/*
 * MIPS specific _mcount support
 *
 * 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.
 *
 * Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
 * Copyright (C) 2010 DSLab, Lanzhou University, China
 * Author: Wu Zhangjin <wuzhangjin@gmail.com>
 */

#include <asm/export.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/ftrace.h>

        .text
        .set noreorder
        .set noat

        .macro MCOUNT_SAVE_REGS
        PTR_SUBU        sp, PT_SIZE
        PTR_S   ra, PT_R31(sp)
        PTR_S   AT, PT_R1(sp)
        PTR_S   a0, PT_R4(sp)
        PTR_S   a1, PT_R5(sp)
        PTR_S   a2, PT_R6(sp)
        PTR_S   a3, PT_R7(sp)
#ifdef CONFIG_64BIT
        PTR_S   a4, PT_R8(sp)
        PTR_S   a5, PT_R9(sp)
        PTR_S   a6, PT_R10(sp)
        PTR_S   a7, PT_R11(sp)
#endif
        .endm

        .macro MCOUNT_RESTORE_REGS
        PTR_L   ra, PT_R31(sp)
        PTR_L   AT, PT_R1(sp)
        PTR_L   a0, PT_R4(sp)
        PTR_L   a1, PT_R5(sp)
        PTR_L   a2, PT_R6(sp)
        PTR_L   a3, PT_R7(sp)
#ifdef CONFIG_64BIT
        PTR_L   a4, PT_R8(sp)
        PTR_L   a5, PT_R9(sp)
        PTR_L   a6, PT_R10(sp)
        PTR_L   a7, PT_R11(sp)
#endif
        PTR_ADDIU       sp, PT_SIZE
        .endm

        .macro RETURN_BACK
        jr ra
         move ra, AT
        .endm

/*
 * The -mmcount-ra-address option of gcc 4.5 uses register $12 to pass
 * the location of the parent's return address.
 */
#define MCOUNT_RA_ADDRESS_REG   $12

#ifdef CONFIG_DYNAMIC_FTRACE

NESTED(ftrace_caller, PT_SIZE, ra)
        .globl _mcount
_mcount:
EXPORT_SYMBOL(_mcount)
        b       ftrace_stub
#ifdef CONFIG_32BIT
         addiu sp,sp,8
#else
         nop
#endif

        /* When tracing is activated, it calls ftrace_caller+8 (aka here) */
        MCOUNT_SAVE_REGS
#ifdef KBUILD_MCOUNT_RA_ADDRESS
        PTR_S   MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
#endif

        PTR_SUBU a0, ra, 8      /* arg1: self address */
        PTR_LA   t1, _stext
        sltu     t2, a0, t1     /* t2 = (a0 < _stext) */
        PTR_LA   t1, _etext
        sltu     t3, t1, a0     /* t3 = (a0 > _etext) */
        or       t1, t2, t3
        beqz     t1, ftrace_call
         nop
#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
        PTR_SUBU a0, a0, 16     /* arg1: adjust to module's recorded callsite */
#else
        PTR_SUBU a0, a0, 12
#endif

        .globl ftrace_call
ftrace_call:
        nop     /* a placeholder for the call to a real tracing function */
         move   a1, AT          /* arg2: parent's return address */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        .globl ftrace_graph_call
ftrace_graph_call:
        nop
         nop
#endif

        MCOUNT_RESTORE_REGS
        .globl ftrace_stub
ftrace_stub:
        RETURN_BACK
        END(ftrace_caller)

#else   /* ! CONFIG_DYNAMIC_FTRACE */

NESTED(_mcount, PT_SIZE, ra)
EXPORT_SYMBOL(_mcount)
        PTR_LA  t1, ftrace_stub
        PTR_L   t2, ftrace_trace_function /* Prepare t2 for (1) */
        beq     t1, t2, fgraph_trace
         nop

        MCOUNT_SAVE_REGS

        move    a0, ra          /* arg1: self return address */
        jalr    t2              /* (1) call *ftrace_trace_function */
         move   a1, AT          /* arg2: parent's return address */

        MCOUNT_RESTORE_REGS

fgraph_trace:
#ifdef  CONFIG_FUNCTION_GRAPH_TRACER
        PTR_LA  t1, ftrace_stub
        PTR_L   t3, ftrace_graph_return
        bne     t1, t3, ftrace_graph_caller
         nop
        PTR_LA  t1, ftrace_graph_entry_stub
        PTR_L   t3, ftrace_graph_entry
        bne     t1, t3, ftrace_graph_caller
         nop
#endif

#ifdef CONFIG_32BIT
        addiu sp, sp, 8
#endif

        .globl ftrace_stub
ftrace_stub:
        RETURN_BACK
        END(_mcount)

#endif  /* ! CONFIG_DYNAMIC_FTRACE */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

NESTED(ftrace_graph_caller, PT_SIZE, ra)
#ifndef CONFIG_DYNAMIC_FTRACE
        MCOUNT_SAVE_REGS
#endif

        /* arg1: Get the location of the parent's return address */
#ifdef KBUILD_MCOUNT_RA_ADDRESS
#ifdef CONFIG_DYNAMIC_FTRACE
        PTR_L   a0, PT_R12(sp)
#else
        move    a0, MCOUNT_RA_ADDRESS_REG
#endif
        bnez    a0, 1f  /* non-leaf func: stored in MCOUNT_RA_ADDRESS_REG */
         nop
#endif
        PTR_LA  a0, PT_R1(sp)   /* leaf func: the location in current stack */
1:

        /* arg2: Get self return address */
#ifdef CONFIG_DYNAMIC_FTRACE
        PTR_L   a1, PT_R31(sp)
#else
        move    a1, ra
#endif

        /* arg3: Get frame pointer of current stack */
#ifdef CONFIG_64BIT
        PTR_LA  a2, PT_SIZE(sp)
#else
        PTR_LA  a2, (PT_SIZE+8)(sp)
#endif

        jal     prepare_ftrace_return
         nop
        MCOUNT_RESTORE_REGS
#ifndef CONFIG_DYNAMIC_FTRACE
#ifdef CONFIG_32BIT
        addiu sp, sp, 8
#endif
#endif
        RETURN_BACK
        END(ftrace_graph_caller)

        .align  2
        .globl  return_to_handler
return_to_handler:
        PTR_SUBU        sp, PT_SIZE
        PTR_S   v0, PT_R2(sp)

        jal     ftrace_return_to_handler
         PTR_S  v1, PT_R3(sp)

        /* restore the real parent address: v0 -> ra */
        move    ra, v0

        PTR_L   v0, PT_R2(sp)
        PTR_L   v1, PT_R3(sp)
        jr      ra
         PTR_ADDIU      sp, PT_SIZE
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

        .set at
        .set reorder