1 // SPDX-License-Identifier: GPL-2.0+
2
3 #include <linux/bitops.h>
4 #include <linux/kernel.h>
5 #include <linux/kprobes.h>
6
7 #include "decode-insn.h"
8 #include "simulate-insn.h"
9
rv_insn_reg_get_val(struct pt_regs * regs,u32 index,unsigned long * ptr)10 static inline bool rv_insn_reg_get_val(struct pt_regs *regs, u32 index,
11 unsigned long *ptr)
12 {
13 if (index == 0)
14 *ptr = 0;
15 else if (index <= 31)
16 *ptr = *((unsigned long *)regs + index);
17 else
18 return false;
19
20 return true;
21 }
22
rv_insn_reg_set_val(struct pt_regs * regs,u32 index,unsigned long val)23 static inline bool rv_insn_reg_set_val(struct pt_regs *regs, u32 index,
24 unsigned long val)
25 {
26 if (index == 0)
27 return false;
28 else if (index <= 31)
29 *((unsigned long *)regs + index) = val;
30 else
31 return false;
32
33 return true;
34 }
35
simulate_jal(u32 opcode,unsigned long addr,struct pt_regs * regs)36 bool __kprobes simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs)
37 {
38 /*
39 * 31 30 21 20 19 12 11 7 6 0
40 * imm [20] | imm[10:1] | imm[11] | imm[19:12] | rd | opcode
41 * 1 10 1 8 5 JAL/J
42 */
43 bool ret;
44 u32 imm;
45 u32 index = (opcode >> 7) & 0x1f;
46
47 ret = rv_insn_reg_set_val(regs, index, addr + 4);
48 if (!ret)
49 return ret;
50
51 imm = ((opcode >> 21) & 0x3ff) << 1;
52 imm |= ((opcode >> 20) & 0x1) << 11;
53 imm |= ((opcode >> 12) & 0xff) << 12;
54 imm |= ((opcode >> 31) & 0x1) << 20;
55
56 instruction_pointer_set(regs, addr + sign_extend32((imm), 20));
57
58 return ret;
59 }
60
simulate_jalr(u32 opcode,unsigned long addr,struct pt_regs * regs)61 bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs)
62 {
63 /*
64 * 31 20 19 15 14 12 11 7 6 0
65 * offset[11:0] | rs1 | 010 | rd | opcode
66 * 12 5 3 5 JALR/JR
67 */
68 bool ret;
69 unsigned long base_addr;
70 u32 imm = (opcode >> 20) & 0xfff;
71 u32 rd_index = (opcode >> 7) & 0x1f;
72 u32 rs1_index = (opcode >> 15) & 0x1f;
73
74 ret = rv_insn_reg_set_val(regs, rd_index, addr + 4);
75 if (!ret)
76 return ret;
77
78 ret = rv_insn_reg_get_val(regs, rs1_index, &base_addr);
79 if (!ret)
80 return ret;
81
82 instruction_pointer_set(regs, (base_addr + sign_extend32((imm), 11))&~1);
83
84 return ret;
85 }
86