src/atomics/init.c

   1 /*
   2  * Copyright (c) 2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <limits.h>
  25 #include <stdint.h>
  26 #include <stdlib.h>
  27 #include <machine/cpu_capabilities.h>
  28
  29 #include <_simple.h>
  30
  31 #include <platform/string.h>
  32 #include <platform/compat.h>
  33
  34 __attribute__ ((visibility ("hidden")))
  35 uintptr_t commpage_pfz_base=0;
  36
  37 __attribute__ ((visibility ("hidden")))
  38 void
  39 __pfz_setup(const char *apple[])
  40 {
  41     const char *p = _simple_getenv(apple, "pfz");
  42     if (p != NULL) {
  43         const char *q;
  44
  45         /* We are given hex starting with 0x */
  46         if (p[0] != '0' || p[1] != 'x') {
  47             goto __pfz_setup_clear;
  48         }
  49
  50         for (q = p + 2; *q; q++) {
  51             commpage_pfz_base <<= 4; // *= 16
  52
  53             if ('0' <= *q && *q <= '9') {
  54                 commpage_pfz_base += *q - '0';
  55             } else if ('a' <= *q && *q <= 'f') {
  56                 commpage_pfz_base += *q - 'a' + 10;
  57             } else if ('A' <= *q && *q <= 'F') {
  58                 commpage_pfz_base += *q - 'A' + 10;
  59             } else {
  60                 commpage_pfz_base=0;
  61                 goto __pfz_setup_clear;
  62             }
  63         }
  64
  65 __pfz_setup_clear:
  66         bzero((void *)((uintptr_t)p - 4), strlen(p) + 4);
  67     }
  68
  69     if (commpage_pfz_base == 0) {
  70         commpage_pfz_base = _COMM_PAGE_TEXT_START;
  71     }
  72 }