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| author | Greentime Hu <greentime.hu@sifive.com> | 2020-03-03 17:34:18 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-03-18 18:44:39 -0700 |
| commit | 3384b043ea1564560ff19591cb9554867c7c6f77 (patch) | |
| tree | 556238b8997e2967f654cc509cf9d7c1e7ac3825 /arch/riscv/kernel | |
| parent | adccfb1a805ea84d2db38eb53032533279bdaa97 (diff) | |
| download | linux-3384b043ea1564560ff19591cb9554867c7c6f77.tar.bz2 | |
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 <greentime.hu@sifive.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv/kernel')
| -rw-r--r-- | arch/riscv/kernel/smp.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index eb878abcaaf8..e0a6293093f1 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -96,7 +96,7 @@ static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op) if (IS_ENABLED(CONFIG_RISCV_SBI)) sbi_send_ipi(cpumask_bits(&hartid_mask)); else - clint_send_ipi_mask(&hartid_mask); + clint_send_ipi_mask(mask); } static void send_ipi_single(int cpu, enum ipi_message_type op) |