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

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

[Greentime Hu]

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 <greentime.hu@sifive.com>
---
 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

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

[Paul Walmsley]

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 <greentime.hu@sifive.com>
> ---
>  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

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

[Greentime Hu]

On Tue, Jan 7, 2020 at 6:54 PM Paul Walmsley <paul.walmsley@sifive.com> 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 <greentime.hu@sifive.com>
> > ---
> >  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.