/*
* 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 __x86_64__
kern_return_t rval = 0;
kernel_segment_command_t *text = 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);
text_start &= ~((512ULL * 1024 * 1024 * 1024) - 1);
text_end = vm_map_round_page(text->vmaddr + text->vmsize);
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;
/* Allocate the subblock 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,
&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%llx - 0x%llx], kernel text [0x%llx - 0x%llx]\n",
kext_alloc_base, kext_alloc_max, text->vmaddr,
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 /* __x86_64__ */
}
/*
* 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,
&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 */
}
