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SubjectRE: [PATCH] arch/riscv: disable too many harts before pick main boot hart
Date


> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org <linux-kernel-
> owner@vger.kernel.org> On Behalf Of Paul Walmsley
> Sent: Thursday, September 19, 2019 3:56 PM
> To: Xiang Wang <merle@hardenedlinux.org>
> Cc: palmer@sifive.com; aou@eecs.berkeley.edu; linux-
> riscv@lists.infradead.org; linux-kernel@vger.kernel.org;
> citypw@hardenedlinux.org
> Subject: Re: [PATCH] arch/riscv: disable too many harts before pick main
> boot hart
>
> On Fri, 6 Sep 2019, Xiang Wang wrote:
>
> > From 12300865d1103618c9d4c375f7d7fbe601b6618c Mon Sep 17 00:00:00
> 2001
> > From: Xiang Wang <merle@hardenedlinux.org>
> > Date: Fri, 6 Sep 2019 11:56:09 +0800
> > Subject: [PATCH] arch/riscv: disable too many harts before pick main
> > boot hart
> >
> > These harts with id greater than or equal to CONFIG_NR_CPUS need to be
> disabled.
> > But pick the main Hart can choose any one. So, before pick the main
> > hart, you need to disable the hart with id greater than or equal to
> CONFIG_NR_CPUS.
> >
> > Signed-off-by: Xiang Wang <merle@hardenedlinux.org>
>
> Thanks, here's what I'm planning to queue for v5.4-rc1. Please let me know
> ASAP if you want to change the patch description.
>
>
> - Paul
>
> From: Xiang Wang <merle@hardenedlinux.org>
> Date: Fri, 6 Sep 2019 11:56:09 +0800
> Subject: [PATCH] arch/riscv: disable excess harts before picking main boot
> hart
>
> Harts with id greater than or equal to CONFIG_NR_CPUS need to be
> disabled. But the kernel can pick any hart as the main hart. So,
> before picking the main hart, the kernel must disable harts with ids
> greater than or equal to CONFIG_NR_CPUS.
>
> Signed-off-by: Xiang Wang <merle@hardenedlinux.org>

You missed my Reviewed-by here.

Regards,
Anup

> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
> [paul.walmsley@sifive.com: updated to apply; cleaned up patch
> description]
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> ---
> arch/riscv/kernel/head.S | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index 15a9189f91ad..72f89b7590dd 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -63,6 +63,11 @@ _start_kernel:
> li t0, SR_FS
> csrc CSR_SSTATUS, t0
>
> +#ifdef CONFIG_SMP
> + li t0, CONFIG_NR_CPUS
> + bgeu a0, t0, .Lsecondary_park
> +#endif
> +
> /* Pick one hart to run the main boot sequence */
> la a3, hart_lottery
> li a2, 1
> @@ -154,9 +159,6 @@ relocate:
>
> .Lsecondary_start:
> #ifdef CONFIG_SMP
> - li a1, CONFIG_NR_CPUS
> - bgeu a0, a1, .Lsecondary_park
> -
> /* Set trap vector to spin forever to help debug */
> la a3, .Lsecondary_park
> csrw CSR_STVEC, a3
> --
> 2.23.0

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