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From:   Guenter Roeck <groeck@google.com>
Date:   Wed, 7 Feb 2018 18:04:43 -0800
Message-ID: <CABXOdTey_CktTkW=GD9W8GLJyJ=fbmLETLpVJzrywdmWBHDDbQ@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] amdgpu/dc/dml: Support clang option for stack alignment
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        David Zhou <David1.Zhou@amd.com>,
        David Airlie <airlied@linux.ie>,
        Harry Wentland <harry.wentland@amd.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>,
        amd-gfx list <amd-gfx@lists.freedesktop.org>,
        Maling list - DRI developers 
        <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Guenter Roeck <groeck@chromium.org>,
        Justin TerAvest <teravest@chromium.org>,
        Craig Bergstrom <craigb@chromium.org>
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On Wed, Feb 7, 2018 at 5:51 PM, Matthias Kaehlcke <mka@chromium.org> wrote:
> DML uses the compiler option -mpreferred-stack-boundary=4 to configure
> a stack alignment of 16 bytes. Clang uses the option -mstack-alignment
> instead, which expects as parameter the alignment in bytes, and not a
> power of two like -mpreferred-stack-boundary.
>
> Probe for both compiler options and use the correct one, similar to
> what is done in arch/x86/Makefile.
>
> Reported-by: Guenter Roeck <groeck@chromium.org>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>

Reviewed-by: Guenter Roeck <groeck@chromium.org>

Guenter

> ---
> Changes in v2:
> - use consistent syntax and formatting for assignment of cc_stack_align
>
>  drivers/gpu/drm/amd/display/dc/dml/Makefile | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> index b8cadf833e71..a92189eddab0 100644
> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> @@ -24,7 +24,13 @@
>  # It provides the general basic services required by other DAL
>  # subcomponents.
>
> -subdir-ccflags-y += -mhard-float -msse -mpreferred-stack-boundary=4
> +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
> +       cc_stack_align := -mpreferred-stack-boundary=4
> +else ifneq ($(call cc-option, -mstack-alignment=16),)
> +       cc_stack_align := -mstack-alignment=16
> +endif
> +
> +subdir-ccflags-y += -mhard-float -msse $(cc_stack_align)
>
>  DML = display_mode_lib.o display_rq_dlg_calc.o \
>           display_rq_dlg_helpers.o dml1_display_rq_dlg_calc.o \
> --
> 2.16.0.rc1.238.g530d649a79-goog
>