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

[Naveen N Rao]

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 at 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