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References: <20240528115146.2870032-1-arnd@kernel.org>
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From: Alex Deucher <alexdeucher@gmail.com>
Date: Wed, 29 May 2024 10:46:27 -0400
Message-ID: <CADnq5_OtL0D+mE8bsoWmPz0e7USC=UrpFjcZZ2LTeaHePToBxQ@mail.gmail.com>
Subject: Re: [PATCH 1/4] [RESEND] drm/amd/display: dynamically allocate
 dml2_configuration_options structures
To: Arnd Bergmann <arnd@kernel.org>
Cc: Harry Wentland <harry.wentland@amd.com>, Leo Li <sunpeng.li@amd.com>, 
	Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>, Arnd Bergmann <arnd@arndb.de>, 
	Alex Deucher <alexander.deucher@amd.com>, =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>, 
	"Pan, Xinhui" <Xinhui.Pan@amd.com>, David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, 
	Wenjing Liu <wenjing.liu@amd.com>, Alvin Lee <alvin.lee2@amd.com>, Jun Lei <jun.lei@amd.com>, 
	Hamza Mahfooz <hamza.mahfooz@amd.com>, Aurabindo Pillai <aurabindo.pillai@amd.com>, 
	Dillon Varone <dillon.varone@amd.com>, Qingqing Zhuo <Qingqing.Zhuo@amd.com>, 
	Roman Li <roman.li@amd.com>, Aric Cyr <aric.cyr@amd.com>, 
	Joshua Aberback <joshua.aberback@amd.com>, amd-gfx@lists.freedesktop.org, 
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
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Applied the series.  Thanks!

Alex

On Tue, May 28, 2024 at 7:52=E2=80=AFAM Arnd Bergmann <arnd@kernel.org> wro=
te:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> This structure is too large to fit on a stack, as shown by the
> newly introduced warnings from a recent code change:
>
> drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn32/dcn32_resource.c:=
 In function 'dcn32_update_bw_bounding_box':
> drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn32/dcn32_resource.c:=
2019:1: error: the frame size of 1180 bytes is larger than 1024 bytes [-Wer=
ror=3Dframe-larger-than=3D]
> drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn321/dcn321_resource.=
c: In function 'dcn321_update_bw_bounding_box':
> drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn321/dcn321_resource.=
c:1597:1: error: the frame size of 1180 bytes is larger than 1024 bytes [-W=
error=3Dframe-larger-than=3D]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c: In function 'dc=
_state_create':
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c:219:1: error: th=
e frame size of 1184 bytes is larger than 1024 bytes [-Werror=3Dframe-large=
r-than=3D]
>
> Instead of open-coding the assignment of a large structure to a stack
> variable, use an explicit kmemdup() in each case to move it off the stack=
.
>
> Fixes: e779f4587f61 ("drm/amd/display: Add handling for DC power mode")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> Originally sent as https://lore.kernel.org/all/20240418083421.3956461-1-a=
rnd@kernel.org/
> ---
>  .../display/dc/resource/dcn32/dcn32_resource.c   | 16 +++++++++++-----
>  .../display/dc/resource/dcn321/dcn321_resource.c | 16 +++++++++++-----
>  2 files changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource=
c b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c
> index 022d320be1d5..0f11d7c8791c 100644
> --- a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c
> +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource.c
> @@ -2007,21 +2007,27 @@ void dcn32_calculate_wm_and_dlg(struct dc *dc, st=
ruct dc_state *context,
>
>  static void dcn32_update_bw_bounding_box(struct dc *dc, struct clk_bw_pa=
rams *bw_params)
>  {
> -       struct dml2_configuration_options dml2_opt =3D dc->dml2_options;
> +       struct dml2_configuration_options *dml2_opt;
> +
> +       dml2_opt =3D kmemdup(&dc->dml2_options, sizeof(dc->dml2_options),=
 GFP_KERNEL);
> +       if (!dml2_opt)
> +               return;
>
>         DC_FP_START();
>
>         dcn32_update_bw_bounding_box_fpu(dc, bw_params);
>
> -       dml2_opt.use_clock_dc_limits =3D false;
> +       dml2_opt->use_clock_dc_limits =3D false;
>         if (dc->debug.using_dml2 && dc->current_state && dc->current_stat=
e->bw_ctx.dml2)
> -               dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml=
2);
> +               dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2=
);
>
> -       dml2_opt.use_clock_dc_limits =3D true;
> +       dml2_opt->use_clock_dc_limits =3D true;
>         if (dc->debug.using_dml2 && dc->current_state && dc->current_stat=
e->bw_ctx.dml2_dc_power_source)
> -               dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml=
2_dc_power_source);
> +               dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2=
_dc_power_source);
>
>         DC_FP_END();
> +
> +       kfree(dml2_opt);
>  }
>
>  static struct resource_funcs dcn32_res_pool_funcs =3D {
> diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resour=
ce.c b/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c
> index e4b360d89b3b..07ca6f58447d 100644
> --- a/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c
> +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn321/dcn321_resource.c
> @@ -1581,21 +1581,27 @@ static struct dc_cap_funcs cap_funcs =3D {
>
>  static void dcn321_update_bw_bounding_box(struct dc *dc, struct clk_bw_p=
arams *bw_params)
>  {
> -       struct dml2_configuration_options dml2_opt =3D dc->dml2_options;
> +       struct dml2_configuration_options *dml2_opt;
> +
> +       dml2_opt =3D kmemdup(&dc->dml2_options, sizeof(dc->dml2_options),=
 GFP_KERNEL);
> +       if (!dml2_opt)
> +               return;
>
>         DC_FP_START();
>
>         dcn321_update_bw_bounding_box_fpu(dc, bw_params);
>
> -       dml2_opt.use_clock_dc_limits =3D false;
> +       dml2_opt->use_clock_dc_limits =3D false;
>         if (dc->debug.using_dml2 && dc->current_state && dc->current_stat=
e->bw_ctx.dml2)
> -               dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml=
2);
> +               dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2=
);
>
> -       dml2_opt.use_clock_dc_limits =3D true;
> +       dml2_opt->use_clock_dc_limits =3D true;
>         if (dc->debug.using_dml2 && dc->current_state && dc->current_stat=
e->bw_ctx.dml2_dc_power_source)
> -               dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml=
2_dc_power_source);
> +               dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2=
_dc_power_source);
>
>         DC_FP_END();
> +
> +       kfree(dml2_opt);
>  }
>
>  static struct resource_funcs dcn321_res_pool_funcs =3D {
> --
> 2.39.2
>