1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <linux/kernel.h>
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun typedef unsigned int instr;
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #define MAJOR_OP 0xfc000000
7*4882a593Smuzhiyun #define LDA_OP 0x20000000
8*4882a593Smuzhiyun #define STQ_OP 0xb4000000
9*4882a593Smuzhiyun #define BR_OP 0xc0000000
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #define STK_ALLOC_1 0x23de8000 /* lda $30,-X($30) */
12*4882a593Smuzhiyun #define STK_ALLOC_1M 0xffff8000
13*4882a593Smuzhiyun #define STK_ALLOC_2 0x43c0153e /* subq $30,X,$30 */
14*4882a593Smuzhiyun #define STK_ALLOC_2M 0xffe01fff
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #define MEM_REG 0x03e00000
17*4882a593Smuzhiyun #define MEM_BASE 0x001f0000
18*4882a593Smuzhiyun #define MEM_OFF 0x0000ffff
19*4882a593Smuzhiyun #define MEM_OFF_SIGN 0x00008000
20*4882a593Smuzhiyun #define BASE_SP 0x001e0000
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun #define STK_ALLOC_MATCH(INSTR) \
23*4882a593Smuzhiyun (((INSTR) & STK_ALLOC_1M) == STK_ALLOC_1 \
24*4882a593Smuzhiyun || ((INSTR) & STK_ALLOC_2M) == STK_ALLOC_2)
25*4882a593Smuzhiyun #define STK_PUSH_MATCH(INSTR) \
26*4882a593Smuzhiyun (((INSTR) & (MAJOR_OP | MEM_BASE | MEM_OFF_SIGN)) == (STQ_OP | BASE_SP))
27*4882a593Smuzhiyun #define MEM_OP_OFFSET(INSTR) \
28*4882a593Smuzhiyun (((long)((INSTR) & MEM_OFF) << 48) >> 48)
29*4882a593Smuzhiyun #define MEM_OP_REG(INSTR) \
30*4882a593Smuzhiyun (((INSTR) & MEM_REG) >> 22)
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun /* Branches, jumps, PAL calls, and illegal opcodes end a basic block. */
33*4882a593Smuzhiyun #define BB_END(INSTR) \
34*4882a593Smuzhiyun (((instr)(INSTR) >= BR_OP) | ((instr)(INSTR) < LDA_OP) | \
35*4882a593Smuzhiyun ((((instr)(INSTR) ^ 0x60000000) < 0x20000000) & \
36*4882a593Smuzhiyun (((instr)(INSTR) & 0x0c000000) != 0)))
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun #define IS_KERNEL_TEXT(PC) ((unsigned long)(PC) > START_ADDR)
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun static char reg_name[][4] = {
41*4882a593Smuzhiyun "v0 ", "t0 ", "t1 ", "t2 ", "t3 ", "t4 ", "t5 ", "t6 ", "t7 ",
42*4882a593Smuzhiyun "s0 ", "s1 ", "s2 ", "s3 ", "s4 ", "s5 ", "s6 ", "a0 ", "a1 ",
43*4882a593Smuzhiyun "a2 ", "a3 ", "a4 ", "a5 ", "t8 ", "t9 ", "t10", "t11", "ra ",
44*4882a593Smuzhiyun "pv ", "at ", "gp ", "sp ", "0"
45*4882a593Smuzhiyun };
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun static instr *
display_stored_regs(instr * pro_pc,unsigned char * sp)49*4882a593Smuzhiyun display_stored_regs(instr * pro_pc, unsigned char * sp)
50*4882a593Smuzhiyun {
51*4882a593Smuzhiyun instr * ret_pc = 0;
52*4882a593Smuzhiyun int reg;
53*4882a593Smuzhiyun unsigned long value;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun printk("Prologue [<%p>], Frame %p:\n", pro_pc, sp);
56*4882a593Smuzhiyun while (!BB_END(*pro_pc))
57*4882a593Smuzhiyun if (STK_PUSH_MATCH(*pro_pc)) {
58*4882a593Smuzhiyun reg = (*pro_pc & MEM_REG) >> 21;
59*4882a593Smuzhiyun value = *(unsigned long *)(sp + (*pro_pc & MEM_OFF));
60*4882a593Smuzhiyun if (reg == 26)
61*4882a593Smuzhiyun ret_pc = (instr *)value;
62*4882a593Smuzhiyun printk("\t\t%s / 0x%016lx\n", reg_name[reg], value);
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun return ret_pc;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun static instr *
seek_prologue(instr * pc)68*4882a593Smuzhiyun seek_prologue(instr * pc)
69*4882a593Smuzhiyun {
70*4882a593Smuzhiyun while (!STK_ALLOC_MATCH(*pc))
71*4882a593Smuzhiyun --pc;
72*4882a593Smuzhiyun while (!BB_END(*(pc - 1)))
73*4882a593Smuzhiyun --pc;
74*4882a593Smuzhiyun return pc;
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun static long
stack_increment(instr * prologue_pc)78*4882a593Smuzhiyun stack_increment(instr * prologue_pc)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun while (!STK_ALLOC_MATCH(*prologue_pc))
81*4882a593Smuzhiyun ++prologue_pc;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun /* Count the bytes allocated. */
84*4882a593Smuzhiyun if ((*prologue_pc & STK_ALLOC_1M) == STK_ALLOC_1M)
85*4882a593Smuzhiyun return -(((long)(*prologue_pc) << 48) >> 48);
86*4882a593Smuzhiyun else
87*4882a593Smuzhiyun return (*prologue_pc >> 13) & 0xff;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun void
stacktrace(void)91*4882a593Smuzhiyun stacktrace(void)
92*4882a593Smuzhiyun {
93*4882a593Smuzhiyun instr * ret_pc;
94*4882a593Smuzhiyun instr * prologue = (instr *)stacktrace;
95*4882a593Smuzhiyun register unsigned char * sp __asm__ ("$30");
96*4882a593Smuzhiyun
97*4882a593Smuzhiyun printk("\tstack trace:\n");
98*4882a593Smuzhiyun do {
99*4882a593Smuzhiyun ret_pc = display_stored_regs(prologue, sp);
100*4882a593Smuzhiyun sp += stack_increment(prologue);
101*4882a593Smuzhiyun prologue = seek_prologue(ret_pc);
102*4882a593Smuzhiyun } while (IS_KERNEL_TEXT(ret_pc));
103*4882a593Smuzhiyun }
104