vboot: allow firmware to signal a wipeout request

It has become necessary to be able to "factory reset" certain devices
on firmware request. The best mechanism for this is NVRAM, as the
request needs to be detected very early in the boot process, before
other means of communications with the upper layers are available.

A previously unused NVRAM bit (bit 0x08 at offset zero) is taken for
this purpose.

A new flag is introduced to allow the firmware to signal the need to
assert this bit.

A new variable name/parameter ('wipeout_request') added to crossystem
to provide user space access to the setting of the dedicated NVRAM
bit.

BRANCH=storm
BUG=chrome-os-partner:37219
TEST=with all the patches applied, on storm, holding the recovery
     button at startup for 10 seconds, causes 'crossystem
     wipeout_request' to report '1'.

Change-Id: If1f6f061ce5b3f357b92aaa74cb129671dc30446
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/259857
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

9 files changed, 27 insertions, 1 deletions

diff --git a/firmware/2lib/2misc.c b/firmware/2lib/2misc.c
index 5fc76042..53f713b5 100644
--- a/firmware/2lib/2misc.c
+++ b/firmware/2lib/2misc.c
@@ -257,6 +257,9 @@ int vb2_check_dev_switch(struct vb2_context *ctx)
 		vb2_nv_set(ctx, VB2_NV_DEV_BOOT_SIGNED_ONLY, 0);
 	}
 
+	if (ctx->flags & VB2_CONTEXT_FORCE_WIPEOUT_MODE)
+		vb2_nv_set(ctx, VB2_NV_REQ_WIPEOUT, 1);
+
 	if (flags != old_flags) {
 		/*
 		 * Just changed dev mode state.  Clear TPM owner.  This must be
diff --git a/firmware/2lib/2nvstorage.c b/firmware/2lib/2nvstorage.c
index 93d704c8..4d3c8bad 100644
--- a/firmware/2lib/2nvstorage.c
+++ b/firmware/2lib/2nvstorage.c
@@ -149,6 +149,9 @@ uint32_t vb2_nv_get(struct vb2_context *ctx, enum vb2_nv_param param)
 
 	case VB2_NV_CLEAR_TPM_OWNER_DONE:
 		return GETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_DONE);
+
+	case VB2_NV_REQ_WIPEOUT:
+		return GETBIT(VB2_NV_OFFS_HEADER , VB2_NV_HEADER_WIPEOUT);
 	}
 
 	/*
@@ -291,6 +294,10 @@ void vb2_nv_set(struct vb2_context *ctx,
 	case VB2_NV_CLEAR_TPM_OWNER_DONE:
 		SETBIT(VB2_NV_OFFS_TPM, VB2_NV_TPM_CLEAR_OWNER_DONE);
 		break;
+
+	case VB2_NV_REQ_WIPEOUT:
+		SETBIT(VB2_NV_OFFS_HEADER , VB2_NV_HEADER_WIPEOUT);
+		break;
 	}
 
 	/*
diff --git a/firmware/2lib/include/2api.h b/firmware/2lib/include/2api.h
index 9d63e449..92b815f8 100644
--- a/firmware/2lib/include/2api.h
+++ b/firmware/2lib/include/2api.h
@@ -87,6 +87,9 @@ enum vb2_context_flags {
 
 	/* RAM should be cleared by caller this boot */
 	VB2_CONTEXT_CLEAR_RAM = (1 << 7),
+
+	/* Wipeout by the app should be requested. */
+	VB2_CONTEXT_FORCE_WIPEOUT_MODE = (1 << 8),
 };
 
 /*
diff --git a/firmware/2lib/include/2nvstorage.h b/firmware/2lib/include/2nvstorage.h
index 3bda9d78..3b3f34c8 100644
--- a/firmware/2lib/include/2nvstorage.h
+++ b/firmware/2lib/include/2nvstorage.h
@@ -78,6 +78,8 @@ enum vb2_nv_param {
 	VB2_NV_FW_PREV_TRIED,
 	/* Result of trying that firmware (see vb2_fw_result) */
 	VB2_NV_FW_PREV_RESULT,
+	/* Request wipeout of the device by the app. */
+	VB2_NV_REQ_WIPEOUT,
 };
 
 /* Firmware result codes for VB2_NV_FW_RESULT and VB2_NV_FW_PREV_RESULT */
diff --git a/firmware/2lib/include/2nvstorage_fields.h b/firmware/2lib/include/2nvstorage_fields.h
index a794f383..1c4fdf41 100644
--- a/firmware/2lib/include/2nvstorage_fields.h
+++ b/firmware/2lib/include/2nvstorage_fields.h
@@ -34,7 +34,8 @@ enum vb2_nv_offset {
 	VB2_NV_OFFS_CRC = 15
 };
 
-/* Fields in VB2_NV_OFFS_HEADER (unused = 0x0f) */
+/* Fields in VB2_NV_OFFS_HEADER (unused = 0x07) */
+#define VB2_NV_HEADER_WIPEOUT		       0x08
 #define VB2_NV_HEADER_KERNEL_SETTINGS_RESET    0x10
 #define VB2_NV_HEADER_FW_SETTINGS_RESET        0x20
 #define VB2_NV_HEADER_SIGNATURE                0x40
diff --git a/firmware/include/vboot_nvstorage.h b/firmware/include/vboot_nvstorage.h
index 4401777e..65cd2e5b 100644
--- a/firmware/include/vboot_nvstorage.h
+++ b/firmware/include/vboot_nvstorage.h
@@ -102,6 +102,8 @@ typedef enum VbNvParam {
 	VBNV_FW_PREV_TRIED,
 	/* Result of trying that firmware (see vb2_fw_result) */
 	VBNV_FW_PREV_RESULT,
+	/* Wipeout request from firmware present. */
+	VBNV_FW_REQ_WIPEOUT,
 
 } VbNvParam;
 
diff --git a/firmware/lib/vboot_nvstorage.c b/firmware/lib/vboot_nvstorage.c
index a0721d7c..9d99b1c7 100644
--- a/firmware/lib/vboot_nvstorage.c
+++ b/firmware/lib/vboot_nvstorage.c
@@ -25,6 +25,7 @@
 #define HEADER_SIGNATURE                0x40
 #define HEADER_FIRMWARE_SETTINGS_RESET  0x20
 #define HEADER_KERNEL_SETTINGS_RESET    0x10
+#define HEADER_WIPEOUT			0x08
 
 #define BOOT_OFFSET                  1
 #define BOOT_DEBUG_RESET_MODE           0x80
@@ -191,6 +192,10 @@ int VbNvGet(VbNvContext *context, VbNvParam param, uint32_t *dest)
 			>> BOOT2_PREV_RESULT_SHIFT;
 		return 0;
 
+	case VBNV_FW_REQ_WIPEOUT:
+		*dest = (raw[HEADER_OFFSET] & HEADER_WIPEOUT) ? 1 : 0;
+		return 0;
+
 	default:
 		return 1;
 	}
diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c
index 43dcc2a4..1eef737b 100644
--- a/host/lib/crossystem.c
+++ b/host/lib/crossystem.c
@@ -496,6 +496,8 @@ int VbGetSystemPropertyInt(const char* name) {
     value = VbGetNvStorage(VBNV_OPROM_NEEDED);
   } else if (!strcasecmp(name,"recovery_subcode")) {
     value = VbGetNvStorage(VBNV_RECOVERY_SUBCODE);
+  } else if (!strcasecmp(name,"wipeout_request")) {
+    value = VbGetNvStorage(VBNV_FW_REQ_WIPEOUT);
   }
   /* Other parameters */
   else if (!strcasecmp(name,"cros_debug")) {
diff --git a/utility/crossystem.c b/utility/crossystem.c
index 41ed8494..adc828d7 100644
--- a/utility/crossystem.c
+++ b/utility/crossystem.c
@@ -94,6 +94,7 @@ const Param sys_param_list[] = {
   {"vdat_lkdebug", IS_STRING|NO_PRINT_ALL,
    "LoadKernel() debug data (not in print-all)"},
   {"vdat_timers", IS_STRING, "Timer values from VbSharedData"},
+  {"wipeout_request", 0, "Firmware requested factory reset (wipeout)"},
   {"wpsw_boot", 0, "Firmware write protect hardware switch position at boot"},
   {"wpsw_cur", 0, "Firmware write protect hardware switch current position"},
   /* Terminate with null name */