powerpc64/ftrace: Move ELFv1 and -pg support code into a separate file

ELFv1 support is deprecated and on the way out. Pre -mprofile-kernel
ftrace support (-pg only) is very limited and is retained primarily for
clang builds. It won't be necessary once clang lands support for
-fpatchable-function-entry.

Copy the existing ftrace code supporting these into ftrace_pg.c.
ftrace.c can then be refactored and enhanced with a focus on ppc32 and
ppc64 ELFv2.

Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1eb6cc6c3141ddb77a2a25f8a9e83d83ff312b02.1687166935.git.naveen@kernel.org

Author: rnav

arch/powerpc/kernel/trace/Makefile

@@ -6,15 +6,16 @@
 ifdef CONFIG_FUNCTION_TRACER
 # do not trace tracer code
 CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_ftrace_pg.o = $(CC_FLAGS_FTRACE)
 endif
 
-obj32-$(CONFIG_FUNCTION_TRACER)		+= ftrace_mprofile.o
+obj32-$(CONFIG_FUNCTION_TRACER)		+= ftrace_mprofile.o ftrace.o
 ifdef CONFIG_MPROFILE_KERNEL
-obj64-$(CONFIG_FUNCTION_TRACER)		+= ftrace_mprofile.o
+obj64-$(CONFIG_FUNCTION_TRACER)		+= ftrace_mprofile.o ftrace.o
 else
-obj64-$(CONFIG_FUNCTION_TRACER)		+= ftrace_64_pg.o
+obj64-$(CONFIG_FUNCTION_TRACER)		+= ftrace_64_pg.o ftrace_pg.o
 endif
-obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace_low.o ftrace.o
+obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace_low.o
 obj-$(CONFIG_TRACING)			+= trace_clock.o
 
 obj-$(CONFIG_PPC64)			+= $(obj64-y)
@@ -25,3 +26,7 @@ GCOV_PROFILE_ftrace.o := n
 KCOV_INSTRUMENT_ftrace.o := n
 KCSAN_SANITIZE_ftrace.o := n
 UBSAN_SANITIZE_ftrace.o := n
+GCOV_PROFILE_ftrace_pg.o := n
+KCOV_INSTRUMENT_ftrace_pg.o := n
+KCSAN_SANITIZE_ftrace_pg.o := n
+UBSAN_SANITIZE_ftrace_pg.o := n

arch/powerpc/kernel/trace/ftrace.c

@@ -864,13 +864,3 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,
 }
 #endif
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-
-#ifdef CONFIG_PPC64_ELF_ABI_V1
-char *arch_ftrace_match_adjust(char *str, const char *search)
-{
-	if (str[0] == '.' && search[0] != '.')
-		return str + 1;
-	else
-		return str;
-}
-#endif /* CONFIG_PPC64_ELF_ABI_V1 */