/*
 * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 */

#include <machine/asm.h>
#include <cpu/specialreg.h>
#include <asmcontext.h>

        /*
         * This function is special-cased because the context it saves
         * includes a stale stack context (because it returns before the
         * caller presumably makes the call to setcontext()).  
         */
        .weak   getcontext
        .set    getcontext,_getcontext
ENTRY(_getcontext)
        /*
         * Retrieve the current signal mask and save it in &ucp->uc_sigmask.
         */
        pushq   %rdi                    /* save ucontext_t pointer passed */
        movq    %rdi,%rdx
        addq    $UC_SIGMASK,%rdx        /* pointer to signal mask */
        movq    $0,%rsi
        movq    $SIG_BLOCK,%rdi
        call    PIC_PLT(CNAME(_sigprocmask))
        /*
         * Save what we need because our stack context is going stale.
         */
        popq    %rdi
        movq    $0,UC_LINK(%rdi)        /* make sure UC_LINK is clear */
        movq    %rdi,%r9                /* save ucontext in %r9 */
        movq    (%rsp),%r8              /* save return PC in %r8 */
        addq    $UC_MCONTEXT,%rdi

        movq    $0,MC_ONSTACK(%rdi)     /*      MC_ONSTACK(%rdi)        */
        movq    %rdi,MC_RDI(%rdi)
        movq    %rsi,MC_RSI(%rdi)
        movq    %rdx,MC_RDX(%rdi)
        movq    %r8,MC_R8(%rdi)
        movq    %r9,MC_R9(%rdi)
        /* movq %rax,MC_RAX(%rdi) - not needed, replaced below */
        movq    %rbx,MC_RBX(%rdi)
        /* movq %rcx,MC_RCX(%rdi) - not needed, scratch */
        movq    %rbp,MC_RBP(%rdi)
        movq    %r10,MC_R10(%rdi)
        movq    %r11,MC_R11(%rdi)
        movq    %r12,MC_R12(%rdi)
        movq    %r13,MC_R13(%rdi)
        movq    %r14,MC_R14(%rdi)
        movq    %r15,MC_R15(%rdi)
        /*      MC_TRAPNO(%rdi) */
        /*      MC_ADDR(%rdi)   */
        /*      MC_FLAGS(%rdi)  */
        /*      MC_ERR(%rdi)    */
        /*      MC_RIP(%rdi)    - see below */
        /*      MC_CS(%rdi)     */
        movq    $KUCSEL,MC_CS(%rdi)

        pushfq
        popq    MC_RFLAGS(%rdi)
        /*      MC_RSP(%rdi)    - see below */
        movq    $KUDSEL,MC_SS(%rdi)

        /*
         * FP registers are scratch, do not save or restore, but make
         * sure the context can be restored by a signal handler (where
         * they might not be) by properly initializing the FP control
         * fields.
         */
        movl    $_MC_FPOWNED_NONE,MC_OWNEDFP(%rdi)
        movl    $_MC_FPFMT_NODEV,MC_FPFORMAT(%rdi)
#if 0
        movl    $_MC_FPFMT_YMM,MC_FPFORMAT(%rdi)
        movq    %rdi,%rsi
        movq    $CPU_XFEATURE_X87 | CPU_XFEATURE_SSE | CPU_XFEATURE_YMM,%rax
        movq    $0,%rdx
        xsave   MC_FPREGS(%rsi)
        movq    %rsi,%rdi
#endif

        /*
         * Saved stack pointer as if we had returned from this
         * procedure.
         */
        movq    %rsp,MC_RSP(%rdi)
        addq    $8,MC_RSP(%rdi)

        /*
         * Save rflags
         * XXX
         */

        /*
         * Saved instruction pointer as if we had returned from
         * this procedure.
         */
        movq    (%rsp),%rdx
        movq    %rdx,MC_RIP(%rdi)

        /*
         * On restore as if procedure returned the value 1
         */
        movq    $1,MC_RAX(%rdi)

        /*
         * Set MC_LEN
         */
        movl    $SIZEOF_MCONTEXT_T,MC_LEN(%rdi)

        /*
         * Return 0
         */
        subq    %rax,%rax
        ret

#if 0
1:
        pushq   %rsi
#ifdef PIC
        movq    PIC_GOT(HIDENAME(cerror)),%rdx
        jmp     *%rdx
#else
        jmp     HIDENAME(cerror)
#endif
#endif
END(_getcontext)

        .section .note.GNU-stack,"",%progbits