diff mbox series

[v2] ftrace: Cleanup ftrace_dyn_arch_init()

Message ID 20210906111626.1259867-1-o451686892@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v2] ftrace: Cleanup ftrace_dyn_arch_init() | expand

Commit Message

Weizhao Ouyang Sept. 6, 2021, 11:16 a.m. UTC
Most of ARCHs use empty ftrace_dyn_arch_init(), introduce a weak common
ftrace_dyn_arch_init() to cleanup them.

Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com> (s390)

---

Changes in v2:
-- correct CONFIG_DYNAMIC_FTRACE on PowerPC
-- add Acked-by tag

---
 arch/arm/kernel/ftrace.c          | 5 -----
 arch/arm64/kernel/ftrace.c        | 5 -----
 arch/csky/kernel/ftrace.c         | 5 -----
 arch/ia64/kernel/ftrace.c         | 6 ------
 arch/microblaze/kernel/ftrace.c   | 5 -----
 arch/mips/include/asm/ftrace.h    | 2 ++
 arch/nds32/kernel/ftrace.c        | 5 -----
 arch/parisc/kernel/ftrace.c       | 5 -----
 arch/powerpc/include/asm/ftrace.h | 4 ++++
 arch/riscv/kernel/ftrace.c        | 5 -----
 arch/s390/kernel/ftrace.c         | 5 -----
 arch/sh/kernel/ftrace.c           | 5 -----
 arch/sparc/kernel/ftrace.c        | 5 -----
 arch/x86/kernel/ftrace.c          | 5 -----
 include/linux/ftrace.h            | 1 -
 kernel/trace/ftrace.c             | 5 +++++
 16 files changed, 11 insertions(+), 62 deletions(-)

Comments

Michael Ellerman Sept. 6, 2021, 2:22 p.m. UTC | #1
Weizhao Ouyang <o451686892@gmail.com> writes:
> Most of ARCHs use empty ftrace_dyn_arch_init(), introduce a weak common
> ftrace_dyn_arch_init() to cleanup them.
>
> Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
> Acked-by: Heiko Carstens <hca@linux.ibm.com> (s390)
>
> ---
>
> Changes in v2:
> -- correct CONFIG_DYNAMIC_FTRACE on PowerPC
> -- add Acked-by tag

> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
> index debe8c4f7062..d59f67c0225f 100644
> --- a/arch/powerpc/include/asm/ftrace.h
> +++ b/arch/powerpc/include/asm/ftrace.h
> @@ -61,6 +61,10 @@ struct dyn_arch_ftrace {
>  };
>  #endif /* __ASSEMBLY__ */
>  
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +int __init ftrace_dyn_arch_init(void);
> +#endif /* CONFIG_DYNAMIC_FTRACE */
> +
>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
>  #define ARCH_SUPPORTS_FTRACE_OPS 1
>  #endif

That breaks the build for powerpc:

  /linux/arch/powerpc/include/asm/ftrace.h: Assembler messages:
  /linux/arch/powerpc/include/asm/ftrace.h:65: Error: unrecognized opcode: `int'
  make[4]: *** [/linux/scripts/Makefile.build:352: arch/powerpc/kernel/trace/ftrace_64.o] Error 1
  make[3]: *** [/linux/scripts/Makefile.build:514: arch/powerpc/kernel/trace] Error 2
  make[2]: *** [/linux/scripts/Makefile.build:514: arch/powerpc/kernel] Error 2
  make[1]: *** [/linux/Makefile:1861: arch/powerpc] Error 2
  make[1]: *** Waiting for unfinished jobs....

It needs to be inside an #ifndef __ASSEMBLY__ section.

cheers
Weizhao Ouyang Sept. 6, 2021, 2:57 p.m. UTC | #2
On 2021/9/6 22:22, Michael Ellerman wrote:
> Weizhao Ouyang <o451686892@gmail.com> writes:
>> Most of ARCHs use empty ftrace_dyn_arch_init(), introduce a weak common
>> ftrace_dyn_arch_init() to cleanup them.
>>
>> Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
>> Acked-by: Heiko Carstens <hca@linux.ibm.com> (s390)
>>
>> ---
>>
>> Changes in v2:
>> -- correct CONFIG_DYNAMIC_FTRACE on PowerPC
>> -- add Acked-by tag
>> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
>> index debe8c4f7062..d59f67c0225f 100644
>> --- a/arch/powerpc/include/asm/ftrace.h
>> +++ b/arch/powerpc/include/asm/ftrace.h
>> @@ -61,6 +61,10 @@ struct dyn_arch_ftrace {
>>  };
>>  #endif /* __ASSEMBLY__ */
>>  
>> +#ifdef CONFIG_DYNAMIC_FTRACE
>> +int __init ftrace_dyn_arch_init(void);
>> +#endif /* CONFIG_DYNAMIC_FTRACE */
>> +
>>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
>>  #define ARCH_SUPPORTS_FTRACE_OPS 1
>>  #endif
> That breaks the build for powerpc:
>
>   /linux/arch/powerpc/include/asm/ftrace.h: Assembler messages:
>   /linux/arch/powerpc/include/asm/ftrace.h:65: Error: unrecognized opcode: `int'
>   make[4]: *** [/linux/scripts/Makefile.build:352: arch/powerpc/kernel/trace/ftrace_64.o] Error 1
>   make[3]: *** [/linux/scripts/Makefile.build:514: arch/powerpc/kernel/trace] Error 2
>   make[2]: *** [/linux/scripts/Makefile.build:514: arch/powerpc/kernel] Error 2
>   make[1]: *** [/linux/Makefile:1861: arch/powerpc] Error 2
>   make[1]: *** Waiting for unfinished jobs....
>
> It needs to be inside an #ifndef __ASSEMBLY__ section.
>
> cheers

Thanks for reply, I'll fix it up.
Helge Deller Sept. 6, 2021, 8:36 p.m. UTC | #3
On 9/6/21 1:16 PM, Weizhao Ouyang wrote:
> Most of ARCHs use empty ftrace_dyn_arch_init(), introduce a weak common
> ftrace_dyn_arch_init() to cleanup them.
>
> Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
> Acked-by: Heiko Carstens <hca@linux.ibm.com> (s390)

Acked-by: Helge Deller <deller@gmx.de> # parisc

Thanks,
Helge


> ---
>
> Changes in v2:
> -- correct CONFIG_DYNAMIC_FTRACE on PowerPC
> -- add Acked-by tag
>
> ---
>   arch/arm/kernel/ftrace.c          | 5 -----
>   arch/arm64/kernel/ftrace.c        | 5 -----
>   arch/csky/kernel/ftrace.c         | 5 -----
>   arch/ia64/kernel/ftrace.c         | 6 ------
>   arch/microblaze/kernel/ftrace.c   | 5 -----
>   arch/mips/include/asm/ftrace.h    | 2 ++
>   arch/nds32/kernel/ftrace.c        | 5 -----
>   arch/parisc/kernel/ftrace.c       | 5 -----
>   arch/powerpc/include/asm/ftrace.h | 4 ++++
>   arch/riscv/kernel/ftrace.c        | 5 -----
>   arch/s390/kernel/ftrace.c         | 5 -----
>   arch/sh/kernel/ftrace.c           | 5 -----
>   arch/sparc/kernel/ftrace.c        | 5 -----
>   arch/x86/kernel/ftrace.c          | 5 -----
>   include/linux/ftrace.h            | 1 -
>   kernel/trace/ftrace.c             | 5 +++++
>   16 files changed, 11 insertions(+), 62 deletions(-)
>
> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> index 3c83b5d29697..a006585e1c09 100644
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -193,11 +193,6 @@ int ftrace_make_nop(struct module *mod,
>
>   	return ret;
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif /* CONFIG_DYNAMIC_FTRACE */
>
>   #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
> index 7f467bd9db7a..fc62dfe73f93 100644
> --- a/arch/arm64/kernel/ftrace.c
> +++ b/arch/arm64/kernel/ftrace.c
> @@ -236,11 +236,6 @@ void arch_ftrace_update_code(int command)
>   	command |= FTRACE_MAY_SLEEP;
>   	ftrace_modify_all_code(command);
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif /* CONFIG_DYNAMIC_FTRACE */
>
>   #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c
> index b4a7ec1517ff..50bfcf129078 100644
> --- a/arch/csky/kernel/ftrace.c
> +++ b/arch/csky/kernel/ftrace.c
> @@ -133,11 +133,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
>   				(unsigned long)func, true, true);
>   	return ret;
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif /* CONFIG_DYNAMIC_FTRACE */
>
>   #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> diff --git a/arch/ia64/kernel/ftrace.c b/arch/ia64/kernel/ftrace.c
> index b2ab2d58fb30..d6360fd404ab 100644
> --- a/arch/ia64/kernel/ftrace.c
> +++ b/arch/ia64/kernel/ftrace.c
> @@ -194,9 +194,3 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
>   	flush_icache_range(addr, addr + 16);
>   	return 0;
>   }
> -
> -/* run from kstop_machine */
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
> diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
> index 224eea40e1ee..188749d62709 100644
> --- a/arch/microblaze/kernel/ftrace.c
> +++ b/arch/microblaze/kernel/ftrace.c
> @@ -163,11 +163,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
>   	return ret;
>   }
>
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
> -
>   int ftrace_update_ftrace_func(ftrace_func_t func)
>   {
>   	unsigned long ip = (unsigned long)(&ftrace_call);
> diff --git a/arch/mips/include/asm/ftrace.h b/arch/mips/include/asm/ftrace.h
> index b463f2aa5a61..ed013e767390 100644
> --- a/arch/mips/include/asm/ftrace.h
> +++ b/arch/mips/include/asm/ftrace.h
> @@ -76,6 +76,8 @@ do {						\
>
>
>   #ifdef CONFIG_DYNAMIC_FTRACE
> +int __init ftrace_dyn_arch_init(void);
> +
>   static inline unsigned long ftrace_call_adjust(unsigned long addr)
>   {
>   	return addr;
> diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
> index 0e23e3a8df6b..f0ef4842d191 100644
> --- a/arch/nds32/kernel/ftrace.c
> +++ b/arch/nds32/kernel/ftrace.c
> @@ -84,11 +84,6 @@ void _ftrace_caller(unsigned long parent_ip)
>   	/* restore all state needed by the compiler epilogue */
>   }
>
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
> -
>   static unsigned long gen_sethi_insn(unsigned long addr)
>   {
>   	unsigned long opcode = 0x46000000;
> diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
> index 0a1e75af5382..01581f715737 100644
> --- a/arch/parisc/kernel/ftrace.c
> +++ b/arch/parisc/kernel/ftrace.c
> @@ -94,11 +94,6 @@ int ftrace_disable_ftrace_graph_caller(void)
>   #endif
>
>   #ifdef CONFIG_DYNAMIC_FTRACE
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   int ftrace_update_ftrace_func(ftrace_func_t func)
>   {
>   	return 0;
> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
> index debe8c4f7062..d59f67c0225f 100644
> --- a/arch/powerpc/include/asm/ftrace.h
> +++ b/arch/powerpc/include/asm/ftrace.h
> @@ -61,6 +61,10 @@ struct dyn_arch_ftrace {
>   };
>   #endif /* __ASSEMBLY__ */
>
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +int __init ftrace_dyn_arch_init(void);
> +#endif /* CONFIG_DYNAMIC_FTRACE */
> +
>   #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
>   #define ARCH_SUPPORTS_FTRACE_OPS 1
>   #endif
> diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
> index 7f1e5203de88..4716f4cdc038 100644
> --- a/arch/riscv/kernel/ftrace.c
> +++ b/arch/riscv/kernel/ftrace.c
> @@ -154,11 +154,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
>
>   	return ret;
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif
>
>   #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
> index 0a464d328467..3fd80397ff52 100644
> --- a/arch/s390/kernel/ftrace.c
> +++ b/arch/s390/kernel/ftrace.c
> @@ -262,11 +262,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
>   	return 0;
>   }
>
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
> -
>   void arch_ftrace_update_code(int command)
>   {
>   	if (ftrace_shared_hotpatch_trampoline(NULL))
> diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
> index 295c43315bbe..930001bb8c6a 100644
> --- a/arch/sh/kernel/ftrace.c
> +++ b/arch/sh/kernel/ftrace.c
> @@ -252,11 +252,6 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
>
>   	return ftrace_modify_code(rec->ip, old, new);
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif /* CONFIG_DYNAMIC_FTRACE */
>
>   #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
> index 684b84ce397f..eaead3da8e03 100644
> --- a/arch/sparc/kernel/ftrace.c
> +++ b/arch/sparc/kernel/ftrace.c
> @@ -82,11 +82,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
>   	new = ftrace_call_replace(ip, (unsigned long)func);
>   	return ftrace_modify_code(ip, old, new);
>   }
> -
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
>   #endif
>
>   #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 1b3ce3b4a2a2..23d221a9a3cd 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -252,11 +252,6 @@ void arch_ftrace_update_code(int command)
>   	ftrace_modify_all_code(command);
>   }
>
> -int __init ftrace_dyn_arch_init(void)
> -{
> -	return 0;
> -}
> -
>   /* Currently only x86_64 supports dynamic trampolines */
>   #ifdef CONFIG_X86_64
>
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 832e65f06754..f1eca123d89d 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -573,7 +573,6 @@ ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
>
>   /* defined in arch */
>   extern int ftrace_ip_converted(unsigned long ip);
> -extern int ftrace_dyn_arch_init(void);
>   extern void ftrace_replace_code(int enable);
>   extern int ftrace_update_ftrace_func(ftrace_func_t func);
>   extern void ftrace_caller(void);
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 7efbc8aaf7f6..4c090323198d 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -6846,6 +6846,11 @@ void __init ftrace_free_init_mem(void)
>   	ftrace_free_mem(NULL, start, end);
>   }
>
> +int __init __weak ftrace_dyn_arch_init(void)
> +{
> +	return 0;
> +}
> +
>   void __init ftrace_init(void)
>   {
>   	extern unsigned long __start_mcount_loc[];
>
diff mbox series

Patch

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 3c83b5d29697..a006585e1c09 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -193,11 +193,6 @@  int ftrace_make_nop(struct module *mod,
 
 	return ret;
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 7f467bd9db7a..fc62dfe73f93 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -236,11 +236,6 @@  void arch_ftrace_update_code(int command)
 	command |= FTRACE_MAY_SLEEP;
 	ftrace_modify_all_code(command);
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/csky/kernel/ftrace.c b/arch/csky/kernel/ftrace.c
index b4a7ec1517ff..50bfcf129078 100644
--- a/arch/csky/kernel/ftrace.c
+++ b/arch/csky/kernel/ftrace.c
@@ -133,11 +133,6 @@  int ftrace_update_ftrace_func(ftrace_func_t func)
 				(unsigned long)func, true, true);
 	return ret;
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
diff --git a/arch/ia64/kernel/ftrace.c b/arch/ia64/kernel/ftrace.c
index b2ab2d58fb30..d6360fd404ab 100644
--- a/arch/ia64/kernel/ftrace.c
+++ b/arch/ia64/kernel/ftrace.c
@@ -194,9 +194,3 @@  int ftrace_update_ftrace_func(ftrace_func_t func)
 	flush_icache_range(addr, addr + 16);
 	return 0;
 }
-
-/* run from kstop_machine */
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index 224eea40e1ee..188749d62709 100644
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -163,11 +163,6 @@  int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 	return ret;
 }
 
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
-
 int ftrace_update_ftrace_func(ftrace_func_t func)
 {
 	unsigned long ip = (unsigned long)(&ftrace_call);
diff --git a/arch/mips/include/asm/ftrace.h b/arch/mips/include/asm/ftrace.h
index b463f2aa5a61..ed013e767390 100644
--- a/arch/mips/include/asm/ftrace.h
+++ b/arch/mips/include/asm/ftrace.h
@@ -76,6 +76,8 @@  do {						\
 
 
 #ifdef CONFIG_DYNAMIC_FTRACE
+int __init ftrace_dyn_arch_init(void);
+
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
 	return addr;
diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
index 0e23e3a8df6b..f0ef4842d191 100644
--- a/arch/nds32/kernel/ftrace.c
+++ b/arch/nds32/kernel/ftrace.c
@@ -84,11 +84,6 @@  void _ftrace_caller(unsigned long parent_ip)
 	/* restore all state needed by the compiler epilogue */
 }
 
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
-
 static unsigned long gen_sethi_insn(unsigned long addr)
 {
 	unsigned long opcode = 0x46000000;
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index 0a1e75af5382..01581f715737 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -94,11 +94,6 @@  int ftrace_disable_ftrace_graph_caller(void)
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 int ftrace_update_ftrace_func(ftrace_func_t func)
 {
 	return 0;
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index debe8c4f7062..d59f67c0225f 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -61,6 +61,10 @@  struct dyn_arch_ftrace {
 };
 #endif /* __ASSEMBLY__ */
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+int __init ftrace_dyn_arch_init(void);
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 #define ARCH_SUPPORTS_FTRACE_OPS 1
 #endif
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c
index 7f1e5203de88..4716f4cdc038 100644
--- a/arch/riscv/kernel/ftrace.c
+++ b/arch/riscv/kernel/ftrace.c
@@ -154,11 +154,6 @@  int ftrace_update_ftrace_func(ftrace_func_t func)
 
 	return ret;
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 0a464d328467..3fd80397ff52 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -262,11 +262,6 @@  int ftrace_update_ftrace_func(ftrace_func_t func)
 	return 0;
 }
 
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
-
 void arch_ftrace_update_code(int command)
 {
 	if (ftrace_shared_hotpatch_trampoline(NULL))
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 295c43315bbe..930001bb8c6a 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -252,11 +252,6 @@  int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 
 	return ftrace_modify_code(rec->ip, old, new);
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
index 684b84ce397f..eaead3da8e03 100644
--- a/arch/sparc/kernel/ftrace.c
+++ b/arch/sparc/kernel/ftrace.c
@@ -82,11 +82,6 @@  int ftrace_update_ftrace_func(ftrace_func_t func)
 	new = ftrace_call_replace(ip, (unsigned long)func);
 	return ftrace_modify_code(ip, old, new);
 }
-
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
 #endif
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1b3ce3b4a2a2..23d221a9a3cd 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -252,11 +252,6 @@  void arch_ftrace_update_code(int command)
 	ftrace_modify_all_code(command);
 }
 
-int __init ftrace_dyn_arch_init(void)
-{
-	return 0;
-}
-
 /* Currently only x86_64 supports dynamic trampolines */
 #ifdef CONFIG_X86_64
 
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 832e65f06754..f1eca123d89d 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -573,7 +573,6 @@  ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 
 /* defined in arch */
 extern int ftrace_ip_converted(unsigned long ip);
-extern int ftrace_dyn_arch_init(void);
 extern void ftrace_replace_code(int enable);
 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 extern void ftrace_caller(void);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7efbc8aaf7f6..4c090323198d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6846,6 +6846,11 @@  void __init ftrace_free_init_mem(void)
 	ftrace_free_mem(NULL, start, end);
 }
 
+int __init __weak ftrace_dyn_arch_init(void)
+{
+	return 0;
+}
+
 void __init ftrace_init(void)
 {
 	extern unsigned long __start_mcount_loc[];