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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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 voidprocess_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_obj(*entry);
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_obj(*rel_head);
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_obj(struct used_bucket);
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 intinitialize_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_objs(**relocation_hashtable, hashtable_size); 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;}