pexpert/arm/pe_consistent_debug.c

   1 /*
   2  * Copyright (c) 2011-2018 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
  29 #include <pexpert/pexpert.h>
  30 #include <pexpert/arm/consistent_debug.h>
  31 #include <pexpert/device_tree.h>
  32 #include <libkern/OSAtomic.h>
  33 #include <machine/machine_routines.h>
  34
  35 static dbg_registry_t * consistent_debug_registry = NULL;
  36
  37 static dbg_record_header_t* consistent_debug_allocate_entry(void) {
  38         unsigned int i;
  39
  40         if (!consistent_debug_registry)
  41                 return NULL;
  42         for (i = 0; i < consistent_debug_registry->top_level_header.num_records; i++) {
  43                 dbg_record_header_t *record = &consistent_debug_registry->records[i];
  44                 if (OSCompareAndSwap64(kDbgIdUnusedEntry, kDbgIdReservedEntry, &record->record_id)) {
  45                         // Reserved an entry at position i.
  46                         return (dbg_record_header_t*)record;
  47                 }
  48         }
  49         return NULL;
  50 }
  51
  52 int PE_consistent_debug_inherit(void)
  53 {
  54         DTEntry         entryP;
  55         uintptr_t       *prop_data;
  56         uintptr_t       root_pointer = 0;
  57         uint32_t        size;
  58
  59         if ((DTLookupEntry(NULL, "/chosen", &entryP) == kSuccess))
  60                 if (DTGetProperty(entryP, "consistent-debug-root", (void **)&prop_data, &size) == kSuccess)
  61                         root_pointer = prop_data[0];
  62         if (root_pointer == 0)
  63                 return -1;
  64         consistent_debug_registry = (dbg_registry_t *)ml_map_high_window(root_pointer, sizeof(dbg_registry_t));
  65         return 0;
  66 }
  67
  68 int PE_consistent_debug_register(uint64_t record_id, uint64_t physaddr, uint64_t length)
  69 {
  70         dbg_record_header_t *allocated_header = consistent_debug_allocate_entry();
  71         if (allocated_header == NULL)
  72                 return -1;
  73         allocated_header->length = length;
  74         allocated_header->physaddr = physaddr;
  75         // Make sure the hdr/length are visible before the record_id.
  76         __asm__ volatile("dmb ish" : : : "memory");
  77         allocated_header->record_id = record_id;
  78         return 0;
  79 }
  80
  81 int PE_consistent_debug_enabled(void)
  82 {
  83         return (consistent_debug_registry != NULL);
  84 }
  85