[Arm-dev] Gigabyte MP30-AR0

[Gordan Bobic]

On 2016-03-01 22:32, Michael Howard wrote:
> On 01/03/2016 22:26, Richard W.M. Jones wrote:
>> On Mon, Feb 29, 2016 at 03:20:03PM +0000, Michael Howard wrote:
>>> Just to let you know, I can't get this to work. aarch64 is supposed
>>> to be binary compatible, with the correct libraries installed, but
>>> I'm thinking the cpu isn't.
>>> 
>>> All I get is 'cannot execute binary file: Exec format error',
>>> regardless  of what I try.
>> As I understand it the problem is page size - 64K was chosen by
>> Red Hat for aarch64, where as 4K is the norm on armv7.
>> 
>> Anyway, you can run a 32 bit VM and it works well -- in fact a lot
>> faster than regular 32 bit armv7 hardware.
>> 
> 
> Yes, with CONFIG_ARM64_4K_PAGES=y and CONFIG_COMPAT=y, 32 bit binaries 
> run fine.

I built a kernel with these options enabled, but chrooting into an
armv5tel subtree segfaults immediately. :-(

# grep -E "CONFIG_COMPAT=|CONFIG_ARM64_4K_PAGES=" /boot/config-4.4.5
CONFIG_ARM64_4K_PAGES=y
CONFIG_COMPAT=y

# chroot /orcone/docker/rsel6/
Segmentation fault

The chroot is armv5tel soft-float, which I think should work.
Oddly, I see no mention of a segfault in dmesg or in /var/log/messages
on the host...

# strace chroot /orcone/docker/media/
execve("/sbin/chroot", ["chroot", "/orcone/docker/media/"], [/* 18 vars 
*/]) = 0
brk(0)                                  = 0x153eb000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) 
= 0x7f98108000
faccessat(AT_FDCWD, "/etc/ld.so.preload", R_OK) = -1 ENOENT (No such 
file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=23876, ...}) = 0
mmap(NULL, 23876, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f98102000
close(3)                                = 0
openat(AT_FDCWD, "/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, 
"\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\267\0\1\0\0\0\270\r\2\0\0\0\0\0"..., 
832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1801536, ...}) = 0
mmap(NULL, 1528796, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 
0) = 0x7f97f66000
mprotect(0x7f980c2000, 65536, PROT_NONE) = 0
mmap(0x7f980d2000, 24576, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15c000) = 0x7f980d2000
mmap(0x7f980d8000, 13276, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f980d8000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) 
= 0x7f98101000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) 
= 0x7f98100000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) 
= 0x7f980ff000
mprotect(0x7f980d2000, 16384, PROT_READ) = 0
mprotect(0x41f000, 4096, PROT_READ)     = 0
mprotect(0x7f9810b000, 4096, PROT_READ) = 0
munmap(0x7f98102000, 23876)             = 0
brk(0)                                  = 0x153eb000
brk(0x1540c000)                         = 0x1540c000
brk(0)                                  = 0x1540c000
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 
3
fstat(3, {st_mode=S_IFREG|0644, st_size=109669264, ...}) = 0
mmap(NULL, 109669264, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f916cf000
close(3)                                = 0
chroot("/orcone/docker/media/")         = 0
chdir("/")                              = 0
execve("/bin/bash", ["/bin/bash", "-i"], [/* 18 vars */]) = 
-1053305918634065933
--- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} ---
+++ killed by SIGSEGV +++
Segmentation fault


What am I doing differently?