Commit b86f6d1e authored by Lukas Auer's avatar Lukas Auer Committed by Andes
Browse files

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

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
Reported-by: Rick Chen's avatarRick Chen <>
Suggested-by: default avatarAnup Patel <>
Signed-off-by: default avatarLukas Auer <>
Reviewed-by: Rick Chen's avatarRick Chen <>
Tested-by: Rick Chen's avatarRick Chen <>
Reviewed-by: default avatarAnup Patel <>
parent 04883bf7
...@@ -70,6 +70,7 @@ void spl_invoke_opensbi(struct spl_image_info *spl_image) ...@@ -70,6 +70,7 @@ void spl_invoke_opensbi(struct spl_image_info *spl_image)
opensbi_info.next_addr = uboot_entry; opensbi_info.next_addr = uboot_entry;
opensbi_info.next_mode = FW_DYNAMIC_INFO_NEXT_MODE_S; opensbi_info.next_mode = FW_DYNAMIC_INFO_NEXT_MODE_S;
opensbi_info.options = SBI_SCRATCH_NO_BOOT_PRINTS; opensbi_info.options = SBI_SCRATCH_NO_BOOT_PRINTS;
opensbi_info.boot_hart = gd->arch.boot_hart;
opensbi_entry = (void (*)(ulong, ulong, ulong))spl_image->entry_point; opensbi_entry = (void (*)(ulong, ulong, ulong))spl_image->entry_point;
invalidate_icache_all(); invalidate_icache_all();
...@@ -11,7 +11,7 @@ ...@@ -11,7 +11,7 @@
#define FW_DYNAMIC_INFO_MAGIC_VALUE 0x4942534f #define FW_DYNAMIC_INFO_MAGIC_VALUE 0x4942534f
/** Maximum supported info version */ /** Maximum supported info version */
/** Possible next mode values */ /** Possible next mode values */
...@@ -35,6 +35,22 @@ struct fw_dynamic_info { ...@@ -35,6 +35,22 @@ struct fw_dynamic_info {
unsigned long next_mode; unsigned long next_mode;
/** Options for OpenSBI library */ /** Options for OpenSBI library */
unsigned long options; 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; } __packed;
#endif #endif
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