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authorLukas Auer <lukas.auer@aisec.fraunhofer.de>2019-12-08 23:28:49 +0100
committerAndes <uboot@andestech.com>2019-12-10 08:23:10 +0800
commitb86f6d1e649f237849297b5ec6b5566b7a92b2b4 (patch)
treec37dc66dde13d4911c6bb1089eb90d6bee072aa0 /include/opensbi.h
parent04883bf7acca36fce8908c2a1c0f8377b10456e5 (diff)
spl: opensbi: specify main hart as preferred boot hart
OpenSBI uses a relocation lottery to determine the hart to relocate OpenSBI to its link address. In the U-Boot SPL boot flow, the main hart schedules the secondary harts to enter OpenSBI before doing so itself. One of the secondary harts will therefore always be the winner of the relocation lottery. This is problematic if the link address ranges of OpenSBI and U-Boot SPL overlap. OpenSBI will be relocated and therefore overwrite U-Boot SPL while some harts may still run it, leading to code corruption. Avoid this problem by specifying the main hart as the preferred boot hart to perform the OpenSBI relocation. The main hart will be the last hart to enter OpenSBI, relocation can therefore occur safely. The boot hart field was added to version 2 of the OpenSBI FW_DYNAMIC info structure. The header file include/opensbi.h is synchronized with include/sbi/fw_dynamic.h from the OpenSBI project to update the info structure. The header file is recent as of commit 7a13beb21326 ("firmware: Add preferred boot HART field in struct fw_dynamic_info"). Reported-by: Rick Chen <rick@andestech.com> Suggested-by: Anup Patel <Anup.Patel@wdc.com> Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de> Reviewed-by: Rick Chen <rick@andestech.com> Tested-by: Rick Chen <rick@andestech.com> Reviewed-by: Anup Patel <anup.patel@wdc.com>
Diffstat (limited to 'include/opensbi.h')
-rw-r--r--include/opensbi.h18
1 files changed, 17 insertions, 1 deletions
diff --git a/include/opensbi.h b/include/opensbi.h
index 9f1d62e7dd..d812cc8ccd 100644
--- a/include/opensbi.h
+++ b/include/opensbi.h
@@ -11,7 +11,7 @@
#define FW_DYNAMIC_INFO_MAGIC_VALUE 0x4942534f
/** Maximum supported info version */
-#define FW_DYNAMIC_INFO_VERSION 0x1
+#define FW_DYNAMIC_INFO_VERSION 0x2
/** Possible next mode values */
#define FW_DYNAMIC_INFO_NEXT_MODE_U 0x0
@@ -35,6 +35,22 @@ struct fw_dynamic_info {
unsigned long next_mode;
/** Options for OpenSBI library */
unsigned long options;
+ /**
+ * Preferred boot HART id
+ *
+ * It is possible that the previous booting stage uses same link
+ * address as the FW_DYNAMIC firmware. In this case, the relocation
+ * lottery mechanism can potentially overwrite the previous booting
+ * stage while other HARTs are still running in the previous booting
+ * stage leading to boot-time crash. To avoid this boot-time crash,
+ * the previous booting stage can specify last HART that will jump
+ * to the FW_DYNAMIC firmware as the preferred boot HART.
+ *
+ * To avoid specifying a preferred boot HART, the previous booting
+ * stage can set it to -1UL which will force the FW_DYNAMIC firmware
+ * to use the relocation lottery mechanism.
+ */
+ unsigned long boot_hart;
} __packed;
#endif