x86/Kconfig: only enable ROX cache in execmem when STRICT_MODULE_RWX is set

Currently ROX cache in execmem is enabled regardless of
STRICT_MODULE_RWX setting. This breaks an assumption that module memory
is writable when STRICT_MODULE_RWX is disabled, for instance for kernel
debuggin.

Only enable ROX cache in execmem when STRICT_MODULE_RWX is set to
restore the original behaviour of module text permissions.

Fixes: 64f6a4e ("x86: re-enable EXECMEM_ROX support")
Signed-off-by: Mike Rapoport (Microsoft) <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

Author: rppt

arch/x86/Kconfig

@@ -89,7 +89,7 @@ config X86
 	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
 	select ARCH_HAS_EARLY_DEBUG		if KGDB
 	select ARCH_HAS_ELF_RANDOMIZE
-	select ARCH_HAS_EXECMEM_ROX		if X86_64
+	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL