pmdomain: airoha: Fix compilation error with Clang-20 and Thumb2 mode

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 <[email protected]> Reported-by: kernel test robot <[email protected]> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ Fixes: 82e703d ("pmdomain: airoha: Add Airoha CPU PM Domain support") Signed-off-by: Christian Marangi <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Ulf Hansson <[email protected]>
gl-prout · Jan 21, 2025 · 885f566 · 885f566
1 parent c2d7aa3
commit 885f566
Showing 1 changed file with 7 additions and 0 deletions.
diff --git 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