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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-01-10 11:29:07 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2016-02-24 15:57:28 +0100
commite4fbf4767440472f9d23b0f25a2b905e1c63b6a8 (patch)
treed1f6ba26628fce6a1aee36e81ab754443729cbcf /drivers/firmware
parentarm64: kaslr: randomize the linear region (diff)
downloadlinux-e4fbf4767440472f9d23b0f25a2b905e1c63b6a8.tar.xz
linux-e4fbf4767440472f9d23b0f25a2b905e1c63b6a8.zip
efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL
This exposes the firmware's implementation of EFI_RNG_PROTOCOL via a new function efi_get_random_bytes(). Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/libstub/Makefile2
-rw-r--r--drivers/firmware/efi/libstub/efistub.h3
-rw-r--r--drivers/firmware/efi/libstub/random.c35
3 files changed, 39 insertions, 1 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index aaf9c0bab42e..ad077944aa0e 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -36,7 +36,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
$(patsubst %.c,lib-%.o,$(arm-deps))
lib-$(CONFIG_ARM) += arm32-stub.o
-lib-$(CONFIG_ARM64) += arm64-stub.o
+lib-$(CONFIG_ARM64) += arm64-stub.o random.o
CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET)
#
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 6b6548fda089..206b7252b9d1 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -43,4 +43,7 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
unsigned long desc_size, efi_memory_desc_t *runtime_map,
int *count);
+efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table,
+ unsigned long size, u8 *out);
+
#endif
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
new file mode 100644
index 000000000000..97941ee5954f
--- /dev/null
+++ b/drivers/firmware/efi/libstub/random.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2016 Linaro Ltd; <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+struct efi_rng_protocol {
+ efi_status_t (*get_info)(struct efi_rng_protocol *,
+ unsigned long *, efi_guid_t *);
+ efi_status_t (*get_rng)(struct efi_rng_protocol *,
+ efi_guid_t *, unsigned long, u8 *out);
+};
+
+efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table_arg,
+ unsigned long size, u8 *out)
+{
+ efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;
+ efi_status_t status;
+ struct efi_rng_protocol *rng;
+
+ status = efi_call_early(locate_protocol, &rng_proto, NULL,
+ (void **)&rng);
+ if (status != EFI_SUCCESS)
+ return status;
+
+ return rng->get_rng(rng, NULL, size, out);
+}