pe_consistent_debug.c   [plain text]

/*
 * Copyright (c) 2011-2018 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
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 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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#include <pexpert/pexpert.h>
#include <pexpert/arm/consistent_debug.h>
#include <pexpert/device_tree.h>
#include <libkern/OSAtomic.h>
#include <machine/machine_routines.h>

static dbg_registry_t * consistent_debug_registry = NULL; 

static dbg_record_header_t* consistent_debug_allocate_entry(void) {
	unsigned int i;

	if (!consistent_debug_registry)
		return NULL;
	for (i = 0; i < consistent_debug_registry->top_level_header.num_records; i++) {
		dbg_record_header_t *record = &consistent_debug_registry->records[i];
		if (OSCompareAndSwap64(kDbgIdUnusedEntry, kDbgIdReservedEntry, &record->record_id)) {
			// Reserved an entry at position i.
			return (dbg_record_header_t*)record;
		}
	}
	return NULL;
}

int PE_consistent_debug_inherit(void)
{
	DTEntry		entryP;
	uintptr_t	*prop_data;
	uintptr_t	root_pointer = 0;
	uint32_t	size;

        if ((DTLookupEntry(NULL, "/chosen", &entryP) == kSuccess))
		if (DTGetProperty(entryP, "consistent-debug-root", (void **)&prop_data, &size) == kSuccess)
			root_pointer = prop_data[0];
	if (root_pointer == 0)
		return -1;
	consistent_debug_registry = (dbg_registry_t *)ml_map_high_window(root_pointer, sizeof(dbg_registry_t));
	return 0;
}

int PE_consistent_debug_register(uint64_t record_id, uint64_t physaddr, uint64_t length)
{
	dbg_record_header_t *allocated_header = consistent_debug_allocate_entry();
	if (allocated_header == NULL)
		return -1;
	allocated_header->length = length;
	allocated_header->physaddr = physaddr;
	// Make sure the hdr/length are visible before the record_id.
	__asm__ volatile("dmb ish" : : : "memory");
	allocated_header->record_id = record_id;
	return 0;
}

int PE_consistent_debug_enabled(void)
{
	return (consistent_debug_registry != NULL);
}