xen/arm: mm: Use memory flags for modify_xen_mappings rather than custom one

This will help to consolidate the page-table code and avoid different
path depending on the action to perform.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

xen/arch/arm/livepatch.c

@@ -146,15 +146,15 @@ int arch_livepatch_secure(const void *va, unsigned int pages, enum va_type type)
     switch ( type )
     {
     case LIVEPATCH_VA_RX:
-        flags = PTE_RO; /* R set, NX clear */
+        flags = PAGE_HYPERVISOR_RX;
         break;
 
     case LIVEPATCH_VA_RW:
-        flags = PTE_NX; /* R clear, NX set */
+        flags = PAGE_HYPERVISOR_RW;
         break;
 
     case LIVEPATCH_VA_RO:
-        flags = PTE_NX | PTE_RO; /* R set, NX set */
+        flags = PAGE_HYPERVISOR_RO;
         break;
 
     default:

xen/arch/arm/mm.c

@@ -1041,8 +1041,8 @@ static int create_xen_entries(enum xenmap_operation op,
                 else
                 {
                     pte = *entry;
-                    pte.pt.ro = PTE_RO_MASK(flags);
-                    pte.pt.xn = PTE_NX_MASK(flags);
+                    pte.pt.ro = PAGE_RO_MASK(flags);
+                    pte.pt.xn = PAGE_XN_MASK(flags);
                     if ( !pte.pt.ro && !pte.pt.xn )
                     {
                         printk("%s: Incorrect combination for addr=%lx\n",
@@ -1085,7 +1085,6 @@ int destroy_xen_mappings(unsigned long v, unsigned long e)
 
 int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int flags)
 {
-    ASSERT((flags & (PTE_NX | PTE_RO)) == flags);
     return create_xen_entries(MODIFY, s, INVALID_MFN, (e - s) >> PAGE_SHIFT,
                               flags);
 }

xen/include/asm-arm/page.h

@@ -95,17 +95,6 @@
 #define PAGE_HYPERVISOR_NOCACHE (_PAGE_DEVICE|MT_DEVICE_nGnRE)
 #define PAGE_HYPERVISOR_WC      (_PAGE_DEVICE|MT_NORMAL_NC)
 
-/*
- * Defines for changing the hypervisor PTE .ro and .nx bits. This is only to be
- * used with modify_xen_mappings.
- */
-#define _PTE_NX_BIT     0U
-#define _PTE_RO_BIT     1U
-#define PTE_NX          (1U << _PTE_NX_BIT)
-#define PTE_RO          (1U << _PTE_RO_BIT)
-#define PTE_NX_MASK(x)  (((x) >> _PTE_NX_BIT) & 0x1U)
-#define PTE_RO_MASK(x)  (((x) >> _PTE_RO_BIT) & 0x1U)
-
 /*
  * Stage 2 Memory Type.
  *