Hello everybody,
I feel sorry to mail everyone and I hope this won't disturb too much
people. But I'm stuck and I'm pretty sure your help will be valuable.
_*First I would like to give all the information :*_
I have a laptop computer (Asus Novago, TP370QL) running on an ARM64
platform (Qualcomm Snapragon 835), with UEFI support, Secure Boot
disabled, and "Boot USB First" enabled. It's a laptop shaped smart-phone
that has the same features that a standard x86_64-efi computer.
It's delivered with Windows 10 Pro on it, installed in the exact same
way that on a x86_64-efi computer (same partitions scheme, ESP,
recovery, same files etc... just it's aarch64 built instead of x86_64).
I have a working USB re-installation media (that can be booted trough
EFI) and I already successfully cleared the entire disk (like dd
if=/dev/zero of=/dev/sda but with Windows "diskpart" and "clean"
commands). And of course the re-installation media is working - if not I
would have been really disappointed ;)
I'm also able to boot EFI files on it, I just have to ensure the USB
disk (or SD card) has GPT partitionning, at least 1 partition that is
ESP type, and FAT32 formatted, containing a "/efi/boot/bootaa64.efi"
file that the computer will execute at startup.
Is some of you are interested in seeing what it looks like :
http://image.noelshack.com/fichiers/2018/52/6/1546083005-infact.png
_*My problem :*__*
*_
GRUB doesn't work (it freezes on the "Asus" logo and I have to force
shutdown the computer by pressing the power button 5 seconds). Same
problem for GRUB versions used in Debian, Ubuntu, even Buster and 18.10
versions (using 4.18 kernel, where all the Qualcomm things are now
mainlined).
And by seeing what are the gcc used options for GRUB, and comparing
those options with the ones that are used for the working "UEFI-SIMPLE"
(https://github.com/pbatard/uefi-simple), I found that the -fno-PIE,
-fno-pie, and -fno-pic and -fno-PIC options shouldn't be used ! The
default compiler behavior is the right one (-fPIC and -fPIE are enabled
by default) but grub Makefiles are disabling it. And it does not work on
this computer when disabled. If one of the "-fno-PIE -fno-pie -fno-pic
-fno-PIC" are used, the computer won't be able to start the resulting
UEFI-SIMPLE efi file.
The "-no-pie" option, however, isn't causing any problem (and can be
used in parallel of -fPIC and -fPIE option, even if it sound pretty
strange : the resulting UEFI-SIMPLE efi file is still working that way).
As I understand, those options are dealing with Global Offset Tables
(GOT) with more information here :
https://en.wikipedia.org/wiki/Position-independent_code
_*What I did and where I'm stuck :*_
I'm trying to create a GRUB efi file that my ARM64 computer will be able
to execute, even if the first result is a working error message ! I
would then be happy because I will then manage to reconfigure things in
order to make the debian installer to start with this grub file. Having
grub to work on this computer is my quest, today. In order to test what
should happen when it will be working, I already did that on a
x86_64-efi computer (and I got an error message and a grub-rescue line
but that's fine).
I downloaded the grub source code here :
ftp://ftp.gnu.org/gnu/grub/grub-2.02.tar.gz
And I found an ARM64 computer already working on Linux (Debian 9) on
"Scaleway" provider, in order to build things in an easy way.
By running ./configure command, then make -j 4, and by playing with
grub-install, it's giving an EFI file that my arm64 computer won't boot
(freeze). So I tried to modify the "configure" file by commenting lines
26055, 26056, 26057, then 26116, 26117.
# Need that, because some distributions ship compilers that include
# `-fPIE' or '-fpie' and '-pie' in the default specs.
# if [ x"$pie_possible" = xyes ]; then
# TARGET_CFLAGS="$TARGET_CFLAGS -fno-PIE -fno-pie"
# fi
if ( test x$target_cpu = xmips || test x$target_cpu = xmipsel ||
test x$target_cpu = xarm64 ) && test "x$grub_cv_cc_target_clang" =
xyes ; then
TARGET_CFLAGS="$TARGET_CFLAGS -fPIC"
#elif [ x"$pic_possible" = xyes ]; then
# TARGET_CFLAGS="$TARGET_CFLAGS -fno-PIC"
fi
Disabling those options are making, by default, the -fPIE and -fPIC
flags active. This is not compatible with the mcmodel=large flag, so I
disabled it too, in conf/Makefile.common : 17, 18, 19
#if COND_arm64
# CFLAGS_PLATFORM += -mcmodel=large
#endif
However, disabling only the -mcmodel=large flag, with no other
modification, is already giving an error at the end of the build
process, when trying to transform the xxx.module files into xxx.mod files.
TARGET_OBJ2ELF= sh genmod.sh moddep.lst disk.module
build-grub-module-verifier disk.mod
build-grub-module-verifier: error: relocation 0x113 is not module-local.
Removing the -fno-PIC, -fno-PIE and -fno-pie flags then leads to a
different error, at the end too.
TARGET_OBJ2ELF= sh genmod.sh moddep.lst acpi.module
build-grub-module-verifier acpi.mod
build-grub-module-verifier: error: LD64_GOT_LO12_NC without matching
ADR_GOT_PAGE.
Enabling the -fpic and -fpie flags (lower case) is leading to another
error :
_GLOBAL_OFFSET_TABLE_ in acpi is not defined
_GLOBAL_OFFSET_TABLE_ in affs is not defined
_GLOBAL_OFFSET_TABLE_ in afs is not defined
_GLOBAL_OFFSET_TABLE_ in [...] is not defined
[...]
I also tried to remove the -no-pie flag but it makes another flag
(-Wl,-r) incompatible. When I removed the -r flag to the linker, I got
sooner build errors when trying to create *.module files from *.o files
gcc [...] -o disk.module lib/disk_module-disk.o
/usr/bin/ld: warning: cannot find entry symbol _start; defaulting to
00000000004004e0
lib/disk_module-disk.o: In function `grub_disk_cache_invalidate':
/home/debian/grub-2.02/grub-core/lib/disk.c:42: undefined reference
to `grub_disk_cache_table'
/home/debian/grub-2.02/grub-core/lib/disk.c:48: undefined reference
to `grub_free'
[...and lot of others 'undefined reference' errors...]
So here I'm stuck ! Despite the days I spent on this, I'm definitely not
able to deal with those flags as finely as you, developers, seemed to
enable it or disable it in different portions of the grub's code.
Can someone help me in this quest of having grub working on those
Qualcomm ARM64 laptops ? I think the initial mission is to re-enable the
-fPIC and -fPIE flags but it's like this missions implies others
missions to succeed.
Thank you (very) much in advance for your help !
Best regards,
Julien ROBIN
_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
