kbuild: add CONFIG_ASM_MODVERSIONS

Add CONFIG_ASM_MODVERSIONS. This allows to remove one if-conditional
nesting in scripts/Makefile.build.

scripts/Makefile.build is run every time Kbuild descends into a
sub-directory. So, I want to avoid $(wildcard ...) evaluation
where possible although computing $(wildcard ...) is so cheap that
it may not make measurable performance difference.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

14 files changed, 27 insertions, 6 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index a7b57dd42c26..7d7b1b6af851 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -289,6 +289,13 @@ config ARCH_32BIT_OFF_T
           still support 32-bit off_t. This option is enabled for all such
           architectures explicitly.
 
+config HAVE_ASM_MODVERSIONS
+        bool
+        help
+          This symbol should be selected by an architecure if it provides
+          <asm/asm-prototypes.h> to support the module versioning for symbols
+          exported from assembly code.
+
 config HAVE_REGS_AND_STACK_ACCESS_API
         bool
         help
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index f7b19b813a70..ef179033a7c2 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -11,6 +11,7 @@ config ALPHA
         select PCI_DOMAINS if PCI
         select PCI_SYSCALL if PCI
         select HAVE_AOUT
+        select HAVE_ASM_MODVERSIONS
         select HAVE_IDE
         select HAVE_OPROFILE
         select HAVE_PCSPKR_PLATFORM
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3adcec05b1f6..cb16d4ade6aa 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -135,6 +135,7 @@ config ARM64
         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
         select HAVE_ARCH_VMAP_STACK
         select HAVE_ARM_SMCCC
+        select HAVE_ASM_MODVERSIONS
         select HAVE_EBPF_JIT
         select HAVE_C_RECORDMCOUNT
         select HAVE_CMPXCHG_DOUBLE
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 7468d8e50467..3dead116a6d7 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -17,6 +17,7 @@ config IA64
         select FORCE_PCI if (!IA64_HP_SIM)
         select PCI_DOMAINS if PCI
         select PCI_SYSCALL if PCI
+        select HAVE_ASM_MODVERSIONS
         select HAVE_UNSTABLE_SCHED_CLOCK
         select HAVE_EXIT_THREAD
         select HAVE_IDE
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index c518d695c376..00a20fa0bdcc 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -14,6 +14,7 @@ config M68K
         select DMA_DIRECT_REMAP if HAS_DMA && MMU && !COLDFIRE
         select HAVE_IDE
         select HAVE_AOUT if MMU
+        select HAVE_ASM_MODVERSIONS
         select HAVE_DEBUG_BUGVERBOSE
         select GENERIC_IRQ_SHOW
         select GENERIC_ATOMIC64
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index d50fafd7bf3a..3db919b5c93a 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -44,6 +44,7 @@ config MIPS
         select HAVE_ARCH_SECCOMP_FILTER
         select HAVE_ARCH_TRACEHOOK
         select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES && 64BIT
+        select HAVE_ASM_MODVERSIONS
         select HAVE_EBPF_JIT if (!CPU_MICROMIPS)
         select HAVE_CONTEXT_TRACKING
         select HAVE_COPY_THREAD_TLS
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 77f6ebf97113..5be32ad8f47b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -178,6 +178,7 @@ config PPC
         select HAVE_ARCH_NVRAM_OPS
         select HAVE_ARCH_SECCOMP_FILTER
         select HAVE_ARCH_TRACEHOOK
+        select HAVE_ASM_MODVERSIONS
         select HAVE_C_RECORDMCOUNT
         select HAVE_CBPF_JIT                    if !PPC64
         select HAVE_STACKPROTECTOR              if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 59a4727ecd6c..66603f02675a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -31,6 +31,7 @@ config RISCV
         select GENERIC_SMP_IDLE_THREAD
         select GENERIC_ATOMIC64 if !64BIT
         select HAVE_ARCH_AUDITSYSCALL
+        select HAVE_ASM_MODVERSIONS
         select HAVE_MEMBLOCK_NODE_MAP
         select HAVE_DMA_CONTIGUOUS
         select HAVE_FUTEX_CMPXCHG if FUTEX
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index a4ad2733eedf..c06ebe34e0f9 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -131,6 +131,7 @@ config S390
         select HAVE_ARCH_TRACEHOOK
         select HAVE_ARCH_TRANSPARENT_HUGEPAGE
         select HAVE_ARCH_VMAP_STACK
+        select HAVE_ASM_MODVERSIONS
         select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
         select HAVE_CMPXCHG_DOUBLE
         select HAVE_CMPXCHG_LOCAL
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 7926a2e11bdc..fbc1aecf0f94 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -17,6 +17,7 @@ config SPARC
         select ARCH_MIGHT_HAVE_PC_SERIO
         select OF
         select OF_PROMTREE
+        select HAVE_ASM_MODVERSIONS
         select HAVE_IDE
         select HAVE_OPROFILE
         select HAVE_ARCH_KGDB if !SMP || SPARC64
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 3c3adfc486f2..fec6b4ca2b6e 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -9,6 +9,7 @@ config UML
         select ARCH_NO_PREEMPT
         select HAVE_ARCH_AUDITSYSCALL
         select HAVE_ARCH_SECCOMP_FILTER
+        select HAVE_ASM_MODVERSIONS
         select HAVE_UID16
         select HAVE_FUTEX_CMPXCHG if FUTEX
         select HAVE_DEBUG_KMEMLEAK
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 222855cc0158..66bb9f25e9df 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -147,6 +147,7 @@ config X86
         select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
         select HAVE_ARCH_VMAP_STACK             if X86_64
         select HAVE_ARCH_WITHIN_STACK_FRAMES
+        select HAVE_ASM_MODVERSIONS
         select HAVE_CMPXCHG_DOUBLE
         select HAVE_CMPXCHG_LOCAL
         select HAVE_CONTEXT_TRACKING            if X86_64
diff --git a/init/Kconfig b/init/Kconfig
index bd7d650d4a99..bf971b5c707d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1989,6 +1989,14 @@ config MODVERSIONS
           make them incompatible with the kernel you are running.  If
           unsure, say N.
 
+config ASM_MODVERSIONS
+        bool
+        default HAVE_ASM_MODVERSIONS && MODVERSIONS
+        help
+          This enables module versioning for exported symbols also from
+          assembly. This can be enabled only when the target architecture
+          supports it.
+
 config MODULE_REL_CRCS
         bool
         depends on MODVERSIONS
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 10adf3b558de..9fa09361aa5d 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -349,11 +349,7 @@ $(obj)/%.s: $(src)/%.S FORCE
 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
       cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
 
-ifdef CONFIG_MODVERSIONS
-
-ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
-
-ifneq ($(ASM_PROTOTYPES),)
+ifdef CONFIG_ASM_MODVERSIONS
 
 # versioning matches the C process described above, with difference that
 # we parse asm-prototypes.h C header to get function definitions.
@@ -369,7 +365,6 @@ cmd_modversions_S =								\
                 rm -f $(@D)/.tmp_$(@F:.o=.ver);                                 \
         fi
 endif
-endif
 
 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
         $(call if_changed_rule,as_o_S)