linux-kernel - Re: [PATCH] arm64/efi: efi

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Date:   Tue, 13 Sep 2016 12:18:04 +0100
From:   Matt Fleming <matt@...eblueprint.co.uk>
To:     Yisheng Xie <xieyisheng1@...wei.com>
Cc:     Will Deacon <will.deacon@....com>, mingo@...nel.org,
        guohanjun@...wei.com, mark.rutland@....com,
        catalin.marinas@....com, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-efi@...r.kernel.org,
        ard.biesheuvel@...aro.org
Subject: Re: [PATCH] arm64/efi: efi_init error handling fix

On Wed, 07 Sep, at 07:15:48PM, Yisheng Xie wrote:
> 
> 
> On 2016/9/5 21:57, Matt Fleming wrote:
> > On Fri, 02 Sep, at 11:26:18AM, Will Deacon wrote:
> >> On Fri, Sep 02, 2016 at 06:18:39PM +0800, Xie Yisheng wrote:
> >>> From: Yisheng Xie <xieyisheng1@...wei.com>
> >>>
> >>> diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
> >>> index c49d50e..5080e40 100644
> >>> --- a/drivers/firmware/efi/arm-init.c
> >>> +++ b/drivers/firmware/efi/arm-init.c
> >>> @@ -243,8 +243,10 @@ void __init efi_init(void)
> >>>  	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
> >>>  	      efi.memmap.desc_version);
> >>>  
> >>> -	if (uefi_init() < 0)
> >>> +	if (uefi_init() < 0) {
> >>> +		early_memunmap(efi.memmap.map, params.mmap_size);
> >>>  		return;
> >>> +	}
> > 
> > This should be a call to efi_memmap_unmap() because the EFI_MEMMAP
> > flag also needs clearing.
> > 
> Hi Matt,
> Thanks for your reply.
> You mean call the function efi_unmap_memmap() like x86?
> 
> however, it seems no need to clear EFI_MEMMAP here. For arm*, the flag
> EFI_MEMMAP is set in function reserve_regions(), which is called
> only when uefi_init() return 0:
> 
> efi_init()
>    -> reserve_regions()
>        -> set_bit(EFI_MEMMAP, &efi.flags);

This patch should be against the 'next' branch here,

  https://git.kernel.org/cgit/linux/kernel/git/mfleming/efi.git/log/?h=next

My comments were made with that branch in mind.