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On amd64, allocate module_map memory from the lowest 2GB.

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pooka 2010-06-09 12:02:37 +00:00
parent 3f4944e6bb
commit aad71fb6e2
1 changed files with 28 additions and 4 deletions
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32
sys/rump/librump/rumpkern/vm.c
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@ -1,4 +1,4 @@
/* $NetBSD: vm.c,v 1.81 2010/06/09 11:35:36 pooka Exp $ */
/* $NetBSD: vm.c,v 1.82 2010/06/09 12:02:37 pooka Exp $ */
/*
* Copyright (c) 2007-2010 Antti Kantee. All Rights Reserved.
@ -43,7 +43,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.81 2010/06/09 11:35:36 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.82 2010/06/09 12:02:37 pooka Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@ -528,15 +528,39 @@ uvm_map_protect(struct vm_map *map, vaddr_t start, vaddr_t end,
vaddr_t
uvm_km_alloc(struct vm_map *map, vsize_t size, vsize_t align, uvm_flag_t flags)
{
void *rv;
void *rv, *desired = NULL;
int alignbit, error;
#ifdef __x86_64__
/*
* On amd64, allocate all module memory from the lowest 2GB.
* This is because NetBSD kernel modules are compiled
* with -mcmodel=kernel and reserve only 4 bytes for
* offsets. If we load code compiled with -mcmodel=kernel
* anywhere except the lowest or highest 2GB, it will not
* work. Since userspace does not have access to the highest
* 2GB, use the lowest 2GB.
*
* Note: this assumes the rump kernel resides in
* the lowest 2GB as well.
*
* Note2: yes, it's a quick hack, but since this the only
* place where we care about the map we're allocating from,
* just use a simple "if" instead of coming up with a fancy
* generic solution.
*/
extern struct vm_map *module_map;
if (map == module_map) {
desired = (void *)(0x80000000 - size);
}
#endif
alignbit = 0;
if (align) {
alignbit = ffs(align)-1;
}
rv = rumpuser_anonmmap(NULL, size, alignbit, flags & UVM_KMF_EXEC,
rv = rumpuser_anonmmap(desired, size, alignbit, flags & UVM_KMF_EXEC,
&error);
if (rv == NULL) {
if (flags & (UVM_KMF_CANFAIL | UVM_KMF_NOWAIT))