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firmware: do not use relocated _boot_status before it is valid

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When OpenSBI is started from an address not equal to the link address,
it is first relocated to the link address. Hart 0 performs the
relocation and notifies the other harts of its completion with the
_boot_status variable. It uses the copy of the variable relative to the
link address. This copy contains valid data only after relocation has
finished. The waiting harts will therefore read invalid data until
relocation has finished. This can cause them to continue execution too
early.

Fix this by using the _boot_status variable relative to the load address
while OpenSBI has not finished relocation.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Lukas Auer
2019-08-12 23:50:42 +02:00
committed by Anup Patel
parent 6c24193293
commit 2e0f3ac758
1 changed files with 10 additions and 3 deletions
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13
firmware/fw_base.S
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@@ -111,8 +111,6 @@ _wait_relocate_copy_done:
REG_L t1, 0(t1)
beq t0, t1, _wait_for_boot_hart
la t2, _boot_status
sub t2, t2, t0
add t2, t2, t1
la t3, _wait_for_boot_hart
sub t3, t3, t0
add t3, t3, t1
@@ -128,8 +126,17 @@ _wait_relocate_copy_done:
jr t3
_relocate_done:
/* mark relocate copy done */
/*
* Mark relocate copy done
* Use _boot_status copy relative to the load address
*/
la t0, _boot_status
la t1, _link_start
REG_L t1, 0(t1)
la t2, _load_start
REG_L t2, 0(t2)
sub t0, t0, t1
add t0, t0, t2
li t1, BOOT_STATUS_RELOCATE_DONE
REG_S t1, 0(t0)
fence rw, rw