Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Daniel Kolesa <daniel@octaforge.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.5 050/176] amdgpu: Prevent build errors regarding soft/hard-float FP ABI tags
Date:   Tue,  3 Mar 2020 18:41:54 +0100
Message-Id: <20200303174310.330447064@linuxfoundation.org>
In-Reply-To: <20200303174304.593872177@linuxfoundation.org>
References: <20200303174304.593872177@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Daniel Kolesa <daniel@octaforge.org>

[ Upstream commit 416611d9b6eebaeae58ed26cc7d23131c69126b1 ]

On PowerPC, the compiler will tag object files with whether they
use hard or soft float FP ABI and whether they use 64 or 128-bit
long double ABI. On systems with 64-bit long double ABI, a tag
will get emitted whenever a double is used, as on those systems
a long double is the same as a double. This will prevent linkage
as other files are being compiled with hard-float.

On ppc64, this code will never actually get used for the time
being, as the only currently existing hardware using it are the
Renoir APUs. Therefore, until this is testable and can be fixed
properly, at least make sure the build will not fail.

Signed-off-by: Daniel Kolesa <daniel@octaforge.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile b/drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile
index b864869cc7e3e..6fa7422c51da5 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/Makefile
@@ -91,6 +91,12 @@ ifdef CONFIG_DRM_AMD_DC_DCN2_1
 ###############################################################################
 CLK_MGR_DCN21 = rn_clk_mgr.o rn_clk_mgr_vbios_smu.o
 
+# prevent build errors regarding soft-float vs hard-float FP ABI tags
+# this code is currently unused on ppc64, as it applies to Renoir APUs only
+ifdef CONFIG_PPC64
+CFLAGS_$(AMDDALPATH)/dc/clk_mgr/dcn21/rn_clk_mgr.o := $(call cc-option,-mno-gnu-attribute)
+endif
+
 AMD_DAL_CLK_MGR_DCN21 = $(addprefix $(AMDDALPATH)/dc/clk_mgr/dcn21/,$(CLK_MGR_DCN21))
 
 AMD_DISPLAY_FILES += $(AMD_DAL_CLK_MGR_DCN21)
-- 
2.20.1