1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> |
3 | |
4 | typedef unsigned int instr; |
5 | |
6 | #define MAJOR_OP 0xfc000000 |
7 | #define LDA_OP 0x20000000 |
8 | #define STQ_OP 0xb4000000 |
9 | #define BR_OP 0xc0000000 |
10 | |
11 | #define STK_ALLOC_1 0x23de8000 /* lda $30,-X($30) */ |
12 | #define STK_ALLOC_1M 0xffff8000 |
13 | #define STK_ALLOC_2 0x43c0153e /* subq $30,X,$30 */ |
14 | #define STK_ALLOC_2M 0xffe01fff |
15 | |
16 | #define MEM_REG 0x03e00000 |
17 | #define MEM_BASE 0x001f0000 |
18 | #define MEM_OFF 0x0000ffff |
19 | #define MEM_OFF_SIGN 0x00008000 |
20 | #define BASE_SP 0x001e0000 |
21 | |
22 | #define STK_ALLOC_MATCH(INSTR) \ |
23 | (((INSTR) & STK_ALLOC_1M) == STK_ALLOC_1 \ |
24 | || ((INSTR) & STK_ALLOC_2M) == STK_ALLOC_2) |
25 | #define STK_PUSH_MATCH(INSTR) \ |
26 | (((INSTR) & (MAJOR_OP | MEM_BASE | MEM_OFF_SIGN)) == (STQ_OP | BASE_SP)) |
27 | #define MEM_OP_OFFSET(INSTR) \ |
28 | (((long)((INSTR) & MEM_OFF) << 48) >> 48) |
29 | #define MEM_OP_REG(INSTR) \ |
30 | (((INSTR) & MEM_REG) >> 22) |
31 | |
32 | /* Branches, jumps, PAL calls, and illegal opcodes end a basic block. */ |
33 | #define BB_END(INSTR) \ |
34 | (((instr)(INSTR) >= BR_OP) | ((instr)(INSTR) < LDA_OP) | \ |
35 | ((((instr)(INSTR) ^ 0x60000000) < 0x20000000) & \ |
36 | (((instr)(INSTR) & 0x0c000000) != 0))) |
37 | |
38 | #define IS_KERNEL_TEXT(PC) ((unsigned long)(PC) > START_ADDR) |
39 | |
40 | static char reg_name[][4] = { |
41 | "v0 " , "t0 " , "t1 " , "t2 " , "t3 " , "t4 " , "t5 " , "t6 " , "t7 " , |
42 | "s0 " , "s1 " , "s2 " , "s3 " , "s4 " , "s5 " , "s6 " , "a0 " , "a1 " , |
43 | "a2 " , "a3 " , "a4 " , "a5 " , "t8 " , "t9 " , "t10" , "t11" , "ra " , |
44 | "pv " , "at " , "gp " , "sp " , "0" |
45 | }; |
46 | |
47 | |
48 | static instr * |
49 | display_stored_regs(instr * pro_pc, unsigned char * sp) |
50 | { |
51 | instr * ret_pc = 0; |
52 | int reg; |
53 | unsigned long value; |
54 | |
55 | printk("Prologue [<%p>], Frame %p:\n" , pro_pc, sp); |
56 | while (!BB_END(*pro_pc)) |
57 | if (STK_PUSH_MATCH(*pro_pc)) { |
58 | reg = (*pro_pc & MEM_REG) >> 21; |
59 | value = *(unsigned long *)(sp + (*pro_pc & MEM_OFF)); |
60 | if (reg == 26) |
61 | ret_pc = (instr *)value; |
62 | printk("\t\t%s / 0x%016lx\n" , reg_name[reg], value); |
63 | } |
64 | return ret_pc; |
65 | } |
66 | |
67 | static instr * |
68 | seek_prologue(instr * pc) |
69 | { |
70 | while (!STK_ALLOC_MATCH(*pc)) |
71 | --pc; |
72 | while (!BB_END(*(pc - 1))) |
73 | --pc; |
74 | return pc; |
75 | } |
76 | |
77 | static long |
78 | stack_increment(instr * prologue_pc) |
79 | { |
80 | while (!STK_ALLOC_MATCH(*prologue_pc)) |
81 | ++prologue_pc; |
82 | |
83 | /* Count the bytes allocated. */ |
84 | if ((*prologue_pc & STK_ALLOC_1M) == STK_ALLOC_1M) |
85 | return -(((long)(*prologue_pc) << 48) >> 48); |
86 | else |
87 | return (*prologue_pc >> 13) & 0xff; |
88 | } |
89 | |
90 | void |
91 | stacktrace(void) |
92 | { |
93 | instr * ret_pc; |
94 | instr * prologue = (instr *)stacktrace; |
95 | unsigned char *sp = (unsigned char *)current_stack_pointer; |
96 | |
97 | printk("\tstack trace:\n" ); |
98 | do { |
99 | ret_pc = display_stored_regs(pro_pc: prologue, sp); |
100 | sp += stack_increment(prologue_pc: prologue); |
101 | prologue = seek_prologue(pc: ret_pc); |
102 | } while (IS_KERNEL_TEXT(ret_pc)); |
103 | } |
104 | |