linux-kernel - Re: [PATCH] x86/efi: earlyprintk - Add 64bit efi fb address support

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Message-ID: <7b08c376-2c34-d462-9d6f-2a104ca48878@canonical.com>
Date:   Wed, 12 Sep 2018 23:09:07 +0800
From:   Aaron Ma <aaron.ma@...onical.com>
To:     Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        the arch/x86 maintainers <x86@...nel.org>,
        linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86/efi: earlyprintk - Add 64bit efi fb address support

On 09/12/2018 11:00 PM, Ard Biesheuvel wrote:
> On 8 September 2018 at 18:23, Aaron Ma <aaron.ma@...onical.com> wrote:
>> EFI GOP uses 64-bit frame buffer address in some BIOS.
>> Add 64bit address support in efi earlyprintk.
>>
>> Signed-off-by: Aaron Ma <aaron.ma@...onical.com>
>> ---
>>  arch/x86/platform/efi/early_printk.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c
>> index 5fdacb322ceb..c0ae25f59acd 100644
>> --- a/arch/x86/platform/efi/early_printk.c
>> +++ b/arch/x86/platform/efi/early_printk.c
>> @@ -32,6 +32,8 @@ static __init int early_efi_map_fb(void)
>>                 return 0;
>>
>>         base = boot_params.screen_info.lfb_base;
>> +       if (boot_params.screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
>> +               base |= (u64)boot_params.screen_info.ext_lfb_base << 32;
>>         size = boot_params.screen_info.lfb_size;
>>         efi_fb = ioremap(base, size);
>>
>> @@ -49,6 +51,8 @@ static __ref void *early_efi_map(unsigned long start, unsigned long len)
>>         unsigned long base;
>>
>>         base = boot_params.screen_info.lfb_base;
>> +       if (boot_params.screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
>> +               base |= (u64)boot_params.screen_info.ext_lfb_base << 32;
>>
>>         if (efi_fb)
>>                 return (efi_fb + start);
> Please fix this in a way that works on 32-bit x86/PAE as well (i.e.,
> use a suitable type for base)
> 

Right, I will send a v2 patch.

Thanks,
Aaron