Re: [Qemu-devel] [PATCH] Rewrite mmap_find_vma() to work fine on 64-bit hosts with 32-bit targets

[Robert Reif <reif@earthlink.net>]

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'
>
>
> Martin
>
>
>
>
>   
I get this same build error now with RedHat 9.