linux-kernel - Re: 2.6.39.1 immediately reboots/resets on EFI system

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Date:	Mon, 13 Jun 2011 19:52:42 +0200
From:	Maarten Lankhorst <m.b.lankhorst@...il.com>
To:	Matthew Garrett <mjg59@...f.ucam.org>
CC:	Yinghai Lu <yinghai@...nel.org>, Jim Bos <jim876@...all.nl>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Greg KH <gregkh@...e.de>,
	"H. Peter Anvin" <hpa@...ux.intel.com>
Subject: Re: 2.6.39.1 immediately reboots/resets on EFI system

Op 13-06-11 18:47, Matthew Garrett schreef:
> Ok, let's just try this in a somewhat more brute force way. Can you try 
> this patch on top of current git, and give me the full dmesg and 
> /proc/iomem ?
>
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 0d3a4fa..ffbe47c 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -312,11 +312,35 @@ void __init efi_reserve_boot_services(void)
>  		efi_memory_desc_t *md = p;
>  		unsigned long long start = md->phys_addr;
>  		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
> +		unsigned long long end = start + size;
>  
> -		if (md->type != EFI_BOOT_SERVICES_CODE &&
> -		    md->type != EFI_BOOT_SERVICES_DATA)
> +		if (md->type != EFI_BOOT_SERVICES_CODE)
>  			continue;
>  
> +		/*
> +		 * Trying to map EFI code over the zero page is just asking
> +		 * for trouble. The good news is that it's almost certainly
> +		 * only there for graphics card bringup at POST time, so
> +		 * we should be able to get away with not having it there
> +		 */
> +
> +		if (start == 0) {
> +			md->num_pages = 0;
> +			continue;
> +		}
> +
> +		/*
> +		 * We probably also want to avoid mapping code over the
> +		 * kernel...
> +		 */
> +
> +		if ((start <= virt_to_phys(_etext)-1 && end >= virt_to_phys(_text)) ||
> +		    (start <= virt_to_phys(_edata)-1 && end >= virt_to_phys(_etext)) ||
_etext -> _sdata perhaps?
> +		    (start <= virt_to_phys(&__bss_stop)-1 && end >= virt_to_phys(&__bss_start))) {
> +			md->num_pages = 0;
> +			continue;
> +		}
> +
>  		memblock_x86_reserve_range(start, start + size, "EFI Boot");
>  	}
>  }
Will test though. It might also be appropriate to put a WARN when that condition happens.

~Maarten
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