cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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module.h (2984B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/* Copyright (C) 2017 Andes Technology Corporation */
      3
      4#ifndef _ASM_RISCV_MODULE_H
      5#define _ASM_RISCV_MODULE_H
      6
      7#include <asm-generic/module.h>
      8
      9struct module;
     10unsigned long module_emit_got_entry(struct module *mod, unsigned long val);
     11unsigned long module_emit_plt_entry(struct module *mod, unsigned long val);
     12
     13#ifdef CONFIG_MODULE_SECTIONS
     14struct mod_section {
     15	Elf_Shdr *shdr;
     16	int num_entries;
     17	int max_entries;
     18};
     19
     20struct mod_arch_specific {
     21	struct mod_section got;
     22	struct mod_section plt;
     23	struct mod_section got_plt;
     24};
     25
     26struct got_entry {
     27	unsigned long symbol_addr;	/* the real variable address */
     28};
     29
     30static inline struct got_entry emit_got_entry(unsigned long val)
     31{
     32	return (struct got_entry) {val};
     33}
     34
     35static inline struct got_entry *get_got_entry(unsigned long val,
     36					      const struct mod_section *sec)
     37{
     38	struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr);
     39	int i;
     40	for (i = 0; i < sec->num_entries; i++) {
     41		if (got[i].symbol_addr == val)
     42			return &got[i];
     43	}
     44	return NULL;
     45}
     46
     47struct plt_entry {
     48	/*
     49	 * Trampoline code to real target address. The return address
     50	 * should be the original (pc+4) before entring plt entry.
     51	 */
     52	u32 insn_auipc;		/* auipc t0, 0x0                       */
     53	u32 insn_ld;		/* ld    t1, 0x10(t0)                  */
     54	u32 insn_jr;		/* jr    t1                            */
     55};
     56
     57#define OPC_AUIPC  0x0017
     58#define OPC_LD     0x3003
     59#define OPC_JALR   0x0067
     60#define REG_T0     0x5
     61#define REG_T1     0x6
     62
     63static inline struct plt_entry emit_plt_entry(unsigned long val,
     64					      unsigned long plt,
     65					      unsigned long got_plt)
     66{
     67	/*
     68	 * U-Type encoding:
     69	 * +------------+----------+----------+
     70	 * | imm[31:12] | rd[11:7] | opc[6:0] |
     71	 * +------------+----------+----------+
     72	 *
     73	 * I-Type encoding:
     74	 * +------------+------------+--------+----------+----------+
     75	 * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] |
     76	 * +------------+------------+--------+----------+----------+
     77	 *
     78	 */
     79	unsigned long offset = got_plt - plt;
     80	u32 hi20 = (offset + 0x800) & 0xfffff000;
     81	u32 lo12 = (offset - hi20);
     82	return (struct plt_entry) {
     83		OPC_AUIPC | (REG_T0 << 7) | hi20,
     84		OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7),
     85		OPC_JALR | (REG_T1 << 15)
     86	};
     87}
     88
     89static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec)
     90{
     91	struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr;
     92	int i;
     93	for (i = 0; i < sec->num_entries; i++) {
     94		if (got_plt[i].symbol_addr == val)
     95			return i;
     96	}
     97	return -1;
     98}
     99
    100static inline struct plt_entry *get_plt_entry(unsigned long val,
    101					      const struct mod_section *sec_plt,
    102					      const struct mod_section *sec_got_plt)
    103{
    104	struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr;
    105	int got_plt_idx = get_got_plt_idx(val, sec_got_plt);
    106	if (got_plt_idx >= 0)
    107		return plt + got_plt_idx;
    108	else
    109		return NULL;
    110}
    111
    112#endif /* CONFIG_MODULE_SECTIONS */
    113
    114#endif /* _ASM_RISCV_MODULE_H */