From 3384b043ea1564560ff19591cb9554867c7c6f77 Mon Sep 17 00:00:00 2001 From: Greentime Hu Date: Tue, 3 Mar 2020 17:34:18 +0800 Subject: riscv: fix the IPI missing issue in nommu mode This patch fixes the IPI(inner processor interrupt) missing issue. It failed because it used hartid_mask to iterate for_each_cpu(), however the cpu_mask and hartid_mask may not be always the same. It will never send the IPI to hartid 4 because it will be skipped in for_each_cpu loop in my case. We can reproduce this case in Qemu sifive_u machine by this command. qemu-system-riscv64 -nographic -smp 5 -m 1G -M sifive_u -kernel \ arch/riscv/boot/loader It will hang in csd_lock_wait(csd) because the csd_unlock(csd) is not called. It is not called because hartid 4 doesn't receive the IPI to release this lock. The caller hart doesn't send the IPI to hartid 4 is because of hartid 4 is skipped in for_each_cpu(). It will be skipped is because "(cpu) < nr_cpu_ids" is not true. The hartid is 4 and nr_cpu_ids is 4. Therefore it should use cpumask in for_each_cpu() instead of hartid_mask. /* Send a message to all CPUs in the map */ arch_send_call_function_ipi_mask(cfd->cpumask_ipi); if (wait) { for_each_cpu(cpu, cfd->cpumask) { call_single_data_t *csd; csd = per_cpu_ptr(cfd->csd, cpu); csd_lock_wait(csd); } } for ((cpu) = -1; \ (cpu) = cpumask_next((cpu), (mask)), \ (cpu) < nr_cpu_ids;) It could boot to login console after this patch applied. Fixes: b2d36b5668f6 ("riscv: provide native clint access for M-mode") Signed-off-by: Greentime Hu Reviewed-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/clint.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/riscv/include/asm/clint.h') diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h index 6eaa2eedd694..a279b17a6aad 100644 --- a/arch/riscv/include/asm/clint.h +++ b/arch/riscv/include/asm/clint.h @@ -15,12 +15,12 @@ static inline void clint_send_ipi_single(unsigned long hartid) writel(1, clint_ipi_base + hartid); } -static inline void clint_send_ipi_mask(const struct cpumask *hartid_mask) +static inline void clint_send_ipi_mask(const struct cpumask *mask) { - int hartid; + int cpu; - for_each_cpu(hartid, hartid_mask) - clint_send_ipi_single(hartid); + for_each_cpu(cpu, mask) + clint_send_ipi_single(cpuid_to_hartid_map(cpu)); } static inline void clint_clear_ipi(unsigned long hartid) -- cgit