Introduce a global lock for the vm subsystem (vm_mtx).

vm_mtx does not recurse and is required for most low level
vm operations.

faults can not be taken without holding Giant.

Memory subsystems can now call the base page allocators safely.

Almost all atomic ops were removed as they are covered under the
vm mutex.

Alpha and ia64 now need to catch up to i386's trap handlers.

FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).

Reviewed (partially) by: jake, jhb

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/kern/link_elf_obj.c b/sys/kern/link_elf_obj.c
index 344f163..613d1e4 100644
--- a/sys/kern/link_elf_obj.c
+++ b/sys/kern/link_elf_obj.c
@@ -653,8 +653,10 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
 
     ef = (elf_file_t) lf;
 #ifdef SPARSE_MAPPING
+    mtx_lock(&vm_mtx);
     ef->object = vm_object_allocate(OBJT_DEFAULT, mapsize >> PAGE_SHIFT);
     if (ef->object == NULL) {
+    	mtx_unlock(&vm_mtx);
 	free(ef, M_LINKER);
 	error = ENOMEM;
 	goto out;
@@ -667,9 +669,11 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
 			VM_PROT_ALL, VM_PROT_ALL, 0);
     if (error) {
 	vm_object_deallocate(ef->object);
+    	mtx_unlock(&vm_mtx);
 	ef->object = 0;
 	goto out;
     }
+    mtx_unlock(&vm_mtx);
 #else
     ef->address = malloc(mapsize, M_LINKER, M_WAITOK);
     if (!ef->address) {
@@ -697,10 +701,12 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
 	/*
 	 * Wire down the pages
 	 */
+	mtx_lock(&vm_mtx);
 	vm_map_pageable(kernel_map,
 			(vm_offset_t) segbase,
 			(vm_offset_t) segbase + segs[i]->p_memsz,
 			FALSE);
+	mtx_unlock(&vm_mtx);
 #endif
     }
 
@@ -824,10 +830,12 @@ link_elf_unload_file(linker_file_t file)
     }
 #ifdef SPARSE_MAPPING
     if (ef->object) {
+	mtx_lock(&vm_mtx);	    
 	vm_map_remove(kernel_map, (vm_offset_t) ef->address,
 		      (vm_offset_t) ef->address
 		      + (ef->object->size << PAGE_SHIFT));
 	vm_object_deallocate(ef->object);
+	mtx_unlock(&vm_mtx);	    
     }
 #else
     if (ef->address)