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linux-pinenote/arch/sh/lib/mcount.S
Paul Mundt e460ab27b6 sh: Fix up stack overflow check with ftrace disabled. 
Presently the STACK_CHECK() code is called in to multiple times, although
it's only necessary from the mcount entry. The code still attempts to
treat the nop case as an ftrace path resulting in superfluous code flow
for the case where ftrace is disabled. And finally, this also fixes up
references to a few undefined symbols when FUNCTION_TRACER=n.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-07-11 21:06:53 +09:00

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/*
* arch/sh/lib/mcount.S
*
* Copyright (C) 2008, 2009 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:
STACK_CHECK()
#ifndef CONFIG_FUNCTION_TRACER
rts
nop
#else
#ifndef CONFIG_DYNAMIC_FTRACE
mov.l .Lfunction_trace_stop, r0
mov.l @r0, r0
tst r0, r0
bf ftrace_stub
#endif
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
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
mov.l .Lftrace_graph_return, r6
mov.l .Lftrace_stub, r7
cmp/eq r6, r7
bt 1f
mov.l .Lftrace_graph_caller, r0
jmp @r0
nop
1:
mov.l .Lftrace_graph_entry, r6
mov.l .Lftrace_graph_entry_stub, r7
cmp/eq r6, r7
bt skip_trace
mov.l .Lftrace_graph_caller, r0
jmp @r0
nop
.align 2
.Lftrace_graph_return:
.long ftrace_graph_return
.Lftrace_graph_entry:
.long ftrace_graph_entry
.Lftrace_graph_entry_stub:
.long ftrace_graph_entry_stub
.Lftrace_graph_caller:
.long ftrace_graph_caller
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
.globl skip_trace
skip_trace:
MCOUNT_LEAVE()
.align 2
.Lftrace_trace_function:
.long ftrace_trace_function
#ifdef CONFIG_DYNAMIC_FTRACE
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* NOTE: Do not move either ftrace_graph_call or ftrace_caller
* as this will affect the calculation of GRAPH_INSN_OFFSET.
*/
.globl ftrace_graph_call
ftrace_graph_call:
mov.l .Lskip_trace, r0
jmp @r0
nop
.align 2
.Lskip_trace:
.long skip_trace
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
.globl ftrace_caller
ftrace_caller:
mov.l .Lfunction_trace_stop, r0
mov.l @r0, r0
tst r0, r0
bf ftrace_stub
MCOUNT_ENTER()
.globl ftrace_call
ftrace_call:
mov.l .Lftrace_stub, r6
jsr @r6
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
bra ftrace_graph_call
nop
#else
MCOUNT_LEAVE()
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#endif /* CONFIG_DYNAMIC_FTRACE */
.align 2
.Lfunction_trace_stop:
.long function_trace_stop
/*
* 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.
*/
.Lftrace_stub:
.long ftrace_stub
.globl ftrace_stub
ftrace_stub:
rts
nop
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_caller
ftrace_graph_caller:
mov.l 2f, r0
mov.l @r0, r0
tst r0, r0
bt 1f
mov.l 3f, r1
jmp @r1
nop
1:
/*
* MCOUNT_ENTER() pushed 5 registers onto the stack, so
* the stack address containing our return address is
* r15 + 20.
*/
mov #20, r0
add r15, r0
mov r0, r4
mov.l .Lprepare_ftrace_return, r0
jsr @r0
nop
MCOUNT_LEAVE()
.align 2
2: .long function_trace_stop
3: .long skip_trace
.Lprepare_ftrace_return:
.long prepare_ftrace_return
.globl return_to_handler
return_to_handler:
/*
* Save the return values.
*/
mov.l r0, @-r15
mov.l r1, @-r15
mov #0, r4
mov.l .Lftrace_return_to_handler, r0
jsr @r0
nop
/*
* The return value from ftrace_return_handler has the real
* address that we should return to.
*/
lds r0, pr
mov.l @r15+, r1
rts
mov.l @r15+, r0
.align 2
.Lftrace_return_to_handler:
.long ftrace_return_to_handler
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#endif /* CONFIG_FUNCTION_TRACER */
#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
.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 */
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