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7dd09bfeca
Using hsm stop in hsm wait loop causes secondary harts to be stuck
forever in OpenSBI on RISC-V platforms where HSM hart hotplug is
available and all harts come-up at the same time during system
power-on.
For example, lets say we have two harts A and B on a RISC-V platform
with HSM hart hotplug which come-up at the same time during system
power-on. The hart A enters OpenSBI before hart B hence it becomes
the primary (or cold-boot) hart whereas hart B becomes the secondary
(or warm-boot) hart. The hart A follows the OpenSBI cold-boot path
and registers hsm device before hart B enters OpenSBI. The hart B
eventually enters OpenSBI and follows the OpenSBI warm-boot path
so it will increment it's own entry_count before entering hsm wait
loop where it sees hsm device and stops itself. Later as part of
the Linux boot-up sequence, hart A issues SBI HSM start call to
bring-up hart B but OpenSBI sees entry_count != init_count for
hart B in sbi_hsm_hart_start() hence hsm_device_hart_start() is
not called for hart B resulting in hart B stuck forever in OpenSBI.
To fix the above issue, revert entry_count before doing hsm stop
in hsm wait loop.
Fixes: d844deadec ("lib: sbi: Use hsm stop for hsm wait")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Nick Hu <nick.hu@sifive.com>
Link: https://lore.kernel.org/r/20250527124821.2113467-1-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
28 lines
540 B
C
28 lines
540 B
C
/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Anup Patel <anup.patel@wdc.com>
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*/
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#ifndef __SBI_INIT_H__
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#define __SBI_INIT_H__
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#include <sbi/sbi_types.h>
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struct sbi_scratch;
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void __noreturn sbi_init(struct sbi_scratch *scratch);
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void sbi_revert_entry_count(struct sbi_scratch *scratch);
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unsigned long sbi_entry_count(u32 hartindex);
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unsigned long sbi_init_count(u32 hartindex);
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void __noreturn sbi_exit(struct sbi_scratch *scratch);
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#endif
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