From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ross Lagerwall <ross.lagerwall@citrix.com>
Subject: Re: [PATCH v4] efi: Avoid calling boot services after
	ExitBootServices()
Date: Tue, 9 Jun 2015 14:05:48 +0100
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To: Ian Campbell <ian.campbell@citrix.com>, Jan Beulich <JBeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>, Keir Fraser <keir@xen.org>, xen-devel@lists.xen.org, Stefano Stabellini <stefano.stabellini@citrix.com>, Andrew Cooper <andrew.cooper3@citrix.com>
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On 06/09/2015 01:53 PM, Ian Campbell wrote:
> On Tue, 2015-06-09 at 12:51 +0100, Jan Beulich wrote:
>>>>> On 09.06.15 at 12:36, <ross.lagerwall@citrix.com> wrote:
>>> ping
>>
>> I'm still waiting for the ARM maintainers to ack ...
>>
>>>> --- a/xen/arch/arm/efi/efi-boot.h
>>>> +++ b/xen/arch/arm/efi/efi-boot.h
>>>> @@ -522,6 +522,11 @@ static void __init efi_arch_blexit(void)
>>>>            efi_bs->FreePool(memmap);
>>>>    }
>>>>
>>>> +static void __init efi_arch_halt(void)
>>>> +{
>>>> +    stop_cpu();
>>>> +}
>>>> +
>>>>    static void __init efi_arch_load_addr_check(EFI_LOADED_IMAGE *loaded_image)
>>>>    {
>>>>        if ( (unsigned long)loaded_image->ImageBase & ((1 << 12) - 1) )
>>
>> ... this.
>
> I think it is ok, it does a bit more than the x86 variant, which is that
> it would interlock correctly with __cpu_die, where the open coded on x86
> wouldn't (assuming you have any interlock anyway.
>
> In terms of the rest of the patch, are those two places changed to use
> SystemTable->BootServices instead of efi_bs, if the point of the patch
> is to not use BootServices after exit is called?
>

GetMemoryMap() and ExitBootServices() are the only functions explicitly 
allowed after the first call to ExitBootServices() so they are called 
via SystemTable->BootServices. efi_bs is set to NULL to ensure that no 
other bootservices are called.

Cheers,
-- 
Ross Lagerwall