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 register unsigned char * sp __asm__ ("$30"); 96 97 printk("\tstack trace:\n"); 98 do { 99 ret_pc = display_stored_regs(prologue, sp); 100 sp += stack_increment(prologue); 101 prologue = seek_prologue(ret_pc); 102 } while (IS_KERNEL_TEXT(ret_pc)); 103 } 104