1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun /* Copyright (C) 2017 Andes Technology Corporation */
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun #ifndef _ASM_RISCV_MODULE_H
5*4882a593Smuzhiyun #define _ASM_RISCV_MODULE_H
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #include <asm-generic/module.h>
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun struct module;
10*4882a593Smuzhiyun unsigned long module_emit_got_entry(struct module *mod, unsigned long val);
11*4882a593Smuzhiyun unsigned long module_emit_plt_entry(struct module *mod, unsigned long val);
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #ifdef CONFIG_MODULE_SECTIONS
14*4882a593Smuzhiyun struct mod_section {
15*4882a593Smuzhiyun Elf_Shdr *shdr;
16*4882a593Smuzhiyun int num_entries;
17*4882a593Smuzhiyun int max_entries;
18*4882a593Smuzhiyun };
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun struct mod_arch_specific {
21*4882a593Smuzhiyun struct mod_section got;
22*4882a593Smuzhiyun struct mod_section plt;
23*4882a593Smuzhiyun struct mod_section got_plt;
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun struct got_entry {
27*4882a593Smuzhiyun unsigned long symbol_addr; /* the real variable address */
28*4882a593Smuzhiyun };
29*4882a593Smuzhiyun
emit_got_entry(unsigned long val)30*4882a593Smuzhiyun static inline struct got_entry emit_got_entry(unsigned long val)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun return (struct got_entry) {val};
33*4882a593Smuzhiyun }
34*4882a593Smuzhiyun
get_got_entry(unsigned long val,const struct mod_section * sec)35*4882a593Smuzhiyun static inline struct got_entry *get_got_entry(unsigned long val,
36*4882a593Smuzhiyun const struct mod_section *sec)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun struct got_entry *got = (struct got_entry *)(sec->shdr->sh_addr);
39*4882a593Smuzhiyun int i;
40*4882a593Smuzhiyun for (i = 0; i < sec->num_entries; i++) {
41*4882a593Smuzhiyun if (got[i].symbol_addr == val)
42*4882a593Smuzhiyun return &got[i];
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun return NULL;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun struct plt_entry {
48*4882a593Smuzhiyun /*
49*4882a593Smuzhiyun * Trampoline code to real target address. The return address
50*4882a593Smuzhiyun * should be the original (pc+4) before entring plt entry.
51*4882a593Smuzhiyun */
52*4882a593Smuzhiyun u32 insn_auipc; /* auipc t0, 0x0 */
53*4882a593Smuzhiyun u32 insn_ld; /* ld t1, 0x10(t0) */
54*4882a593Smuzhiyun u32 insn_jr; /* jr t1 */
55*4882a593Smuzhiyun };
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun #define OPC_AUIPC 0x0017
58*4882a593Smuzhiyun #define OPC_LD 0x3003
59*4882a593Smuzhiyun #define OPC_JALR 0x0067
60*4882a593Smuzhiyun #define REG_T0 0x5
61*4882a593Smuzhiyun #define REG_T1 0x6
62*4882a593Smuzhiyun
emit_plt_entry(unsigned long val,unsigned long plt,unsigned long got_plt)63*4882a593Smuzhiyun static inline struct plt_entry emit_plt_entry(unsigned long val,
64*4882a593Smuzhiyun unsigned long plt,
65*4882a593Smuzhiyun unsigned long got_plt)
66*4882a593Smuzhiyun {
67*4882a593Smuzhiyun /*
68*4882a593Smuzhiyun * U-Type encoding:
69*4882a593Smuzhiyun * +------------+----------+----------+
70*4882a593Smuzhiyun * | imm[31:12] | rd[11:7] | opc[6:0] |
71*4882a593Smuzhiyun * +------------+----------+----------+
72*4882a593Smuzhiyun *
73*4882a593Smuzhiyun * I-Type encoding:
74*4882a593Smuzhiyun * +------------+------------+--------+----------+----------+
75*4882a593Smuzhiyun * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] |
76*4882a593Smuzhiyun * +------------+------------+--------+----------+----------+
77*4882a593Smuzhiyun *
78*4882a593Smuzhiyun */
79*4882a593Smuzhiyun unsigned long offset = got_plt - plt;
80*4882a593Smuzhiyun u32 hi20 = (offset + 0x800) & 0xfffff000;
81*4882a593Smuzhiyun u32 lo12 = (offset - hi20);
82*4882a593Smuzhiyun return (struct plt_entry) {
83*4882a593Smuzhiyun OPC_AUIPC | (REG_T0 << 7) | hi20,
84*4882a593Smuzhiyun OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7),
85*4882a593Smuzhiyun OPC_JALR | (REG_T1 << 15)
86*4882a593Smuzhiyun };
87*4882a593Smuzhiyun }
88*4882a593Smuzhiyun
get_got_plt_idx(unsigned long val,const struct mod_section * sec)89*4882a593Smuzhiyun static inline int get_got_plt_idx(unsigned long val, const struct mod_section *sec)
90*4882a593Smuzhiyun {
91*4882a593Smuzhiyun struct got_entry *got_plt = (struct got_entry *)sec->shdr->sh_addr;
92*4882a593Smuzhiyun int i;
93*4882a593Smuzhiyun for (i = 0; i < sec->num_entries; i++) {
94*4882a593Smuzhiyun if (got_plt[i].symbol_addr == val)
95*4882a593Smuzhiyun return i;
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun return -1;
98*4882a593Smuzhiyun }
99*4882a593Smuzhiyun
get_plt_entry(unsigned long val,const struct mod_section * sec_plt,const struct mod_section * sec_got_plt)100*4882a593Smuzhiyun static inline struct plt_entry *get_plt_entry(unsigned long val,
101*4882a593Smuzhiyun const struct mod_section *sec_plt,
102*4882a593Smuzhiyun const struct mod_section *sec_got_plt)
103*4882a593Smuzhiyun {
104*4882a593Smuzhiyun struct plt_entry *plt = (struct plt_entry *)sec_plt->shdr->sh_addr;
105*4882a593Smuzhiyun int got_plt_idx = get_got_plt_idx(val, sec_got_plt);
106*4882a593Smuzhiyun if (got_plt_idx >= 0)
107*4882a593Smuzhiyun return plt + got_plt_idx;
108*4882a593Smuzhiyun else
109*4882a593Smuzhiyun return NULL;
110*4882a593Smuzhiyun }
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun #endif /* CONFIG_MODULE_SECTIONS */
113*4882a593Smuzhiyun
114*4882a593Smuzhiyun #endif /* _ASM_RISCV_MODULE_H */
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