LXR linux/arch/alpha/lib/stacktrace.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/kernel.h>
   3
   4typedef 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
  40static 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
  48static instr *
  49display_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
  67static instr *
  68seek_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
  77static long
  78stack_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
  90void
  91stacktrace(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