linux-kernel - Re: [PATCH 15/15] riscv: disable the EFI PECOFF header for M-mode

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Message-Id: <3BF39A0F-558D-40E0-880D-27829486F9F0@sifive.com>
Date:   Tue, 20 Aug 2019 21:14:41 -0700
From:   Troy Benjegerdes <troy.benjegerdes@...ive.com>
To:     Christoph Hellwig <hch@....de>
Cc:     Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Damien Le Moal <damien.lemoal@....com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 15/15] riscv: disable the EFI PECOFF header for M-mode

> On Aug 13, 2019, at 8:47 AM, Christoph Hellwig <hch@....de> wrote:
> 
> No point in bloating the kernel image with a bootloader header if
> we run bare metal.

I would say the same for S-mode. EFI booting should be an option, not
a requirement. I have M-mode U-boot working with bootelf to start BBL,
and at some point, I’m hoping we can have a M-mode linux kernel be
the SBI provider for S-mode kernels, which seem most logical to me
to start using the vmlinux elf binaries using something like kexec()

> 
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> arch/riscv/kernel/head.S | 2 ++
> 1 file changed, 2 insertions(+)
> 
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index 670e5cacb24e..09fcf3d000c0 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -16,6 +16,7 @@
> 
> __INIT
> ENTRY(_start)
> +#ifndef CONFIG_M_MODE
> 	/*
> 	 * Image header expected by Linux boot-loaders. The image header data
> 	 * structure is described in asm/image.h.
> @@ -47,6 +48,7 @@ ENTRY(_start)
> 
> .global _start_kernel
> _start_kernel:
> +#endif /* CONFIG_M_MODE */
> 	/* Mask all interrupts */
> 	csrw CSR_XIE, zero
> 	csrw CSR_XIP, zero
> -- 
> 2.20.1
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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