/*
   * 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 __bss_stop) 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 > __bss_stop 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 < __bss_stop, 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_init_thread_union:
  	.long	init_thread_union
  .L_ebss:
  	.long	__bss_stop
  .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 */