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dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729846AbeHMRbr (ORCPT ); Mon, 13 Aug 2018 13:31:47 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:37655 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728455AbeHMRbr (ORCPT ); Mon, 13 Aug 2018 13:31:47 -0400 Received: by mail-wm0-f65.google.com with SMTP id n11-v6so9101669wmc.2 for ; Mon, 13 Aug 2018 07:49:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=hJfC5STYzXEphqWEI1QvgCS87bgkTpkqu6GGN8Q+W0Q=; b=Dr44zRM9lMTB3NkxyidUDtzj03zm3s8TsChhiMmz7ZccUp6m8g5Y3vEbcNXgffFolM cWVbHJcFgrUfS03em9sgDX6BvJo5NHGhNCjomOlRmz7kDStri4I3DaWUatho0dCTTnjF 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AA+uWPx0v0zsskschu5zqcwXga0y0Dp/iSh/H41XOQ+CQdimmaAbfFuRMEIU1i9wqv8lPLsojcwP/VTwvJvcw6kubhM= X-Received: by 2002:a1c:4b0c:: with SMTP id y12-v6mr7704804wma.22.1534171750755; Mon, 13 Aug 2018 07:49:10 -0700 (PDT) MIME-Version: 1.0 References: <20180811155554.3382650-1-arnd@arndb.de> <593dd8e1-fa23-3216-3550-274401d88bcb@gmail.com> In-Reply-To: <593dd8e1-fa23-3216-3550-274401d88bcb@gmail.com> From: Alex Deucher Date: Mon, 13 Aug 2018 10:48:57 -0400 Message-ID: Subject: Re: [PATCH] [v3] drm: amd: dc: don't use FP math when Kcov is enabled To: Christian Koenig Cc: Arnd Bergmann , "Deucher, Alexander" , Chunming Zhou , "Wentland, Harry" , Dave Airlie , "Daenzer, Michel" , LKML , amd-gfx list , "S, Shirish" , Jerry Zuo , Maling list - DRI developers Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 12, 2018 at 3:55 AM Christian K=C3=B6nig wrote: > > Adding Harry as well. > > Am 11.08.2018 um 17:54 schrieb Arnd Bergmann: > > Building the DCN 1.0 Raven display driver with CONFIG_KCOV_INSTRUMENT_A= LL=3Dy > > and CONFIG_KCOV_ENABLE_COMPARISONS=3Dy results in warnings about many f= unctions > > that do a comparison of floating-point variables: > > > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_bw_c= alc_rq_dlg_ttu': > > dcn_calcs.c:(.text+0x263): undefined reference to `__sanitizer_cov_trac= e_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `hack_for= ce_pipe_split': > > dcn_calcs.c:(.text+0x155b): undefined reference to `__sanitizer_cov_tra= ce_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_find= _dcfclk_suits_all': > > dcn_calcs.c:(.text+0x190e): undefined reference to `__sanitizer_cov_tra= ce_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_vali= date_bandwidth': > > dcn_calcs.c:(.text+0xe121): undefined reference to `__sanitizer_cov_tra= ce_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_mod': > > dcn_calc_math.c:(.text+0x22): undefined reference to `__sanitizer_cov_t= race_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_min2': > > dcn_calc_math.c:(.text+0xb2): undefined reference to `__sanitizer_cov_t= race_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_ceil2': > > dcn_calc_math.c:(.text+0x2a0): undefined reference to `__sanitizer_cov_= trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_max3': > > dcn_calc_math.c:(.text+0x325): undefined reference to `__sanitizer_cov_= trace_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_max5': > > dcn_calc_math.c:(.text+0x3c3): undefined reference to `__sanitizer_cov_= trace_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_= bw_log': > > dcn_calc_math.c:(.text+0x54e): undefined reference to `__sanitizer_cov_= trace_cmpd' > > dcn_calc_math.c:(.text+0x57c): undefined reference to `__sanitizer_cov_= trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `scal= er_settings_calculation': > > dcn_calc_auto.c:(.text+0x5c5): undefined reference to `__sanitizer_cov_= trace_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode= _support_and_system_configuration': > > dcn_calc_auto.c:(.text+0x137c): undefined reference to `__sanitizer_cov= _trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode= _support_and_system_configuration': > > dcn_calc_auto.c:(.text+0x9233): undefined reference to `__sanitizer_cov= _trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode= _support_and_system_configuration': > > dcn_calc_auto.c:(.text+0xb70f): undefined reference to `__sanitizer_cov= _trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode= _support_and_system_configuration': > > dcn_calc_auto.c:(.text+0x121fd): undefined reference to `__sanitizer_co= v_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `disp= lay_pipe_configuration': > > dcn_calc_auto.c:(.text+0x15a2f): undefined reference to `__sanitizer_co= v_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `disp= clkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_c= alculation': > > dcn_calc_auto.c:(.text+0x17c2d): undefined reference to `__sanitizer_co= v_trace_cmpf' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `disp= clkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_c= alculation': > > dcn_calc_auto.c:(.text+0x19362): undefined reference to `__sanitizer_co= v_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `disp= clkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_c= alculation': > > dcn_calc_auto.c:(.text+0x25575): undefined reference to `__sanitizer_co= v_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `disp= clkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_c= alculation': > > dcn_calc_auto.c:(.text+0x27f33): undefined reference to `__sanitizer_co= v_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `= get_refcyc_per_delivery': > > display_rq_dlg_calc.c:(.text+0xb5): undefined reference to `__sanitizer= _cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `= calculate_ttu_cursor.isra.1': > > display_rq_dlg_calc.c:(.text+0x9f6): undefined reference to `__sanitize= r_cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `= dml_rq_dlg_get_dlg_params': > > display_rq_dlg_calc.c:(.text+0x82cc): undefined reference to `__sanitiz= er_cov_trace_cmpf' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `get_refcyc_per_delivery.isra.0': > > dml1_display_rq_dlg_calc.c:(.text+0x6c4): undefined reference to `__san= itizer_cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `get_vratio_pre.isra.2': > > dml1_display_rq_dlg_calc.c:(.text+0x957): undefined reference to `__san= itizer_cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `get_swath_need.isra.3': > > dml1_display_rq_dlg_calc.c:(.text+0xc8e): undefined reference to `__san= itizer_cov_trace_cmpf' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `dml1_extract_rq_regs': > > dml1_display_rq_dlg_calc.c:(.text+0x30a8): undefined reference to `__sa= nitizer_cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `dml1_rq_dlg_get_dlg_params': > > dml1_display_rq_dlg_calc.c:(.text+0x41ee): undefined reference to `__sa= nitizer_cov_trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In funct= ion `dml1_rq_dlg_get_dlg_params': > > dml1_display_rq_dlg_calc.c:(.text+0x8f95): undefined reference to `__sa= nitizer_cov_trace_cmpf' > > drivers/gpu/drm/amd/display/dc/dml/dml_common_defs.o: In function `dml_= round': > > dml_common_defs.c:(.text+0x77): undefined reference to `__sanitizer_cov= _trace_cmpd' > > drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.o: In function `adj= ust_ReturnBW': > > display_mode_vba.c:(.text+0x4490): undefined reference to `__sanitizer_= cov_trace_cmpd' > > > > We already prevent the driver from being built on non-x86 architectures > > because of its use of floating-point arithmetic, this extends the > > dependency to also cover Kcov-enabled builds, which arguably is a much > > more severe limitation. > > > > I tried implementing the two functions in KCOV: __sanitizer_cov_trace_c= mpd > > and __sanitizer_cov_trace_cmpf, but that fails to build on architecture= s > > that do not support any floating-point functions, or would require maki= ng > > that code x86 specific as well. I also looked at what it would take to > > convert the code to fixed-point arithmetic, but quickly gave up. This > > is probably the right approach, but it requires a non-trivial amount of > > work and certainly won't be appropriate as a bugfix. > > > > Fixes: bf2e2e2e0ea9 ("drm/amd/display: Limit DCN to x86 arch") > > Fixes: 4841203102a3 ("drm/amdgpu/display: Replace CONFIG_DRM_AMD_DC_DCN= 1_0 with CONFIG_X86") Maybe it would be better to revert 4841203102a3 so we can limit the scope of this to DCN support. Alex > > Link: drm: amd: dc: don't use FP math when Kcov is enabled > > Signed-off-by: Arnd Bergmann > > --- > > v3: rebase on top of 4841203102a3, which removed the option for > > CONFIG_DRM_AMD_DC_DCN1_0. The problem still gets hit occasionally > > in randconfig testing. > > --- > > drivers/gpu/drm/amd/display/Kconfig | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/= display/Kconfig > > index 325083b0297e..b132d434e572 100644 > > --- a/drivers/gpu/drm/amd/display/Kconfig > > +++ b/drivers/gpu/drm/amd/display/Kconfig > > @@ -3,6 +3,7 @@ menu "Display Engine Configuration" > > > > config DRM_AMD_DC > > bool "AMD DC - Enable new display engine" > > + depends on !X86 || !(KCOV_INSTRUMENT_ALL && KCOV_ENABLE_COMPARISO= NS) || BROKEN > > default y > > help > > Choose this option if you want to use the new display engine > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel