vboot: remove vboot_handoff_get_recovery_reason

Two functions retrieve vboot recovery_reason:
* vboot_handoff_get_recovery_reason
* vboot_get_recovery_reason_shared_data

Previously, when CBMEM comes online, a vboot_handoff data
structure is created, and depending on the architecture,
coreboot may eventually lose access to vboot_working_data.

After implementing vboot_working_data CBMEM migration,
vboot_working_data is always guaranteed to be accessible.

vboot_get_recovery_reason_shared_data is corrected to also
allow accessing vboot_working_data in ramstage and postcar.

Now, vboot_handoff_get_recovery reason returning a valid recovery
reason implies that vboot_get_recovery_reason_shared_data should
*also* return a valid recovery reason.  Thus we may remove the
former.

BUG=b:124141368, b:124192753
TEST=make clean && make test-abuild
BRANCH=none

Change-Id: Iac216dc968dd155d9d4f8bd0f2dfd5034762f9a0
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33532
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/security/vboot/bootmode.c

@@ -26,10 +26,6 @@
 
 static int vboot_get_recovery_reason_shared_data(void)
 {
-	/* Shared data does not exist for Ramstage and Post-CAR stage. */
-	if (ENV_RAMSTAGE || ENV_POSTCAR)
-		return 0;
-
 	struct vb2_shared_data *sd = vboot_get_shared_data();
 	assert(sd);
 	return sd->recovery_reason;
@@ -96,11 +92,10 @@ static int vboot_possibly_executed(void)
  * VB2_RECOVERY_RO_MANUAL.
  * 2. Checks if recovery request is present in VBNV and returns the code read
  * from it.
- * 3. Checks recovery request in handoff for stages post-cbmem.
+ * 3. Checks if vboot verification is done and looks up selected region
- * 4. For non-CBMEM stages, check if vboot verification is done and look-up
+ * to identify if vboot_reference library has requested recovery path.
- * selected region to identify if vboot_reference library has requested recovery
+ * If yes, return the reason code from shared data.
- * path. If yes, return the reason code from shared data.
+ * 4. If nothing applies, return 0 indicating no recovery request.
- * 5. If nothing applies, return 0 indicating no recovery request.
  */
 int vboot_check_recovery_request(void)
 {
@@ -115,19 +110,8 @@ int vboot_check_recovery_request(void)
 		return reason;
 
 	/*
-	 * Check recovery flag in vboot_handoff for stages post CBMEM coming
+	 * Identify if vboot verification is already complete and no slot
-	 * online. Since for some stages there is no way to know if cbmem has
+	 * was selected i.e. recovery path was requested.
-	 * already come online, try looking up handoff anyways. If it fails,
-	 * flow will fallback to looking up shared data.
-	 */
-	if (cbmem_possibly_online() &&
-	    ((reason = vboot_handoff_get_recovery_reason()) != 0))
-		return reason;
-
-	/*
-	 * For stages where CBMEM might not be online, identify if vboot
-	 * verification is already complete and no slot was selected
-	 * i.e. recovery path was requested.
 	 */
 	if (vboot_possibly_executed() && vboot_logic_executed() &&
 	    !vboot_is_slot_selected())

src/security/vboot/vboot_common.c

@@ -93,19 +93,6 @@ int vboot_handoff_check_recovery_flag(void)
 	return vboot_get_handoff_flag(VB_INIT_OUT_ENABLE_RECOVERY);
 }
 
-int vboot_handoff_get_recovery_reason(void)
-{
-	struct vboot_handoff *vbho;
-	VbSharedDataHeader *sd;
-
-	if (vboot_get_handoff_info((void **)&vbho, NULL))
-		return 0;
-
-	sd = (VbSharedDataHeader *)vbho->shared_data;
-
-	return sd->recovery_reason;
-}
-
 /* ============================ VBOOT REBOOT ============================== */
 void __weak vboot_platform_prepare_reboot(void)
 {

src/security/vboot/vboot_common.h

@@ -54,15 +54,13 @@ struct vboot_handoff {
 int vboot_get_handoff_info(void **addr, uint32_t *size);
 
 /*
- * The following functions read vboot_handoff structure to obtain requested
+ * The following function reads vboot_handoff structure to obtain requested
  * information. If vboot handoff is not available, 0 is returned by default.
  * If vboot handoff is available:
  * Returns 1 for flag if true
  * Returns 0 for flag if false
- * Returns value read for other fields
  */
 int vboot_handoff_check_recovery_flag(void);
-int vboot_handoff_get_recovery_reason(void);
 
 /* ============================ VBOOT REBOOT ============================== */
 /*