vboot: restructure vboot work buffer handling

For the purpose of isolating the work buffer logic
the surface area of the API was slimmed down.  The
vb2_working_data structure is no longer exposed,
and the function signatures are updated accordingly.

BUG=chrome-os-partner:44827
BRANCH=None
TEST=Built and booted glados.

Change-Id: If64184a79e9571ee8ef9822cfce1eda20fceee00
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11818
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

5 files changed, 89 insertions, 83 deletions

diff --git a/src/vendorcode/google/chromeos/vboot2/common.c b/src/vendorcode/google/chromeos/vboot2/common.c
index f6f5b96070..a33fb8e98e 100644
--- a/src/vendorcode/google/chromeos/vboot2/common.c
+++ b/src/vendorcode/google/chromeos/vboot2/common.c
@@ -21,14 +21,30 @@
 #include <cbmem.h>
 #include <console/console.h>
 #include <reset.h>
+#include <string.h>
+#include <vb2_api.h>
 #include "../chromeos.h"
 #include "../symbols.h"
 #include "../vboot_handoff.h"
 #include "misc.h"
 
+/*
+ * this is placed at the start of the vboot work buffer. selected_region is used
+ * for the verstage to return the location of the selected slot. buffer is used
+ * by the vboot2 core. Keep the struct cpu architecture agnostic as it crosses
+ * stage boundaries.
+ */
+struct vb2_working_data {
+	uint32_t selected_region_offset;
+	uint32_t selected_region_size;
+	/* offset of the buffer from the start of this struct */
+	uint32_t buffer_offset;
+	uint32_t buffer_size;
+};
+
 static const size_t vb_work_buf_size = 16 * KiB;
 
-struct vb2_working_data * const vboot_get_working_data(void)
+static struct vb2_working_data * const vboot_get_working_data(void)
 {
 	if (IS_ENABLED(CONFIG_VBOOT_DYNAMIC_WORK_BUFFER))
 		/* cbmem_add() does a cbmem_find() first. */
@@ -37,7 +53,7 @@ struct vb2_working_data * const vboot_get_working_data(void)
 		return (struct vb2_working_data *)_vboot2_work;
 }
 
-size_t vb2_working_data_size(void)
+static size_t vb2_working_data_size(void)
 {
 	if (IS_ENABLED(CONFIG_VBOOT_DYNAMIC_WORK_BUFFER))
 		return vb_work_buf_size;
@@ -45,7 +61,60 @@ size_t vb2_working_data_size(void)
 		return _vboot2_work_size;
 }
 
-void *vboot_get_work_buffer(struct vb2_working_data *wd)
+void vb2_init_work_context(struct vb2_context *ctx)
 {
+	struct vb2_working_data *wd;
+	size_t work_size;
+
+	/* First initialize the working data region. */
+	work_size = vb2_working_data_size();
+	wd = vboot_get_working_data();
+	memset(wd, 0, work_size);
+
+	/*
+	 * vboot prefers 16-byte alignment. This takes away 16 bytes
+	 * from the VBOOT2_WORK region, but the vboot devs said that's okay.
+	 */
+	wd->buffer_offset = ALIGN_UP(sizeof(*wd), 16);
+	wd->buffer_size = work_size - wd->buffer_offset;
+
+	/* Initialize the vb2_context. */
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->workbuf = (void *)vb2_get_shared_data();
+	ctx->workbuf_size = wd->buffer_size;
+
+}
+
+struct vb2_shared_data *vb2_get_shared_data(void)
+{
+	struct vb2_working_data *wd = vboot_get_working_data();
 	return (void *)((uintptr_t)wd + wd->buffer_offset);
 }
+
+int vb2_get_selected_region(struct region_device *rdev)
+{
+	const struct vb2_working_data *wd = vboot_get_working_data();
+	struct region reg = {
+		.offset = wd->selected_region_offset,
+		.size = wd->selected_region_size,
+	};
+	return vboot_region_device(&reg, rdev);
+}
+
+void vb2_set_selected_region(struct region_device *rdev)
+{
+	struct vb2_working_data *wd = vboot_get_working_data();
+	wd->selected_region_offset = region_device_offset(rdev);
+	wd->selected_region_size = region_device_sz(rdev);
+}
+
+int vboot_is_slot_selected(void)
+{
+	const struct vb2_working_data *wd = vboot_get_working_data();
+	return wd->selected_region_size > 0;
+}
+
+int vboot_is_readonly_path(void)
+{
+	return !vboot_is_slot_selected();
+}
diff --git a/src/vendorcode/google/chromeos/vboot2/misc.h b/src/vendorcode/google/chromeos/vboot2/misc.h
index 305d0daf1a..fbbc46ef5c 100644
--- a/src/vendorcode/google/chromeos/vboot2/misc.h
+++ b/src/vendorcode/google/chromeos/vboot2/misc.h
@@ -22,55 +22,21 @@
 
 #include "../vboot_common.h"
 
+struct vb2_context;
+struct vb2_shared_data;
+
 void vboot_fill_handoff(void);
 void *vboot_load_stage(int stage_index,
 		       struct region *fw_main,
 		       struct vboot_components *fw_info);
 
-/*
- * this is placed at the start of the vboot work buffer. selected_region is used
- * for the verstage to return the location of the selected slot. buffer is used
- * by the vboot2 core. Keep the struct cpu architecture agnostic as it crosses
- * stage boundaries.
- */
-struct vb2_working_data {
-	uint32_t selected_region_offset;
-	uint32_t selected_region_size;
-	/* offset of the buffer from the start of this struct */
-	uint32_t buffer_offset;
-	uint32_t buffer_size;
-};
-
-struct vb2_working_data * const vboot_get_working_data(void);
-size_t vb2_working_data_size(void);
-void *vboot_get_work_buffer(struct vb2_working_data *wd);
+void vb2_init_work_context(struct vb2_context *ctx);
+struct vb2_shared_data *vb2_get_shared_data(void);
 
 /* Returns 0 on success. < 0 on failure. */
-static inline int vb2_get_selected_region(struct vb2_working_data *wd,
-					   struct region_device *rdev)
-{
-	struct region reg = {
-		.offset = wd->selected_region_offset,
-		.size = wd->selected_region_size,
-	};
-	return vboot_region_device(&reg, rdev);
-}
-
-static inline void vb2_set_selected_region(struct vb2_working_data *wd,
-					   struct region_device *rdev)
-{
-	wd->selected_region_offset = region_device_offset(rdev);
-	wd->selected_region_size = region_device_sz(rdev);
-}
-
-static inline int vboot_is_slot_selected(struct vb2_working_data *wd)
-{
-	return wd->selected_region_size > 0;
-}
-
-static inline int vboot_is_readonly_path(struct vb2_working_data *wd)
-{
-	return wd->selected_region_size == 0;
-}
+int vb2_get_selected_region(struct region_device *rdev);
+void vb2_set_selected_region(struct region_device *rdev);
+int vboot_is_slot_selected(void);
+int vboot_is_readonly_path(void);
 
 #endif /* __CHROMEOS_VBOOT2_MISC_H__ */
diff --git a/src/vendorcode/google/chromeos/vboot2/vboot_handoff.c b/src/vendorcode/google/chromeos/vboot2/vboot_handoff.c
index 8e12fdcad0..bf7d6542eb 100644
--- a/src/vendorcode/google/chromeos/vboot2/vboot_handoff.c
+++ b/src/vendorcode/google/chromeos/vboot2/vboot_handoff.c
@@ -130,9 +130,8 @@ void vboot_fill_handoff(void)
 	struct region_device fw_main;
 	struct vboot_components *fw_info;
 	size_t metadata_sz;
-	struct vb2_working_data *wd = vboot_get_working_data();
 
-	sd = vboot_get_work_buffer(wd);
+	sd = vb2_get_shared_data();
 	sd->workbuf_hash_offset = 0;
 	sd->workbuf_hash_size = 0;
 
@@ -149,10 +148,10 @@ void vboot_fill_handoff(void)
 	fill_vboot_handoff(vh, sd);
 
 	/* Nothing left to do in readonly path. */
-	if (vboot_is_readonly_path(wd))
+	if (vboot_is_readonly_path())
 		return;
 
-	if (vb2_get_selected_region(wd, &fw_main))
+	if (vb2_get_selected_region(&fw_main))
 		die("No component metadata.\n");
 
 	metadata_sz = sizeof(*fw_info);
diff --git a/src/vendorcode/google/chromeos/vboot2/vboot_loader.c b/src/vendorcode/google/chromeos/vboot2/vboot_loader.c
index 8517a30999..bb7bc4c828 100644
--- a/src/vendorcode/google/chromeos/vboot2/vboot_loader.c
+++ b/src/vendorcode/google/chromeos/vboot2/vboot_loader.c
@@ -65,7 +65,6 @@ static int verstage_should_load(void)
 
 static int vboot_active(struct asset *asset)
 {
-	struct vb2_working_data *wd;
 	int run_verification;
 
 	run_verification = verification_should_run();
@@ -104,12 +103,7 @@ static int vboot_active(struct asset *asset)
 	if (ENV_ROMSTAGE)
 		vboot_fill_handoff();
 
-	wd = vboot_get_working_data();
-
-	if (vboot_is_slot_selected(wd))
-		return 1;
-
-	return 0;
+	return vboot_is_slot_selected();
 }
 
 static int vboot_locate_by_components(const struct region_device *fw_main,
@@ -189,7 +183,6 @@ static int vboot_asset_locate(const struct region_device *fw_main,
  * means we are taking vboot paths. */
 static int vboot_locate(struct asset *asset)
 {
-	struct vb2_working_data *wd;
 	struct region_device fw_main;
 
 	/* Code size optimization. We'd never actually get called under the
@@ -198,8 +191,7 @@ static int vboot_locate(struct asset *asset)
 	if (verstage_should_load() && !IS_ENABLED(CONFIG_RETURN_FROM_VERSTAGE))
 		return 0;
 
-	wd = vboot_get_working_data();
-	if (vb2_get_selected_region(wd, &fw_main))
+	if (vb2_get_selected_region(&fw_main))
 		die("failed to reference selected region\n");
 
 	return vboot_asset_locate(&fw_main, asset);
diff --git a/src/vendorcode/google/chromeos/vboot2/vboot_logic.c b/src/vendorcode/google/chromeos/vboot2/vboot_logic.c
index 76355ecdab..0767454db4 100644
--- a/src/vendorcode/google/chromeos/vboot2/vboot_logic.c
+++ b/src/vendorcode/google/chromeos/vboot2/vboot_logic.c
@@ -209,22 +209,6 @@ static uint32_t extend_pcrs(struct vb2_context *ctx)
 	       tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
 }
 
-static void init_vb2_working_data(void)
-{
-	struct vb2_working_data *wd;
-	size_t work_size;
-
-	work_size = vb2_working_data_size();
-	wd = vboot_get_working_data();
-	memset(wd, 0, work_size);
-	/*
-	 * vboot prefers 16-byte alignment. This takes away 16 bytes
-	 * from the VBOOT2_WORK region, but the vboot devs said that's okay.
-	 */
-	wd->buffer_offset = ALIGN_UP(sizeof(*wd), 16);
-	wd->buffer_size = work_size - wd->buffer_offset;
-}
-
 /**
  * Verify and select the firmware in the RW image
  *
@@ -235,16 +219,12 @@ void verstage_main(void)
 {
 	struct vb2_context ctx;
 	struct region_device fw_main;
-	struct vb2_working_data *wd;
 	int rv;
-	init_vb2_working_data();
-	wd = vboot_get_working_data();
+
 	timestamp_add_now(TS_START_VBOOT);
 
 	/* Set up context and work buffer */
-	memset(&ctx, 0, sizeof(ctx));
-	ctx.workbuf = vboot_get_work_buffer(wd);
-	ctx.workbuf_size = wd->buffer_size;
+	vb2_init_work_context(&ctx);
 
 	/* Read nvdata from a non-volatile storage */
 	read_vbnv(ctx.nvdata);
@@ -347,6 +327,6 @@ void verstage_main(void)
 	}
 
 	printk(BIOS_INFO, "Slot %c is selected\n", is_slot_a(&ctx) ? 'A' : 'B');
-	vb2_set_selected_region(wd, &fw_main);
+	vb2_set_selected_region(&fw_main);
 	timestamp_add_now(TS_END_VBOOT);
 }