4 files changed, 64 insertions, 15 deletions
diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 7207219509f6..3cf34912abfe 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -27,7 +27,6 @@ CONFIG_CGROUP_MISC=y
 CONFIG_CGROUP_DEBUG=y
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_KALLSYMS_ALL=y
-# CONFIG_COMPAT_BRK is not set
 CONFIG_PROFILING=y
 CONFIG_SMP=y
 CONFIG_HYPERVISOR_GUEST=y
@@ -44,6 +43,7 @@ CONFIG_EFI_STUB=y
 CONFIG_HZ_1000=y
 CONFIG_KEXEC=y
 CONFIG_CRASH_DUMP=y
+# CONFIG_RETHUNK is not set
 CONFIG_HIBERNATION=y
 CONFIG_PM_DEBUG=y
 CONFIG_PM_TRACE_RTC=y
@@ -62,6 +62,7 @@ CONFIG_BLK_CGROUP_IOLATENCY=y
 CONFIG_BLK_CGROUP_IOCOST=y
 CONFIG_BLK_CGROUP_IOPRIO=y
 CONFIG_BINFMT_MISC=y
+# CONFIG_COMPAT_BRK is not set
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
@@ -269,9 +270,10 @@ CONFIG_SECURITY_SELINUX=y
 CONFIG_SECURITY_SELINUX_BOOTPARAM=y
 CONFIG_SECURITY_SELINUX_DISABLE=y
 CONFIG_PRINTK_TIME=y
+CONFIG_DEBUG_KERNEL=y
 CONFIG_FRAME_WARN=1024
 CONFIG_MAGIC_SYSRQ=y
-CONFIG_DEBUG_KERNEL=y
+CONFIG_DEBUG_WX=y
 CONFIG_DEBUG_STACK_USAGE=y
 # CONFIG_SCHED_DEBUG is not set
 CONFIG_SCHEDSTATS=y
diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
index 5ce67b73e218..27759236fd60 100644
--- a/arch/x86/configs/x86_64_defconfig
+++ b/arch/x86/configs/x86_64_defconfig
@@ -26,7 +26,6 @@ CONFIG_CGROUP_MISC=y
 CONFIG_CGROUP_DEBUG=y
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_KALLSYMS_ALL=y
-# CONFIG_COMPAT_BRK is not set
 CONFIG_PROFILING=y
 CONFIG_SMP=y
 CONFIG_HYPERVISOR_GUEST=y
@@ -62,6 +61,7 @@ CONFIG_BLK_CGROUP_IOLATENCY=y
 CONFIG_BLK_CGROUP_IOCOST=y
 CONFIG_BLK_CGROUP_IOPRIO=y
 CONFIG_BINFMT_MISC=y
+# CONFIG_COMPAT_BRK is not set
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y
@@ -267,8 +267,9 @@ CONFIG_SECURITY_SELINUX=y
 CONFIG_SECURITY_SELINUX_BOOTPARAM=y
 CONFIG_SECURITY_SELINUX_DISABLE=y
 CONFIG_PRINTK_TIME=y
-CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
+CONFIG_MAGIC_SYSRQ=y
+CONFIG_DEBUG_WX=y
 CONFIG_DEBUG_STACK_USAGE=y
 # CONFIG_SCHED_DEBUG is not set
 CONFIG_SCHEDSTATS=y
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 0fe690ebc269..7ea7d4745681 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -90,6 +90,12 @@ DEFINE_ENTRY(pud, pud, init)
 DEFINE_ENTRY(pmd, pmd, init)
 DEFINE_ENTRY(pte, pte, init)
 
+static inline pgprot_t prot_sethuge(pgprot_t prot)
+{
+	WARN_ON_ONCE(pgprot_val(prot) & _PAGE_PAT);
+
+	return __pgprot(pgprot_val(prot) | _PAGE_PSE);
+}
 
 /*
  * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
@@ -557,9 +563,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end,
 		if (page_size_mask & (1<<PG_LEVEL_2M)) {
 			pages++;
 			spin_lock(&init_mm.page_table_lock);
-			set_pte_init((pte_t *)pmd,
-				     pfn_pte((paddr & PMD_MASK) >> PAGE_SHIFT,
-					     __pgprot(pgprot_val(prot) | _PAGE_PSE)),
+			set_pmd_init(pmd,
+				     pfn_pmd(paddr >> PAGE_SHIFT, prot_sethuge(prot)),
 				     init);
 			spin_unlock(&init_mm.page_table_lock);
 			paddr_last = paddr_next;
@@ -644,12 +649,8 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end,
 		if (page_size_mask & (1<<PG_LEVEL_1G)) {
 			pages++;
 			spin_lock(&init_mm.page_table_lock);
-
-			prot = __pgprot(pgprot_val(prot) | _PAGE_PSE);
-
-			set_pte_init((pte_t *)pud,
-				     pfn_pte((paddr & PUD_MASK) >> PAGE_SHIFT,
-					     prot),
+			set_pud_init(pud,
+				     pfn_pud(paddr >> PAGE_SHIFT, prot_sethuge(prot)),
 				     init);
 			spin_unlock(&init_mm.page_table_lock);
 			paddr_last = paddr_next;
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 1abd5438f126..97342c42dda8 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -580,6 +580,46 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,
 }
 
 /*
+ * Validate strict W^X semantics.
+ */
+static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,
+				  unsigned long pfn, unsigned long npg)
+{
+	unsigned long end;
+
+	/*
+	 * 32-bit has some unfixable W+X issues, like EFI code
+	 * and writeable data being in the same page.  Disable
+	 * detection and enforcement there.
+	 */
+	if (IS_ENABLED(CONFIG_X86_32))
+		return new;
+
+	/* Only verify when NX is supported: */
+	if (!(__supported_pte_mask & _PAGE_NX))
+		return new;
+
+	if (!((pgprot_val(old) ^ pgprot_val(new)) & (_PAGE_RW | _PAGE_NX)))
+		return new;
+
+	if ((pgprot_val(new) & (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)
+		return new;
+
+	end = start + npg * PAGE_SIZE - 1;
+	WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
+		  (unsigned long long)pgprot_val(old),
+		  (unsigned long long)pgprot_val(new),
+		  start, end, pfn);
+
+	/*
+	 * For now, allow all permission change attempts by returning the
+	 * attempted permissions.  This can 'return old' to actively
+	 * refuse the permission change at a later time.
+	 */
+	return new;
+}
+
+/*
  * Lookup the page table entry for a virtual address in a specific pgd.
  * Return a pointer to the entry and the level of the mapping.
  */
@@ -885,6 +925,8 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
 	new_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,
 				      psize, CPA_DETECT);
 
+	new_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages);
+
 	/*
 	 * If there is a conflict, split the large page.
 	 *
@@ -1525,6 +1567,7 @@ repeat:
 
 	if (level == PG_LEVEL_4K) {
 		pte_t new_pte;
+		pgprot_t old_prot = pte_pgprot(old_pte);
 		pgprot_t new_prot = pte_pgprot(old_pte);
 		unsigned long pfn = pte_pfn(old_pte);
 
@@ -1536,6 +1579,8 @@ repeat:
 		new_prot = static_protections(new_prot, address, pfn, 1, 0,
 					      CPA_PROTECT);
 
+		new_prot = verify_rwx(old_prot, new_prot, address, pfn, 1);
+
 		new_prot = pgprot_clear_protnone_bits(new_prot);
 
 		/*
@@ -1944,7 +1989,7 @@ int set_mce_nospec(unsigned long pfn)
 	return rc;
 }
 
-static int set_memory_present(unsigned long *addr, int numpages)
+static int set_memory_p(unsigned long *addr, int numpages)
 {
 	return change_page_attr_set(addr, numpages, __pgprot(_PAGE_PRESENT), 0);
 }
@@ -1954,7 +1999,7 @@ int clear_mce_nospec(unsigned long pfn)
 {
 	unsigned long addr = (unsigned long) pfn_to_kaddr(pfn);
 
-	return set_memory_present(&addr, 1);
+	return set_memory_p(&addr, 1);
 }
 EXPORT_SYMBOL_GPL(clear_mce_nospec);
 #endif /* CONFIG_X86_64 */