Re: [PATCH] MIPS: VDSO: Fix binutils version test

[James Hogan <james.hogan@imgtec.com>]

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Hi Tony,

On Tue, Jan 05, 2016 at 03:21:01PM +0800, Tony Wu wrote:
> Commit 2a037f310bab ("MIPS: VDSO: Fix build error") fixed the logic
> for testing binutils version, but introduced another issue.
> 
> The ld-ifversion macro is defined as follows:
> 
>   $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
> 
> This macro checks ld version to echo $(3) or echo $(4) based on
> the given condition.
> 
> It is called as follows in arch/mips/vdso/Makefile:
> 
>   ifeq ($(call ld-ifversion, -lt, 22500000, y),)
>     $(warning MIPS VDSO requires binutils >= 2.25)
>     obj-vdso-y := $(filter-out gettimeofday.o, $(obj-vdso-y))
>     ccflags-vdso += -DDISABLE_MIPS_VDSO
>   endif
> 
> Since $(4) is empty, echo $(4) will evaluate to a simple 'echo'. So, in
> case binutils version is indeed greater than 2.25.0, ld-ifversion macro
> will return a newline, not the empty string as expected, and that makes
> the test fail.
> 
> This patch fixes the test condition.

See:
- http://patchwork.linux-mips.org/patch/11926/
  (now merged into mainline)
- http://patchwork.linux-mips.org/patch/11931/
  (in mips-for-linux-next / linux-next for v4.4)

Thanks
James
  
> 
> Signed-off-by: Tony Wu <tung7970@gmail.com>
> Cc: Qais Yousef <qais.yousef@imgtec.com>
> Cc: Alex Smith <alex@alex-smith.me.uk>
> 
> diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
> index 018f8c7..a54a082 100644
> --- a/arch/mips/vdso/Makefile
> +++ b/arch/mips/vdso/Makefile
> @@ -26,7 +26,7 @@ aflags-vdso := $(ccflags-vdso) \
>  # the comments on that file.
>  #
>  ifndef CONFIG_CPU_MIPSR6
> -  ifeq ($(call ld-ifversion, -lt, 22500000, y),)
> +  ifneq ($(call ld-ifversion,-ge,22500000,y),y)
>      $(warning MIPS VDSO requires binutils >= 2.25)
>      obj-vdso-y := $(filter-out gettimeofday.o, $(obj-vdso-y))
>      ccflags-vdso += -DDISABLE_MIPS_VDSO
> 

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