linux-kernel - Re: [PATCH v7u1 06/31] x86, 64bit, realmode: use init_level4_pgt to set trapmoline

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Date:	Fri, 4 Jan 2013 17:18:31 +0000
From:	"Sakkinen, Jarkko" <jarkko.sakkinen@...el.com>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>, Jan Kiszka <jan.kiszka@....de>,
	Jason Wessel <jason.wessel@...driver.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7u1 06/31] x86, 64bit, realmode: use init_level4_pgt to
 set trapmoline_pgt directly

On Thu, 2013-01-03 at 16:48 -0800, Yinghai Lu wrote:
> with #PF handler way to set early page table, level3_ident will go away with
> 64bit native path.
> 
> So just use entries in init_level4_pgt to set them in tramopline_pgt
> 
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@...el.com>

Acked-by: Jarkko Sakkinen <jarkko.sakkinen@...el.com>

> ---
>  arch/x86/realmode/init.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
> index b96fe6f..384b3f4 100644
> --- a/arch/x86/realmode/init.c
> +++ b/arch/x86/realmode/init.c
> @@ -78,8 +78,8 @@ void __init setup_real_mode(void)
>  	*trampoline_cr4_features = read_cr4();
>  
>  	trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
> -	trampoline_pgd[0] = __pa_symbol(level3_ident_pgt) + _KERNPG_TABLE;
> -	trampoline_pgd[511] = __pa_symbol(level3_kernel_pgt) + _KERNPG_TABLE;
> +	trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
> +	trampoline_pgd[511] = init_level4_pgt[511].pgd;
>  #endif
>  }
>