linux-kernel - Re: [PATCH] riscv: to make sure the cores in .Lsecondary

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Message-ID: <alpine.DEB.2.21.9999.2001070253000.75790@viisi.sifive.com>
Date:   Tue, 7 Jan 2020 02:54:07 -0800 (PST)
From:   Paul Walmsley <paul.walmsley@...ive.com>
To:     Greentime Hu <greentime.hu@...ive.com>
cc:     green.hu@...il.com, greentime@...nel.org, palmer@...belt.com,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
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 <greentime.hu@...ive.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