diff --git a/openmp/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt b/openmp/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt --- a/openmp/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt +++ b/openmp/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt @@ -56,6 +56,7 @@ set(cuda_sources ${CMAKE_CURRENT_SOURCE_DIR}/src/amdgcn_smid.hip + ${CMAKE_CURRENT_SOURCE_DIR}/src/amdgcn_locks.hip ${CMAKE_CURRENT_SOURCE_DIR}/src/target_impl.hip ${devicertl_base_directory}/common/src/cancel.cu ${devicertl_base_directory}/common/src/critical.cu diff --git a/openmp/libomptarget/deviceRTLs/amdgcn/src/amdgcn_locks.hip b/openmp/libomptarget/deviceRTLs/amdgcn/src/amdgcn_locks.hip new file mode 100644 --- /dev/null +++ b/openmp/libomptarget/deviceRTLs/amdgcn/src/amdgcn_locks.hip @@ -0,0 +1,51 @@ +//===-- amdgcn_locks.hip - AMDGCN OpenMP GPU lock implementation -- HIP -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// Definitions of openmp lock functions +// A 'thread' maps onto a lane of the wavefront. This means a per-thread lock +// cannot be implemented - if one thread gets the lock, it can't continue on to +// the next instruction in order to do anything as the other threads are waiting +// to take the lock +// The closest approximatation we can implement is to lock per-wavefront. +// +//===----------------------------------------------------------------------===// + +#include "common/support.h" +#include "common/target_atomic.h" +#include "target_impl.h" + +#define UNSET 0u +#define SET 1u + +DEVICE void __kmpc_impl_init_lock(omp_lock_t *lock) { + __kmpc_impl_unset_lock(lock); +} + +DEVICE void __kmpc_impl_destroy_lock(omp_lock_t *lock) { + __kmpc_impl_unset_lock(lock); +} + +DEVICE void __kmpc_impl_set_lock(omp_lock_t *lock) { + uint64_t lowestActiveThread = __kmpc_impl_ffs(__kmpc_impl_activemask()) - 1; + if (GetLaneId() == lowestActiveThread) { + while (__kmpc_atomic_cas(lock, UNSET, SET) != UNSET) { + __builtin_amdgcn_s_sleep(0); + } + } + // test_lock will now return true for any thread in the wavefront +} + +DEVICE void __kmpc_impl_unset_lock(omp_lock_t *lock) { + // Could be an atomic store of UNSET + (void)__kmpc_atomic_exchange(lock, UNSET); +} + +DEVICE int __kmpc_impl_test_lock(omp_lock_t *lock) { + // Could be an atomic load + return __kmpc_atomic_add(lock, 0u); +}