[PATCH] kbuild: add CONFIG_ASM_MODVERSIONS

From: Masahiro Yamada
Date: Mon Aug 19 2019 - 01:54:46 EST

Add CONFIG_ASM_MODVERSIONS to remove one if-conditional nesting
from Makefile.build

This also avoid $(wildcard ...) evaluation for every descending,
but I did not see measurable performance improvement.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

arch/Kconfig | 7 +++++++
arch/alpha/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/ia64/Kconfig | 1 +
arch/m68k/Kconfig | 1 +
arch/mips/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/riscv/Kconfig | 1 +
arch/s390/Kconfig | 1 +
arch/sparc/Kconfig | 1 +
arch/um/Kconfig | 1 +
arch/x86/Kconfig | 1 +
init/Kconfig | 8 ++++++++
scripts/Makefile.build | 7 +------
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 d8dcd8820369..ec1e047200f3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -177,6 +177,7 @@ 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 2f66ed388d1c..f58c9396aba4 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -356,11 +356,7 @@ $(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.
@@ -376,7 +372,6 @@ 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)
--
2.17.1