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: 832f15f42646 ("RISC-V: Treat IPIs as normal Linux IRQs")
Reported-by: Conor Dooley <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
Cc: Anup Patel <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Linus Torvalds <[email protected]>
---
arch/riscv/kernel/smpboot.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index bb0b76e1a6d4..f4d6acb38dd0 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -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);
--
2.34.1
On Mon, 03 Jul 2023 11:31:26 PDT (-0700), Marc Zyngier wrote:
> 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: 832f15f42646 ("RISC-V: Treat IPIs as normal Linux IRQs")
> Reported-by: Conor Dooley <[email protected]>
> Signed-off-by: Marc Zyngier <[email protected]>
> Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
> Cc: Anup Patel <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> ---
> arch/riscv/kernel/smpboot.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index bb0b76e1a6d4..f4d6acb38dd0 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -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);
Thanks. I was going to send another PR this week anyway, I can just
pick this up if you want? Either way I'll look, I've still got a few
hiccups from trying to clean up my staging bits post-merge but hopefully
it's not too bad...
On Mon, 03 Jul 2023 19:45:43 +0100,
Palmer Dabbelt <[email protected]> wrote:
>
> On Mon, 03 Jul 2023 11:31:26 PDT (-0700), Marc Zyngier wrote:
> > 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: 832f15f42646 ("RISC-V: Treat IPIs as normal Linux IRQs")
> > Reported-by: Conor Dooley <[email protected]>
> > Signed-off-by: Marc Zyngier <[email protected]>
> > Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
> > Cc: Anup Patel <[email protected]>
> > Cc: Palmer Dabbelt <[email protected]>
> > Cc: Linus Torvalds <[email protected]>
> > ---
> > arch/riscv/kernel/smpboot.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > index bb0b76e1a6d4..f4d6acb38dd0 100644
> > --- a/arch/riscv/kernel/smpboot.c
> > +++ b/arch/riscv/kernel/smpboot.c
> > @@ -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);
>
> Thanks. I was going to send another PR this week anyway, I can just
> pick this up if you want?
Yes please!
M.
--
Without deviation from the norm, progress is not possible.
On Mon, Jul 03, 2023 at 07:31:26PM +0100, Marc Zyngier wrote:
> 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: 832f15f42646 ("RISC-V: Treat IPIs as normal Linux IRQs")
> Reported-by: Conor Dooley <[email protected]>
RCU no longer chucks the toys at least, and none of the wheels seem to
have fallen off the pram in the process.
Tested-by: Conor Dooley <[email protected]>
Thanks guys!
> Signed-off-by: Marc Zyngier <[email protected]>
> Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
> Cc: Anup Patel <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Linus Torvalds <[email protected]>
> ---
> arch/riscv/kernel/smpboot.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index bb0b76e1a6d4..f4d6acb38dd0 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -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);
> --
> 2.34.1
>
On Mon, 03 Jul 2023 19:31:26 +0100, Marc Zyngier wrote:
> 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.
>
> [...]
Applied, thanks!
[1/1] risc-v: Fix order of IPI enablement vs RCU startup
https://git.kernel.org/palmer/c/6259f3443c6a
Best regards,
--
Palmer Dabbelt <[email protected]>