/* * xchg/cmpxchg operations for the Hexagon architecture * * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. */ #ifndef _ASM_CMPXCHG_H #define _ASM_CMPXCHG_H /* * __xchg - atomically exchange a register and a memory location * @x: value to swap * @ptr: pointer to memory * @size: size of the value * * Only 4 bytes supported currently. * * Note: there was an errata for V2 about .new's and memw_locked. * */ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) { unsigned long retval; /* Can't seem to use printk or panic here, so just stop */ if (size != 4) do { asm volatile("brkpt;\n"); } while (1); __asm__ __volatile__ ( "1: %0 = memw_locked(%1);\n" /* load into retval */ " memw_locked(%1,P0) = %2;\n" /* store into memory */ " if (!P0) jump 1b;\n" : "=&r" (retval) : "r" (ptr), "r" (x) : "memory", "p0" ); return retval; } /* * Atomically swap the contents of a register with memory. Should be atomic * between multiple CPU's and within interrupts on the same CPU. */ #define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \ sizeof(*(ptr)))) /* * see rt-mutex-design.txt; cmpxchg supposedly checks if *ptr == A and swaps. * looks just like atomic_cmpxchg on our arch currently with a bunch of * variable casting. */ #define cmpxchg(ptr, old, new) \ ({ \ __typeof__(ptr) __ptr = (ptr); \ __typeof__(*(ptr)) __old = (old); \ __typeof__(*(ptr)) __new = (new); \ __typeof__(*(ptr)) __oldval = 0; \ \ asm volatile( \ "1: %0 = memw_locked(%1);\n" \ " { P0 = cmp.eq(%0,%2);\n" \ " if (!P0.new) jump:nt 2f; }\n" \ " memw_locked(%1,p0) = %3;\n" \ " if (!P0) jump 1b;\n" \ "2:\n" \ : "=&r" (__oldval) \ : "r" (__ptr), "r" (__old), "r" (__new) \ : "memory", "p0" \ ); \ __oldval; \ }) #endif /* _ASM_CMPXCHG_H */
Name | Type | Size | Permission | Actions |
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Kbuild | File | 886 B | 0644 |
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asm-offsets.h | File | 35 B | 0644 |
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atomic.h | File | 5.27 KB | 0644 |
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bitops.h | File | 6.62 KB | 0644 |
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cache.h | File | 1.16 KB | 0644 |
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cacheflush.h | File | 3.8 KB | 0644 |
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checksum.h | File | 1.61 KB | 0644 |
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cmpxchg.h | File | 2.55 KB | 0644 |
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delay.h | File | 978 B | 0644 |
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dma-mapping.h | File | 1.31 KB | 0644 |
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dma.h | File | 934 B | 0644 |
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elf.h | File | 6.34 KB | 0644 |
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exec.h | File | 1.01 KB | 0644 |
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fixmap.h | File | 1.11 KB | 0644 |
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fpu.h | File | 90 B | 0644 |
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futex.h | File | 2.25 KB | 0644 |
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hexagon_vm.h | File | 6.39 KB | 0644 |
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intrinsics.h | File | 1003 B | 0644 |
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io.h | File | 6.95 KB | 0644 |
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irq.h | File | 1.13 KB | 0644 |
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irqflags.h | File | 1.46 KB | 0644 |
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kgdb.h | File | 1.36 KB | 0644 |
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linkage.h | File | 871 B | 0644 |
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mem-layout.h | File | 3.42 KB | 0644 |
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mmu.h | File | 1.1 KB | 0644 |
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mmu_context.h | File | 2.59 KB | 0644 |
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module.h | File | 910 B | 0644 |
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page.h | File | 4.74 KB | 0644 |
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perf_event.h | File | 841 B | 0644 |
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pgalloc.h | File | 4.08 KB | 0644 |
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pgtable.h | File | 14.15 KB | 0644 |
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processor.h | File | 3.8 KB | 0644 |
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smp.h | File | 1.31 KB | 0644 |
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spinlock.h | File | 3.84 KB | 0644 |
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spinlock_types.h | File | 1.15 KB | 0644 |
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string.h | File | 1.08 KB | 0644 |
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suspend.h | File | 872 B | 0644 |
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switch_to.h | File | 1.09 KB | 0644 |
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syscall.h | File | 1.38 KB | 0644 |
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thread_info.h | File | 4.05 KB | 0644 |
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time.h | File | 980 B | 0644 |
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timer-regs.h | File | 1.23 KB | 0644 |
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timex.h | File | 1.13 KB | 0644 |
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tlb.h | File | 1.21 KB | 0644 |
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tlbflush.h | File | 2.08 KB | 0644 |
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traps.h | File | 1.02 KB | 0644 |
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uaccess.h | File | 3.67 KB | 0644 |
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vdso.h | File | 941 B | 0644 |
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vm_fault.h | File | 993 B | 0644 |
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vm_mmu.h | File | 3.37 KB | 0644 |
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