darling-xnu/libsa/lastkerneldataconst.c
2023-05-16 21:41:14 -07:00

51 lines
2.3 KiB
C

/*
* Copyright (c) 2014 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 <mach/vm_param.h>
/*
* This file is compiled and linked to be the last .o of the __const section
* of the __DATA segment (see MakeInc.kernel, lastkernelconstructor is placed
* in the __LAST segment.)
*
* This blank page allows us to safely map the const section RO while the rest
* of __DATA is RW. This is needed since ld has no way of specifying section size
* alignment and no straight forward way to specify section ordering.
*/
#if defined(__arm64__)
/* PAGE_SIZE on ARM64 is an expression derived from a non-const global variable */
#define PAD_SIZE PAGE_MAX_SIZE
#else
#define PAD_SIZE PAGE_SIZE
#endif
static const uint8_t __attribute__((section("__DATA,__const"))) data_const_padding[PAD_SIZE] = {[0 ... PAD_SIZE - 1] = 0xFF};
const vm_offset_t __attribute__((section("__DATA,__data"))) _lastkerneldataconst = (vm_offset_t)&data_const_padding[0];
const vm_size_t __attribute__((section("__DATA,__data"))) _lastkerneldataconst_padsize = sizeof(data_const_padding);