// SPDX-License-Identifier: GPL-2.0 #include <linux/kernel.h> typedef unsigned int instr; #define MAJOR_OP 0xfc000000 #define LDA_OP 0x20000000 #define STQ_OP 0xb4000000 #define BR_OP 0xc0000000 #define STK_ALLOC_1 0x23de8000 /* lda $30,-X($30) */ #define STK_ALLOC_1M 0xffff8000 #define STK_ALLOC_2 0x43c0153e /* subq $30,X,$30 */ #define STK_ALLOC_2M 0xffe01fff #define MEM_REG 0x03e00000 #define MEM_BASE 0x001f0000 #define MEM_OFF 0x0000ffff #define MEM_OFF_SIGN 0x00008000 #define BASE_SP 0x001e0000 #define STK_ALLOC_MATCH(INSTR) \ (((INSTR) & STK_ALLOC_1M) == STK_ALLOC_1 \ || ((INSTR) & STK_ALLOC_2M) == STK_ALLOC_2) #define STK_PUSH_MATCH(INSTR) \ (((INSTR) & (MAJOR_OP | MEM_BASE | MEM_OFF_SIGN)) == (STQ_OP | BASE_SP)) #define MEM_OP_OFFSET(INSTR) \ (((long)((INSTR) & MEM_OFF) << 48) >> 48) #define MEM_OP_REG(INSTR) \ (((INSTR) & MEM_REG) >> 22) /* Branches, jumps, PAL calls, and illegal opcodes end a basic block. */ #define BB_END(INSTR) \ (((instr)(INSTR) >= BR_OP) | ((instr)(INSTR) < LDA_OP) | \ ((((instr)(INSTR) ^ 0x60000000) < 0x20000000) & \ (((instr)(INSTR) & 0x0c000000) != 0))) #define IS_KERNEL_TEXT(PC) ((unsigned long)(PC) > START_ADDR) static char reg_name[][4] = { "v0 ", "t0 ", "t1 ", "t2 ", "t3 ", "t4 ", "t5 ", "t6 ", "t7 ", "s0 ", "s1 ", "s2 ", "s3 ", "s4 ", "s5 ", "s6 ", "a0 ", "a1 ", "a2 ", "a3 ", "a4 ", "a5 ", "t8 ", "t9 ", "t10", "t11", "ra ", "pv ", "at ", "gp ", "sp ", "0" }; static instr * display_stored_regs(instr * pro_pc, unsigned char * sp) { instr * ret_pc = 0; int reg; unsigned long value; printk("Prologue [<%p>], Frame %p:\n", pro_pc, sp); while (!BB_END(*pro_pc)) if (STK_PUSH_MATCH(*pro_pc)) { reg = (*pro_pc & MEM_REG) >> 21; value = *(unsigned long *)(sp + (*pro_pc & MEM_OFF)); if (reg == 26) ret_pc = (instr *)value; printk("\t\t%s / 0x%016lx\n", reg_name[reg], value); } return ret_pc; } static instr * seek_prologue(instr * pc) { while (!STK_ALLOC_MATCH(*pc)) --pc; while (!BB_END(*(pc - 1))) --pc; return pc; } static long stack_increment(instr * prologue_pc) { while (!STK_ALLOC_MATCH(*prologue_pc)) ++prologue_pc; /* Count the bytes allocated. */ if ((*prologue_pc & STK_ALLOC_1M) == STK_ALLOC_1M) return -(((long)(*prologue_pc) << 48) >> 48); else return (*prologue_pc >> 13) & 0xff; } void stacktrace(void) { instr * ret_pc; instr * prologue = (instr *)stacktrace; unsigned char *sp = (unsigned char *)current_stack_pointer; printk("\tstack trace:\n"); do { ret_pc = display_stored_regs(prologue, sp); sp += stack_increment(prologue); prologue = seek_prologue(ret_pc); } while (IS_KERNEL_TEXT(ret_pc)); }