/*
* Copyright (c) 2000-2004 Apple Computer, 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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*
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/*
* @OSF_COPYRIGHT@
*/
/*
* Mach Operating System
* Copyright (c) 1991,1990,1989 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
*/
/*
* File: ipc/ipc_entry.h
* Author: Rich Draves
* Date: 1989
*
* Definitions for translation entries, which represent
* tasks' capabilities for ports and port sets.
*/
#ifndef _IPC_IPC_ENTRY_H_
#define _IPC_IPC_ENTRY_H_
#include <mach/mach_types.h>
#include <mach/port.h>
#include <mach/kern_return.h>
#include <kern/kern_types.h>
#include <kern/kalloc.h>
#include <kern/smr_types.h>
#include <ipc/ipc_types.h>
/*
* Spaces hold capabilities for ipc_object_t's.
* Each ipc_entry_t records a capability. Most capabilities have
* small names, and the entries are elements of a table.
*
* The ie_index field of entries in the table implements
* a ordered hash table with open addressing and linear probing.
*
* The ie_dist field holds the distance to the desired spot,
* which is used to implement robin-hood hashing.
*
* This hash table converts (space, object) -> name.
* It is used independently of the other fields.
*
* Free (unallocated) entries in the table have null ie_object
* fields. The ie_bits field is zero except for IE_BITS_GEN.
* The ie_next (ie_request) field links free entries into a free list.
*
* The first entry in the table (index 0) is always free.
* It is used as the head of the free list.
*/
#define IPC_ENTRY_DIST_BITS 12
#define IPC_ENTRY_DIST_MAX ((1 << IPC_ENTRY_DIST_BITS) - 1)
#define IPC_ENTRY_INDEX_BITS 32
#define IPC_ENTRY_INDEX_MAX (UINT32_MAX)
struct ipc_entry {
union {
struct ipc_object *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_object") ie_object;
struct ipc_object *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_object") volatile ie_volatile_object;
struct ipc_entry_table *XNU_PTRAUTH_SIGNED_PTR("ipc_entry.ie_self") ie_self;
};
union {
struct {
ipc_entry_bits_t ie_bits;
union {
mach_port_index_t ie_next; /* next in freelist, or... */
ipc_table_index_t ie_request; /* dead name request notify */
};
/* hash fields */
uint32_t ie_dist;
mach_port_index_t ie_index;
};
struct smr_node ie_smr_node;
};
};
#define IPC_ENTRY_TABLE_MIN 32
#define IPC_ENTRY_TABLE_PERIOD 16
KALLOC_ARRAY_TYPE_DECL(ipc_entry_table, struct ipc_entry);
#define IE_REQ_NONE 0 /* no request */
#define IE_BITS_UREFS_MASK 0x0000ffff /* 16 bits of user-reference */
#define IE_BITS_UREFS(bits) ((bits) & IE_BITS_UREFS_MASK)
#define IE_BITS_TYPE_MASK 0x001f0000 /* 5 bits of capability type */
#define IE_BITS_TYPE(bits) ((bits) & IE_BITS_TYPE_MASK)
#define IE_BITS_EXTYPE_MASK 0x00200000 /* 1 bit for extended capability */
#ifndef NO_PORT_GEN
#define IE_BITS_GEN_MASK 0xff000000 /* 8 bits for generation */
#define IE_BITS_GEN(bits) ((bits) & IE_BITS_GEN_MASK)
#define IE_BITS_GEN_ONE 0x04000000 /* low bit of generation */
#define IE_BITS_ROLL_POS 22 /* LSB pos of generation rollover */
#define IE_BITS_ROLL_BITS 2 /* number of generation rollover bits */
#define IE_BITS_ROLL_MASK (((1 << IE_BITS_ROLL_BITS) - 1) << IE_BITS_ROLL_POS)
#define IE_BITS_ROLL(bits) ((((bits) & IE_BITS_ROLL_MASK) << 8) ^ IE_BITS_GEN_MASK)
/*
* Restart a generation counter with the specified bits for the rollover point.
* There are 4 different rollover points:
* bits rollover period
* 0 0 64
* 0 1 48
* 1 0 32
* 1 1 16
*/
static inline ipc_entry_bits_t
ipc_entry_new_rollpoint(
ipc_entry_bits_t rollbits)
{
rollbits = (rollbits << IE_BITS_ROLL_POS) & IE_BITS_ROLL_MASK;
ipc_entry_bits_t newgen = IE_BITS_GEN_MASK + IE_BITS_GEN_ONE;
return newgen | rollbits;
}
/*
* Get the next gencount, modulo the entry's rollover point. If the sum rolls over,
* the caller should re-start the generation counter with a different rollpoint.
*/
static inline ipc_entry_bits_t
ipc_entry_new_gen(
ipc_entry_bits_t oldgen)
{
ipc_entry_bits_t sum = (oldgen + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK;
ipc_entry_bits_t roll = oldgen & IE_BITS_ROLL_MASK;
ipc_entry_bits_t newgen = (sum % IE_BITS_ROLL(oldgen)) | roll;
return newgen;
}
/* Determine if a gencount has rolled over or not. */
static inline boolean_t
ipc_entry_gen_rolled(
ipc_entry_bits_t oldgen,
ipc_entry_bits_t newgen)
{
return (oldgen & IE_BITS_GEN_MASK) > (newgen & IE_BITS_GEN_MASK);
}
#else
#define IE_BITS_GEN_MASK 0
#define IE_BITS_GEN(bits) 0
#define IE_BITS_GEN_ONE 0
#define IE_BITS_ROLL_POS 0
#define IE_BITS_ROLL_MASK 0
#define IE_BITS_ROLL(bits) (bits)
static inline ipc_entry_bits_t
ipc_entry_new_rollpoint(
ipc_entry_bits_t rollbits)
{
return 0;
}
static inline ipc_entry_bits_t
ipc_entry_new_gen(
ipc_entry_bits_t oldgen)
{
return 0;
}
static inline boolean_t
ipc_entry_gen_rolled(
ipc_entry_bits_t oldgen,
ipc_entry_bits_t newgen)
{
return FALSE;
}
#endif /* !USE_PORT_GEN */
#define IE_BITS_RIGHT_MASK 0x007fffff /* relevant to the right */
/*
* Exported interfaces
*/
extern unsigned int ipc_entry_table_count_max(void) __pure2;
/* Search for entry in a space by name */
extern ipc_entry_t ipc_entry_lookup(
ipc_space_t space,
mach_port_name_t name);
/* Hold a number of entries in a locked space */
extern kern_return_t ipc_entries_hold(
ipc_space_t space,
natural_t count);
/* claim and initialize a held entry in a locked space */
extern kern_return_t ipc_entry_claim(
ipc_space_t space,
ipc_object_t object,
mach_port_name_t *namep,
ipc_entry_t *entryp);
/* Allocate an entry in a space, growing the space if necessary */
extern kern_return_t ipc_entry_alloc(
ipc_space_t space,
ipc_object_t object,
mach_port_name_t *namep,
ipc_entry_t *entryp);
/* Allocate/find an entry in a space with a specific name */
extern kern_return_t ipc_entry_alloc_name(
ipc_space_t space,
mach_port_name_t name,
ipc_entry_t *entryp);
/* Deallocate an entry from a space */
extern void ipc_entry_dealloc(
ipc_space_t space,
ipc_object_t object,
mach_port_name_t name,
ipc_entry_t entry);
/* Mark and entry modified in a space */
extern void ipc_entry_modified(
ipc_space_t space,
mach_port_name_t name,
ipc_entry_t entry);
/* Grow the table in a space */
extern kern_return_t ipc_entry_grow_table(
ipc_space_t space,
ipc_table_elems_t target_size);
/* mask on/off default entry generation bits */
extern mach_port_name_t ipc_entry_name_mask(
mach_port_name_t name);
#endif /* _IPC_IPC_ENTRY_H_ */