arch: add ARCH_HAS_SET_MEMORY config

Currently, there's no good way to test for the presence of
set_memory_ro/rw/x/nx() helpers implemented by archs such as
x86, arm, arm64 and s390.

There's DEBUG_SET_MODULE_RONX and DEBUG_RODATA, however both
don't really reflect that: set_memory_*() are also available
even when DEBUG_SET_MODULE_RONX is turned off, and DEBUG_RODATA
is set by parisc, but doesn't implement above functions. Thus,
add ARCH_HAS_SET_MEMORY that is selected by mentioned archs,
where generic code can test against this.

This also allows later on to move DEBUG_SET_MODULE_RONX out of
the arch specific Kconfig to define it only once depending on
ARCH_HAS_SET_MEMORY.

Suggested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/Kconfig b/arch/Kconfig
index bd04eac..e8ada79 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -222,6 +222,10 @@
 config GENERIC_IDLE_POLL_SETUP
        bool
 
+# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h
+config ARCH_HAS_SET_MEMORY
+	bool
+
 # Select if arch init_task initializer is different to init/init_task.c
 config ARCH_INIT_TASK
        bool
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 186c4c2..edae056 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -4,6 +4,7 @@
 	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
+	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_CUSTOM_GPIO_H
 	select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1117421..1853405 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -12,6 +12,7 @@
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_USE_CMPXCHG_LOCKREF
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c6722112..094deb1 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -72,6 +72,7 @@
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e487493..434dd2a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -53,6 +53,7 @@
 	select ARCH_HAS_KCOV			if X86_64
 	select ARCH_HAS_MMIO_FLUSH
 	select ARCH_HAS_PMEM_API		if X86_64
+	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG