c2f7aa6939
(don't fill in the mailbox pointer until we have unloaded all the previous contents of the mailbox context block)
153 lines
5.4 KiB
ArmAsm
153 lines
5.4 KiB
ArmAsm
/*
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* Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>.
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* Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <machine/asm.h>
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__FBSDID("$FreeBSD$");
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/*
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* Where do we define these?
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*/
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#define MC_SIZE 640 /* sizeof mcontext_t */
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#define UC_MC_OFFSET 16 /* offset to mcontext from ucontext */
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#define UC_MC_LEN_OFFSET 96 /* offset to mc_len from mcontext */
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#define MC_LEN_OFFSET 80 /* offset to mc_len from mcontext */
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#define MC_FP_REGS_OFFSET 96 /* offset to FP regs from mcontext */
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#define MC_FP_CW_OFFSET 96 /* offset to FP control word */
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#define MC_OWNEDFP_OFFSET 88 /* offset to mc_ownedfp from mcontext */
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#define KM_STACK_SP_OFFSET 36 /* offset to km_stack.ss_sp */
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#define KM_STACK_SIZE_OFFSET 40 /* offset to km_stack.ss_sp */
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#define KM_FUNC_OFFSET 32 /* offset to km_func */
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/*
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* int uts_to_thread(struct kse_thr_mailbox *tdp,
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* struct kse_thr_mailbox **curthreadp);
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*
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* Does not return on success, returns -1 otherwise.
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*/
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ENTRY(uts_to_thread)
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movl 4(%esp), %edx /* get address of kse_thr_mailbox */
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/* .. ucontext_t is at offset 0 */
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cmpl $0, %edx /* check for null pointer */
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jne 1f
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movl $-1, %eax
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jmp 5f
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1: cmpl $MC_SIZE, UC_MC_LEN_OFFSET(%edx) /* is context valid? */
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je 2f
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movl $-1, %eax /* bzzzt, invalid context */
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jmp 5f
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2: movl 8(%esp), %eax /* get address of curthreadp */
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movl %edx, %ebx /* save the pointer for later */
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/*
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* From here on, we don't touch the old stack.
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*/
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addl $UC_MC_OFFSET, %edx /* add offset to mcontext */
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movl 4(%edx), %gs
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movl 8(%edx), %fs
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movl 12(%edx), %es
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movl 16(%edx), %ds
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movl 76(%edx), %ss
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movl 20(%edx), %edi
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movl 24(%edx), %esi
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movl 28(%edx), %ebp
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movl 72(%edx), %esp /* switch to context defined stack */
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subl $4, %esp /* leave space for the return address */
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movl 60(%edx), %eax /* put return address at top of stack */
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movl %eax, (%esp)
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cmpl $0, MC_OWNEDFP_OFFSET(%edx) /* are FP regs valid? */
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jz 3f
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frstor MC_FP_REGS_OFFSET(%edx) /* restore FP regs */
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jmp 4f
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3: fninit
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fldcw MC_FP_CW_OFFSET(%edx)
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4: pushl 68(%edx) /* flags */
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pushl 48(%edx) /* eax */
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pushl 36(%edx) /* ebx */
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movl 40(%edx), %edx /* edx */
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movl %ebx, (%eax) /* <---- set new mailbox pointer */
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popl %ebx
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popl %eax
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popf
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5: ret
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/*
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* int thread_to_uts(struct kse_thr_mailbox *tm, struct kse_mailbox *km);
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*
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* Does not return on success, returns -1 otherwise.
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*/
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ENTRY(thread_to_uts)
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movl 4(%esp), %eax /* get address of context */
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cmpl $0, %eax /* check for null pointer */
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jne 1f
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movl $-1, %eax
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jmp 2f
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1: pushl %edx /* save value of edx */
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movl %eax, %edx /* get address of context */
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addl $UC_MC_OFFSET, %edx /* add offset to mcontext */
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movl %gs, 4(%edx)
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movl %fs, 8(%edx)
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movl %es, 12(%edx)
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movl %ds, 16(%edx)
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movl %edi, 20(%edx)
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movl %esi, 24(%edx)
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movl %ebp, 28(%edx)
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movl %ebx, 36(%edx)
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movl $0, 48(%edx) /* store successful return in eax */
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popl %eax /* get saved value of edx */
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movl %eax, 40(%edx) /* save edx */
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movl %ecx, 44(%edx)
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movl (%esp), %eax /* get return address */
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movl %eax, 60(%edx) /* save return address */
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movl %ss, 76(%edx)
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/*
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* Don't save floating point registers here.
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*
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* This is an explicit call to get the current context, so
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* the caller is done with the floating point registers.
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* Contexts formed by involuntary switches, such as signal delivery,
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* have floating point registers saved by the kernel.
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*/
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fnstcw MC_FP_CW_OFFSET(%edx)
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movl $0, MC_OWNEDFP_OFFSET(%edx) /* no FP */
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pushfl /* get eflags */
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popl %eax
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movl %eax, 68(%edx) /* store eflags */
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movl %esp, %eax /* setcontext pushes the return */
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addl $4, %eax /* address onto the top of the */
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movl %eax, 72(%edx) /* stack; account for this */
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movl $MC_SIZE, MC_LEN_OFFSET(%edx) /* context is now valid */
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movl 8(%esp), %edx /* get address of mailbox */
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movl KM_STACK_SP_OFFSET(%edx), %eax /* get bottom of stack */
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addl KM_STACK_SIZE_OFFSET(%edx), %eax /* add length */
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movl %eax, %esp /* switch to the uts's stack */
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pushl %edx /* push the address of the mailbox */
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pushl KM_FUNC_OFFSET(%edx) /* .. the uts can return to itself */
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pushl KM_FUNC_OFFSET(%edx) /* push the address of the uts func */
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2: ret
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