Merge pull request #52 from jgunthorpe/arch-fix

Support compiling on architectures without cache coherent DMA

Author: dledford

CMakeLists.txt

@@ -203,6 +203,10 @@ CHECK_C_SOURCE_COMPILES("
   HAVE_FUNC_ATTRIBUTE_ALWAYS_INLINE
   FAIL_REGEX "warning")
 
+# Provide a shim if C11 stdatomic.h is not supported.
+CHECK_INCLUDE_FILE("stdatomic.h" HAVE_STDATOMIC)
+RDMA_DoFixup("${HAVE_STDATOMIC}" "stdatomic.h")
+
 # Enable development support features
 # Prune unneeded shared libraries during linking
 RDMA_AddOptLDFlag(CMAKE_EXE_LINKER_FLAGS SUPPORTS_AS_NEEDED "-Wl,--as-needed")
@@ -278,6 +282,14 @@ check_type_size("long" SIZEOF_LONG BUILTIN_TYPES_ONLY LANGUAGE C)
 
 include(RDMA_LinuxHeaders)
 
+# Determine if this arch supports cache coherent DMA. This isn't really an
+# arch specific property, but for our purposes arches that do not support it
+# also do not define wmb/etc which breaks our compile.
+CHECK_C_SOURCE_COMPILES("
+#include \"${CMAKE_CURRENT_SOURCE_DIR}/libibverbs/arch.h\"
+ int main(int argc,const char *argv[]) {return 0;}"
+  HAVE_COHERENT_DMA)
+
 #-------------------------
 # Apply fixups
 
@@ -358,18 +370,21 @@ add_subdirectory(librdmacm/man)
 add_subdirectory(libibcm)
 
 # Providers
+if (HAVE_COHERENT_DMA)
 add_subdirectory(providers/cxgb3)
 add_subdirectory(providers/cxgb4)
-add_subdirectory(providers/hfi1verbs)
 add_subdirectory(providers/hns)
 add_subdirectory(providers/i40iw)
-add_subdirectory(providers/ipathverbs)
 add_subdirectory(providers/mlx4)
 add_subdirectory(providers/mlx5)
 add_subdirectory(providers/mthca)
 add_subdirectory(providers/nes)
 add_subdirectory(providers/ocrdma)
 add_subdirectory(providers/qedr)
+endif()
+
+add_subdirectory(providers/hfi1verbs)
+add_subdirectory(providers/ipathverbs)
 add_subdirectory(providers/rxe)
 add_subdirectory(providers/rxe/man)
 
@@ -396,6 +411,12 @@ message(STATUS "Missing Optional Items:")
 if (NOT HAVE_FUNC_ATTRIBUTE_ALWAYS_INLINE)
   message(STATUS " Compiler attribute always_inline NOT supported")
 endif()
+if (NOT HAVE_COHERENT_DMA)
+  message(STATUS " Architecture NOT able to do coherent DMA (check libibverbs/arch.h) some providers disabled!")
+endif()
+if (NOT HAVE_STDATOMIC)
+  message(STATUS " C11 stdatomic.h NOT available (old compiler)")
+endif()
 if (NOT HAVE_VALGRIND_MEMCHECK)
   message(STATUS " Valgrind memcheck.h NOT enabled")
 endif()

buildlib/RDMA_EnableCStd.cmake

@@ -33,16 +33,17 @@ function(RDMA_AddOptCFlag TO_VAR CACHE_VAR FLAG)
   endif()
 endfunction()
 
-# Enable the minimum required gnu99 standard in the compiler.
+# Enable the minimum required gnu11 standard in the compiler
+# This was introduced in GCC 4.7
 function(RDMA_EnableCStd)
   if (CMAKE_VERSION VERSION_LESS "3.1")
     # Check for support of the usual flag
-    CHECK_C_COMPILER_FLAG("-std=gnu99" SUPPORTS_GNU99)
-    if (SUPPORTS_GNU99)
-      SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99" PARENT_SCOPE)
+    CHECK_C_COMPILER_FLAG("-std=gnu11" SUPPORTS_GNU11)
+    if (SUPPORTS_GNU11)
+      SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11" PARENT_SCOPE)
     endif()
   else()
     # Newer cmake can do this internally
-    set(CMAKE_C_STANDARD 99 PARENT_SCOPE)
+    set(CMAKE_C_STANDARD 11 PARENT_SCOPE)
   endif()
 endfunction()