1 files changed, 22 insertions, 0 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index dd38bfbefd1f..1d4eb93d333c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -279,6 +279,22 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
                    __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
                 pgprot_val(forbidden) |= _PAGE_RW;
 
+#if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA)
+        /*
+         * Once the kernel maps the text as RO (kernel_set_to_readonly is set),
+         * kernel text mappings for the large page aligned text, rodata sections
+         * will be always read-only. For the kernel identity mappings covering
+         * the holes caused by this alignment can be anything that user asks.
+         *
+         * This will preserve the large page mappings for kernel text/data
+         * at no extra cost.
+         */
+        if (kernel_set_to_readonly &&
+            within(address, (unsigned long)_text,
+                   (unsigned long)__end_rodata_hpage_align))
+                pgprot_val(forbidden) |= _PAGE_RW;
+#endif
+
         prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
 
         return prot;
@@ -1069,12 +1085,18 @@ EXPORT_SYMBOL(set_memory_array_wb);
 
 int set_memory_x(unsigned long addr, int numpages)
 {
+        if (!(__supported_pte_mask & _PAGE_NX))
+                return 0;
+
         return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_NX), 0);
 }
 EXPORT_SYMBOL(set_memory_x);
 
 int set_memory_nx(unsigned long addr, int numpages)
 {
+        if (!(__supported_pte_mask & _PAGE_NX))
+                return 0;
+
         return change_page_attr_set(&addr, numpages, __pgprot(_PAGE_NX), 0);
 }
 EXPORT_SYMBOL(set_memory_nx);