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 cmp %sp, %g7 68 bleu,pt %xcc, 2f 69 sethi %hi(THREAD_SIZE), %g3 70 add %g7, %g3, %g7 71 cmp %sp, %g7 72 blu,pn %xcc, 1f 73 nop 74 /* If we are already on ovstack, don't hop onto it 75 * again, we are already trying to output the stack overflow 76 * message. 77 */ 78 sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough 79 or %g7, %lo(ovstack), %g7 80 add %g7, OVSTACKSIZE, %g3 81 sub %g3, STACK_BIAS + 192, %g3 82 sub %g7, STACK_BIAS, %g7 83 cmp %sp, %g7 84 blu,pn %xcc, 2f 85 cmp %sp, %g3 86 bleu,pn %xcc, 1f 87 nop 882: mov %g3, %sp 89 sethi %hi(panicstring), %g3 90 call prom_printf 91 or %g3, %lo(panicstring), %o0 92 call prom_halt 93 nop 941: 95#endif 96#ifdef CONFIG_FUNCTION_TRACER 97#ifdef CONFIG_DYNAMIC_FTRACE 98 mov %o7, %o0 99 .globl mcount_call 100mcount_call: 101 call ftrace_stub 102 mov %o0, %o7 103#else 104 sethi %hi(ftrace_trace_function), %g1 105 sethi %hi(ftrace_stub), %g2 106 ldx [%g1 + %lo(ftrace_trace_function)], %g1 107 or %g2, %lo(ftrace_stub), %g2 108 cmp %g1, %g2 109 be,pn %icc, 1f 110 mov %i7, %o1 111 jmpl %g1, %g0 112 mov %o7, %o0 113 /* not reached */ 1141: 115#endif 116#endif 117 retl 118 nop 119 .size _mcount,.-_mcount 120 .size mcount,.-mcount 121 122#ifdef CONFIG_FUNCTION_TRACER 123 .globl ftrace_stub 124 .type ftrace_stub,#function 125ftrace_stub: 126 retl 127 nop 128 .size ftrace_stub,.-ftrace_stub 129#ifdef CONFIG_DYNAMIC_FTRACE 130 .globl ftrace_caller 131 .type ftrace_caller,#function 132ftrace_caller: 133 mov %i7, %o1 134 mov %o7, %o0 135 .globl ftrace_call 136ftrace_call: 137 call ftrace_stub 138 mov %o0, %o7 139 retl 140 nop 141 .size ftrace_caller,.-ftrace_caller 142#endif 143#endif 144