/*
* Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com)
*
* This file implements mcount(), which is used to collect profiling data.
* This can also be tweaked for kernel stack overflow detection.
*/
#include <linux/linkage.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
/*
* This is the main variant and is called by C code. GCC's -pg option
* automatically instruments every C function with a call to this.
*/
#ifdef CONFIG_STACK_DEBUG
#define OVSTACKSIZE 4096 /* lets hope this is enough */
.data
.align 8
panicstring:
.asciz "Stack overflow\n"
.align 8
ovstack:
.skip OVSTACKSIZE
#endif
.text
.align 32
.globl mcount, _mcount
mcount:
_mcount:
#ifdef CONFIG_STACK_DEBUG
/*
* Check whether %sp is dangerously low.
*/
ldub [%g6 + TI_FPDEPTH], %g1
srl %g1, 1, %g3
add %g3, 1, %g3
sllx %g3, 8, %g3 ! each fpregs frame is 256b
add %g3, 192, %g3
add %g6, %g3, %g3 ! where does task_struct+frame end?
sub %g3, STACK_BIAS, %g3
cmp %sp, %g3
bg,pt %xcc, 1f
sethi %hi(panicstring), %g3
sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
or %g7, %lo(ovstack), %g7
add %g7, OVSTACKSIZE, %g7
sub %g7, STACK_BIAS, %g7
mov %g7, %sp
call prom_printf
or %g3, %lo(panicstring), %o0
call prom_halt
nop
#endif
1: retl
nop
