Allow building for non-CrOS environments

There's some code that is architecture specific, but looking at
it, it's code for Chrome OS devices that just happens to be
split along ISA lines.

When building on systems that we don't ship crossystems integration for,
these parts are replaced by stubs that always return error conditions,
which allows building on unsupported ISA (such as POWER).

The issue was reported at https://ticket.coreboot.org/issues/145
where a coreboot user wanted to build a vboot-enabled coreboot
configuration (which builds futility for the signing part) on a
POWER host system, which failed because we lack an implementation
of the crossystem interfaces for POWER.

BUG=none
BRANCH=none
TEST=Built upstream coreboot with a vboot-enabled target inside
qemu-user-ppc64. Doing so works with these patches applied
while it failed without them.

Change-Id: I4aaeb56d4521c426a520bc9a1bb49497bec86c35
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2270096
Commit-Queue: Patrick Georgi <pgeorgi@chromium.org>
Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

2 files changed, 57 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index e3b66303..274fe2a0 100644
--- a/Makefile
+++ b/Makefile
@@ -104,6 +104,12 @@ else ifeq (${ARCH},amd64)
   override ARCH := x86_64
 endif
 
+ifneq ($(wildcard host/arch/${ARCH}/lib/crossystem_arch.c),)
+	CROSSYSTEM_ARCH_C := host/arch/${ARCH}/lib/crossystem_arch.c
+else
+	CROSSYSTEM_ARCH_C := host/arch/stub/lib/crossystem_arch.c
+endif
+
 # FIRMWARE_ARCH is only defined by the Chromium OS ebuild if compiling
 # for a firmware target (coreboot or depthcharge). It must map to the same
 # consistent set of architectures as the host.
@@ -445,7 +451,7 @@ UTILLIB_SRCS = \
 	cgpt/cgpt_repair.c \
 	cgpt/cgpt_show.c \
 	futility/dump_kernel_config_lib.c \
-	host/arch/${ARCH}/lib/crossystem_arch.c \
+	$(CROSSYSTEM_ARCH_C) \
 	host/lib/chromeos_config.c \
 	host/lib/crossystem.c \
 	host/lib/crypto.c \
@@ -505,7 +511,7 @@ HOSTLIB_SRCS = \
 	firmware/stub/vboot_api_stub_disk.c \
 	firmware/stub/vboot_api_stub_init.c \
 	futility/dump_kernel_config_lib.c \
-	host/arch/${ARCH}/lib/crossystem_arch.c \
+	$(CROSSYSTEM_ARCH_C) \
 	host/lib/chromeos_config.c \
 	host/lib/crossystem.c \
 	host/lib/crypto.c \
diff --git a/host/arch/stub/lib/crossystem_arch.c b/host/arch/stub/lib/crossystem_arch.c
new file mode 100644
index 00000000..4a71dddc
--- /dev/null
+++ b/host/arch/stub/lib/crossystem_arch.c
@@ -0,0 +1,49 @@
+/* Copyright (c) 2020 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "crossystem_arch.h"
+#include "crossystem.h"
+#include "crossystem_vbnv.h"
+#include "host_common.h"
+#include "vboot_struct.h"
+
+int vb2_read_nv_storage(struct vb2_context *ctx)
+{
+	return -1;
+}
+
+
+int vb2_write_nv_storage(struct vb2_context *ctx)
+{
+	return -1;
+}
+
+VbSharedDataHeader* VbSharedDataRead(void)
+{
+	return NULL;
+}
+
+int VbGetArchPropertyInt(const char* name)
+{
+	return -1;
+}
+
+
+const char* VbGetArchPropertyString(const char* name, char* dest,
+				    size_t size)
+{
+	return NULL;
+}
+
+
+int VbSetArchPropertyInt(const char* name, int value)
+{
+	return -1;
+}
+
+int VbSetArchPropertyString(const char* name, const char* value)
+{
+	return -1;
+}