Re: [dpdk-dev] [PATCH] Pass CC option when building kernel modules

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Oct 06, 2014 at 04:57:02PM +0100, Sergio Gonzalez Monroy wrote:
> At least on kernels 3.15 or newer, DPDK build is broken for CLANG target.
> The issue is that the kernel build system sets the flags before including
> DPDK makefile and therefore assumes the incorrect compiler.
> 
> Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

I can confirm that this patch fixes the clang compile for me on Fedora 20 
with kernel 3.16.3-200.fc20.x86_64.

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

> ---
>  mk/rte.module.mk               | 2 +-
>  mk/target/generic/rte.vars.mk  | 2 ++
>  mk/toolchain/clang/rte.vars.mk | 5 +----
>  mk/toolchain/gcc/rte.vars.mk   | 1 +
>  mk/toolchain/icc/rte.vars.mk   | 5 +----
>  5 files changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/mk/rte.module.mk b/mk/rte.module.mk
> index c4ca3fd..41c0d0f 100644
> --- a/mk/rte.module.mk
> +++ b/mk/rte.module.mk
> @@ -78,7 +78,7 @@ build: _postbuild
>  $(MODULE).ko: $(SRCS_LINKS)
>  	@if [ ! -f $(notdir Makefile) ]; then ln -nfs $(SRCDIR)/Makefile . ; fi
>  	@$(MAKE) -C $(RTE_KERNELDIR) M=$(CURDIR) O=$(RTE_KERNELDIR) \
> -		CROSS_COMPILE=$(CROSS)
> +		CC=$(KERNELCC) CROSS_COMPILE=$(CROSS)
>  
>  # install module in $(RTE_OUTPUT)/kmod
>  $(RTE_OUTPUT)/kmod/$(MODULE).ko: $(MODULE).ko
> diff --git a/mk/target/generic/rte.vars.mk b/mk/target/generic/rte.vars.mk
> index 6020f20..74ff771 100644
> --- a/mk/target/generic/rte.vars.mk
> +++ b/mk/target/generic/rte.vars.mk
> @@ -149,4 +149,6 @@ endif
>  export CFLAGS
>  export LDFLAGS
>  
> +else # ! ifeq ($(KERNELRELEASE),)
> +CC = $(KERNELCC)
>  endif
> diff --git a/mk/toolchain/clang/rte.vars.mk b/mk/toolchain/clang/rte.vars.mk
> index ee4f451..40cb389 100644
> --- a/mk/toolchain/clang/rte.vars.mk
> +++ b/mk/toolchain/clang/rte.vars.mk
> @@ -38,11 +38,8 @@
>  #   - define TOOLCHAIN_ASFLAGS variable (overriden by cmdline value)
>  #
>  
> -ifeq ($(KERNELRELEASE),)
>  CC        = $(CROSS)clang
> -else
> -CC        = $(CROSS)gcc
> -endif
> +KERNELCC  = $(CROSS)gcc
>  CPP       = $(CROSS)cpp
>  # for now, we don't use as but nasm.
>  # AS      = $(CROSS)as
> diff --git a/mk/toolchain/gcc/rte.vars.mk b/mk/toolchain/gcc/rte.vars.mk
> index 262ebdf..993eb26 100644
> --- a/mk/toolchain/gcc/rte.vars.mk
> +++ b/mk/toolchain/gcc/rte.vars.mk
> @@ -39,6 +39,7 @@
>  #
>  
>  CC        = $(CROSS)gcc
> +KERNELCC  = $(CROSS)gcc
>  CPP       = $(CROSS)cpp
>  # for now, we don't use as but nasm.
>  # AS      = $(CROSS)as
> diff --git a/mk/toolchain/icc/rte.vars.mk b/mk/toolchain/icc/rte.vars.mk
> index 612370d..f03a2a2 100644
> --- a/mk/toolchain/icc/rte.vars.mk
> +++ b/mk/toolchain/icc/rte.vars.mk
> @@ -41,11 +41,8 @@
>  # Warning: we do not use CROSS environment variable as icc is mainly a
>  # x86->x86 compiler
>  
> -ifeq ($(KERNELRELEASE),)
>  CC        = icc
> -else
> -CC        = gcc
> -endif
> +KERNELCC  = gcc
>  CPP       = cpp
>  AS        = nasm
>  AR        = ar
> -- 
> 1.9.3
>