tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com)
3 *
4 * This file implements mcount(), which is used to collect profiling data.
5 * This can also be tweaked for kernel stack overflow detection.
6 */
7
8#include <linux/linkage.h>
9
10#include <asm/ptrace.h>
11#include <asm/thread_info.h>
12
13/*
14 * This is the main variant and is called by C code. GCC's -pg option
15 * automatically instruments every C function with a call to this.
16 */
17
18#ifdef CONFIG_STACK_DEBUG
19
20#define OVSTACKSIZE 4096 /* lets hope this is enough */
21
22 .data
23 .align 8
24panicstring:
25 .asciz "Stack overflow\n"
26 .align 8
27ovstack:
28 .skip OVSTACKSIZE
29#endif
30 .text
31 .align 32
32 .globl _mcount
33 .type _mcount,#function
34 .globl mcount
35 .type mcount,#function
36_mcount:
37mcount:
38#ifdef CONFIG_STACK_DEBUG
39 /*
40 * Check whether %sp is dangerously low.
41 */
42 ldub [%g6 + TI_FPDEPTH], %g1
43 srl %g1, 1, %g3
44 add %g3, 1, %g3
45 sllx %g3, 8, %g3 ! each fpregs frame is 256b
46 add %g3, 192, %g3
47 add %g6, %g3, %g3 ! where does task_struct+frame end?
48 sub %g3, STACK_BIAS, %g3
49 cmp %sp, %g3
50 bg,pt %xcc, 1f
51 nop
52 lduh [%g6 + TI_CPU], %g1
53 sethi %hi(hardirq_stack), %g3
54 or %g3, %lo(hardirq_stack), %g3
55 sllx %g1, 3, %g1
56 ldx [%g3 + %g1], %g7
57 sub %g7, STACK_BIAS, %g7
58 cmp %sp, %g7
59 bleu,pt %xcc, 2f
60 sethi %hi(THREAD_SIZE), %g3
61 add %g7, %g3, %g7
62 cmp %sp, %g7
63 blu,pn %xcc, 1f
642: sethi %hi(softirq_stack), %g3
65 or %g3, %lo(softirq_stack), %g3
66 ldx [%g3 + %g1], %g7
67 sub %g7, STACK_BIAS, %g7
68 cmp %sp, %g7
69 bleu,pt %xcc, 3f
70 sethi %hi(THREAD_SIZE), %g3
71 add %g7, %g3, %g7
72 cmp %sp, %g7
73 blu,pn %xcc, 1f
74 nop
75 /* If we are already on ovstack, don't hop onto it
76 * again, we are already trying to output the stack overflow
77 * message.
78 */
793: sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
80 or %g7, %lo(ovstack), %g7
81 add %g7, OVSTACKSIZE, %g3
82 sub %g3, STACK_BIAS + 192, %g3
83 sub %g7, STACK_BIAS, %g7
84 cmp %sp, %g7
85 blu,pn %xcc, 2f
86 cmp %sp, %g3
87 bleu,pn %xcc, 1f
88 nop
892: mov %g3, %sp
90 sethi %hi(panicstring), %g3
91 call prom_printf
92 or %g3, %lo(panicstring), %o0
93 call prom_halt
94 nop
951:
96#endif
97#ifdef CONFIG_FUNCTION_TRACER
98#ifdef CONFIG_DYNAMIC_FTRACE
99 mov %o7, %o0
100 .globl mcount_call
101mcount_call:
102 call ftrace_stub
103 mov %o0, %o7
104#else
105 sethi %hi(ftrace_trace_function), %g1
106 sethi %hi(ftrace_stub), %g2
107 ldx [%g1 + %lo(ftrace_trace_function)], %g1
108 or %g2, %lo(ftrace_stub), %g2
109 cmp %g1, %g2
110 be,pn %icc, 1f
111 mov %i7, %o1
112 jmpl %g1, %g0
113 mov %o7, %o0
114 /* not reached */
1151:
116#endif
117#endif
118 retl
119 nop
120 .size _mcount,.-_mcount
121 .size mcount,.-mcount
122
123#ifdef CONFIG_FUNCTION_TRACER
124 .globl ftrace_stub
125 .type ftrace_stub,#function
126ftrace_stub:
127 retl
128 nop
129 .size ftrace_stub,.-ftrace_stub
130#ifdef CONFIG_DYNAMIC_FTRACE
131 .globl ftrace_caller
132 .type ftrace_caller,#function
133ftrace_caller:
134 mov %i7, %o1
135 mov %o7, %o0
136 .globl ftrace_call
137ftrace_call:
138 call ftrace_stub
139 mov %o0, %o7
140 retl
141 nop
142 .size ftrace_caller,.-ftrace_caller
143#endif
144#endif