[RFC PATCH v4 01/17] powerpc/trace: Account for -fpatchable-function-entry support by toolchain

Naveen N Rao
2024-07-14T08:30:07Z

So far, we have relied on the fact that gcc supports both
-mprofile-kernel, as well as -fpatchable-function-entry, and clang
supports neither. Our Makefile only checks for CONFIG_MPROFILE_KERNEL to
decide which files to build. Clang has a feature request out [*] to
implement -fpatchable-function-entry, and is unlikely to support
-mprofile-kernel.

Update our Makefile checks so that we pick up the correct files to build
once clang picks up support for -fpatchable-function-entry.

[*] https://github.com/llvm/llvm-project/issues/57031

Signed-off-by: Naveen N Rao <naveen@kernel.org>
---
arch/powerpc/kernel/trace/Makefile | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile
index 125f4ca588b9..d6c3885453bd 100644
--- a/arch/powerpc/kernel/trace/Makefile
+++ b/arch/powerpc/kernel/trace/Makefile
@@ -9,12 +9,15 @@ CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_ftrace_64_pg.o = $(CC_FLAGS_FTRACE)
endif

-obj32-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o
-ifdef CONFIG_MPROFILE_KERNEL
-obj64-$(CONFIG_FUNCTION_TRACER) += ftrace.o ftrace_entry.o
+ifdef CONFIG_FUNCTION_TRACER
+obj32-y += ftrace.o ftrace_entry.o
+ifeq ($(CONFIG_MPROFILE_KERNEL)$(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY),)
+obj64-y += ftrace_64_pg.o ftrace_64_pg_entry.o
else
-obj64-$(CONFIG_FUNCTION_TRACER) += ftrace_64_pg.o ftrace_64_pg_entry.o
+obj64-y += ftrace.o ftrace_entry.o
endif
+endif
+
obj-$(CONFIG_TRACING) += trace_clock.o

obj-$(CONFIG_PPC64) += $(obj64-y)
--
2.45.2