[PATCH v15 3/9] powerpc/modules: Make module_alloc() Strict Module RWX aware

[Jordan Niethe]

Make module_alloc() use PAGE_KERNEL protections instead of
PAGE_KERNEL_EXEX if Strict Module RWX is enabled.

Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
---
v14: - Split out from powerpc: Set ARCH_HAS_STRICT_MODULE_RWX
     - Add and use strict_module_rwx_enabled() helper
---
 arch/powerpc/include/asm/mmu.h | 5 +++++
 arch/powerpc/kernel/module.c   | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 998fe01dd1a8..27016b98ecb2 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -345,6 +345,11 @@ static inline bool strict_kernel_rwx_enabled(void)
 	return false;
 }
 #endif
+
+static inline bool strict_module_rwx_enabled(void)
+{
+	return IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && strict_kernel_rwx_enabled();
+}
 #endif /* !__ASSEMBLY__ */
 
 /* The kernel use the constants below to index in the page sizes array.
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index 3f35c8d20be7..ed04a3ba66fe 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -92,12 +92,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 static __always_inline void *
 __module_alloc(unsigned long size, unsigned long start, unsigned long end)
 {
+	pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
+
 	/*
 	 * Don't do huge page allocations for modules yet until more testing
 	 * is done. STRICT_MODULE_RWX may require extra work to support this
 	 * too.
 	 */
-	return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, PAGE_KERNEL_EXEC,
+	return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL, prot,
 				    VM_FLUSH_RESET_PERMS | VM_NO_HUGE_VMAP,
 				    NUMA_NO_NODE, __builtin_return_address(0));
 }
-- 
2.25.1