1 /*-
2 * Copyright (c) 2016 Nuxi, https://nuxi.nl/
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/lock.h>
32 #include <sys/sysent.h>
33 #include <sys/rwlock.h>
34
35 #include <vm/vm.h>
36 #include <vm/pmap.h>
37 #include <vm/vm_extern.h>
38 #include <vm/vm_object.h>
39 #include <vm/vm_page.h>
40 #include <vm/vm_pager.h>
41
42 #include <compat/cloudabi/cloudabi_util.h>
43
44 void
cloudabi_vdso_init(struct sysentvec * sv,char * begin,char * end)45 cloudabi_vdso_init(struct sysentvec *sv, char *begin, char *end)
46 {
47 vm_page_t m;
48 vm_object_t obj;
49 vm_offset_t addr;
50 size_t i, pages, pages_length, vdso_length;
51
52 /* Determine the number of pages needed to store the vDSO. */
53 vdso_length = end - begin;
54 pages = howmany(vdso_length, PAGE_SIZE);
55 pages_length = pages * PAGE_SIZE;
56
57 /* Allocate a VM object and fill it with the vDSO. */
58 obj = vm_pager_allocate(OBJT_PHYS, 0, pages_length,
59 VM_PROT_DEFAULT, 0, NULL);
60 addr = kva_alloc(PAGE_SIZE);
61 for (i = 0; i < pages; ++i) {
62 VM_OBJECT_WLOCK(obj);
63 m = vm_page_grab(obj, i, VM_ALLOC_ZERO);
64 VM_OBJECT_WUNLOCK(obj);
65 vm_page_valid(m);
66 vm_page_xunbusy(m);
67
68 pmap_qenter(addr, &m, 1);
69 memcpy((void *)addr, begin + i * PAGE_SIZE,
70 MIN(vdso_length - i * PAGE_SIZE, PAGE_SIZE));
71 pmap_qremove(addr, 1);
72 }
73 kva_free(addr, PAGE_SIZE);
74
75 /*
76 * Place the vDSO at the top of the address space. The user
77 * stack can start right below it.
78 */
79 sv->sv_shared_page_base = sv->sv_maxuser - pages_length;
80 sv->sv_shared_page_len = pages_length;
81 sv->sv_shared_page_obj = obj;
82 sv->sv_usrstack = sv->sv_shared_page_base;
83 }
84
85 void
cloudabi_vdso_destroy(struct sysentvec * sv)86 cloudabi_vdso_destroy(struct sysentvec *sv)
87 {
88
89 vm_object_deallocate(sv->sv_shared_page_obj);
90 }
91