efi: Add support for EFI_MEMORY_RO attribute introduced by UEFIv2.5

The UEFI spec v2.5 introduces a new memory attribute
EFI_MEMORY_RO, which is now the preferred attribute to convey
that the nature of the contents of such a region allows it to be
mapped read-only (i.e., it contains .text and .rodata only).

The specification of the existing EFI_MEMORY_WP attribute has been
updated to align more closely with its common use as a
cacheability attribute rather than a permission attribute.

Add the #define and add the attribute to the memory map dumping
routine.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438936621-5215-1-git-send-email-matt@codeblueprint.co.ukSigned-off-by: Ingo Molnar <mingo@kernel.org>

drivers/firmware/efi/efi.c

@@ -588,16 +588,18 @@ char * __init efi_md_typeattr_format(char *buf, size_t size,
 
 	attr = md->attribute;
 	if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT |
-		     EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_WP |
-		     EFI_MEMORY_RP | EFI_MEMORY_XP | EFI_MEMORY_RUNTIME))
+		     EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_RO |
+		     EFI_MEMORY_WP | EFI_MEMORY_RP | EFI_MEMORY_XP |
+		     EFI_MEMORY_RUNTIME))
 		snprintf(pos, size, "|attr=0x%016llx]",
 			 (unsigned long long)attr);
 	else
-		snprintf(pos, size, "|%3s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]",
+		snprintf(pos, size, "|%3s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]",
 			 attr & EFI_MEMORY_RUNTIME ? "RUN" : "",
 			 attr & EFI_MEMORY_XP      ? "XP"  : "",
 			 attr & EFI_MEMORY_RP      ? "RP"  : "",
 			 attr & EFI_MEMORY_WP      ? "WP"  : "",
+			 attr & EFI_MEMORY_RO      ? "RO"  : "",
 			 attr & EFI_MEMORY_UCE     ? "UCE" : "",
 			 attr & EFI_MEMORY_WB      ? "WB"  : "",
 			 attr & EFI_MEMORY_WT      ? "WT"  : "",

include/linux/efi.h

@@ -99,6 +99,7 @@ typedef	struct {
 #define EFI_MEMORY_XP		((u64)0x0000000000004000ULL)	/* execute-protect */
 #define EFI_MEMORY_MORE_RELIABLE \
 				((u64)0x0000000000010000ULL)	/* higher reliability */
+#define EFI_MEMORY_RO		((u64)0x0000000000020000ULL)	/* read-only */
 #define EFI_MEMORY_RUNTIME	((u64)0x8000000000000000ULL)	/* range requires runtime mapping */
 #define EFI_MEMORY_DESCRIPTOR_VERSION	1