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riscv: Fix SMP when shadow call stacks are enabled

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This fixes two bugs in SCS initialization for secondary CPUs. First,
the SCS was not initialized at all in the spinwait boot path. Second,
the code for the SBI HSM path attempted to initialize the SCS before
enabling the MMU. However, that involves dereferencing the thread
pointer, which requires the MMU to be enabled.

Fix both issues by setting up the SCS in the common secondary entry
path, after enabling the MMU.

Fixes: d1584d791a ("riscv: Implement Shadow Call Stack")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20231121211958.3158576-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Samuel Holland 2023-11-21 13:19:29 -08:00 committed by Palmer Dabbelt
parent 96ba4a47d1
commit f40cab8e18
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1 changed files with 1 additions and 1 deletions
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arch/riscv/kernel/head.S
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@ -154,7 +154,6 @@ secondary_start_sbi:
XIP_FIXUP_OFFSET a3
add a3, a3, a1
REG_L sp, (a3)
scs_load_current
.Lsecondary_start_common:
@ -165,6 +164,7 @@ secondary_start_sbi:
call relocate_enable_mmu
#endif
call .Lsetup_trap_vector
scs_load_current
tail smp_callin
#endif /* CONFIG_SMP */