397 строки
11 KiB
C
397 строки
11 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Copyright (C) 2017 Zihao Yu
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*/
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#include <linux/elf.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/moduleloader.h>
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static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
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{
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if (v != (u32)v) {
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pr_err("%s: value %016llx out of range for 32-bit field\n",
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me->name, v);
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return -EINVAL;
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}
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*location = v;
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return 0;
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}
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static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
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{
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*(u64 *)location = v;
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return 0;
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}
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static int apply_r_riscv_branch_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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u32 imm12 = (offset & 0x1000) << (31 - 12);
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u32 imm11 = (offset & 0x800) >> (11 - 7);
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u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
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u32 imm4_1 = (offset & 0x1e) << (11 - 4);
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*location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1;
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return 0;
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}
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static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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u32 imm20 = (offset & 0x100000) << (31 - 20);
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u32 imm19_12 = (offset & 0xff000);
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u32 imm11 = (offset & 0x800) << (20 - 11);
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u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
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*location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1;
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return 0;
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}
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static int apply_r_riscv_rcv_branch_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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u16 imm8 = (offset & 0x100) << (12 - 8);
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u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
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u16 imm5 = (offset & 0x20) >> (5 - 2);
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u16 imm4_3 = (offset & 0x18) << (12 - 5);
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u16 imm2_1 = (offset & 0x6) << (12 - 10);
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*(u16 *)location = (*(u16 *)location & 0xe383) |
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imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
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return 0;
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}
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static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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u16 imm11 = (offset & 0x800) << (12 - 11);
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u16 imm10 = (offset & 0x400) >> (10 - 8);
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u16 imm9_8 = (offset & 0x300) << (12 - 11);
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u16 imm7 = (offset & 0x80) >> (7 - 6);
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u16 imm6 = (offset & 0x40) << (12 - 11);
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u16 imm5 = (offset & 0x20) >> (5 - 2);
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u16 imm4 = (offset & 0x10) << (12 - 5);
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u16 imm3_1 = (offset & 0xe) << (12 - 10);
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*(u16 *)location = (*(u16 *)location & 0xe003) |
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imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1;
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return 0;
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}
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static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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s32 hi20;
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if (offset != (s32)offset) {
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pr_err(
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"%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
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me->name, v, location);
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return -EINVAL;
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}
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hi20 = (offset + 0x800) & 0xfffff000;
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*location = (*location & 0xfff) | hi20;
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return 0;
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}
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static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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/*
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* v is the lo12 value to fill. It is calculated before calling this
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* handler.
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*/
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*location = (*location & 0xfffff) | ((v & 0xfff) << 20);
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return 0;
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}
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static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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/*
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* v is the lo12 value to fill. It is calculated before calling this
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* handler.
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*/
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u32 imm11_5 = (v & 0xfe0) << (31 - 11);
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u32 imm4_0 = (v & 0x1f) << (11 - 4);
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*location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
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return 0;
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}
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static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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s32 hi20;
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if (IS_ENABLED(CMODEL_MEDLOW)) {
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pr_err(
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"%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
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me->name, v, location);
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return -EINVAL;
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}
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hi20 = ((s32)v + 0x800) & 0xfffff000;
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*location = (*location & 0xfff) | hi20;
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return 0;
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}
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static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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/* Skip medlow checking because of filtering by HI20 already */
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s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
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s32 lo12 = ((s32)v - hi20);
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*location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20);
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return 0;
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}
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static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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/* Skip medlow checking because of filtering by HI20 already */
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s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
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s32 lo12 = ((s32)v - hi20);
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u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
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u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
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*location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
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return 0;
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}
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static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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s32 hi20;
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/* Always emit the got entry */
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if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
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offset = module_emit_got_entry(me, v);
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offset = (void *)offset - (void *)location;
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} else {
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pr_err(
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"%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
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me->name, v, location);
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return -EINVAL;
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}
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hi20 = (offset + 0x800) & 0xfffff000;
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*location = (*location & 0xfff) | hi20;
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return 0;
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}
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static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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s32 fill_v = offset;
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u32 hi20, lo12;
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if (offset != fill_v) {
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/* Only emit the plt entry if offset over 32-bit range */
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if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
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offset = module_emit_plt_entry(me, v);
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offset = (void *)offset - (void *)location;
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} else {
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pr_err(
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"%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
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me->name, v, location);
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return -EINVAL;
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}
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}
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hi20 = (offset + 0x800) & 0xfffff000;
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lo12 = (offset - hi20) & 0xfff;
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*location = (*location & 0xfff) | hi20;
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*(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
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return 0;
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}
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static int apply_r_riscv_call_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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ptrdiff_t offset = (void *)v - (void *)location;
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s32 fill_v = offset;
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u32 hi20, lo12;
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if (offset != fill_v) {
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pr_err(
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"%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
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me->name, v, location);
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return -EINVAL;
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}
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hi20 = (offset + 0x800) & 0xfffff000;
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lo12 = (offset - hi20) & 0xfff;
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*location = (*location & 0xfff) | hi20;
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*(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
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return 0;
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}
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static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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return 0;
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}
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static int apply_r_riscv_align_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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pr_err(
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"%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
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me->name, location);
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return -EINVAL;
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}
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static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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*(u32 *)location += (u32)v;
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return 0;
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}
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static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
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Elf_Addr v)
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{
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*(u32 *)location -= (u32)v;
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return 0;
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}
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static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
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Elf_Addr v) = {
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[R_RISCV_32] = apply_r_riscv_32_rela,
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[R_RISCV_64] = apply_r_riscv_64_rela,
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[R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
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[R_RISCV_JAL] = apply_r_riscv_jal_rela,
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[R_RISCV_RVC_BRANCH] = apply_r_riscv_rcv_branch_rela,
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[R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
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[R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
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[R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
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[R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
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[R_RISCV_HI20] = apply_r_riscv_hi20_rela,
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[R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
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[R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
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[R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
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[R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
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[R_RISCV_CALL] = apply_r_riscv_call_rela,
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[R_RISCV_RELAX] = apply_r_riscv_relax_rela,
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[R_RISCV_ALIGN] = apply_r_riscv_align_rela,
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[R_RISCV_ADD32] = apply_r_riscv_add32_rela,
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[R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
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};
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int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
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unsigned int symindex, unsigned int relsec,
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struct module *me)
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{
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Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
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int (*handler)(struct module *me, u32 *location, Elf_Addr v);
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Elf_Sym *sym;
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u32 *location;
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unsigned int i, type;
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Elf_Addr v;
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int res;
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pr_debug("Applying relocate section %u to %u\n", relsec,
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sechdrs[relsec].sh_info);
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for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
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/* This is where to make the change */
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location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
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+ rel[i].r_offset;
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/* This is the symbol it is referring to */
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sym = (Elf_Sym *)sechdrs[symindex].sh_addr
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+ ELF_RISCV_R_SYM(rel[i].r_info);
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if (IS_ERR_VALUE(sym->st_value)) {
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/* Ignore unresolved weak symbol */
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if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
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continue;
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pr_warning("%s: Unknown symbol %s\n",
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me->name, strtab + sym->st_name);
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return -ENOENT;
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}
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type = ELF_RISCV_R_TYPE(rel[i].r_info);
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if (type < ARRAY_SIZE(reloc_handlers_rela))
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handler = reloc_handlers_rela[type];
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else
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handler = NULL;
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if (!handler) {
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pr_err("%s: Unknown relocation type %u\n",
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me->name, type);
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return -EINVAL;
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}
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v = sym->st_value + rel[i].r_addend;
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if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
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unsigned int j;
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for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
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unsigned long hi20_loc =
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sechdrs[sechdrs[relsec].sh_info].sh_addr
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+ rel[j].r_offset;
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u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
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/* Find the corresponding HI20 relocation entry */
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if (hi20_loc == sym->st_value
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&& (hi20_type == R_RISCV_PCREL_HI20
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|| hi20_type == R_RISCV_GOT_HI20)) {
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s32 hi20, lo12;
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Elf_Sym *hi20_sym =
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(Elf_Sym *)sechdrs[symindex].sh_addr
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+ ELF_RISCV_R_SYM(rel[j].r_info);
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unsigned long hi20_sym_val =
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hi20_sym->st_value
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+ rel[j].r_addend;
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/* Calculate lo12 */
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size_t offset = hi20_sym_val - hi20_loc;
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if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
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&& hi20_type == R_RISCV_GOT_HI20) {
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offset = module_emit_got_entry(
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me, hi20_sym_val);
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offset = offset - hi20_loc;
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}
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hi20 = (offset + 0x800) & 0xfffff000;
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lo12 = offset - hi20;
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v = lo12;
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break;
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}
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}
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if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
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pr_err(
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"%s: Can not find HI20 relocation information\n",
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me->name);
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return -EINVAL;
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}
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}
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res = handler(me, location, v);
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if (res)
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return res;
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}
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return 0;
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}
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