📄 locks.h
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/* * linux/include/asm-arm/locks.h * * Copyright (C) 2000 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Interrupt safe locking assembler. */#ifndef __ASM_PROC_LOCKS_H#define __ASM_PROC_LOCKS_H#if __LINUX_ARM_ARCH__ >= 6#define __down_op(ptr,fail) \ ({ \ __asm__ __volatile__( \ "@ down_op\n" \"1: ldrex lr, [%0]\n" \" sub lr, lr, %1\n" \" strex ip, lr, [%0]\n" \" teq ip, #0\n" \" bne 1b\n" \" teq lr, #0\n" \" movmi ip, %0\n" \" blmi " #fail \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })#define __down_op_ret(ptr,fail) \ ({ \ unsigned int ret; \ __asm__ __volatile__( \ "@ down_op_ret\n" \"1: ldrex lr, [%1]\n" \" sub lr, lr, %2\n" \" strex ip, lr, [%1]\n" \" teq ip, #0\n" \" bne 1b\n" \" teq lr, #0\n" \" movmi ip, %1\n" \" movpl ip, #0\n" \" blmi " #fail "\n" \" mov %0, ip" \ : "=&r" (ret) \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ ret; \ })#define __up_op(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op\n" \"1: ldrex lr, [%0]\n" \" add lr, lr, %1\n" \" strex ip, lr, [%0]\n" \" teq ip, #0\n" \" bne 1b\n" \" teq lr, #0\n" \" movle ip, %0\n" \" blle " #wake \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })/* * The value 0x01000000 supports up to 128 processors and * lots of processes. BIAS must be chosen such that sub'ing * BIAS once per CPU will result in the long remaining * negative. */#define RW_LOCK_BIAS 0x01000000#define RW_LOCK_BIAS_STR "0x01000000"#define __down_op_write(ptr,fail) \ ({ \ __asm__ __volatile__( \ "@ down_op_write\n" \"1: ldrex lr, [%0]\n" \" sub lr, lr, %1\n" \" strex ip, lr, [%0]\n" \" teq ip, #0\n" \" bne 1b\n" \" teq lr, #0\n" \" movne ip, %0\n" \" blne " #fail \ : \ : "r" (ptr), "I" (RW_LOCK_BIAS) \ : "ip", "lr", "cc", "memory"); \ })#define __up_op_write(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op_read\n" \"1: ldrex lr, [%0]\n" \" add lr, lr, %1\n" \" strex ip, lr, [%0]\n" \" teq ip, #0\n" \" bne 1b\n" \" movcs ip, %0\n" \" blcs " #wake \ : \ : "r" (ptr), "I" (RW_LOCK_BIAS) \ : "ip", "lr", "cc", "memory"); \ })#define __down_op_read(ptr,fail) \ __down_op(ptr, fail)#define __up_op_read(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op_read\n" \"1: ldrex lr, [%0]\n" \" add lr, lr, %1\n" \" strex ip, lr, [%0]\n" \" teq ip, #0\n" \" bne 1b\n" \" teq lr, #0\n" \" moveq ip, %0\n" \" bleq " #wake \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })#else#define __down_op(ptr,fail) \ ({ \ __asm__ __volatile__( \ "@ down_op\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%0]\n" \" subs lr, lr, %1\n" \" str lr, [%0]\n" \" msr cpsr_c, ip\n" \" movmi ip, %0\n" \" blmi " #fail \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })#define __down_op_ret(ptr,fail) \ ({ \ unsigned int ret; \ __asm__ __volatile__( \ "@ down_op_ret\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%1]\n" \" subs lr, lr, %2\n" \" str lr, [%1]\n" \" msr cpsr_c, ip\n" \" movmi ip, %1\n" \" movpl ip, #0\n" \" blmi " #fail "\n" \" mov %0, ip" \ : "=&r" (ret) \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ ret; \ })#define __up_op(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%0]\n" \" adds lr, lr, %1\n" \" str lr, [%0]\n" \" msr cpsr_c, ip\n" \" movle ip, %0\n" \" blle " #wake \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })/* * The value 0x01000000 supports up to 128 processors and * lots of processes. BIAS must be chosen such that sub'ing * BIAS once per CPU will result in the long remaining * negative. */#define RW_LOCK_BIAS 0x01000000#define RW_LOCK_BIAS_STR "0x01000000"#define __down_op_write(ptr,fail) \ ({ \ __asm__ __volatile__( \ "@ down_op_write\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%0]\n" \" subs lr, lr, %1\n" \" str lr, [%0]\n" \" msr cpsr_c, ip\n" \" movne ip, %0\n" \" blne " #fail \ : \ : "r" (ptr), "I" (RW_LOCK_BIAS) \ : "ip", "lr", "cc", "memory"); \ })#define __up_op_write(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op_read\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%0]\n" \" adds lr, lr, %1\n" \" str lr, [%0]\n" \" msr cpsr_c, ip\n" \" movcs ip, %0\n" \" blcs " #wake \ : \ : "r" (ptr), "I" (RW_LOCK_BIAS) \ : "ip", "lr", "cc", "memory"); \ })#define __down_op_read(ptr,fail) \ __down_op(ptr, fail)#define __up_op_read(ptr,wake) \ ({ \ __asm__ __volatile__( \ "@ up_op_read\n" \" mrs ip, cpsr\n" \" orr lr, ip, #128\n" \" msr cpsr_c, lr\n" \" ldr lr, [%0]\n" \" adds lr, lr, %1\n" \" str lr, [%0]\n" \" msr cpsr_c, ip\n" \" moveq ip, %0\n" \" bleq " #wake \ : \ : "r" (ptr), "I" (1) \ : "ip", "lr", "cc", "memory"); \ })#endif#endif
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