[RFC V1 10/31] x86/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT

[Anshuman Khandual <anshuman.khandual@arm.com>]

From: Christoph Hellwig <hch@infradead.org>

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
macros can be dropped which are no longer needed. This also unsubscribes
from ARCH_HAS_FILTER_PGPROT, after dropping off arch_filter_pgprot() and
arch_vm_get_page_prot().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
 arch/x86/Kconfig                     |  2 +-
 arch/x86/include/asm/pgtable.h       |  5 --
 arch/x86/include/asm/pgtable_types.h | 19 --------
 arch/x86/include/uapi/asm/mman.h     | 14 ------
 arch/x86/mm/Makefile                 |  2 +-
 arch/x86/mm/mem_encrypt_amd.c        |  4 --
 arch/x86/mm/pgprot.c                 | 71 ++++++++++++++++++++++++++++
 7 files changed, 73 insertions(+), 44 deletions(-)
 create mode 100644 arch/x86/mm/pgprot.c

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5f33a10d3dcc..00ab039044ba 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -75,7 +75,6 @@ config X86
 	select ARCH_HAS_EARLY_DEBUG		if KGDB
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FAST_MULTIPLIER
-	select ARCH_HAS_FILTER_PGPROT
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV			if X86_64
@@ -94,6 +93,7 @@ config X86
 	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
 	select ARCH_HAS_SYSCALL_WRAPPER
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
+	select ARCH_HAS_VM_GET_PAGE_PROT
 	select ARCH_HAS_DEBUG_WX
 	select ARCH_HAS_ZONE_DMA_SET if EXPERT
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 8a9432fb3802..985e1b823691 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -648,11 +648,6 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 
 #define canon_pgprot(p) __pgprot(massage_pgprot(p))
 
-static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
-{
-	return canon_pgprot(prot);
-}
-
 static inline int is_new_memtype_allowed(u64 paddr, unsigned long size,
 					 enum page_cache_mode pcm,
 					 enum page_cache_mode new_pcm)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 40497a9020c6..1a9dd933088e 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -228,25 +228,6 @@ enum page_cache_mode {
 
 #endif	/* __ASSEMBLY__ */
 
-/*         xwr */
-#define __P000	PAGE_NONE
-#define __P001	PAGE_READONLY
-#define __P010	PAGE_COPY
-#define __P011	PAGE_COPY
-#define __P100	PAGE_READONLY_EXEC
-#define __P101	PAGE_READONLY_EXEC
-#define __P110	PAGE_COPY_EXEC
-#define __P111	PAGE_COPY_EXEC
-
-#define __S000	PAGE_NONE
-#define __S001	PAGE_READONLY
-#define __S010	PAGE_SHARED
-#define __S011	PAGE_SHARED
-#define __S100	PAGE_READONLY_EXEC
-#define __S101	PAGE_READONLY_EXEC
-#define __S110	PAGE_SHARED_EXEC
-#define __S111	PAGE_SHARED_EXEC
-
 /*
  * early identity mapping  pte attrib macros.
  */
diff --git a/arch/x86/include/uapi/asm/mman.h b/arch/x86/include/uapi/asm/mman.h
index d4a8d0424bfb..775dbd3aff73 100644
--- a/arch/x86/include/uapi/asm/mman.h
+++ b/arch/x86/include/uapi/asm/mman.h
@@ -5,20 +5,6 @@
 #define MAP_32BIT	0x40		/* only give out 32bit addresses */
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-/*
- * Take the 4 protection key bits out of the vma->vm_flags
- * value and turn them in to the bits that we can put in
- * to a pte.
- *
- * Only override these if Protection Keys are available
- * (which is only on 64-bit).
- */
-#define arch_vm_get_page_prot(vm_flags)	__pgprot(	\
-		((vm_flags) & VM_PKEY_BIT0 ? _PAGE_PKEY_BIT0 : 0) |	\
-		((vm_flags) & VM_PKEY_BIT1 ? _PAGE_PKEY_BIT1 : 0) |	\
-		((vm_flags) & VM_PKEY_BIT2 ? _PAGE_PKEY_BIT2 : 0) |	\
-		((vm_flags) & VM_PKEY_BIT3 ? _PAGE_PKEY_BIT3 : 0))
-
 #define arch_calc_vm_prot_bits(prot, key) (		\
 		((key) & 0x1 ? VM_PKEY_BIT0 : 0) |      \
 		((key) & 0x2 ? VM_PKEY_BIT1 : 0) |      \
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index fe3d3061fc11..fb6b41a48ae5 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -20,7 +20,7 @@ CFLAGS_REMOVE_mem_encrypt_identity.o	= -pg
 endif
 
 obj-y				:=  init.o init_$(BITS).o fault.o ioremap.o extable.o mmap.o \
-				    pgtable.o physaddr.o setup_nx.o tlb.o cpu_entry_area.o maccess.o
+				    pgtable.o physaddr.o setup_nx.o tlb.o cpu_entry_area.o maccess.o pgprot.o
 
 obj-y				+= pat/
 
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 2b2d018ea345..e0ac16ee08f4 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -188,10 +188,6 @@ void __init sme_early_init(void)
 
 	__supported_pte_mask = __sme_set(__supported_pte_mask);
 
-	/* Update the protection map with memory encryption mask */
-	for (i = 0; i < ARRAY_SIZE(protection_map); i++)
-		protection_map[i] = pgprot_encrypted(protection_map[i]);
-
 	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
 		swiotlb_force = SWIOTLB_FORCE;
 }
diff --git a/arch/x86/mm/pgprot.c b/arch/x86/mm/pgprot.c
new file mode 100644
index 000000000000..a813adabfe4f
--- /dev/null
+++ b/arch/x86/mm/pgprot.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <asm/pgtable.h>
+
+static inline pgprot_t __vm_get_page_prot(unsigned long vm_flags)
+{
+	switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
+	case 0:
+		return PAGE_NONE;
+	case VM_READ:
+		return PAGE_READONLY;
+	case VM_WRITE:
+		return PAGE_COPY;
+	case VM_READ | VM_WRITE:
+		return PAGE_COPY;
+	case VM_EXEC:
+	case VM_EXEC | VM_READ:
+		return PAGE_READONLY_EXEC;
+	case VM_EXEC | VM_WRITE:
+	case VM_EXEC | VM_READ | VM_WRITE:
+		return PAGE_COPY_EXEC;
+	case VM_SHARED:
+		return PAGE_NONE;
+	case VM_SHARED | VM_READ:
+		return PAGE_READONLY;
+	case VM_SHARED | VM_WRITE:
+	case VM_SHARED | VM_READ | VM_WRITE:
+		return PAGE_SHARED;
+	case VM_SHARED | VM_EXEC:
+	case VM_SHARED | VM_READ | VM_EXEC:
+		return PAGE_READONLY_EXEC;
+	case VM_SHARED | VM_WRITE | VM_EXEC:
+	case VM_SHARED | VM_READ | VM_WRITE | VM_EXEC:
+		return PAGE_SHARED_EXEC;
+	default:
+		BUILD_BUG();
+		return PAGE_NONE;
+	}
+}
+
+
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+	unsigned long val = pgprot_val(__vm_get_page_prot(vm_flags));
+
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+	/*
+	 * Take the 4 protection key bits out of the vma->vm_flags value and
+	 * turn them in to the bits that we can put in to a pte.
+	 *
+	 * Only override these if Protection Keys are available (which is only
+	 * on 64-bit).
+	 */
+	if (vm_flags & VM_PKEY_BIT0)
+		val |= _PAGE_PKEY_BIT0;
+	if (vm_flags & VM_PKEY_BIT1)
+		val |= _PAGE_PKEY_BIT1;
+	if (vm_flags & VM_PKEY_BIT2)
+		val |= _PAGE_PKEY_BIT2;
+	if (vm_flags & VM_PKEY_BIT3)
+		val |= _PAGE_PKEY_BIT3;
+#endif
+
+	val = __sme_set(val);
+	if (val & _PAGE_PRESENT)
+		val &= __supported_pte_mask;
+	return __pgprot(val);
+}
+EXPORT_SYMBOL(vm_get_page_prot);
-- 
2.25.1