[Qemu-devel] qemu and glibc version

[Kirill A. Shutemov]

On Mon, Dec 08, 2008 at 10:02:59PM +0100, Martin Mohring wrote:
> Kirill A. Shutemov wrote:
> > On Wed, Dec 03, 2008 at 02:50:57PM +0200, Kirill A. Shutemov wrote:
> >   
> >> On Wed, Dec 03, 2008 at 12:34:18PM +0000, Paul Brook wrote:
> >>     
> >>> On Wednesday 03 December 2008, Kirill A. Shutemov wrote:
> >>>       
> >>>> qemu's page table can be incomple if /proc/self/maps is unavailable or
> >>>> host allocating a memory with mmap(), so we can't use it to find free
> >>>> memory area.
> >>>>         
> >>> Do we really care? Do such systems exist?
> >>>       
> >> I use qemu-arm to build packages in restricted environment -- in hasher[1].
> >> hasher mounts /proc only for packages that really need it for building
> >> (java, for example).
> >>
> >> [1] http://en.altlinux.org/Hasher
> >>     
> >
> > Paul, do you have any objection or not? I really want to see it into
> > upstream.
> >   
> And last, but not least: what if I have a very old Debian Etch, where
> the kernel does not have MREMAP defined? E.g.:
> 
> gcc -I. -I.. -I/usr/src/packages/BUILD/target-i386
> -I/usr/src/packages/BUILD -MMD -MT mmap.o -MP -DNEED_CPU_H -D_GNU_SOURCE
> -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -I/usr/src/packages/BUILD/tcg
> -I/usr/src/packages/BUILD/tcg/i386 -I/usr/src/packages/BUILD/fpu
> -I/usr/src/packages/BUILD/linux-user
> -I/usr/src/packages/BUILD/linux-user/i386 -O2 -g -fno-strict-aliasing
> -Wall -Wundef -Wendif-labels -Wwrite-strings -Wmissing-prototypes
> -Wstrict-prototypes -Wredundant-decls -m32 -c -o mmap.o
> /usr/src/packages/BUILD/linux-user/mmap.c
> /usr/src/packages/BUILD/linux-user/mmap.c:265: warning: no previous
> prototype for 'mmap_find_vma'
> /usr/src/packages/BUILD/linux-user/mmap.c: In function 'target_mremap':
> /usr/src/packages/BUILD/linux-user/mmap.c:556: error: 'MREMAP_FIXED'
> undeclared (first use in this function)
> /usr/src/packages/BUILD/linux-user/mmap.c:556: error: (Each undeclared
> identifier is reported only once
> /usr/src/packages/BUILD/linux-user/mmap.c:556: error: for each function
> it appears in.)
> /usr/src/packages/BUILD/linux-user/mmap.c:558: error: too many arguments
> to function 'mremap'
> /usr/src/packages/BUILD/linux-user/mmap.c:569: error: too many arguments
> to function 'mremap'

Oops... My fault. glibc < 2.4 doesn't provide this functionality. I'll try to
fix it.

Another way is increase version of glibc required for linux user emulation in
qemu. After it we can strip a lot of crap from linux-user/syscall.c and
meke it easier for supporting. 

What do you think.

-- 
Regards,  Kirill A. Shutemov
 + Belarus, Minsk
 + ALT Linux Team, http://www.altlinux.org/

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