2020-01-07 09:17:49

by Greentime Hu

Subject: [PATCH] riscv: to make sure the cores in .Lsecondary_park

The code in secondary_park is currently placed in the .init section. The
kernel reclaims and clears this code when it finishes booting. That
causes the cores parked in it to go to somewhere unpredictable, so we
move this function out of init to make sure the cores stay looping there.

Signed-off-by: Greentime Hu <[email protected]>
---
arch/riscv/kernel/head.S | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index f8f996916c5b..d8da076fc69e 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -217,11 +217,6 @@ relocate:
tail smp_callin
#endif

-.align 2
-.Lsecondary_park:
- /* We lack SMP support or have too many harts, so park this hart */
- wfi
- j .Lsecondary_park
END(_start)

#ifdef CONFIG_RISCV_M_MODE
@@ -303,6 +298,14 @@ ENTRY(reset_regs)
END(reset_regs)
#endif /* CONFIG_RISCV_M_MODE */

+__FINIT
+.section ".text", "ax",@progbits
+.align 2
+.Lsecondary_park:
+ /* We lack SMP support or have too many harts, so park this hart */
+ wfi
+ j .Lsecondary_park
+
__PAGE_ALIGNED_BSS
/* Empty zero page */
.balign PAGE_SIZE
--
2.17.1

2020-01-07 10:56:14

by Paul Walmsley

Subject: Re: [PATCH] riscv: to make sure the cores in .Lsecondary_park

Hi Greentime,

On Tue, 7 Jan 2020, Greentime Hu wrote:

> The code in secondary_park is currently placed in the .init section. The
> kernel reclaims and clears this code when it finishes booting. That
> causes the cores parked in it to go to somewhere unpredictable, so we
> move this function out of init to make sure the cores stay looping there.
>
> Signed-off-by: Greentime Hu <[email protected]>
> ---
> arch/riscv/kernel/head.S | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index f8f996916c5b..d8da076fc69e 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -217,11 +217,6 @@ relocate:
> tail smp_callin
> #endif
>
> -.align 2
> -.Lsecondary_park:
> - /* We lack SMP support or have too many harts, so park this hart */
> - wfi
> - j .Lsecondary_park
> END(_start)
>
> #ifdef CONFIG_RISCV_M_MODE
> @@ -303,6 +298,14 @@ ENTRY(reset_regs)
> END(reset_regs)
> #endif /* CONFIG_RISCV_M_MODE */
>
> +__FINIT
> +.section ".text", "ax",@progbits

Can the __FINIT be dropped?

> +.align 2
> +.Lsecondary_park:
> + /* We lack SMP support or have too many harts, so park this hart */
> + wfi
> + j .Lsecondary_park
> +
> __PAGE_ALIGNED_BSS
> /* Empty zero page */
> .balign PAGE_SIZE


- Paul

2020-01-08 02:41:51

by Greentime Hu

Subject: Re: [PATCH] riscv: to make sure the cores in .Lsecondary_park

On Tue, Jan 7, 2020 at 6:54 PM Paul Walmsley <[email protected]> wrote:
>
> Hi Greentime,
>
> On Tue, 7 Jan 2020, Greentime Hu wrote:
>
> > The code in secondary_park is currently placed in the .init section. The
> > kernel reclaims and clears this code when it finishes booting. That
> > causes the cores parked in it to go to somewhere unpredictable, so we
> > move this function out of init to make sure the cores stay looping there.
> >
> > Signed-off-by: Greentime Hu <[email protected]>
> > ---
> > arch/riscv/kernel/head.S | 13 ++++++++-----
> > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> > index f8f996916c5b..d8da076fc69e 100644
> > --- a/arch/riscv/kernel/head.S
> > +++ b/arch/riscv/kernel/head.S
> > @@ -217,11 +217,6 @@ relocate:
> > tail smp_callin
> > #endif
> >
> > -.align 2
> > -.Lsecondary_park:
> > - /* We lack SMP support or have too many harts, so park this hart */
> > - wfi
> > - j .Lsecondary_park
> > END(_start)
> >
> > #ifdef CONFIG_RISCV_M_MODE
> > @@ -303,6 +298,14 @@ ENTRY(reset_regs)
> > END(reset_regs)
> > #endif /* CONFIG_RISCV_M_MODE */
> >
> > +__FINIT
> > +.section ".text", "ax",@progbits
>
> Can the __FINIT be dropped?

Yes, Paul.
It can be dropped. I'll send v2.