X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/c0fea4742e91338fffdcf79f86a7c1d5e2b97eb1..8f6c56a50524aa785f7e596d52dddfb331e18961:/osfmk/i386/commpage/spinlocks.s?ds=sidebyside diff --git a/osfmk/i386/commpage/spinlocks.s b/osfmk/i386/commpage/spinlocks.s index f8d6329fa..e69f875bd 100644 --- a/osfmk/i386/commpage/spinlocks.s +++ b/osfmk/i386/commpage/spinlocks.s @@ -1,31 +1,51 @@ /* - * Copyright (c) 2003-2006 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2003 Apple Computer, Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #include #include #include -#include - +/* + * We need a relative branch within the comm page, and don't want the linker + * to relocate it, so we have to hand-code the instructions. LEN is to account + * for the length of a .long, since the jmp is relative to the next instruction. + */ + +#define JNZ .byte 0x0f, 0x85; .long +#define JMP .byte 0xe9; .long +#define LEN 4 + +/* + * Branch prediction prefixes + */ + +#define LIKELY .byte 0x3e +#define UNLIKELY .byte 0x2e #define MP_SPIN_TRIES 1024 @@ -43,7 +63,6 @@ Lspin_lock_try_up: COMMPAGE_DESCRIPTOR(spin_lock_try_up,_COMM_PAGE_SPINLOCK_TRY,kUP,0) - .align 4, 0x90 Lspin_lock_try_mp: movl 4(%esp), %ecx @@ -57,29 +76,21 @@ Lspin_lock_try_mp: COMMPAGE_DESCRIPTOR(spin_lock_try_mp,_COMM_PAGE_SPINLOCK_TRY,0,kUP) +.set Lrelinquish_off, _COMM_PAGE_RELINQUISH - _COMM_PAGE_SPINLOCK_LOCK .align 4, 0x90 Lspin_lock_up: movl 4(%esp), %ecx xorl %eax, %eax +.set Lretry, . - Lspin_lock_up orl $-1, %edx cmpxchgl %edx, (%ecx) - jnz,pn 1f /* predict not taken */ + UNLIKELY + JNZ Lrelinquish_off - . + Lspin_lock_up - LEN ret -1: - /* failed to get lock so relinquish the processor immediately on UP */ - pushl $1 /* 1 ms */ - pushl $1 /* SWITCH_OPTION_DEPRESS */ - pushl $0 /* THREAD_NULL */ - pushl $0 /* push dummy stack ret addr */ - movl $-61,%eax /* SYSCALL_THREAD_SWITCH */ - int $(MACH_INT) - addl $16, %esp /* adjust stack*/ - jmp Lspin_lock_up COMMPAGE_DESCRIPTOR(spin_lock_up,_COMM_PAGE_SPINLOCK_LOCK,kUP,0) - .align 4, 0x90 Lspin_lock_mp: movl 4(%esp), %ecx @@ -88,7 +99,8 @@ Lspin_lock_mp: orl $-1, %edx lock cmpxchgl %edx, (%ecx) - jnz,pn 1f /* predict not taken */ + UNLIKELY + jnz 1f ret 1: xorl %eax, %eax @@ -96,22 +108,15 @@ Lspin_lock_mp: 2: pause cmpl %eax, (%ecx) - jz,pt 0b /* favor success and slow down spin loop */ + LIKELY + jz 0b decl %edx - jnz,pn 2b /* slow down spin loop with a mispredict */ - /* failed to get lock after spinning so relinquish */ - pushl $1 /* 1 ms */ - pushl $1 /* SWITCH_OPTION_DEPRESS */ - pushl $0 /* THREAD_NULL */ - pushl $0 /* push dummy stack ret addr */ - movl $-61,%eax /* SYSCALL_THREAD_SWITCH */ - int $(MACH_INT) - addl $16, %esp /* adjust stack*/ - jmp Lspin_lock_mp + LIKELY + jnz 2b + JMP Lrelinquish_off - . + Lspin_lock_mp - LEN COMMPAGE_DESCRIPTOR(spin_lock_mp,_COMM_PAGE_SPINLOCK_LOCK,0,kUP) - .align 4, 0x90 Lspin_unlock: movl 4(%esp), %ecx @@ -120,93 +125,16 @@ Lspin_unlock: COMMPAGE_DESCRIPTOR(spin_unlock,_COMM_PAGE_SPINLOCK_UNLOCK,0,0) - -/* ============================ 64-bit versions follow ===================== */ - - - .text - .code64 .align 4, 0x90 +Lrelinquish: /* relinquish the processor */ + pushl $1 /* 1 ms */ + pushl $1 /* SWITCH_OPTION_DEPRESS */ + pushl $0 /* THREAD_NULL */ + pushl $0 /* push dummy stack ret addr */ + movl $-61, %eax /* syscall_thread_switch */ + lcall $7, $0 + addl $16, %esp /* adjust stack*/ + xorl %eax, %eax /* set %eax to 0 again */ + JMP Lretry - Lrelinquish_off - . + Lrelinquish - LEN -Lspin_lock_try_up_64: - xorl %eax, %eax - orl $-1, %edx - cmpxchgl %edx, (%rdi) - setz %dl - movzbl %dl, %eax - ret - - COMMPAGE_DESCRIPTOR(spin_lock_try_up_64,_COMM_PAGE_SPINLOCK_TRY,kUP,0) - - - .align 4, 0x90 -Lspin_lock_try_mp_64: - xorl %eax, %eax - orl $-1, %edx - lock - cmpxchgl %edx, (%rdi) - setz %dl - movzbl %dl, %eax - ret - - COMMPAGE_DESCRIPTOR(spin_lock_try_mp_64,_COMM_PAGE_SPINLOCK_TRY,0,kUP) - - - .align 4, 0x90 -Lspin_lock_up_64: - movq %rdi,%r8 -0: - xorl %eax, %eax - orl $-1, %edx - cmpxchgl %edx, (%r8) - jnz,pn 1f /* predict not taken */ - ret -1: - /* failed to get lock so relinquish the processor immediately on UP */ - xorl %edi,%edi /* THREAD_NULL */ - movl $1,%esi /* SWITCH_OPTION_DEPRESS */ - movl $1,%edx /* 1 ms */ - movl $(SYSCALL_CONSTRUCT_MACH(61)),%eax /* 61 = thread_switch */ - syscall - jmp 0b - - COMMPAGE_DESCRIPTOR(spin_lock_up_64,_COMM_PAGE_SPINLOCK_LOCK,kUP,0) - - - - .align 4, 0x90 -Lspin_lock_mp_64: - movq %rdi,%r8 -0: - xorl %eax, %eax - orl $-1, %edx - lock - cmpxchgl %edx, (%r8) - jnz,pn 1f /* predict not taken */ - ret -1: - xorl %eax, %eax - movl $(MP_SPIN_TRIES), %edx -2: /* spin for awhile before relinquish */ - pause - cmpl %eax, (%r8) - jz 0b - decl %edx - jnz 2b - /* failed to get lock after spinning so relinquish */ - xorl %edi,%edi /* THREAD_NULL */ - movl $1,%esi /* SWITCH_OPTION_DEPRESS */ - movl $1,%edx /* 1 ms */ - movl $(SYSCALL_CONSTRUCT_MACH(61)),%eax /* 61 = thread_switch */ - syscall - jmp 0b - - COMMPAGE_DESCRIPTOR(spin_lock_mp_64,_COMM_PAGE_SPINLOCK_LOCK,0,kUP) - - - .align 4, 0x90 -Lspin_unlock_64: - movl $0, (%rdi) - ret - - COMMPAGE_DESCRIPTOR(spin_unlock_64,_COMM_PAGE_SPINLOCK_UNLOCK,0,0) + COMMPAGE_DESCRIPTOR(relinquish,_COMM_PAGE_RELINQUISH,0,0)