tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD

Ftrace is tightly coupled with architecture specific code because it
requires the use of trampolines written in assembly. This means that when
a new feature or optimization is made, it must be done for all
architectures. To simplify the approach, CONFIG_HAVE_FTRACE_* configs are
added to denote which architecture has the new enhancement so that other
architectures can still function until they too have been updated.

The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant
with the HAVE_DYNAMIC_FTRACE.

Remove the HAVE_FTRACE_MCOUNT config and use DYNAMIC_FTRACE directly where
applicable.

Link: https://lore.kernel.org/all/20250703154916.48e3ada7@gandalf.local.home/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/20250704104838.27a18690@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Documentation/trace/ftrace-design.rst

@@ -238,19 +238,15 @@ You need very few things to get the syscalls tracing in an arch.
   - Tag this arch as HAVE_SYSCALL_TRACEPOINTS.
 
 
-HAVE_FTRACE_MCOUNT_RECORD
--------------------------
+HAVE_DYNAMIC_FTRACE
+-------------------
 
 See scripts/recordmcount.pl for more info.  Just fill in the arch-specific
 details for how to locate the addresses of mcount call sites via objdump.
 This option doesn't make much sense without also implementing dynamic ftrace.
 
-
-HAVE_DYNAMIC_FTRACE
--------------------
-
-You will first need HAVE_FTRACE_MCOUNT_RECORD and HAVE_FUNCTION_TRACER, so
-scroll your reader back up if you got over eager.
+You will first need HAVE_FUNCTION_TRACER, so scroll your reader back up if you
+got over eager.
 
 Once those are out of the way, you will need to implement:
 	- asm/ftrace.h:

arch/arm/Kconfig

@@ -107,7 +107,6 @@ config ARM
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
 	select HAVE_EXIT_THREAD
 	select HAVE_GUP_FAST if ARM_LPAE
-	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL

arch/arm64/Kconfig

@@ -223,7 +223,6 @@ config ARM64
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_GUP_FAST
 	select HAVE_FTRACE_GRAPH_FUNC
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_FREGS

arch/csky/Kconfig

@@ -80,7 +80,6 @@ config CSKY
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_ERROR_INJECTION
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZO
 	select HAVE_KERNEL_LZMA

arch/loongarch/Kconfig

@@ -144,7 +144,6 @@ config LOONGARCH
 	select HAVE_EXIT_THREAD
 	select HAVE_GUP_FAST
 	select HAVE_FTRACE_GRAPH_FUNC
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_FREGS

arch/microblaze/Kconfig

@@ -28,7 +28,6 @@ config MICROBLAZE
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_DYNAMIC_FTRACE
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_PAGE_SIZE_4KB

arch/mips/Kconfig

@@ -73,7 +73,6 @@ config MIPS
 	select HAVE_EBPF_JIT if !CPU_MICROMIPS
 	select HAVE_EXIT_THREAD
 	select HAVE_GUP_FAST
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_GCC_PLUGINS

arch/parisc/Kconfig

@@ -81,7 +81,6 @@ config PARISC
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_DYNAMIC_FTRACE if $(cc-option,-fpatchable-function-entry=1,1)
-	select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
 	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS

arch/powerpc/Kconfig

@@ -246,7 +246,6 @@ config PPC
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_GUP_FAST
 	select HAVE_FTRACE_GRAPH_FUNC
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_FUNCTION_DESCRIPTORS	if PPC64_ELF_ABI_V1
 	select HAVE_FUNCTION_ERROR_INJECTION

arch/riscv/Kconfig

@@ -159,7 +159,6 @@ config RISCV
 	select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS if (DYNAMIC_FTRACE_WITH_ARGS && !CFI_CLANG)
 	select HAVE_DYNAMIC_FTRACE_WITH_ARGS if HAVE_DYNAMIC_FTRACE
 	select HAVE_FTRACE_GRAPH_FUNC
-	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
 	select HAVE_FUNCTION_GRAPH_TRACER if HAVE_DYNAMIC_FTRACE_WITH_ARGS
 	select HAVE_FUNCTION_GRAPH_FREGS
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL

arch/s390/Kconfig

@@ -199,7 +199,6 @@ config S390
 	select HAVE_GUP_FAST
 	select HAVE_FENTRY
 	select HAVE_FTRACE_GRAPH_FUNC
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_FREGS

arch/sh/Kconfig

@@ -40,7 +40,6 @@ config SUPERH
 	select HAVE_GUP_FAST if MMU
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_HW_BREAKPOINT
 	select HAVE_IOREMAP_PROT if MMU && !X2TLB
 	select HAVE_KERNEL_BZIP2

arch/sparc/Kconfig

@@ -78,7 +78,6 @@ config SPARC64
 	select MMU_GATHER_NO_FLUSH_CACHE
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_DYNAMIC_FTRACE
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_PAGE_SIZE_8KB
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_CONTEXT_TRACKING_USER

arch/x86/Kconfig

@@ -244,7 +244,6 @@ config X86
 	select HAVE_GUP_FAST
 	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
 	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
-	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
 	select HAVE_FUNCTION_TRACER

include/asm-generic/vmlinux.lds.h

@@ -167,7 +167,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
 #define FTRACE_STUB_HACK
 #endif
 
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CONFIG_DYNAMIC_FTRACE
 /*
  * The ftrace call sites are logged to a section whose name depends on the
  * compiler option used. A given kernel image will only use one, AKA

include/linux/ftrace.h

@@ -1108,7 +1108,7 @@ static __always_inline unsigned long get_lock_parent_ip(void)
 # define trace_preempt_off(a0, a1) do { } while (0)
 #endif
 
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CONFIG_DYNAMIC_FTRACE
 extern void ftrace_init(void);
 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
 #define FTRACE_CALLSITE_SECTION	"__patchable_function_entries"

include/linux/kernel.h

@@ -373,9 +373,9 @@ ftrace_vprintk(const char *fmt, va_list ap)
 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 #endif /* CONFIG_TRACING */
 
-/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
-# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
+/* Rebuild everything on CONFIG_DYNAMIC_FTRACE */
+#ifdef CONFIG_DYNAMIC_FTRACE
+# define REBUILD_DUE_TO_DYNAMIC_FTRACE
 #endif
 
 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */

include/linux/module.h

@@ -539,7 +539,7 @@ struct module {
 	struct trace_eval_map **trace_evals;
 	unsigned int num_trace_evals;
 #endif
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CONFIG_DYNAMIC_FTRACE
 	unsigned int num_ftrace_callsites;
 	unsigned long *ftrace_callsites;
 #endif

kernel/module/main.c

@@ -2639,7 +2639,7 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 					 sizeof(*mod->trace_bprintk_fmt_start),
 					 &mod->num_trace_bprintk_fmt);
 #endif
-#ifdef CONFIG_FTRACE_MCOUNT_RECORD
+#ifdef CONFIG_DYNAMIC_FTRACE
 	/* sechdrs[0].sh_size is always zero */
 	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
 					     sizeof(*mod->ftrace_callsites),

kernel/trace/Kconfig

@@ -74,11 +74,6 @@ config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
 	  If the architecture generates __patchable_function_entries sections
 	  but does not want them included in the ftrace locations.
 
-config HAVE_FTRACE_MCOUNT_RECORD
-	bool
-	help
-	  See Documentation/trace/ftrace-design.rst
-
 config HAVE_SYSCALL_TRACEPOINTS
 	bool
 	help
@@ -803,27 +798,22 @@ config BPF_KPROBE_OVERRIDE
 	 Allows BPF to override the execution of a probed function and
 	 set a different return value.  This is used for error injection.
 
-config FTRACE_MCOUNT_RECORD
-	def_bool y
-	depends on DYNAMIC_FTRACE
-	depends on HAVE_FTRACE_MCOUNT_RECORD
-
 config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	bool
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config FTRACE_MCOUNT_USE_CC
 	def_bool y
 	depends on $(cc-option,-mrecord-mcount)
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config FTRACE_MCOUNT_USE_OBJTOOL
 	def_bool y
 	depends on HAVE_OBJTOOL_MCOUNT
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	depends on !FTRACE_MCOUNT_USE_CC
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 	select OBJTOOL
 
 config FTRACE_MCOUNT_USE_RECORDMCOUNT
@@ -831,7 +821,7 @@ config FTRACE_MCOUNT_USE_RECORDMCOUNT
 	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
 	depends on !FTRACE_MCOUNT_USE_CC
 	depends on !FTRACE_MCOUNT_USE_OBJTOOL
-	depends on FTRACE_MCOUNT_RECORD
+	depends on DYNAMIC_FTRACE
 
 config TRACING_MAP
 	bool

kernel/trace/ftrace.c

@@ -1042,10 +1042,6 @@ static struct ftrace_ops *removed_ops;
  */
 static bool update_all_ops;
 
-#ifndef CONFIG_FTRACE_MCOUNT_RECORD
-# error Dynamic ftrace depends on MCOUNT_RECORD
-#endif
-
 struct ftrace_func_probe {
 	struct ftrace_probe_ops	*probe_ops;
 	struct ftrace_ops	ops;

scripts/recordmcount.pl

@@ -359,7 +359,7 @@ if ($arch eq "x86_64") {
     $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_CKCORE_PCREL_JSR_IMM26BY2\\s+_mcount\$";
     $alignment = 2;
 } else {
-    die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
+    die "Arch $arch is not supported with CONFIG_DYNAMIC_FTRACE";
 }
 
 my $text_found = 0;