lkml.org 
[lkml]   [2019]   [Jan]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 077/105] raid6/ppc: Fix build for clang
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Joel Stanley <joel@jms.id.au>

    commit e213574a449f7a57d4202c1869bbc7680b6b5521 upstream.

    We cannot build these files with clang as it does not allow altivec
    instructions in assembly when -msoft-float is passed.

    Jinsong Ji <jji@us.ibm.com> wrote:
    > We currently disable Altivec/VSX support when enabling soft-float. So
    > any usage of vector builtins will break.
    >
    > Enable Altivec/VSX with soft-float may need quite some clean up work, so
    > I guess this is currently a limitation.
    >
    > Removing -msoft-float will make it work (and we are lucky that no
    > floating point instructions will be generated as well).

    This is a workaround until the issue is resolved in clang.

    Link: https://bugs.llvm.org/show_bug.cgi?id=31177
    Link: https://github.com/ClangBuiltLinux/linux/issues/239
    Signed-off-by: Joel Stanley <joel@jms.id.au>
    Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    [nc: Use 'ifeq ($(cc-name),clang)' instead of 'ifdef CONFIG_CC_IS_CLANG'
    because that config does not exist in 4.14; the Kconfig rewrite
    that added that config happened in 4.18]
    Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    lib/raid6/Makefile | 15 +++++++++++++++
    1 file changed, 15 insertions(+)

    --- a/lib/raid6/Makefile
    +++ b/lib/raid6/Makefile
    @@ -18,6 +18,21 @@ quiet_cmd_unroll = UNROLL $@

    ifeq ($(CONFIG_ALTIVEC),y)
    altivec_flags := -maltivec $(call cc-option,-mabi=altivec)
    +
    +ifeq ($(cc-name),clang)
    +# clang ppc port does not yet support -maltivec when -msoft-float is
    +# enabled. A future release of clang will resolve this
    +# https://bugs.llvm.org/show_bug.cgi?id=31177
    +CFLAGS_REMOVE_altivec1.o += -msoft-float
    +CFLAGS_REMOVE_altivec2.o += -msoft-float
    +CFLAGS_REMOVE_altivec4.o += -msoft-float
    +CFLAGS_REMOVE_altivec8.o += -msoft-float
    +CFLAGS_REMOVE_altivec8.o += -msoft-float
    +CFLAGS_REMOVE_vpermxor1.o += -msoft-float
    +CFLAGS_REMOVE_vpermxor2.o += -msoft-float
    +CFLAGS_REMOVE_vpermxor4.o += -msoft-float
    +CFLAGS_REMOVE_vpermxor8.o += -msoft-float
    +endif
    endif

    # The GCC option -ffreestanding is required in order to compile code containing

    \
     
     \ /
      Last update: 2019-01-11 16:01    [W:7.943 / U:0.044 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site