From: Adhemerval Zanella Date: Thu, 11 Sep 2025 13:49:35 +0000 (-0300) Subject: arm: Consolidate atomic-machine.h and Remove ununsed atomic macros X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=5a7a9a57c2fb329ee90a1c8701a62af4848499d3;p=thirdparty%2Fglibc.git arm: Consolidate atomic-machine.h and Remove ununsed atomic macros The libgcc provides the required support to calling the kernel auxiliary routines for !__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4. Reviewed-by: Wilco Dijkstra --- diff --git a/sysdeps/arm/atomic-machine.h b/sysdeps/arm/atomic-machine.h index 39cdef1715..1ba328c546 100644 --- a/sysdeps/arm/atomic-machine.h +++ b/sysdeps/arm/atomic-machine.h @@ -17,122 +17,6 @@ . */ #define __HAVE_64B_ATOMICS 0 -#define USE_ATOMIC_COMPILER_BUILTINS 1 #define ATOMIC_EXCHANGE_USES_CAS 1 -void __arm_link_error (void); - -#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 -# define atomic_full_barrier() __sync_synchronize () -#else -# define atomic_full_barrier() __arm_assisted_full_barrier () -#endif - -/* An OS-specific atomic-machine.h file will define this macro if - the OS can provide something. If not, we'll fail to build - with a compiler that doesn't supply the operation. */ -#ifndef __arm_assisted_full_barrier -# define __arm_assisted_full_barrier() __arm_link_error() -#endif - -/* Use the atomic builtins provided by GCC in case the backend provides - a pattern to do this efficiently. */ -#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 - -# 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) - -/* Atomic exchange (without compare). */ - -# define __arch_exchange_8_int(mem, newval, model) \ - (__arm_link_error (), (typeof (*mem)) 0) - -# define __arch_exchange_16_int(mem, newval, model) \ - (__arm_link_error (), (typeof (*mem)) 0) - -# define __arch_exchange_32_int(mem, newval, model) \ - __atomic_exchange_n (mem, newval, model) - -# define __arch_exchange_64_int(mem, newval, model) \ - (__arm_link_error (), (typeof (*mem)) 0) - -/* 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) - -/* Compare and exchange. - For all "bool" routines, we return FALSE if exchange successful. */ - -# define __arch_compare_and_exchange_bool_8_int(mem, newval, oldval, model) \ - ({__arm_link_error (); 0; }) - -# define __arch_compare_and_exchange_bool_16_int(mem, newval, oldval, model) \ - ({__arm_link_error (); 0; }) - -# 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) \ - ({__arm_link_error (); 0; }) - -# define __arch_compare_and_exchange_val_8_int(mem, newval, oldval, model) \ - ({__arm_link_error (); oldval; }) - -# define __arch_compare_and_exchange_val_16_int(mem, newval, oldval, model) \ - ({__arm_link_error (); 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) \ - ({__arm_link_error (); oldval; }) - -#else -# define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \ - __arm_assisted_compare_and_exchange_val_32_acq ((mem), (newval), (oldval)) -#endif - -#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 -/* We don't support atomic operations on any non-word types. - So make them link errors. */ -# define __arch_compare_and_exchange_val_8_acq(mem, newval, oldval) \ - ({ __arm_link_error (); oldval; }) - -# define __arch_compare_and_exchange_val_16_acq(mem, newval, oldval) \ - ({ __arm_link_error (); oldval; }) - -# define __arch_compare_and_exchange_val_64_acq(mem, newval, oldval) \ - ({ __arm_link_error (); oldval; }) -#endif - -/* An OS-specific atomic-machine.h file will define this macro if - the OS can provide something. If not, we'll fail to build - with a compiler that doesn't supply the operation. */ -#ifndef __arm_assisted_compare_and_exchange_val_32_acq -# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \ - ({ __arm_link_error (); oldval; }) -#endif +#define atomic_full_barrier() __sync_synchronize () diff --git a/sysdeps/unix/sysv/linux/arm/atomic-machine.h b/sysdeps/unix/sysv/linux/arm/atomic-machine.h deleted file mode 100644 index 1734bcd98d..0000000000 --- a/sysdeps/unix/sysv/linux/arm/atomic-machine.h +++ /dev/null @@ -1,115 +0,0 @@ -/* Atomic operations. ARM/Linux version. - Copyright (C) 2002-2025 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library 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 - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library. If not, see - . */ - -#include - -/* If the compiler doesn't provide a primitive, we'll use this macro - to get assistance from the kernel. */ -#ifdef __thumb2__ -# define __arm_assisted_full_barrier() \ - __asm__ __volatile__ \ - ("movw\tip, #0x0fa0\n\t" \ - "movt\tip, #0xffff\n\t" \ - "blx\tip" \ - : : : "ip", "lr", "cc", "memory"); -#else -# define __arm_assisted_full_barrier() \ - __asm__ __volatile__ \ - ("mov\tip, #0xffff0fff\n\t" \ - "mov\tlr, pc\n\t" \ - "add\tpc, ip, #(0xffff0fa0 - 0xffff0fff)" \ - : : : "ip", "lr", "cc", "memory"); -#endif - -/* Atomic compare and exchange. This sequence relies on the kernel to - provide a compare and exchange operation which is atomic on the - current architecture, either via cleverness on pre-ARMv6 or via - ldrex / strex on ARMv6. - - It doesn't matter what register is used for a_oldval2, but we must - specify one to work around GCC PR rtl-optimization/21223. Otherwise - it may cause a_oldval or a_tmp to be moved to a different register. - - We use the union trick rather than simply using __typeof (...) in the - declarations of A_OLDVAL et al because when NEWVAL or OLDVAL is of the - form *PTR and PTR has a 'volatile ... *' type, then __typeof (*PTR) has - a 'volatile ...' type and this triggers -Wvolatile-register-var to - complain about 'register volatile ... asm ("reg")'. - - We use the same union trick in the declaration of A_PTR because when - MEM is of the from *PTR and PTR has a 'const ... *' type, then __typeof - (*PTR) has a 'const ...' type and this enables the compiler to substitute - the variable with its initializer in asm statements, which may cause the - corresponding operand to appear in a different register. */ -#ifdef __thumb2__ -/* Thumb-2 has ldrex/strex. However it does not have barrier instructions, - so we still need to use the kernel helper. */ -# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \ - ({ union { __typeof (mem) a; uint32_t v; } mem_arg = { .a = (mem) }; \ - union { __typeof (oldval) a; uint32_t v; } oldval_arg = { .a = (oldval) };\ - union { __typeof (newval) a; uint32_t v; } newval_arg = { .a = (newval) };\ - register uint32_t a_oldval asm ("r0"); \ - register uint32_t a_newval asm ("r1") = newval_arg.v; \ - register uint32_t a_ptr asm ("r2") = mem_arg.v; \ - register uint32_t a_tmp asm ("r3"); \ - register uint32_t a_oldval2 asm ("r4") = oldval_arg.v; \ - __asm__ __volatile__ \ - ("0:\tldr\t%[tmp],[%[ptr]]\n\t" \ - "cmp\t%[tmp], %[old2]\n\t" \ - "bne\t1f\n\t" \ - "mov\t%[old], %[old2]\n\t" \ - "movw\t%[tmp], #0x0fc0\n\t" \ - "movt\t%[tmp], #0xffff\n\t" \ - "blx\t%[tmp]\n\t" \ - "bcc\t0b\n\t" \ - "mov\t%[tmp], %[old2]\n\t" \ - "1:" \ - : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \ - : [new] "r" (a_newval), [ptr] "r" (a_ptr), \ - [old2] "r" (a_oldval2) \ - : "ip", "lr", "cc", "memory"); \ - (__typeof (oldval)) a_tmp; }) -#else -# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \ - ({ union { __typeof (mem) a; uint32_t v; } mem_arg = { .a = (mem) }; \ - union { __typeof (oldval) a; uint32_t v; } oldval_arg = { .a = (oldval) };\ - union { __typeof (newval) a; uint32_t v; } newval_arg = { .a = (newval) };\ - register uint32_t a_oldval asm ("r0"); \ - register uint32_t a_newval asm ("r1") = newval_arg.v; \ - register uint32_t a_ptr asm ("r2") = mem_arg.v; \ - register uint32_t a_tmp asm ("r3"); \ - register uint32_t a_oldval2 asm ("r4") = oldval_arg.v; \ - __asm__ __volatile__ \ - ("0:\tldr\t%[tmp],[%[ptr]]\n\t" \ - "cmp\t%[tmp], %[old2]\n\t" \ - "bne\t1f\n\t" \ - "mov\t%[old], %[old2]\n\t" \ - "mov\t%[tmp], #0xffff0fff\n\t" \ - "mov\tlr, pc\n\t" \ - "add\tpc, %[tmp], #(0xffff0fc0 - 0xffff0fff)\n\t" \ - "bcc\t0b\n\t" \ - "mov\t%[tmp], %[old2]\n\t" \ - "1:" \ - : [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \ - : [new] "r" (a_newval), [ptr] "r" (a_ptr), \ - [old2] "r" (a_oldval2) \ - : "ip", "lr", "cc", "memory"); \ - (__typeof (oldval)) a_tmp; }) -#endif - -#include