1596f53aae
return path only when neither thread was context switched while executing syscall code nor syscall explicitely modified LDT or MSRs. Save segment registers in trap handlers before interrupts are enabled, to not allow context switches to happen before registers are saved. Use separated byte in pcb for indication of fast/full return, since pcb_flags are not synchronized with context switches. The change puts back syscall microbenchmark numbers that were slowed down after commit of the support for LDT on amd64. Reviewed by: jeff Tested (and tested, and tested ...) by: pho Approved by: re (kensmith)
75 lines
2.5 KiB
ArmAsm
75 lines
2.5 KiB
ArmAsm
/*-
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* Copyright (c) 2003 Peter Wemm
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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. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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/asmacros.h>
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#include "assym.s"
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.text
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/*
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* Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80)
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*
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* This is a SDT_SYSIDT entry point (unlike the i386 port) so that we
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* can do a swapgs before enabling interrupts. This is critical because
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* if we took an interrupt before swapgs, the interrupt code would see
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* that it originated in supervisor mode and skip the swapgs.
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*/
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SUPERALIGN_TEXT
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IDTVEC(int0x80_syscall)
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swapgs
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pushq $2 /* sizeof "int 0x80" */
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subq $TF_ERR,%rsp /* skip over tf_trapno */
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movq %rdi,TF_RDI(%rsp)
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movq PCPU(CURPCB),%rdi
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movb $0,PCB_FULL_IRET(%rdi)
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movw %fs,TF_FS(%rsp)
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movw %gs,TF_GS(%rsp)
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movw %es,TF_ES(%rsp)
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movw %ds,TF_DS(%rsp)
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sti
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movq %rsi,TF_RSI(%rsp)
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movq %rdx,TF_RDX(%rsp)
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movq %rcx,TF_RCX(%rsp)
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movq %r8,TF_R8(%rsp)
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movq %r9,TF_R9(%rsp)
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movq %rax,TF_RAX(%rsp)
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movq %rbx,TF_RBX(%rsp)
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movq %rbp,TF_RBP(%rsp)
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movq %r10,TF_R10(%rsp)
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movq %r11,TF_R11(%rsp)
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movq %r12,TF_R12(%rsp)
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movq %r13,TF_R13(%rsp)
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movq %r14,TF_R14(%rsp)
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movq %r15,TF_R15(%rsp)
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movl $TF_HASSEGS,TF_FLAGS(%rsp)
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FAKE_MCOUNT(TF_RIP(%rsp))
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movq %rsp, %rdi
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call ia32_syscall
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MEXITCOUNT
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jmp doreti
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