kernel-fxtec-pro1x/arch/sh/lib/mcount.S
Matt Fleming b99610fb9c sh: Provide diagnostic kernel stack checks
Enable kernel stack checking code in both the dynamic ftrace and mcount
code paths. Check the stack to see if it's overflowing and make sure
that the stack pointer contains an address that's either in init_stack
or after the bss.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-07-11 10:07:58 +09:00

190 lines
3.5 KiB
ArmAsm

/*
* arch/sh/lib/mcount.S
*
* Copyright (C) 2008 Paul Mundt
* Copyright (C) 2008, 2009 Matt Fleming
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <asm/ftrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#define MCOUNT_ENTER() \
mov.l r4, @-r15; \
mov.l r5, @-r15; \
mov.l r6, @-r15; \
mov.l r7, @-r15; \
sts.l pr, @-r15; \
\
mov.l @(20,r15),r4; \
sts pr, r5
#define MCOUNT_LEAVE() \
lds.l @r15+, pr; \
mov.l @r15+, r7; \
mov.l @r15+, r6; \
mov.l @r15+, r5; \
rts; \
mov.l @r15+, r4
#ifdef CONFIG_STACK_DEBUG
/*
* Perform diagnostic checks on the state of the kernel stack.
*
* Check for stack overflow. If there is less than 1KB free
* then it has overflowed.
*
* Make sure the stack pointer contains a valid address. Valid
* addresses for kernel stacks are anywhere after the bss
* (after _ebss) and anywhere in init_thread_union (init_stack).
*/
#define STACK_CHECK() \
mov #(THREAD_SIZE >> 10), r0; \
shll8 r0; \
shll2 r0; \
\
/* r1 = sp & (THREAD_SIZE - 1) */ \
mov #-1, r1; \
add r0, r1; \
and r15, r1; \
\
mov #TI_SIZE, r3; \
mov #(STACK_WARN >> 8), r2; \
shll8 r2; \
add r3, r2; \
\
/* Is the stack overflowing? */ \
cmp/hi r2, r1; \
bf stack_panic; \
\
/* If sp > _ebss then we're OK. */ \
mov.l .L_ebss, r1; \
cmp/hi r1, r15; \
bt 1f; \
\
/* If sp < init_stack, we're not OK. */ \
mov.l .L_init_thread_union, r1; \
cmp/hs r1, r15; \
bf stack_panic; \
\
/* If sp > init_stack && sp < _ebss, not OK. */ \
add r0, r1; \
cmp/hs r1, r15; \
bt stack_panic; \
1:
#else
#define STACK_CHECK()
#endif /* CONFIG_STACK_DEBUG */
.align 2
.globl _mcount
.type _mcount,@function
.globl mcount
.type mcount,@function
_mcount:
mcount:
#ifndef CONFIG_DYNAMIC_FTRACE
mov.l .Lfunction_trace_stop, r0
mov.l @r0, r0
tst r0, r0
bf ftrace_stub
#endif
STACK_CHECK()
MCOUNT_ENTER()
#ifdef CONFIG_DYNAMIC_FTRACE
.globl mcount_call
mcount_call:
mov.l .Lftrace_stub, r6
#else
mov.l .Lftrace_trace_function, r6
mov.l ftrace_stub, r7
cmp/eq r6, r7
bt skip_trace
mov.l @r6, r6
#endif
jsr @r6
nop
skip_trace:
MCOUNT_LEAVE()
.align 2
.Lftrace_trace_function:
.long ftrace_trace_function
#ifdef CONFIG_DYNAMIC_FTRACE
.globl ftrace_caller
ftrace_caller:
mov.l .Lfunction_trace_stop, r0
mov.l @r0, r0
tst r0, r0
bf ftrace_stub
STACK_CHECK()
MCOUNT_ENTER()
.globl ftrace_call
ftrace_call:
mov.l .Lftrace_stub, r6
jsr @r6
nop
MCOUNT_LEAVE()
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
* NOTE: From here on the locations of the .Lftrace_stub label and
* ftrace_stub itself are fixed. Adding additional data here will skew
* the displacement for the memory table and break the block replacement.
* Place new labels either after the ftrace_stub body, or before
* ftrace_caller. You have been warned.
*/
.align 2
.Lftrace_stub:
.long ftrace_stub
.globl ftrace_stub
ftrace_stub:
rts
nop
#ifdef CONFIG_STACK_DEBUG
.globl stack_panic
stack_panic:
mov.l .Ldump_stack, r0
jsr @r0
nop
mov.l .Lpanic, r0
jsr @r0
mov.l .Lpanic_s, r4
rts
nop
.align 2
.Lfunction_trace_stop:
.long function_trace_stop
.L_ebss:
.long _ebss
.L_init_thread_union:
.long init_thread_union
.Lpanic:
.long panic
.Lpanic_s:
.long .Lpanic_str
.Ldump_stack:
.long dump_stack
.section .rodata
.align 2
.Lpanic_str:
.string "Stack error"
#endif /* CONFIG_STACK_DEBUG */