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linux-stable/arch/riscv/kernel/module.c

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// 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/vmalloc.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);
}
kfree(*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;
}
rel_head->rel_entry =
kmalloc(sizeof(struct list_head), GFP_KERNEL);
if (!rel_head->rel_entry) {
kfree(entry);
kfree(rel_head);
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->rel_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;
*relocation_hashtable = kmalloc_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;
struct list_head used_buckets_list;
unsigned int hashtable_bits;
hashtable_bits = initialize_relocation_hashtable(num_relocations,
&relocation_hashtable);
if (!relocation_hashtable)
return -ENOMEM;
INIT_LIST_HEAD(&used_buckets_list);
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 > sechdrs[relsec].sh_size / sizeof(*rel))
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;
}
#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
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;
}
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