Put __cpu_up_stack_pointer and __cpu_up_task_pointer in data section.
Currently, these two variables are put in bss section, there is a
potential risk that secondary harts get the uninitialized value before
main hart finishing the bss clearing. In this case, all secondary
harts would pass the waiting loop and enable the MMU before main hart
set up the page table.
This issue happened on random booting of multiple harts, which means
it will manifest for BBL and OpenSBI which older than v0.6. In OpenSBI
v0.7, it had included HSM extension, all the secondary harts are
waiting in firmware, so it could work fine without this change.
Changes in v2:
- Add commit description about random booting.
Signed-off-by: Zong Li <[email protected]>
Reviewed-by: Greentime Hu <[email protected]>
---
arch/riscv/kernel/cpu_ops.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
index c4c33bf02369..0ec22354018c 100644
--- a/arch/riscv/kernel/cpu_ops.c
+++ b/arch/riscv/kernel/cpu_ops.c
@@ -15,8 +15,8 @@
const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
-void *__cpu_up_stack_pointer[NR_CPUS];
-void *__cpu_up_task_pointer[NR_CPUS];
+void *__cpu_up_stack_pointer[NR_CPUS] __section(.data);
+void *__cpu_up_task_pointer[NR_CPUS] __section(.data);
extern const struct cpu_operations cpu_ops_sbi;
extern const struct cpu_operations cpu_ops_spinwait;
--
2.26.1
On Mon, May 4, 2020 at 9:24 AM Zong Li <[email protected]> wrote:
>
> Put __cpu_up_stack_pointer and __cpu_up_task_pointer in data section.
> Currently, these two variables are put in bss section, there is a
> potential risk that secondary harts get the uninitialized value before
> main hart finishing the bss clearing. In this case, all secondary
> harts would pass the waiting loop and enable the MMU before main hart
> set up the page table.
>
> This issue happened on random booting of multiple harts, which means
> it will manifest for BBL and OpenSBI which older than v0.6. In OpenSBI
> v0.7, it had included HSM extension, all the secondary harts are
> waiting in firmware, so it could work fine without this change.
Slightly improved text:
This issue happens on random booting of multiple harts, which means
it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
v0.7 (or higher version), we have HSM extension so all the secondary harts
are brought-up by Linux kernel in an orderly fashion. This means we don't
this change for OpenSBI v0.7 (or higher version).
>
> Changes in v2:
> - Add commit description about random booting.
>
> Signed-off-by: Zong Li <[email protected]>
> Reviewed-by: Greentime Hu <[email protected]>
> ---
> arch/riscv/kernel/cpu_ops.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/cpu_ops.c b/arch/riscv/kernel/cpu_ops.c
> index c4c33bf02369..0ec22354018c 100644
> --- a/arch/riscv/kernel/cpu_ops.c
> +++ b/arch/riscv/kernel/cpu_ops.c
> @@ -15,8 +15,8 @@
>
> const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
>
> -void *__cpu_up_stack_pointer[NR_CPUS];
> -void *__cpu_up_task_pointer[NR_CPUS];
> +void *__cpu_up_stack_pointer[NR_CPUS] __section(.data);
> +void *__cpu_up_task_pointer[NR_CPUS] __section(.data);
>
> extern const struct cpu_operations cpu_ops_sbi;
> extern const struct cpu_operations cpu_ops_spinwait;
> --
> 2.26.1
>
Apart from above, looks good to me.
Reviewed-by: Anup Patel <[email protected]>
Regards,
Anup
On Mai 04 2020, Anup Patel wrote:
> Slightly improved text:
>
> This issue happens on random booting of multiple harts, which means
> it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
> v0.7 (or higher version), we have HSM extension so all the secondary harts
> are brought-up by Linux kernel in an orderly fashion. This means we don't
> this change for OpenSBI v0.7 (or higher version).
+need
Andreas.
--
Andreas Schwab, [email protected]
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
On Mon, May 4, 2020 at 12:50 AM Andreas Schwab <[email protected]> wrote:
>
> On Mai 04 2020, Anup Patel wrote:
>
> > Slightly improved text:
> >
> > This issue happens on random booting of multiple harts, which means
> > it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
> > v0.7 (or higher version), we have HSM extension so all the secondary harts
> > are brought-up by Linux kernel in an orderly fashion. This means we don't
> > this change for OpenSBI v0.7 (or higher version).
>
> +need
>
> Andreas.
>
> --
> Andreas Schwab, [email protected]
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
With Andreas & Anup's nitpick addressed,
Reviewed-by: Atish Patra <[email protected]>
--
Regards,
Atish
On Mon, 04 May 2020 10:37:40 PDT (-0700), [email protected] wrote:
> On Mon, May 4, 2020 at 12:50 AM Andreas Schwab <[email protected]> wrote:
>>
>> On Mai 04 2020, Anup Patel wrote:
>>
>> > Slightly improved text:
>> >
>> > This issue happens on random booting of multiple harts, which means
>> > it will manifest for BBL and OpenSBI v0.6 (or older version). In OpenSBI
>> > v0.7 (or higher version), we have HSM extension so all the secondary harts
>> > are brought-up by Linux kernel in an orderly fashion. This means we don't
>> > this change for OpenSBI v0.7 (or higher version).
>>
>> +need
>>
>> Andreas.
>>
>> --
>> Andreas Schwab, [email protected]
>> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
>> "And now for something completely different."
>
> With Andreas & Anup's nitpick addressed,
>
> Reviewed-by: Atish Patra <[email protected]>
Thanks! It should be on fixes, with the new commit text.