Greetings! I think we have a somewhat workable solution committed to
master.
We define an __end variable in msbrk.c in assembler, using the xcode
.zerofill directive, and place it in its own segment and section to get
it past .bss and .common. Note that if the size is too large, the xcode
linker will ignore the segment/section designation and fold the variable
into a newly created __huge section under __DATA, and interleave it with
other variables, which is not what we want. So we have a 1-2Gb heap for
the raw image, and then expand the vmsize to 128Gb (currently) on
unexec. I sure would appreciate if a knowledgeable user could show me
how to avoid this two step process. Initializing the raw image may
require setting GCL_MEM_BOUND to 29 or so to make sure we stay within
this reserved range. If this two step process stays in we will put that
in explicitly in the Makefile.am rule.
If the linker behaves, then otool -t unixport/raw_pre_gcl |sort should
have something like
000000010278a060 l O __DATA,__bss _begin_tzp.4
000000010278a060 l d *UND* _begin_tzp.4
000000010278c000 g O __HEAP,__heap __end
SYMBOL TABLE:
near the bottom, with no variables between __end and the SYMBOL TABLE.
In any case, the heap is now growing at the correct place with no holes
at all stages. The resulting saved images should be able to adapt to
any user runtime memory up to 128Gb. We might need another power of two
in the end, but you get the idea, and this can now be tested.
If other people's linkers do not behave like I describe please let me
know quickly and we will pursue another route.
Take care,
=============================================================================
msbrk.c
=============================================================================
#if defined(DARWIN)
/*This initial heap must be large enough to initialize the raw image,
but not so large that the Mac linker ignores the segment designation
and creates a __huge section under __DATA for this and other
variables. We enlarge this on unexec.*/
asm (".zerofill __HEAP,__heap,__end,0x70000000\n\t.globl __end");
#endif
=============================================================================
--
Camm Maguire c...@maguirefamily.org
==========================================================================
"The earth is but one country, and mankind its citizens." -- Baha'u'llah
