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/*
* Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>.
* Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>.
* All rights reserved.
*
* 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. Neither the name of the author 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 DANIEL EISCHEN 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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
/*
* Where do we define these?
*/
#define MC_SIZE 640 /* sizeof mcontext_t */
#define UC_MC_OFFSET 16 /* offset to mcontext from ucontext */
#define UC_MC_LEN_OFFSET 96 /* offset to mc_len from mcontext */
#define MC_LEN_OFFSET 80 /* offset to mc_len from mcontext */
#define MC_FP_REGS_OFFSET 96 /* offset to FP regs from mcontext */
#define MC_FP_CW_OFFSET 96 /* offset to FP control word */
#define MC_OWNEDFP_OFFSET 88 /* offset to mc_ownedfp from mcontext */
#define KM_STACK_SP_OFFSET 36 /* offset to km_stack.ss_sp */
#define KM_STACK_SIZE_OFFSET 40 /* offset to km_stack.ss_sp */
#define KM_FUNC_OFFSET 32 /* offset to km_func */
/*
* int uts_to_thread(struct kse_thr_mailbox *tdp,
* struct kse_thr_mailbox **curthreadp);
*
* Does not return on success, returns -1 otherwise.
*/
ENTRY(uts_to_thread)
movl 4(%esp), %edx /* get address of kse_thr_mailbox */
/* .. ucontext_t is at offset 0 */
cmpl $0, %edx /* check for null pointer */
jne 1f
movl $-1, %eax
jmp 5f
1: cmpl $MC_SIZE, UC_MC_LEN_OFFSET(%edx) /* is context valid? */
je 2f
movl $-1, %eax /* bzzzt, invalid context */
jmp 5f
2: movl 8(%esp), %ecx /* get address of curthreadp */
movl %edx, %ebx /* save the pointer for later */
/*
* From here on, we don't touch the old stack.
*/
addl $UC_MC_OFFSET, %edx /* add offset to mcontext */
movl 4(%edx), %gs
movl 8(%edx), %fs
movl 12(%edx), %es
movl 16(%edx), %ds
movl 76(%edx), %ss
movl 20(%edx), %edi
movl 24(%edx), %esi
movl 28(%edx), %ebp
movl 72(%edx), %esp /* switch to context defined stack */
subl $4, %esp /* leave space for the return address */
movl 60(%edx), %eax /* put return address at top of stack */
movl %eax, (%esp)
cmpl $0, MC_OWNEDFP_OFFSET(%edx) /* are FP regs valid? */
jz 3f
frstor MC_FP_REGS_OFFSET(%edx) /* restore FP regs */
jmp 4f
3: fninit
fldcw MC_FP_CW_OFFSET(%edx)
4: movl 48(%edx), %eax /* restore ax, bx, cx, dx */
pushl 68(%edx) /* flags on stack */
pushl 36(%edx) /* %ebx on stack */
pushl 44(%edx) /* %ecx on stack */
movl 40(%edx), %edx /* %edx */
/*
* all registers are now moved out of mailbox,
* it's safe to set current thread pointer
*/
movl %ebx,(%ecx)
popl %ecx /* %ecx off stack */
pop %ebx /* %ebx off stack */
popf /* flags off stack */
5: ret /* %eip off stack */
/*
* int thread_to_uts(struct kse_thr_mailbox *tm, struct kse_mailbox *km);
*
* Does not return on success, returns -1 otherwise.
*/
ENTRY(thread_to_uts)
movl 4(%esp), %eax /* get address of context */
cmpl $0, %eax /* check for null pointer */
jne 1f
movl $-1, %eax
jmp 2f
1: pushl %edx /* save value of edx */
movl %eax, %edx /* get address of context */
addl $UC_MC_OFFSET, %edx /* add offset to mcontext */
movl %gs, 4(%edx)
movl %fs, 8(%edx)
movl %es, 12(%edx)
movl %ds, 16(%edx)
movl %edi, 20(%edx)
movl %esi, 24(%edx)
movl %ebp, 28(%edx)
movl %ebx, 36(%edx)
movl $0, 48(%edx) /* store successful return in eax */
popl %eax /* get saved value of edx */
movl %eax, 40(%edx) /* save edx */
movl %ecx, 44(%edx)
movl (%esp), %eax /* get return address */
movl %eax, 60(%edx) /* save return address */
movl %ss, 76(%edx)
/*
* Don't save floating point registers here.
*
* This is an explicit call to get the current context, so
* the caller is done with the floating point registers.
* Contexts formed by involuntary switches, such as signal delivery,
* have floating point registers saved by the kernel.
*/
fnstcw MC_FP_CW_OFFSET(%edx)
movl $0, MC_OWNEDFP_OFFSET(%edx) /* no FP */
pushfl /* get eflags */
popl %eax
movl %eax, 68(%edx) /* store eflags */
movl %esp, %eax /* setcontext pushes the return */
addl $4, %eax /* address onto the top of the */
movl %eax, 72(%edx) /* stack; account for this */
movl $MC_SIZE, MC_LEN_OFFSET(%edx) /* context is now valid */
movl 8(%esp), %edx /* get address of mailbox */
movl KM_STACK_SP_OFFSET(%edx), %eax /* get bottom of stack */
addl KM_STACK_SIZE_OFFSET(%edx), %eax /* add length */
movl %eax, %esp /* switch to the uts's stack */
pushl %edx /* push the address of the mailbox */
pushl KM_FUNC_OFFSET(%edx) /* .. the uts can return to itself */
pushl KM_FUNC_OFFSET(%edx) /* push the address of the uts func */
2: ret
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