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Merge branch 'pm-opp'
[mirror_ubuntu-zesty-kernel.git] / arch / alpha / lib / stacktrace.c
1 #include <linux/kernel.h>
2
3 typedef unsigned int instr;
4
5 #define MAJOR_OP 0xfc000000
6 #define LDA_OP 0x20000000
7 #define STQ_OP 0xb4000000
8 #define BR_OP 0xc0000000
9
10 #define STK_ALLOC_1 0x23de8000 /* lda $30,-X($30) */
11 #define STK_ALLOC_1M 0xffff8000
12 #define STK_ALLOC_2 0x43c0153e /* subq $30,X,$30 */
13 #define STK_ALLOC_2M 0xffe01fff
14
15 #define MEM_REG 0x03e00000
16 #define MEM_BASE 0x001f0000
17 #define MEM_OFF 0x0000ffff
18 #define MEM_OFF_SIGN 0x00008000
19 #define BASE_SP 0x001e0000
20
21 #define STK_ALLOC_MATCH(INSTR) \
22 (((INSTR) & STK_ALLOC_1M) == STK_ALLOC_1 \
23 || ((INSTR) & STK_ALLOC_2M) == STK_ALLOC_2)
24 #define STK_PUSH_MATCH(INSTR) \
25 (((INSTR) & (MAJOR_OP | MEM_BASE | MEM_OFF_SIGN)) == (STQ_OP | BASE_SP))
26 #define MEM_OP_OFFSET(INSTR) \
27 (((long)((INSTR) & MEM_OFF) << 48) >> 48)
28 #define MEM_OP_REG(INSTR) \
29 (((INSTR) & MEM_REG) >> 22)
30
31 /* Branches, jumps, PAL calls, and illegal opcodes end a basic block. */
32 #define BB_END(INSTR) \
33 (((instr)(INSTR) >= BR_OP) | ((instr)(INSTR) < LDA_OP) | \
34 ((((instr)(INSTR) ^ 0x60000000) < 0x20000000) & \
35 (((instr)(INSTR) & 0x0c000000) != 0)))
36
37 #define IS_KERNEL_TEXT(PC) ((unsigned long)(PC) > START_ADDR)
38
39 static char reg_name[][4] = {
40 "v0 ", "t0 ", "t1 ", "t2 ", "t3 ", "t4 ", "t5 ", "t6 ", "t7 ",
41 "s0 ", "s1 ", "s2 ", "s3 ", "s4 ", "s5 ", "s6 ", "a0 ", "a1 ",
42 "a2 ", "a3 ", "a4 ", "a5 ", "t8 ", "t9 ", "t10", "t11", "ra ",
43 "pv ", "at ", "gp ", "sp ", "0"
44 };
45
46
47 static instr *
48 display_stored_regs(instr * pro_pc, unsigned char * sp)
49 {
50 instr * ret_pc = 0;
51 int reg;
52 unsigned long value;
53
54 printk("Prologue [<%p>], Frame %p:\n", pro_pc, sp);
55 while (!BB_END(*pro_pc))
56 if (STK_PUSH_MATCH(*pro_pc)) {
57 reg = (*pro_pc & MEM_REG) >> 21;
58 value = *(unsigned long *)(sp + (*pro_pc & MEM_OFF));
59 if (reg == 26)
60 ret_pc = (instr *)value;
61 printk("\t\t%s / 0x%016lx\n", reg_name[reg], value);
62 }
63 return ret_pc;
64 }
65
66 static instr *
67 seek_prologue(instr * pc)
68 {
69 while (!STK_ALLOC_MATCH(*pc))
70 --pc;
71 while (!BB_END(*(pc - 1)))
72 --pc;
73 return pc;
74 }
75
76 static long
77 stack_increment(instr * prologue_pc)
78 {
79 while (!STK_ALLOC_MATCH(*prologue_pc))
80 ++prologue_pc;
81
82 /* Count the bytes allocated. */
83 if ((*prologue_pc & STK_ALLOC_1M) == STK_ALLOC_1M)
84 return -(((long)(*prologue_pc) << 48) >> 48);
85 else
86 return (*prologue_pc >> 13) & 0xff;
87 }
88
89 void
90 stacktrace(void)
91 {
92 instr * ret_pc;
93 instr * prologue = (instr *)stacktrace;
94 register unsigned char * sp __asm__ ("$30");
95
96 printk("\tstack trace:\n");
97 do {
98 ret_pc = display_stored_regs(prologue, sp);
99 sp += stack_increment(prologue);
100 prologue = seek_prologue(ret_pc);
101 } while (IS_KERNEL_TEXT(ret_pc));
102 }