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780a0cfda9
Hexagon requires that register predicates in assembly be parenthesized. Link: https://github.com/ClangBuiltLinux/linux/issues/754 Link: http://lkml.kernel.org/r/20191209222956.239798-3-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Suggested-by: Sid Manning <sidneym@codeaurora.org> Acked-by: Brian Cain <bcain@codeaurora.org> Cc: Lee Jones <lee.jones@linaro.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Tuowen Zhao <ztuowen@gmail.com> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexios Zavras <alexios.zavras@intel.com> Cc: Allison Randal <allison@lohutok.net> Cc: Will Deacon <will@kernel.org> Cc: Richard Fontana <rfontana@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* xchg/cmpxchg operations for the Hexagon architecture
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*
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
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*/
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#ifndef _ASM_CMPXCHG_H
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#define _ASM_CMPXCHG_H
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/*
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* __xchg - atomically exchange a register and a memory location
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* @x: value to swap
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* @ptr: pointer to memory
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* @size: size of the value
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*
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* Only 4 bytes supported currently.
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*
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* Note: there was an errata for V2 about .new's and memw_locked.
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*
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*/
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static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
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int size)
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{
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unsigned long retval;
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/* Can't seem to use printk or panic here, so just stop */
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if (size != 4) do { asm volatile("brkpt;\n"); } while (1);
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__asm__ __volatile__ (
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"1: %0 = memw_locked(%1);\n" /* load into retval */
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" memw_locked(%1,P0) = %2;\n" /* store into memory */
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" if (!P0) jump 1b;\n"
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: "=&r" (retval)
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: "r" (ptr), "r" (x)
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: "memory", "p0"
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);
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return retval;
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}
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/*
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* Atomically swap the contents of a register with memory. Should be atomic
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* between multiple CPU's and within interrupts on the same CPU.
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*/
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#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \
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sizeof(*(ptr))))
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/*
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* see rt-mutex-design.txt; cmpxchg supposedly checks if *ptr == A and swaps.
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* looks just like atomic_cmpxchg on our arch currently with a bunch of
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* variable casting.
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*/
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#define cmpxchg(ptr, old, new) \
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({ \
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__typeof__(ptr) __ptr = (ptr); \
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__typeof__(*(ptr)) __old = (old); \
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__typeof__(*(ptr)) __new = (new); \
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__typeof__(*(ptr)) __oldval = 0; \
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\
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asm volatile( \
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"1: %0 = memw_locked(%1);\n" \
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" { P0 = cmp.eq(%0,%2);\n" \
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" if (!P0.new) jump:nt 2f; }\n" \
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" memw_locked(%1,p0) = %3;\n" \
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" if (!P0) jump 1b;\n" \
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"2:\n" \
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: "=&r" (__oldval) \
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: "r" (__ptr), "r" (__old), "r" (__new) \
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: "memory", "p0" \
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); \
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__oldval; \
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})
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#endif /* _ASM_CMPXCHG_H */
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