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risc-v: Fix order of IPI enablement vs RCU startup

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Conor reports that risc-v tries to enable IPIs before telling the
core code to enable RCU. With the introduction of the mapple tree
as a backing store for the irq descriptors, this results in
a very shouty boot sequence, as RCU is legitimately upset.

Restore some sanity by moving the risc_ipi_enable() call after
notify_cpu_starting(), which explicitly enables RCU on the calling
CPU.

Fixes: 832f15f426 ("RISC-V: Treat IPIs as normal Linux IRQs")
Reported-by: Conor Dooley <conor@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230703183126.1567625-1-maz@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Marc Zyngier 2023-07-03 19:31:26 +01:00 committed by Palmer Dabbelt
parent 62ba41d276
commit 6259f3443c
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1 changed files with 3 additions and 2 deletions
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5
arch/riscv/kernel/smpboot.c
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@ -238,10 +238,11 @@ asmlinkage __visible void smp_callin(void)
mmgrab(mm);
current->active_mm = mm;
riscv_ipi_enable();
store_cpu_topology(curr_cpuid);
notify_cpu_starting(curr_cpuid);
riscv_ipi_enable();
numa_add_cpu(curr_cpuid);
set_cpu_online(curr_cpuid, 1);
probe_vendor_features(curr_cpuid);