means that the dynamic linker gets mapped in at the top of available
user virtual memory (typically just below the stack), shared libraries
get mapped downwards from that point, and calls to mmap() that don't
specify a preferred address will get mapped in below those.
This means that the heap and the mmap()ed allocations will grow
towards each other, allowing one or the other to grow larger than
before. Previously, the heap was limited to MAXDSIZ by the placement
of the dynamic linker (and the process's rlimits) and the space
available to mmap was hobbled by this reservation.
This is currently only enabled via an *option* for the i386 platform
(though other platforms are expected to follow). Add "options
USE_TOPDOWN_VM" to your kernel config file, rerun config, and rebuild
your kernel to take advantage of this.
Note that the pmap_prefer() interface has not yet been modified to
play nicely with this, so those platforms require a bit more work
(most notably the sparc) before they can use this new memory
arrangement.
This change also introduces a VM_DEFAULT_ADDRESS() macro that picks
the appropriate default address based on the size of the allocation or
the size of the process's text segment accordingly. Several drivers
and the SYSV SHM address assignment were changed to use this instead
of each one picking their own "default".
malloc types into a structure, a pointer to which is passed around,
instead of an int constant. Allow the limit to be adjusted when the
malloc type is defined, or with a function call, as suggested by
Jonathan Stone.
(1) ELFNAME(load_file)() now takes a pointer to the entry point
offset, instead of taking a pointer to the entry point itself. This
allows proper adjustment of the ultimate entry point at a higher level
if the object containing the entry point is moved before the exec is
finished.
(2) Introduce VMCMD_FIXED, which means the address at which a given
vmcmd describes a mapping is fixed (ie, should not be moved). Don't
set this for entries pertaining to ld.so.
Also some minor comment/whitespace tweaks.
routine. Works similarly fto pmap_prefer(), but allows callers
to specify a minimum power-of-two alignment of the region.
How we ever got along without this for so long is beyond me.
"KERN_SYSVIPC_SEM_INFO" and "KERN_SYSVIPC_SHM_INFO" to return the
info and data structures for the relevent SysV IPC types. The return
structures use fixed-size types and should be compat32 safe. All
user-visible changes are protected with
#if !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)
Make all variable declarations extern in msg.h, sem.h and shm.h and
add relevent variable declarations to sysv_*.c and remove unneeded
header files from those .c files.
Make compat14 SysV IPC conversion functions and sysctl_file() static.
Change the data pointer to "void *" in sysctl_clockrate(),
sysctl_ntptime(), sysctl_file() and sysctl_doeproc().
* Remove the casts to vaddr_t from the round_page() and trunc_page() macros to
make them type-generic, which is necessary i.e. to operate on file offsets
without truncating them.
* In due course, cast pointer arguments to these macros to an appropriate
integral type (paddr_t, vaddr_t).
Originally done by Chuck Silvers, updated by myself.
by the Single UNIX Specification version 2, rather than the SVR2-derived
types. While I was here, I did a namespace sweep to expose the constants
and strucutures, and structure members described by SUSv2; documentation
updates coming shortly.
Fixes kern/8158.
UVM was written by chuck cranor <chuck@maria.wustl.edu>, with some
minor portions derived from the old Mach code. i provided some help
getting swap and paging working, and other bug fixes/ideas. chuck
silvers <chuq@chuq.com> also provided some other fixes.
this is the rest of the MI portion changes.
this will be KNF'd shortly. :-)
p->p_vmspace->vm_shm would be NULL. Protected the rest of the cases where
that might happen too. This was the reason why sunxdoom would panic the
system in SVR4 emulation.
sysv_shm.c: make shm_find_segment_by_shmid global so it can be used by
COMPAT_HPUX. There should be a better way...
rest: Add #ifdef COMPAT_HPUX where needed
atatat