From: Christian Marangi <ansuelsmth@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Christian Marangi <ansuelsmth@gmail.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, llvm@lists.linux.dev
Cc: Sudeep Holla <sudeep.holla@arm.com>, kernel test robot <lkp@intel.com>
Subject: [PATCH] pmdomain: airoha: Fix compilation error with Clang-20 and Thumb2 mode
Date: Mon, 20 Jan 2025 16:38:09 +0100 [thread overview]
Message-ID: <20250120153817.11807-1-ansuelsmth@gmail.com> (raw)
The use of R7 in the SMCCC conflicts with the compiler's use of R7 as a frame
pointer in Thumb2 mode, which is forcibly enabled by Clang when profiling
hooks are inserted via the -pg switch.
This is a known issue and similar driver workaround this with a Makefile
ifdef. Exact workaround are applied in
drivers/firmware/arm_scmi/transports/Makefile and other similar driver.
Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501201840.XmpHXpQ4-lkp@intel.com/
Fixes: 82e703dd438b ("pmdomain: airoha: Add Airoha CPU PM Domain support")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
drivers/pmdomain/mediatek/Makefile | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/pmdomain/mediatek/Makefile b/drivers/pmdomain/mediatek/Makefile
index 0f6edce9239b..18ba92e3c418 100644
--- a/drivers/pmdomain/mediatek/Makefile
+++ b/drivers/pmdomain/mediatek/Makefile
@@ -2,3 +2,10 @@
obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
obj-$(CONFIG_MTK_SCPSYS_PM_DOMAINS) += mtk-pm-domains.o
obj-$(CONFIG_AIROHA_CPU_PM_DOMAIN) += airoha-cpu-pmdomain.o
+
+ifeq ($(CONFIG_THUMB2_KERNEL)$(CONFIG_CC_IS_CLANG),yy)
+# The use of R7 in the SMCCC conflicts with the compiler's use of R7 as a frame
+# pointer in Thumb2 mode, which is forcibly enabled by Clang when profiling
+# hooks are inserted via the -pg switch.
+CFLAGS_REMOVE_airoha-cpu-pmdomain.o += $(CC_FLAGS_FTRACE)
+endif
--
2.47.1
next reply other threads:[~2025-01-20 15:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-20 15:38 Christian Marangi [this message]
2025-01-21 9:46 ` [PATCH] pmdomain: airoha: Fix compilation error with Clang-20 and Thumb2 mode Ulf Hansson
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