File: /usr/src/linux/arch/alpha/lib/stacktrace.c

1     #include <linux/kernel.h>
2     #include <asm/system.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