[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_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@
	5	*
	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.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	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.
	25	*
	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	*/
	63	void
	64	kext_alloc_init(void)
	65	{
316670eb	66	#if CONFIG_KEXT_BASEMENT
b0d623f7 A	67	kern_return_t rval = 0;
b0d623f7 A	68	kernel_segment_command_t *text = NULL;
316670eb	69	kernel_segment_command_t *prelinkTextSegment = NULL;
b0d623f7 A	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);
39236c6e A	79	text_start = vm_map_trunc_page(text->vmaddr,
39236c6e A	80	VM_MAP_PAGE_MASK(kernel_map));
b0d623f7	81	text_start &= ~((512ULL * 1024 * 1024 * 1024) - 1);
39236c6e A	82	text_end = vm_map_round_page(text->vmaddr + text->vmsize,
39236c6e A	83	VM_MAP_PAGE_MASK(kernel_map));
b0d623f7 A	84	text_size = text_end - text_start;
b0d623f7 A	85
6d2010ae A	86	kext_alloc_base = KEXT_ALLOC_BASE(text_end);
6d2010ae A	87	kext_alloc_size = KEXT_ALLOC_SIZE(text_size);
b0d623f7	88	kext_alloc_max = kext_alloc_base + kext_alloc_size;
316670eb A	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 =
39236c6e A	97	vm_map_round_page(kext_alloc_base + prelinkTextSegment->vmsize,
39236c6e A	98	VM_MAP_PAGE_MASK(kernel_map));
316670eb A	99	}
	100	else {
	101	kext_post_boot_base = kext_alloc_base;
	102	}
b0d623f7	103
316670eb	104	/* Allocate the sub block of the kernel map */
b0d623f7 A	105	rval = kmem_suballoc(kernel_map, (vm_offset_t *) &kext_alloc_base,
b0d623f7 A	106	kext_alloc_size, /* pageable */ TRUE,
5ba3f43e A	107	VM_FLAGS_FIXED\|VM_FLAGS_OVERWRITE,
5ba3f43e A	108	VM_MAP_KERNEL_FLAGS_NONE, VM_KERN_MEMORY_KEXT,
b0d623f7 A	109	&g_kext_map);
	110	if (rval != KERN_SUCCESS) {
	111	panic("kext_alloc_init: kmem_suballoc failed 0x%x\n", rval);
	112	}
	113
	114	if ((kext_alloc_base + kext_alloc_size) > kext_alloc_max) {
	115	panic("kext_alloc_init: failed to get first 2GB\n");
	116	}
	117
	118	if (kernel_map->min_offset > kext_alloc_base) {
	119	kernel_map->min_offset = kext_alloc_base;
	120	}
	121
316670eb A	122	printf("kext submap [0x%lx - 0x%lx], kernel text [0x%lx - 0x%lx]\n",
	123	VM_KERNEL_UNSLIDE(kext_alloc_base),
	124	VM_KERNEL_UNSLIDE(kext_alloc_max),
	125	VM_KERNEL_UNSLIDE(text->vmaddr),
	126	VM_KERNEL_UNSLIDE(text->vmaddr + text->vmsize));
	127
b0d623f7 A	128	#else
	129	g_kext_map = kernel_map;
	130	kext_alloc_base = VM_MIN_KERNEL_ADDRESS;
	131	kext_alloc_max = VM_MAX_KERNEL_ADDRESS;
316670eb	132	#endif /* CONFIG_KEXT_BASEMENT */
b0d623f7 A	133	}
	134
	135	kern_return_t
	136	kext_alloc(vm_offset_t *_addr, vm_size_t size, boolean_t fixed)
	137	{
	138	kern_return_t rval = 0;
316670eb A	139	#if CONFIG_KEXT_BASEMENT
	140	mach_vm_offset_t addr = (fixed) ? *_addr : kext_post_boot_base;
	141	#else
b0d623f7	142	mach_vm_offset_t addr = (fixed) ? *_addr : kext_alloc_base;
316670eb	143	#endif
b0d623f7 A	144	int flags = (fixed) ? VM_FLAGS_FIXED : VM_FLAGS_ANYWHERE;
b0d623f7 A	145
316670eb A	146	#if CONFIG_KEXT_BASEMENT
	147	/* Allocate the kext virtual memory
	148	* 10608884 - use mach_vm_map since we want VM_FLAGS_ANYWHERE allocated past
	149	* kext_post_boot_base (when possible). mach_vm_allocate will always
	150	* start at 0 into the map no matter what you pass in addr. We want non
	151	* fixed (post boot) kext allocations to start looking for free space
	152	* just past where prelinked kexts have loaded.
	153	*/
5ba3f43e	154	rval = mach_vm_map_kernel(g_kext_map,
316670eb A	155	&addr,
	156	size,
	157	0,
	158	flags,
5ba3f43e	159	VM_KERN_MEMORY_KEXT,
316670eb A	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	}
	170	#else
5ba3f43e	171	rval = mach_vm_allocate_kernel(g_kext_map, &addr, size, flags, VM_KERN_MEMORY_KEXT);
b0d623f7 A	172	if (rval != KERN_SUCCESS) {
	173	printf("vm_allocate failed - %d\n", rval);
	174	goto finish;
	175	}
316670eb	176	#endif
b0d623f7 A	177
	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);
316670eb	181	rval = KERN_INVALID_ADDRESS;
b0d623f7 A	182	goto finish;
	183	}
	184
	185	*_addr = (vm_offset_t)addr;
	186	rval = KERN_SUCCESS;
5ba3f43e A	187	#if KASAN
	188	kasan_notify_address(addr, size);
	189	#endif
b0d623f7 A	190
	191	finish:
	192	return rval;
	193	}
	194
	195	void
	196	kext_free(vm_offset_t addr, vm_size_t size)
	197	{
	198	kern_return_t rval;
	199
	200	rval = mach_vm_deallocate(g_kext_map, addr, size);
	201	assert(rval == KERN_SUCCESS);
	202	}
	203