Bug#824449: firefox: FTBFS on sparc64 due to wrong platform definitions

[John Paul Adrian Glaubitz]

On Fri, May 20, 2016 at 11:06:06PM +0200, John Paul Adrian Glaubitz wrote:
> Thus, in order to fix this issue on sparc64/Linux, a more elaborate
> fix will have to be developed.

I just made a test installation of NetBSD to verify the theory.

On Linux:

glaubitz at ikarus:~$ cat vmtest.c 
#include <stdio.h>
#include <sys/mman.h>

int main(void)
{
	void *ptr1, *ptr2, *ptr3, *ptr4, *ptr5, *ptr6;
	ptr1 = mmap(NULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr2 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr3 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr4 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr5 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr6 = mmap(NULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	printf("%p %p %p %p %p %p\n", ptr1, ptr2, ptr3, ptr4, ptr5, ptr6);
}
glaubitz at ikarus:~$ ./vmtest 
0x7f80c32f6000 0x70000000000 0x7f80c2d5d000 0x7f80c2c5d000 0x7f80c2b5d000 0x7f80c2a5d000
glaubitz at ikarus:~$ uname -vm
#1 SMP Debian 4.5.1-1 (2016-04-14) x86_64
glaubitz at ikarus:~$

On NetBSD:

testbsd# cat vmtest.c
#include <stdio.h>
#include <sys/mman.h>

int main(void)
{
	void *ptr1, *ptr2, *ptr3, *ptr4, *ptr5, *ptr6;
	ptr1 = mmap(NULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr2 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr3 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr4 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr5 = mmap((void*)0x0000070000000000ULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	ptr6 = mmap(NULL, 1024*1024, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	printf("%p %p %p %p %p %p\n", ptr1, ptr2, ptr3, ptr4, ptr5, ptr6);
}
testbsd# ./vmtest
0x7f7ff7ef8000 0x70000000000 0x6fffff00000 0x6ffffe00000 0x6ffffd00000 0x7f7ff7b00000
testbsd# uname -vm
NetBSD 7.0 (GENERIC.201509250726Z) amd64
testbsd#

As you can see, on NetBSD, mmmap with a hint will always return memory
in the requested region, even if the memory has already been allocated
before. On Linux, the hint is ignored when the memory pointed to by it
is already allocated.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
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