linux-kernel - Re: [PATCH 5/8] x86 boot: remap efi systab runtime from phys to virt

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Date:	Mon, 16 Jun 2008 15:02:39 +0800
From:	"Huang, Ying" <ying.huang@...el.com>
To:	Paul Jackson <pj@....com>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	Yinghai Lu <yhlu.kernel@...il.com>,
	Jack Steiner <steiner@....com>, Mike Travis <travis@....com>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 5/8] x86 boot: remap efi systab runtime from phys to
	virt

On Sun, 2008-06-15 at 23:30 -0700, Paul Jackson wrote:
> From: Paul Jackson <pj@....com>
> 
> One more efi entry needs its address converted from physical
> to virtual during boot: efi.systab->runtime.
> 
> Signed-off-by: Paul Jackson <pj@....com>
> 
> ---
>  arch/x86/kernel/efi.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> --- linux.orig/arch/x86/kernel/efi.c	2008-06-13 00:53:10.053599898 -0700
> +++ linux/arch/x86/kernel/efi.c	2008-06-13 00:53:21.762309008 -0700
> @@ -486,6 +486,7 @@ void __init efi_enter_virtual_mode(void)
>  		if (md->phys_addr <= systab && systab < end) {
>  			systab += md->virt_addr - md->phys_addr;
>  			efi.systab = (efi_system_table_t *) (unsigned long) systab;
> +			efi.systab->runtime = __va(efi.systab->runtime);
>  		}
>  	}

Why do you need this? This should be done by firmware in
efi_set_virtual_address_map(). And this doesn't work on i386, because
runtime code/data area may be not in identity map area (that is > 768M).
even on x86_64, runtime code/data area can be non-identity mapped (For
example identity map is restricted by mem=xxx kernel parameter). Same
problem for

[PATCH 6/8] x86 boot: virtualize the efi runtime function callback
addresses

Best Regards,
Huang Ying

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