[uclibc-ng-devel] [PATCH 2/5] kvx: atomic: rework using compiler builtins

From: Yann Sionneau &lt;ysionneau(a)kalray.eu&gt; Signed-off-by: Yann Sionneau &lt;ysionneau(a)kalray.eu&gt; --- libc/sysdeps/linux/kvx/bits/atomic.h | 212 +++++++++++++++++---------- 1 file changed, 133 insertions(+), 79 deletions(-) diff --git a/libc/sysdeps/linux/kvx/bits/atomic.h b/libc/sysdeps/linux/kvx/bits/atomic.h index 3c423e9ba..cbab813fd 100644 --- a/libc/sysdeps/linux/kvx/bits/atomic.h +++ b/libc/sysdeps/linux/kvx/bits/atomic.h @@ -1,6 +1,7 @@ -/* Copyright (C) 2010-2012 Free Software Foundation, Inc. +/* Copyright (C) 2003-2017 Free Software Foundation, Inc. + Copyright (C) 2023 Kalray Inc. + This file is part of the GNU C Library. - Contributed by Maxim Kuvyrkov &lt;maxim(a)codesourcery.com&gt;om>, 2010. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public @@ -16,10 +17,15 @@ License along with the GNU C Library. If not, see <http://www.gnu.org/licenses/>. */ +/* Mostly copied from aarch64 atomic.h */ + #ifndef _KVX_BITS_ATOMIC_H #define _KVX_BITS_ATOMIC_H +#define typeof __typeof__ + #include <stdint.h> +#include <sysdep.h> typedef int8_t atomic8_t; typedef uint8_t uatomic8_t; @@ -60,82 +66,130 @@ typedef uintmax_t uatomic_max_t; # define atomic_write_barrier() __builtin_kvx_fence() #endif -/* - * On kvx, we have a boolean compare and swap which means that the operation - * returns only the success of operation. - * If operation succeeds, this is simple, we just need to return the provided - * old value. However, if it fails, we need to load the value to return it for - * the caller. If the loaded value is different from the "old" provided by the - * caller, we can return it since it will mean it failed. - * However, if for some reason the value we read is equal to the old value - * provided by the caller, we can't simply return it or the caller will think it - * succeeded. So if the value we read is the same as the "old" provided by - * the caller, we try again until either we succeed or we fail with a different - * value than the provided one. - */ -#define __cmpxchg(ptr, old, new, op_suffix, load_suffix) \ -({ \ - register unsigned long __rn __asm__("r62"); \ - register unsigned long __ro __asm__("r63"); \ - __asm__ __volatile__ ( \ - /* Fence to guarantee previous store to be committed */ \ - "fence\n" \ - /* Init "expect" with previous value */ \ - "copyd $r63 = %[rOld]\n" \ - ";;\n" \ - "1:\n" \ - /* Init "update" value with new */ \ - "copyd $r62 = %[rNew]\n" \ - ";;\n" \ - "acswap" #op_suffix " 0[%[rPtr]], $r62r63\n" \ - ";;\n" \ - /* if acswap succeeds, simply return */ \ - "cb.dnez $r62? 2f\n" \ - ";;\n" \ - /* We failed, load old value */ \ - "l" #op_suffix #load_suffix" $r63 = 0[%[rPtr]]\n" \ - ";;\n" \ - /* Check if equal to "old" one */ \ - "compd.ne $r62 = $r63, %[rOld]\n" \ - ";;\n" \ - /* If different from "old", return it to caller */ \ - "cb.deqz $r62? 1b\n" \ - ";;\n" \ - "2:\n" \ - : "+r" (__rn), "+r" (__ro) \ - : [rPtr] "r" (ptr), [rOld] "r" (old), [rNew] "r" (new) \ - : "memory"); \ - (__ro); \ -}) - -#define cmpxchg(ptr, o, n) \ -({ \ - unsigned long __cmpxchg__ret; \ - switch (sizeof(*(ptr))) { \ - case 4: \ - __cmpxchg__ret = __cmpxchg((ptr), (o), (n), w, s); \ - break; \ - case 8: \ - __cmpxchg__ret = __cmpxchg((ptr), (o), (n), d, ); \ - break; \ - } \ - (__typeof(*(ptr))) (__cmpxchg__ret); \ -}) - -#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \ - cmpxchg((mem), (oldval), (newval)) - - -#define atomic_exchange_acq(mem, newval) \ -({ \ - unsigned long __aea__ret, __aea__old; \ - volatile __typeof((mem)) __aea__m = (mem); \ - do { \ - __aea__old = *__aea__m; \ - __aea__ret = atomic_compare_and_exchange_val_acq((mem), \ - (newval), (__aea__old));\ - } while (__aea__old != __aea__ret); \ - (__aea__old); \ -}) +#define __HAVE_64B_ATOMICS 1 +#define USE_ATOMIC_COMPILER_BUILTINS 1 + +/* Compare and exchange. + For all "bool" routines, we return FALSE if exchange succesful. */ + +# define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + }) + +# define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + }) + +# define __arch_compare_and_exchange_bool_32_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + }) + +# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + !__atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + }) + +# define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + __oldval; \ + }) + +# define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + __oldval; \ + }) + +# define __arch_compare_and_exchange_val_32_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + __oldval; \ + }) + +# define __arch_compare_and_exchange_val_64_int(mem, newval, oldval, model) \ + ({ \ + typeof (*mem) __oldval = (oldval); \ + __atomic_compare_exchange_n (mem, (void *) &__oldval, newval, 0, \ + model, __ATOMIC_RELAXED); \ + __oldval; \ + }) + + +/* Compare and exchange with "acquire" semantics, ie barrier after. */ + +# define atomic_compare_and_exchange_bool_acq(mem, new, old) \ + __atomic_bool_bysize (__arch_compare_and_exchange_bool, int, \ + mem, new, old, __ATOMIC_ACQUIRE) + +# define atomic_compare_and_exchange_val_acq(mem, new, old) \ + __atomic_val_bysize (__arch_compare_and_exchange_val, int, \ + mem, new, old, __ATOMIC_ACQUIRE) + +/* Compare and exchange with "release" semantics, ie barrier before. */ + +# define atomic_compare_and_exchange_val_rel(mem, new, old) \ + __atomic_val_bysize (__arch_compare_and_exchange_val, int, \ + mem, new, old, __ATOMIC_RELEASE) + + +/* Atomic exchange (without compare). */ + +# define __arch_exchange_8_int(mem, newval, model) \ + __atomic_exchange_n (mem, newval, model) + +# define __arch_exchange_16_int(mem, newval, model) \ + __atomic_exchange_n (mem, newval, model) + +# define __arch_exchange_32_int(mem, newval, model) \ + __atomic_exchange_n (mem, newval, model) + +# define __arch_exchange_64_int(mem, newval, model) \ + __atomic_exchange_n (mem, newval, model) + +# define atomic_exchange_acq(mem, value) \ + __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_ACQUIRE) + +# define atomic_exchange_rel(mem, value) \ + __atomic_val_bysize (__arch_exchange, int, mem, value, __ATOMIC_RELEASE) + + +/* Atomically add value and return the previous (unincremented) value. */ + +# define __arch_exchange_and_add_8_int(mem, value, model) \ + __atomic_fetch_add (mem, value, model) + +# define __arch_exchange_and_add_16_int(mem, value, model) \ + __atomic_fetch_add (mem, value, model) + +# define __arch_exchange_and_add_32_int(mem, value, model) \ + __atomic_fetch_add (mem, value, model) + +# define __arch_exchange_and_add_64_int(mem, value, model) \ + __atomic_fetch_add (mem, value, model) + +# define atomic_exchange_and_add_acq(mem, value) \ + __atomic_val_bysize (__arch_exchange_and_add, int, mem, value, \ + __ATOMIC_ACQUIRE) + +# define atomic_exchange_and_add_rel(mem, value) \ + __atomic_val_bysize (__arch_exchange_and_add, int, mem, value, \ #endif -- 2.42.0