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arch/alpha/lib/stacktrace.c 2.59 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  #include <linux/kernel.h>
  #include <asm/system.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:
  ", 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
  ", 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;
  	register unsigned char * sp __asm__ ("$30");
  
  	printk("\tstack trace:
  ");
  	do {
  		ret_pc = display_stored_regs(prologue, sp);
  		sp += stack_increment(prologue);
  		prologue = seek_prologue(ret_pc);
  	} while (IS_KERNEL_TEXT(ret_pc));
  }