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/*
* 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
.type _mcount,#function
.globl mcount
.type mcount,#function
_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
nop
lduh [%g6 + TI_CPU], %g1
sethi %hi(hardirq_stack), %g3
or %g3, %lo(hardirq_stack), %g3
sllx %g1, 3, %g1
ldx [%g3 + %g1], %g7
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
bleu,pt %xcc, 2f
sethi %hi(THREAD_SIZE), %g3
add %g7, %g3, %g7
cmp %sp, %g7
blu,pn %xcc, 1f
2: sethi %hi(softirq_stack), %g3
or %g3, %lo(softirq_stack), %g3
ldx [%g3 + %g1], %g7
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
bleu,pt %xcc, 3f
sethi %hi(THREAD_SIZE), %g3
add %g7, %g3, %g7
cmp %sp, %g7
blu,pn %xcc, 1f
nop
/* If we are already on ovstack, don't hop onto it
* again, we are already trying to output the stack overflow
* message.
*/
3: sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough
or %g7, %lo(ovstack), %g7
add %g7, OVSTACKSIZE, %g3
sub %g3, STACK_BIAS + 192, %g3
sub %g7, STACK_BIAS, %g7
cmp %sp, %g7
blu,pn %xcc, 2f
cmp %sp, %g3
bleu,pn %xcc, 1f
nop
2: mov %g3, %sp
sethi %hi(panicstring), %g3
call prom_printf
or %g3, %lo(panicstring), %o0
call prom_halt
nop
1:
#endif
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
/* Do nothing, the retl/nop below is all we need. */
#else
sethi %hi(function_trace_stop), %g1
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, 1f
sethi %hi(ftrace_trace_function), %g1
sethi %hi(ftrace_stub), %g2
ldx [%g1 + %lo(ftrace_trace_function)], %g1
or %g2, %lo(ftrace_stub), %g2
cmp %g1, %g2
be,pn %icc, 1f
mov %i7, %o1
jmpl %g1, %g0
mov %o7, %o0
/* not reached */
1:
#endif
#endif
retl
nop
.size _mcount,.-_mcount
.size mcount,.-mcount
#ifdef CONFIG_FUNCTION_TRACER
.globl ftrace_stub
.type ftrace_stub,#function
ftrace_stub:
retl
nop
.size ftrace_stub,.-ftrace_stub
#ifdef CONFIG_DYNAMIC_FTRACE
.globl ftrace_caller
.type ftrace_caller,#function
ftrace_caller:
sethi %hi(function_trace_stop), %g1
mov %i7, %o1
lduw [%g1 + %lo(function_trace_stop)], %g2
brnz,pn %g2, ftrace_stub
mov %o7, %o0
.globl ftrace_call
ftrace_call:
/* If the final kernel link ever turns on relaxation, we'll need
* to do something about this tail call. Otherwise the linker
* will rewrite the call into a branch and nop out the move
* instruction.
*/
call ftrace_stub
mov %o0, %o7
retl
nop
.size ftrace_call,.-ftrace_call
.size ftrace_caller,.-ftrace_caller
#endif
#endif
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