf_Addr v); + int (*accumulate_handler)(struct module *me, void *location, + long buffer); +}; + +/* + * 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 riscv_insn_rmw(void *location, u32 keep, u32 set) +{ + __le16 *parcel = location; + u32 insn = (u32)le16_to_cpu(parcel[0]) | (u32)le16_to_cpu(parcel[1]) << 16; + + insn &= keep; + insn |= set; + + parcel[0] = cpu_to_le16(insn); + parcel[1] = cpu_to_le16(insn >> 16); + return 0; +} + +static int riscv_insn_rvc_rmw(void *location, u16 keep, u16 set) +{ + __le16 *parcel = location; + u16 insn = le16_to_cpu(*parcel); + + insn &= keep; + insn |= set; + + *parcel = cpu_to_le16(insn); + return 0; +} + +static int apply_r_riscv_32_rela(struct module *me, void *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; + } + *(u32 *)location = v; + return 0; +} + +static int apply_r_riscv_64_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u64 *)location = v; + return 0; +} + +static int apply_r_riscv_branch_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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); + + return riscv_insn_rmw(location, 0x1fff07f, imm12 | imm11 | imm10_5 | imm4_1); +} + +static int apply_r_riscv_jal_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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); + + return riscv_insn_rmw(location, 0xfff, imm20 | imm19_12 | imm11 | imm10_1); +} + +static int apply_r_riscv_rvc_branch_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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); + + return riscv_insn_rvc_rmw(location, 0xe383, + imm8 | imm7_6 | imm5 | imm4_3 | imm2_1); +} + +static int apply_r_riscv_rvc_jump_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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); + + return riscv_insn_rvc_rmw(location, 0xe003, + imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1); +} + +static int apply_r_riscv_pcrel_hi20_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - location; + + 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; + } + + return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); +} + +static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, void *location, + Elf_Addr v) +{ + /* + * v is the lo12 value to fill. It is calculated before calling this + * handler. + */ + return riscv_insn_rmw(location, 0xfffff, (v & 0xfff) << 20); +} + +static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, void *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); + + return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); +} + +static int apply_r_riscv_hi20_rela(struct module *me, void *location, + Elf_Addr v) +{ + 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; + } + + return riscv_insn_rmw(location, 0xfff, ((s32)v + 0x800) & 0xfffff000); +} + +static int apply_r_riscv_lo12_i_rela(struct module *me, void *location, + Elf_Addr v) +{ + /* Skip medlow checking because of filtering by HI20 already */ + s32 hi20 = ((s32)v + 0x800) & 0xfffff000; + s32 lo12 = ((s32)v - hi20); + + return riscv_insn_rmw(location, 0xfffff, (lo12 & 0xfff) << 20); +} + +static int apply_r_riscv_lo12_s_rela(struct module *me, void *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); + + return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); +} + +static int apply_r_riscv_got_hi20_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - location; + + /* Always emit the got entry */ + if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { + offset = (void *)module_emit_got_entry(me, v) - 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; + } + + return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); +} + +static int apply_r_riscv_call_plt_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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 = (void *)module_emit_plt_entry(me, v) - 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; + riscv_insn_rmw(location, 0xfff, hi20); + return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); +} + +static int apply_r_riscv_call_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - 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; + riscv_insn_rmw(location, 0xfff, hi20); + return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); +} + +static int apply_r_riscv_relax_rela(struct module *me, void *location, + Elf_Addr v) +{ + return 0; +} + +static int apply_r_riscv_align_rela(struct module *me, void *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_add8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location += (u8)v; + return 0; +} + +static int apply_r_riscv_add16_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u16 *)location += (u16)v; + return 0; +} + +static int apply_r_riscv_add32_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location += (u32)v; + return 0; +} + +static int apply_r_riscv_add64_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u64 *)location += (u64)v; + return 0; +} + +static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location -= (u8)v; + return 0; +} + +static int apply_r_riscv_sub16_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u16 *)location -= (u16)v; + return 0; +} + +static int apply_r_riscv_sub32_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location -= (u32)v; + return 0; +} + +static int apply_r_riscv_sub64_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u64 *)location -= (u64)v; + return 0; +} + +static int dynamic_linking_not_supported(struct module *me, void *location, + Elf_Addr v) +{ + pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", + me->name, location); + return -EINVAL; +} + +static int tls_not_supported(struct module *me, void *location, Elf_Addr v) +{ + pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", + me->name, location); + return -EINVAL; +} + +static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) +{ + u8 *byte = location; + u8 value = v; + + *byte = (*byte - (value & 0x3f)) & 0x3f; + return 0; +} + +static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) +{ + u8 *byte = location; + u8 value = v; + + *byte = (*byte & 0xc0) | (value & 0x3f); + return 0; +} + +static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) +{ + *(u8 *)location = (u8)v; + return 0; +} + +static int apply_r_riscv_set16_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u16 *)location = (u16)v; + return 0; +} + +static int apply_r_riscv_set32_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location = (u32)v; + return 0; +} + +static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, + Elf_Addr v) +{ + *(u32 *)location = v - (uintptr_t)location; + return 0; +} + +static int apply_r_riscv_plt32_rela(struct module *me, void *location, + Elf_Addr v) +{ + ptrdiff_t offset = (void *)v - location; + + 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 = (void *)module_emit_plt_entry(me, v) - 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; + } + } + + *(u32 *)location = (u32)offset; + return 0; +} + +static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) +{ + *(long *)location = v; + return 0; +} + +static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) +{ + *(long *)location -= v; + return 0; +} + +static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) +{ + u8 *byte = location; + u8 value = buffer; + + if (buffer > 0x3f) { + pr_err("%s: value %ld out of range for 6-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + + *byte = (*byte & 0xc0) | (value & 0x3f); + return 0; +} + +static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer > U8_MAX) { + pr_err("%s: value %ld out of range for 8-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u8 *)location = (u8)buffer; + return 0; +} + +static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer > U16_MAX) { + pr_err("%s: value %ld out of range for 16-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u16 *)location = (u16)buffer; + return 0; +} + +static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) +{ + if (buffer > U32_MAX) { + pr_err("%s: value %ld out of range for 32-bit relocation.\n", + me->name, buffer); + return -EINVAL; + } + *(u32 *)location = (u32)buffer; + return 0; +} + +static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) +{ + *(u64 *)location = (u64)buffer; + return 0; +} + +static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) +{ + /* + * ULEB128 is a variable length encoding. Encode the buffer into + * the ULEB128 data format. + */ + u8 *p = location; + + while (buffer != 0) { + u8 value = buffer & 0x7f; + + buffer >>= 7; + value |= (!!buffer) << 7; + + *p++ = value; + } + return 0; +} + +/* + * Relocations defined in the riscv-elf-psabi-doc. + * This handles static linking only. + */ +static const struct relocation_handlers reloc_handlers[] = { + [R_RISCV_32] = { .reloc_handler = apply_r_riscv_32_rela }, + [R_RISCV_64] = { .reloc_handler = apply_r_riscv_64_rela }, + [R_RISCV_RELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_COPY] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_JUMP_SLOT] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_DTPMOD32] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_DTPMOD64] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_DTPREL32] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_DTPREL64] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_TPREL32] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_TLS_TPREL64] = { .reloc_handler = dynamic_linking_not_supported }, + /* 12-15 undefined */ + [R_RISCV_BRANCH] = { .reloc_handler = apply_r_riscv_branch_rela }, + [R_RISCV_JAL] = { .reloc_handler = apply_r_riscv_jal_rela }, + [R_RISCV_CALL] = { .reloc_handler = apply_r_riscv_call_rela }, + [R_RISCV_CALL_PLT] = { .reloc_handler = apply_r_riscv_call_plt_rela }, + [R_RISCV_GOT_HI20] = { .reloc_handler = apply_r_riscv_got_hi20_rela }, + [R_RISCV_TLS_GOT_HI20] = { .reloc_handler = tls_not_supported }, + [R_RISCV_TLS_GD_HI20] = { .reloc_handler = tls_not_supported }, + [R_RISCV_PCREL_HI20] = { .reloc_handler = apply_r_riscv_pcrel_hi20_rela }, + [R_RISCV_PCREL_LO12_I] = { .reloc_handler = apply_r_riscv_pcrel_lo12_i_rela }, + [R_RISCV_PCREL_LO12_S] = { .reloc_handler = apply_r_riscv_pcrel_lo12_s_rela }, + [R_RISCV_HI20] = { .reloc_handler = apply_r_riscv_hi20_rela }, + [R_RISCV_LO12_I] = { .reloc_handler = apply_r_riscv_lo12_i_rela }, + [R_RISCV_LO12_S] = { .reloc_handler = apply_r_riscv_lo12_s_rela }, + [R_RISCV_TPREL_HI20] = { .reloc_handler = tls_not_supported }, + [R_RISCV_TPREL_LO12_I] = { .reloc_handler = tls_not_supported }, + [R_RISCV_TPREL_LO12_S] = { .reloc_handler = tls_not_supported }, + [R_RISCV_TPREL_ADD] = { .reloc_handler = tls_not_supported }, + [R_RISCV_ADD8] = { .reloc_handler = apply_r_riscv_add8_rela, + .accumulate_handler = apply_8_bit_accumulation }, + [R_RISCV_ADD16] = { .reloc_handler = apply_r_riscv_add16_rela, + .accumulate_handler = apply_16_bit_accumulation }, + [R_RISCV_ADD32] = { .reloc_handler = apply_r_riscv_add32_rela, + .accumulate_handler = apply_32_bit_accumulation }, + [R_RISCV_ADD64] = { .reloc_handler = apply_r_riscv_add64_rela, + .accumulate_handler = apply_64_bit_accumulation }, + [R_RISCV_SUB8] = { .reloc_handler = apply_r_riscv_sub8_rela, + .accumulate_handler = apply_8_bit_accumulation }, + [R_RISCV_SUB16] = { .reloc_handler = apply_r_riscv_sub16_rela, + .accumulate_handler = apply_16_bit_accumulation }, + [R_RISCV_SUB32] = { .reloc_handler = apply_r_riscv_sub32_rela, + .accumulate_handler = apply_32_bit_accumulation }, + [R_RISCV_SUB64] = { .reloc_handler = apply_r_riscv_sub64_rela, + .accumulate_handler = apply_64_bit_accumulation }, + /* 41-42 reserved for future standard use */ + [R_RISCV_ALIGN] = { .reloc_handler = apply_r_riscv_align_rela }, + [R_RISCV_RVC_BRANCH] = { .reloc_handler = apply_r_riscv_rvc_branch_rela }, + [R_RISCV_RVC_JUMP] = { .reloc_handler = apply_r_riscv_rvc_jump_rela }, + /* 46-50 reserved for future standard use */ + [R_RISCV_RELAX] = { .reloc_handler = apply_r_riscv_relax_rela }, + [R_RISCV_SUB6] = { .reloc_handler = apply_r_riscv_sub6_rela, + .accumulate_handler = apply_6_bit_accumulation }, + [R_RISCV_SET6] = { .reloc_handler = apply_r_riscv_set6_rela, + .accumulate_handler = apply_6_bit_accumulation }, + [R_RISCV_SET8] = { .reloc_handler = apply_r_riscv_set8_rela, + .accumulate_handler = apply_8_bit_accumulation }, + [R_RISCV_SET16] = { .reloc_handler = apply_r_riscv_set16_rela, + .accumulate_handler = apply_16_bit_accumulation }, + [R_RISCV_SET32] = { .reloc_handler = apply_r_riscv_set32_rela, + .accumulate_handler = apply_32_bit_accumulation }, + [R_RISCV_32_PCREL] = { .reloc_handler = apply_r_riscv_32_pcrel_rela }, + [R_RISCV_IRELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, + [R_RISCV_PLT32] = { .reloc_handler = apply_r_riscv_plt32_rela }, + [R_RISCV_SET_ULEB128] = { .reloc_handler = apply_r_riscv_set_uleb128, + .accumulate_handler = apply_uleb128_accumulation }, + [R_RISCV_SUB_ULEB128] = { .reloc_handler = apply_r_riscv_sub_uleb128, + .accumulate_handler = apply_uleb128_accumulation }, + /* 62-191 reserved for future standard use */ + /* 192-255 nonstandard ABI extensions */ +}; + +static void +process_accumulated_relocations(struct module *me, + struct hlist_head **relocation_hashtable, + struct list_head *used_buckets_list) +{ + /* + * Only ADD/SUB/SET/ULEB128 should end up here. + * + * Each bucket may have more than one relocation location. All + * relocations for a location are stored in a list in a bucket. + * + * Relocations are applied to a temp variable before being stored to the + * provided location to check for overflow. This also allows ULEB128 to + * properly decide how many entries are needed before storing to + * location. The final value is stored into location using the handler + * for the last relocation to an address. + * + * Three layers of indexing: + * - Each of the buckets in use + * - Groups of relocations in each bucket by location address + * - Each relocation entry for a location address + */ + struct used_bucket *bucket_iter; + struct used_bucket *bucket_iter_tmp; + struct relocation_head *rel_head_iter; + struct hlist_node *rel_head_iter_tmp; + struct relocation_entry *rel_entry_iter; + struct relocation_entry *rel_entry_iter_tmp; + int curr_type; + void *location; + long buffer; + + list_for_each_entry_safe(bucket_iter, bucket_iter_tmp, + used_buckets_list, head) { + hlist_for_each_entry_safe(rel_head_iter, rel_head_iter_tmp, + bucket_iter->bucket, node) { + buffer = 0; + location = rel_head_iter->location; + list_for_each_entry_safe(rel_entry_iter, + rel_entry_iter_tmp, + &rel_head_iter->rel_entry, + head) { + curr_type = rel_entry_iter->type; + reloc_handlers[curr_type].reloc_handler( + me, &buffer, rel_entry_iter->value); + kfree(rel_entry_iter); + } + reloc_handlers[curr_type].accumulate_handler( + me, location, buffer); + kfree(rel_head_iter); + } + kfree(bucket_iter); + } + + kvfree(*relocation_hashtable); +} + +static int add_relocation_to_accumulate(struct module *me, int type, + void *location, + unsigned int hashtable_bits, Elf_Addr v, + struct hlist_head *relocation_hashtable, + struct list_head *used_buckets_list) +{ + struct relocation_entry *entry; + struct relocation_head *rel_head; + struct hlist_head *current_head; + struct used_bucket *bucket; + unsigned long hash; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + + if (!entry) + return -ENOMEM; + + INIT_LIST_HEAD(&entry->head); + entry->type = type; + entry->value = v; + + hash = hash_min((uintptr_t)location, hashtable_bits); + + current_head = &relocation_hashtable[hash]; + + /* + * Search for the relocation_head for the relocations that happen at the + * provided location + */ + bool found = false; + struct relocation_head *rel_head_iter; + + hlist_for_each_entry(rel_head_iter, current_head, node) { + if (rel_head_iter->location == location) { + found = true; + rel_head = rel_head_iter; + break; + } + } + + /* + * If there has not yet been any relocations at the provided location, + * create a relocation_head for that location and populate it with this + * relocation_entry. + */ + if (!found) { + rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); + + if (!rel_head) { + kfree(entry); + return -ENOMEM; + } + + INIT_LIST_HEAD(&rel_head->rel_entry); + rel_head->location = location; + INIT_HLIST_NODE(&rel_head->node); + if (!current_head->first) { + bucket = + kmalloc(sizeof(struct used_bucket), GFP_KERNEL); + + if (!bucket) { + kfree(entry); + kfree(rel_head); + return -ENOMEM; + } + + INIT_LIST_HEAD(&bucket->head); + bucket->bucket = current_head; + list_add(&bucket->head, used_buckets_list); + } + hlist_add_head(&rel_head->node, current_head); + } + + /* Add relocation to head of discovered rel_head */ + list_add_tail(&entry->head, &rel_head->rel_entry); + + return 0; +} + +static unsigned int +initialize_relocation_hashtable(unsigned int num_relocations, + struct hlist_head **relocation_hashtable) +{ + /* Can safely assume that bits is not greater than sizeof(long) */ + unsigned long hashtable_size = roundup_pow_of_two(num_relocations); + /* + * When hashtable_size == 1, hashtable_bits == 0. + * This is valid because the hashing algorithm returns 0 in this case. + */ + unsigned int hashtable_bits = ilog2(hashtable_size); + + /* + * Double size of hashtable if num_relocations * 1.25 is greater than + * hashtable_size. + */ + int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); + + hashtable_bits += should_double_size; + + hashtable_size <<= should_double_size; + + /* Number of relocations may be large, so kvmalloc it */ + *relocation_hashtable = kvmalloc_array(hashtable_size, + sizeof(**relocation_hashtable), + GFP_KERNEL); + if (!*relocation_hashtable) + return 0; + + __hash_init(*relocation_hashtable, hashtable_size); + + return hashtable_bits; +} + +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, void *location, Elf_Addr v); + Elf_Sym *sym; + void *location; + unsigned int i, type; + unsigned int j_idx = 0; + Elf_Addr v; + int res; + unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); + struct hlist_head *relocation_hashtable; + unsigned int hashtable_bits; + LIST_HEAD(used_buckets_list); + + hashtable_bits = initialize_relocation_hashtable(num_relocations, + &relocation_hashtable); + + if (!relocation_hashtable) + return -ENOMEM; + + pr_debug("Applying relocate section %u to %u\n", relsec, + sechdrs[relsec].sh_info); + + for (i = 0; i < num_relocations; 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)) + handler = reloc_handlers[type].reloc_handler; + 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 = j_idx; + bool found = false; + + do { + 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; + found = true; + + break; + } + + j++; + if (j == num_relocations) + j = 0; + + } while (j_idx != j); + + if (!found) { + pr_err( + "%s: Can not find HI20 relocation information\n", + me->name); + return -EINVAL; + } + + /* Record the previous j-loop end index */ + j_idx = j; + } + + if (reloc_handlers[type].accumulate_handler) + res = add_relocation_to_accumulate(me, type, location, + hashtable_bits, v, + relocation_hashtable, + &used_buckets_list); + else + res = handler(me, location, v); + if (res) + return res; + } + + process_accumulated_relocations(me, &relocation_hashtable, + &used_buckets_list); + + return 0; +} + +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; +} |