[apple/xnu.git] / osfmk / kern / kext_alloc.c

/*
 * Copyright (c) 2008 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
#include <kern/assert.h>
#include <kern/debug.h>
#include <kern/kext_alloc.h>
#include <kern/misc_protos.h>

#include <mach/host_priv_server.h>
#include <mach/kern_return.h>
#include <mach/mach_vm.h>
#include <mach/vm_map.h>
#include <mach/vm_types.h>

#include <mach-o/loader.h>
#include <libkern/kernel_mach_header.h>
#include <san/kasan.h>

#define KASLR_IOREG_DEBUG 0


vm_map_t g_kext_map = 0;
#if KASLR_IOREG_DEBUG
mach_vm_offset_t kext_alloc_base = 0;
mach_vm_offset_t kext_alloc_max = 0;
#else
static mach_vm_offset_t kext_alloc_base = 0;
static mach_vm_offset_t kext_alloc_max = 0;
#if CONFIG_KEXT_BASEMENT
static mach_vm_offset_t kext_post_boot_base = 0;
#endif
#endif

/*
 * On x86_64 systems, kernel extension text must remain within 2GB of the
 * kernel's text segment.  To ensure this happens, we snag 2GB of kernel VM
 * as early as possible for kext allocations.
 */
void
kext_alloc_init(void)
{
#if CONFIG_KEXT_BASEMENT
	kern_return_t rval = 0;
	kernel_segment_command_t *text = NULL;
	kernel_segment_command_t *prelinkTextSegment = NULL;
	mach_vm_offset_t text_end, text_start;
	mach_vm_size_t text_size;
	mach_vm_size_t kext_alloc_size;

	/* Determine the start of the kernel's __TEXT segment and determine the
	 * lower bound of the allocated submap for kext allocations.
	 */

	text = getsegbyname(SEG_TEXT);
	text_start = vm_map_trunc_page(text->vmaddr,
	    VM_MAP_PAGE_MASK(kernel_map));
	text_start &= ~((512ULL * 1024 * 1024 * 1024) - 1);
	text_end = vm_map_round_page(text->vmaddr + text->vmsize,
	    VM_MAP_PAGE_MASK(kernel_map));
	text_size = text_end - text_start;

	kext_alloc_base = KEXT_ALLOC_BASE(text_end);
	kext_alloc_size = KEXT_ALLOC_SIZE(text_size);
	kext_alloc_max = kext_alloc_base + kext_alloc_size;

	/* Post boot kext allocation will start after the prelinked kexts */
	prelinkTextSegment = getsegbyname("__PRELINK_TEXT");
	if (prelinkTextSegment) {
		/* use kext_post_boot_base to start allocations past all the prelinked
		 * kexts
		 */
		kext_post_boot_base =
		    vm_map_round_page(kext_alloc_base + prelinkTextSegment->vmsize,
		    VM_MAP_PAGE_MASK(kernel_map));
	} else {
		kext_post_boot_base = kext_alloc_base;
	}

	/* Allocate the sub block of the kernel map */
	rval = kmem_suballoc(kernel_map, (vm_offset_t *) &kext_alloc_base,
	    kext_alloc_size, /* pageable */ TRUE,
	    VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE,
	    VM_MAP_KERNEL_FLAGS_NONE, VM_KERN_MEMORY_KEXT,
	    &g_kext_map);
	if (rval != KERN_SUCCESS) {
		panic("kext_alloc_init: kmem_suballoc failed 0x%x\n", rval);
	}

	if ((kext_alloc_base + kext_alloc_size) > kext_alloc_max) {
		panic("kext_alloc_init: failed to get first 2GB\n");
	}

	if (kernel_map->min_offset > kext_alloc_base) {
		kernel_map->min_offset = kext_alloc_base;
	}

	printf("kext submap [0x%lx - 0x%lx], kernel text [0x%lx - 0x%lx]\n",
	    VM_KERNEL_UNSLIDE(kext_alloc_base),
	    VM_KERNEL_UNSLIDE(kext_alloc_max),
	    VM_KERNEL_UNSLIDE(text->vmaddr),
	    VM_KERNEL_UNSLIDE(text->vmaddr + text->vmsize));

#else
	g_kext_map = kernel_map;
	kext_alloc_base = VM_MIN_KERNEL_ADDRESS;
	kext_alloc_max = VM_MAX_KERNEL_ADDRESS;
#endif /* CONFIG_KEXT_BASEMENT */
}

kern_return_t
kext_alloc(vm_offset_t *_addr, vm_size_t size, boolean_t fixed)
{
	kern_return_t rval = 0;
#if CONFIG_KEXT_BASEMENT
	mach_vm_offset_t addr = (fixed) ? *_addr : kext_post_boot_base;
#else
	mach_vm_offset_t addr = (fixed) ? *_addr : kext_alloc_base;
#endif
	int flags = (fixed) ? VM_FLAGS_FIXED : VM_FLAGS_ANYWHERE;

#if CONFIG_KEXT_BASEMENT
	/* Allocate the kext virtual memory
	 * 10608884 - use mach_vm_map since we want VM_FLAGS_ANYWHERE allocated past
	 * kext_post_boot_base (when possible).  mach_vm_allocate will always
	 * start at 0 into the map no matter what you pass in addr.  We want non
	 * fixed (post boot) kext allocations to start looking for free space
	 * just past where prelinked kexts have loaded.
	 */
	rval = mach_vm_map_kernel(g_kext_map,
	    &addr,
	    size,
	    0,
	    flags,
	    VM_MAP_KERNEL_FLAGS_NONE,
	    VM_KERN_MEMORY_KEXT,
	    MACH_PORT_NULL,
	    0,
	    TRUE,
	    VM_PROT_DEFAULT,
	    VM_PROT_ALL,
	    VM_INHERIT_DEFAULT);
	if (rval != KERN_SUCCESS) {
		printf("mach_vm_map failed - %d\n", rval);
		goto finish;
	}
#else
	rval = mach_vm_allocate_kernel(g_kext_map, &addr, size, flags, VM_KERN_MEMORY_KEXT);
	if (rval != KERN_SUCCESS) {
		printf("vm_allocate failed - %d\n", rval);
		goto finish;
	}
#endif

	/* Check that the memory is reachable by kernel text */
	if ((addr + size) > kext_alloc_max) {
		kext_free((vm_offset_t)addr, size);
		rval = KERN_INVALID_ADDRESS;
		goto finish;
	}

	*_addr = (vm_offset_t)addr;
	rval = KERN_SUCCESS;
#if KASAN
	kasan_notify_address(addr, size);
#endif

finish:
	return rval;
}

void
kext_free(vm_offset_t addr, vm_size_t size)
{
	kern_return_t rval;

	rval = mach_vm_deallocate(g_kext_map, addr, size);
	assert(rval == KERN_SUCCESS);
}
Commit	Line	Data
b0d623f7 A	1	/*
	2	* Copyright (c) 2008 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
0a7de745	5	*
b0d623f7 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
0a7de745	14	*
b0d623f7 A	15	* Please obtain a copy of the License at
b0d623f7 A	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
0a7de745	17	*
b0d623f7 A	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
0a7de745	25	*
b0d623f7 A	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28	#include <kern/assert.h>
	29	#include <kern/debug.h>
	30	#include <kern/kext_alloc.h>
	31	#include <kern/misc_protos.h>
	32
	33	#include <mach/host_priv_server.h>
	34	#include <mach/kern_return.h>
	35	#include <mach/mach_vm.h>
	36	#include <mach/vm_map.h>
	37	#include <mach/vm_types.h>
	38
	39	#include <mach-o/loader.h>
	40	#include <libkern/kernel_mach_header.h>
5ba3f43e	41	#include <san/kasan.h>
b0d623f7	42
316670eb A	43	#define KASLR_IOREG_DEBUG 0
316670eb A	44
b0d623f7 A	45
b0d623f7 A	46	vm_map_t g_kext_map = 0;
316670eb A	47	#if KASLR_IOREG_DEBUG
	48	mach_vm_offset_t kext_alloc_base = 0;
	49	mach_vm_offset_t kext_alloc_max = 0;
	50	#else
b0d623f7 A	51	static mach_vm_offset_t kext_alloc_base = 0;
b0d623f7 A	52	static mach_vm_offset_t kext_alloc_max = 0;
316670eb A	53	#if CONFIG_KEXT_BASEMENT
	54	static mach_vm_offset_t kext_post_boot_base = 0;
	55	#endif
	56	#endif
b0d623f7 A	57
	58	/*
	59	* On x86_64 systems, kernel extension text must remain within 2GB of the
	60	* kernel's text segment. To ensure this happens, we snag 2GB of kernel VM
	61	* as early as possible for kext allocations.
	62	*/
0a7de745	63	void
b0d623f7 A	64	kext_alloc_init(void)
b0d623f7 A	65	{
316670eb	66	#if CONFIG_KEXT_BASEMENT
0a7de745 A	67	kern_return_t rval = 0;
	68	kernel_segment_command_t *text = NULL;
	69	kernel_segment_command_t *prelinkTextSegment = NULL;
	70	mach_vm_offset_t text_end, text_start;
	71	mach_vm_size_t text_size;
	72	mach_vm_size_t kext_alloc_size;
	73
	74	/* Determine the start of the kernel's __TEXT segment and determine the
	75	* lower bound of the allocated submap for kext allocations.
	76	*/
	77
	78	text = getsegbyname(SEG_TEXT);
	79	text_start = vm_map_trunc_page(text->vmaddr,
	80	VM_MAP_PAGE_MASK(kernel_map));
	81	text_start &= ~((512ULL * 1024 * 1024 * 1024) - 1);
	82	text_end = vm_map_round_page(text->vmaddr + text->vmsize,
	83	VM_MAP_PAGE_MASK(kernel_map));
	84	text_size = text_end - text_start;
	85
	86	kext_alloc_base = KEXT_ALLOC_BASE(text_end);
	87	kext_alloc_size = KEXT_ALLOC_SIZE(text_size);
	88	kext_alloc_max = kext_alloc_base + kext_alloc_size;
	89
	90	/* Post boot kext allocation will start after the prelinked kexts */
	91	prelinkTextSegment = getsegbyname("__PRELINK_TEXT");
	92	if (prelinkTextSegment) {
	93	/* use kext_post_boot_base to start allocations past all the prelinked
	94	* kexts
	95	*/
	96	kext_post_boot_base =
	97	vm_map_round_page(kext_alloc_base + prelinkTextSegment->vmsize,
	98	VM_MAP_PAGE_MASK(kernel_map));
	99	} else {
	100	kext_post_boot_base = kext_alloc_base;
	101	}
	102
	103	/* Allocate the sub block of the kernel map */
	104	rval = kmem_suballoc(kernel_map, (vm_offset_t *) &kext_alloc_base,
	105	kext_alloc_size, /* pageable */ TRUE,
	106	VM_FLAGS_FIXED \| VM_FLAGS_OVERWRITE,
	107	VM_MAP_KERNEL_FLAGS_NONE, VM_KERN_MEMORY_KEXT,
	108	&g_kext_map);
	109	if (rval != KERN_SUCCESS) {
	110	panic("kext_alloc_init: kmem_suballoc failed 0x%x\n", rval);
	111	}
	112
	113	if ((kext_alloc_base + kext_alloc_size) > kext_alloc_max) {
	114	panic("kext_alloc_init: failed to get first 2GB\n");
	115	}
	116
	117	if (kernel_map->min_offset > kext_alloc_base) {
	118	kernel_map->min_offset = kext_alloc_base;
	119	}
	120
	121	printf("kext submap [0x%lx - 0x%lx], kernel text [0x%lx - 0x%lx]\n",
	122	VM_KERNEL_UNSLIDE(kext_alloc_base),
	123	VM_KERNEL_UNSLIDE(kext_alloc_max),
	124	VM_KERNEL_UNSLIDE(text->vmaddr),
	125	VM_KERNEL_UNSLIDE(text->vmaddr + text->vmsize));
316670eb	126
b0d623f7	127	#else
0a7de745 A	128	g_kext_map = kernel_map;
	129	kext_alloc_base = VM_MIN_KERNEL_ADDRESS;
	130	kext_alloc_max = VM_MAX_KERNEL_ADDRESS;
316670eb	131	#endif /* CONFIG_KEXT_BASEMENT */
b0d623f7 A	132	}
	133
	134	kern_return_t
	135	kext_alloc(vm_offset_t *_addr, vm_size_t size, boolean_t fixed)
	136	{
0a7de745	137	kern_return_t rval = 0;
316670eb	138	#if CONFIG_KEXT_BASEMENT
0a7de745	139	mach_vm_offset_t addr = (fixed) ? *_addr : kext_post_boot_base;
316670eb	140	#else
0a7de745	141	mach_vm_offset_t addr = (fixed) ? *_addr : kext_alloc_base;
316670eb	142	#endif
0a7de745 A	143	int flags = (fixed) ? VM_FLAGS_FIXED : VM_FLAGS_ANYWHERE;
0a7de745 A	144
316670eb	145	#if CONFIG_KEXT_BASEMENT
0a7de745 A	146	/* Allocate the kext virtual memory
	147	* 10608884 - use mach_vm_map since we want VM_FLAGS_ANYWHERE allocated past
	148	* kext_post_boot_base (when possible). mach_vm_allocate will always
	149	* start at 0 into the map no matter what you pass in addr. We want non
	150	* fixed (post boot) kext allocations to start looking for free space
	151	* just past where prelinked kexts have loaded.
	152	*/
	153	rval = mach_vm_map_kernel(g_kext_map,
	154	&addr,
	155	size,
	156	0,
	157	flags,
	158	VM_MAP_KERNEL_FLAGS_NONE,
	159	VM_KERN_MEMORY_KEXT,
	160	MACH_PORT_NULL,
	161	0,
	162	TRUE,
	163	VM_PROT_DEFAULT,
	164	VM_PROT_ALL,
	165	VM_INHERIT_DEFAULT);
	166	if (rval != KERN_SUCCESS) {
	167	printf("mach_vm_map failed - %d\n", rval);
	168	goto finish;
	169	}
316670eb	170	#else
0a7de745 A	171	rval = mach_vm_allocate_kernel(g_kext_map, &addr, size, flags, VM_KERN_MEMORY_KEXT);
	172	if (rval != KERN_SUCCESS) {
	173	printf("vm_allocate failed - %d\n", rval);
	174	goto finish;
	175	}
316670eb	176	#endif
b0d623f7	177
0a7de745 A	178	/* Check that the memory is reachable by kernel text */
	179	if ((addr + size) > kext_alloc_max) {
	180	kext_free((vm_offset_t)addr, size);
	181	rval = KERN_INVALID_ADDRESS;
	182	goto finish;
	183	}
b0d623f7	184
0a7de745 A	185	*_addr = (vm_offset_t)addr;
0a7de745 A	186	rval = KERN_SUCCESS;
5ba3f43e	187	#if KASAN
0a7de745	188	kasan_notify_address(addr, size);
5ba3f43e	189	#endif
b0d623f7 A	190
b0d623f7 A	191	finish:
0a7de745	192	return rval;
b0d623f7 A	193	}
b0d623f7 A	194
0a7de745	195	void
b0d623f7 A	196	kext_free(vm_offset_t addr, vm_size_t size)
b0d623f7 A	197	{
0a7de745	198	kern_return_t rval;
b0d623f7	199
0a7de745 A	200	rval = mach_vm_deallocate(g_kext_map, addr, size);
0a7de745 A	201	assert(rval == KERN_SUCCESS);
b0d623f7	202	}