linux-kernel - Re: [PATCH]x86 efi: do not export efi runtime map in case old map

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Date:	Fri, 30 May 2014 08:59:00 -0400
From:	Vivek Goyal <vgoyal@...hat.com>
To:	Dave Young <dyoung@...hat.com>
Cc:	matt.fleming@...el.com, bp@...en8.de, linux-kernel@...r.kernel.org,
	linux-efi@...r.kernel.org
Subject: Re: [PATCH]x86 efi: do not export efi runtime map in case old map

On Fri, May 30, 2014 at 11:20:10AM +0800, Dave Young wrote:
> 
> For ioremapped efi memory aka old_map the virt addresses are not persistant
> across kexec reboot. kexec-tools will read the runtime maps from sysfs then
> pass them to 2nd kernel and assuming kexec efi boot is ok. This will cause
> kexec boot failure.
> 
> To address this issue do not export runtime maps in case efi old_map so
> userspace can use no efi boot instead.
> 
> Signed-off-by: Dave Young <dyoung@...hat.com>

Looks good to me.

Acked-by: Vivek Goyal <vgoyal@...hat.com>

Vivek

> ---
>  arch/x86/platform/efi/efi.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 3781dd3..4d36932 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -919,6 +919,9 @@ static void __init save_runtime_map(void)
>  	void *tmp, *p, *q = NULL;
>  	int count = 0;
>  
> +	if (efi_enabled(EFI_OLD_MEMMAP))
> +		return;
> +
>  	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
>  		md = p;
>  
> -- 
> 1.8.3.1
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