[U-Boot] [PATCH 00/82] x86: Add initial support for 64-bit U-Boot

[Bin Meng]

Hi Simon,

On Tue, Oct 18, 2016 at 6:17 AM, Simon Glass <sjg at chromium.org> wrote:
> Hi Bin,
>
> On 10 October 2016 at 23:36, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi Simon,
>>
>> On Mon, Sep 26, 2016 at 11:33 AM, Simon Glass <sjg at chromium.org> wrote:
>>> At present U-Boot runs entirely in 32-bit mode on x86, except for the
>>> initial switch from 16-bit mode. On 64-bit machines it is possible to run
>>> in 64-bit mode. This series starts the process of adding this support.
>>>
>>> The main benefit of 64-bit mode for a boot loader is direct access to all
>>> available memory. There are also more registers, but this makes very little
>>> difference.
>>>
>>> This feature is implemented by putting all of the 32-bit code in an SPL
>>> build. SPL then runs through all the init that has to be done in 32-bit
>>> mode, changes to 64-bit mode and then jumps to U-Boot proper.
>>>
>>> Typically the total code size increases slightly. For example, on link in
>>> 32-bit mode, U-Boot has around 480KB of code (admittedly with a large
>>> number of features enabled). In 64-bit mode, U-Boot falls to around 460KB,
>>> but SPL adds another 60KB, for a net increase of 40KB. Partly this is due
>>> to code duplication and partly it is due to the worse code density of
>>> 64-bit code on x86.
>>>
>>> Many major features are not implemented yet, for example:
>>> - SDRAM sizing
>>> - Booting linux
>>> - FSP support
>>> - EFI support
>>> - SCSI device init
>>> - Running video ROMs
>>>
>>> Still, this is a big step forward towards full 64-bit support. To enable it,
>>> select CONFIG_X86_RUN_64BIT.
>>>
>>> This series is available at u-boot-x86/64-working
>>>
>>
>> Looks it requires a 64-bit toolchain to compile 64-bit U-Boot. For
>> example, I used kernel.org i386 toolchain to compile 64-bit U-Boot, I
>> got:
>>
>> include/asm-generic/bitops/__fls.h: In function '__fls':
>> include/asm-generic/bitops/__fls.h:17:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << 32))) {
>>   ^
>> include/asm-generic/bitops/__fls.h:19:3: warning: left shift count >=
>> width of type
>>    word <<= 32;
>>    ^
>> include/asm-generic/bitops/__fls.h:22:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
>>   ^
>> include/asm-generic/bitops/__fls.h:26:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
>>   ^
>> include/asm-generic/bitops/__fls.h:30:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
>>   ^
>> include/asm-generic/bitops/__fls.h:34:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
>>   ^
>> include/asm-generic/bitops/__fls.h:38:2: warning: left shift count >=
>> width of type
>>   if (!(word & (~0ul << (BITS_PER_LONG-1))))
>>   ^
>> arch/x86/cpu/intel_common/microcode.c: In function 'microcode_read_rev':
>> arch/x86/cpu/intel_common/microcode.c:79:2: error: PIC register
>> clobbered by 'ebx' in 'asm'
>>   asm volatile (
>>   ^
>> make[2]: *** [arch/x86/cpu/intel_common/microcode.o] Error 1
>
> Yes, that is expected.

Can we make the i386 toolchain work? Linux 64-bit kernel build does
not require the toolchain to be 64-bit.

>>
>> After I switched to 64-bit toolchain from kernel.org (x86_64-linux),
>> there was no such warnings/errors, but I still got build failure at
>> last.
>>
>>   ./tools/binman/binman -d u-boot.dtb -O . -I . -I
>> ./board/google/chromebook_link u-boot-x86-16bit.bin
>> Traceback (most recent call last):
>>   File "./tools/binman/binman", line 31, in <module>
>>     import control
>>   File "./tools/binman/control.py", line 17, in <module>
>>     from image import Image
>>   File "./tools/binman/image.py", line 12, in <module>
>>     import entry
>>   File "./tools/binman/etype/entry.py", line 8, in <module>
>>     import importlib
>> ImportError: No module named importlib
>> make: *** [u-boot.rom] Error 1
>
> What version of python do you use?

$ python -V
Python 2.7.12

Regards,
Bin