Merge tag 'efi-fixes-for-v6.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:

 - Force the use of SetVirtualAddressMap() on Ampera Altra arm64
   machines, which crash in SetTime() if no virtual remapping is used

   This is the first time we've added an SMBIOS based quirk on arm64,
   but fortunately, we can just call a EFI protocol to grab the type #1
   SMBIOS record when running in the stub, so we don't need all the
   machinery we have in the kernel proper to parse SMBIOS data.

 - Drop a spurious warning on misaligned runtime regions when using 16k
   or 64k pages on arm64

* tag 'efi-fixes-for-v6.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  arm64: efi: Fix handling of misaligned runtime regions and drop warning
  arm64: efi: Force the use of SetVirtualAddressMap() on Altra machines

4 files changed, 93 insertions, 2 deletions

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index b1601aad7e1a..ef5045a53ce0 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -82,7 +82,7 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
 lib-$(CONFIG_EFI_GENERIC_STUB)	+= efi-stub.o string.o intrinsics.o systable.o
 
 lib-$(CONFIG_ARM)		+= arm32-stub.o
-lib-$(CONFIG_ARM64)		+= arm64-stub.o
+lib-$(CONFIG_ARM64)		+= arm64-stub.o smbios.o
 lib-$(CONFIG_X86)		+= x86-stub.o
 lib-$(CONFIG_RISCV)		+= riscv-stub.o
 lib-$(CONFIG_LOONGARCH)		+= loongarch-stub.o
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 259e4b852d63..f9de5217ea65 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -15,6 +15,21 @@
 
 #include "efistub.h"
 
+static bool system_needs_vamap(void)
+{
+	const u8 *type1_family = efi_get_smbios_string(1, family);
+
+	/*
+	 * Ampere Altra machines crash in SetTime() if SetVirtualAddressMap()
+	 * has not been called prior.
+	 */
+	if (!type1_family || strcmp(type1_family, "Altra"))
+		return false;
+
+	efi_warn("Working around broken SetVirtualAddressMap()\n");
+	return true;
+}
+
 efi_status_t check_platform_features(void)
 {
 	u64 tg;
@@ -24,7 +39,7 @@ efi_status_t check_platform_features(void)
 	 * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is
 	 * unnecessary.
 	 */
-	if (VA_BITS_MIN >= 48)
+	if (VA_BITS_MIN >= 48 && !system_needs_vamap())
 		efi_novamap = true;
 
 	/* UEFI mandates support for 4 KB granularity, no need to check */
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index a30fb5d8ef05..eb03d5a9aac8 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -975,4 +975,32 @@ efi_enable_reset_attack_mitigation(void) { }
 
 void efi_retrieve_tpm2_eventlog(void);
 
+struct efi_smbios_record {
+	u8	type;
+	u8	length;
+	u16	handle;
+};
+
+struct efi_smbios_type1_record {
+	struct efi_smbios_record	header;
+
+	u8				manufacturer;
+	u8				product_name;
+	u8				version;
+	u8				serial_number;
+	efi_guid_t			uuid;
+	u8				wakeup_type;
+	u8				sku_number;
+	u8				family;
+};
+
+#define efi_get_smbios_string(__type, __name) ({			\
+	int size = sizeof(struct efi_smbios_type ## __type ## _record);	\
+	int off = offsetof(struct efi_smbios_type ## __type ## _record,	\
+			   __name);					\
+	__efi_get_smbios_string(__type, off, size);			\
+})
+
+const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize);
+
 #endif
diff --git a/drivers/firmware/efi/libstub/smbios.c b/drivers/firmware/efi/libstub/smbios.c
new file mode 100644
index 000000000000..460418b7f5f5
--- /dev/null
+++ b/drivers/firmware/efi/libstub/smbios.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright 2022 Google LLC
+// Author: Ard Biesheuvel <ardb@google.com>
+
+#include <linux/efi.h>
+
+#include "efistub.h"
+
+typedef struct efi_smbios_protocol efi_smbios_protocol_t;
+
+struct efi_smbios_protocol {
+	efi_status_t (__efiapi *add)(efi_smbios_protocol_t *, efi_handle_t,
+				     u16 *, struct efi_smbios_record *);
+	efi_status_t (__efiapi *update_string)(efi_smbios_protocol_t *, u16 *,
+					       unsigned long *, u8 *);
+	efi_status_t (__efiapi *remove)(efi_smbios_protocol_t *, u16);
+	efi_status_t (__efiapi *get_next)(efi_smbios_protocol_t *, u16 *, u8 *,
+					  struct efi_smbios_record **,
+					  efi_handle_t *);
+
+	u8 major_version;
+	u8 minor_version;
+};
+
+const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize)
+{
+	struct efi_smbios_record *record;
+	efi_smbios_protocol_t *smbios;
+	efi_status_t status;
+	u16 handle = 0xfffe;
+	const u8 *strtable;
+
+	status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL,
+			     (void **)&smbios) ?:
+		 efi_call_proto(smbios, get_next, &handle, &type, &record, NULL);
+	if (status != EFI_SUCCESS)
+		return NULL;
+
+	strtable = (u8 *)record + recsize;
+	for (int i = 1; i < ((u8 *)record)[offset]; i++) {
+		int len = strlen(strtable);
+
+		if (!len)
+			return NULL;
+		strtable += len + 1;
+	}
+	return strtable;
+}