/* LUFA Library Copyright (C) Dean Camera, 2010. dean [at] fourwalledcubicle [dot] com www.fourwalledcubicle.com */ /* Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com) Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that the copyright notice and this permission notice and warranty disclaimer appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. The author disclaim all warranties with regard to this software, including all implied warranties of merchantability and fitness. In no event shall the author be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of this software. */ #if defined(ENABLE_DHCP_CLIENT) || defined(__DOXYGEN__) /** \file * * DHCP Client Application. When connected to the uIP stack, this will retrieve IP configuration settings from the * DHCP server on the network. */ #define INCLUDE_FROM_DHCPCLIENTAPP_C #include "DHCPClientApp.h" /** Initialization function for the DHCP client. */ void DHCPClientApp_Init(void) { /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */ struct uip_udp_conn* Connection = uip_udp_new(&uip_broadcast_addr, HTONS(DHCPC_SERVER_PORT)); /* If the connection was successfully created, bind it to the local DHCP client port */ if (Connection != NULL) { uip_udp_appstate_t* const AppState = &Connection->appstate; uip_udp_bind(Connection, HTONS(DHCPC_CLIENT_PORT)); /* Set the initial client state */ AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover; /* Set timeout period to half a second for a DHCP server to respond */ timer_set(&AppState->DHCPClient.Timeout, CLOCK_SECOND / 2); } } /** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack * needs a UDP packet to be processed. */ void DHCPClientApp_Callback(void) { uip_udp_appstate_t* const AppState = &uip_udp_conn->appstate; DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata; uint16_t AppDataSize = 0; switch (AppState->DHCPClient.CurrentState) { case DHCP_STATE_SendDiscover: /* Clear all DHCP settings, reset client IP address */ memset(&AppState->DHCPClient.DHCPOffer_Data, 0x00, sizeof(AppState->DHCPClient.DHCPOffer_Data)); uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP); /* Fill out the DHCP response header */ AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState); /* Add the required DHCP options list to the packet */ uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER}; AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList), RequiredOptionList); /* Send the DHCP DISCOVER packet */ uip_udp_send(AppDataSize); /* Reset the timeout timer, progress to next state */ timer_reset(&AppState->DHCPClient.Timeout); AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForOffer; break; case DHCP_STATE_WaitForOffer: if (!(uip_newdata())) { /* Check if the DHCP timeout period has expired while waiting for a response */ if (timer_expired(&AppState->DHCPClient.Timeout)) AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover; break; } uint8_t OfferResponse_MessageType; if ((AppData->TransactionID == DHCP_TRANSACTION_ID) && DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) && (OfferResponse_MessageType == DHCP_OFFER)) { /* Received a DHCP offer for an IP address, copy over values for later request */ memcpy(&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t)); DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPClient.DHCPOffer_Data.Netmask); DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_ROUTER, &AppState->DHCPClient.DHCPOffer_Data.GatewayIP); DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID, &AppState->DHCPClient.DHCPOffer_Data.ServerIP); timer_reset(&AppState->DHCPClient.Timeout); AppState->DHCPClient.CurrentState = DHCP_STATE_SendRequest; } break; case DHCP_STATE_SendRequest: /* Fill out the DHCP response header */ AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState); /* Add the DHCP REQUESTED IP ADDRESS option to the packet */ AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t), &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP); /* Add the DHCP SERVER IP ADDRESS option to the packet */ AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t), &AppState->DHCPClient.DHCPOffer_Data.ServerIP); /* Send the DHCP REQUEST packet */ uip_udp_send(AppDataSize); /* Reset the timeout timer, progress to next state */ timer_reset(&AppState->DHCPClient.Timeout); AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForACK; break; case DHCP_STATE_WaitForACK: if (!(uip_newdata())) { /* Check if the DHCP timeout period has expired while waiting for a response */ if (timer_expired(&AppState->DHCPClient.Timeout)) AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover; break; } uint8_t RequestResponse_MessageType; if ((AppData->TransactionID == DHCP_TRANSACTION_ID) && DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) && (RequestResponse_MessageType == DHCP_ACK)) { /* Set the new network parameters from the DHCP server */ uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP); uip_setnetmask((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.Netmask); uip_setdraddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.GatewayIP); /* Indicate to the user that we now have a valid IP configuration */ HaveIPConfiguration = true; AppState->DHCPClient.CurrentState = DHCP_STATE_AddressLeased; } break; } } /** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required * fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP server. * * \param[out] DHCPHeader Location in the packet buffer where the BOOTP header should be written to * \param[in] DHCPMessageType DHCP Message type, such as DHCP_DISCOVER * \param[in] AppState Application state of the current UDP connection * * \return Size in bytes of the created DHCP packet */ static uint16_t DHCPClientApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader, const uint8_t DHCPMessageType, uip_udp_appstate_t* AppState) { /* Erase existing packet data so that we start will all 0x00 DHCP header data */ memset(DHCPHeader, 0, sizeof(DHCP_Header_t)); /* Fill out the DHCP packet header */ DHCPHeader->Operation = DHCP_OP_BOOTREQUEST; DHCPHeader->HardwareType = DHCP_HTYPE_ETHERNET; DHCPHeader->HardwareAddressLength = sizeof(MACAddress); DHCPHeader->Hops = 0; DHCPHeader->TransactionID = DHCP_TRANSACTION_ID; DHCPHeader->ElapsedSeconds = 0; DHCPHeader->Flags = HTONS(BOOTP_BROADCAST); memcpy(&DHCPHeader->ClientIP, &uip_hostaddr, sizeof(uip_ipaddr_t)); memcpy(&DHCPHeader->YourIP, &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t)); memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPClient.DHCPOffer_Data.ServerIP, sizeof(uip_ipaddr_t)); memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr)); DHCPHeader->Cookie = DHCP_MAGIC_COOKIE; /* Add a DHCP message type and terminator options to the start of the DHCP options field */ DHCPHeader->Options[0] = DHCP_OPTION_MSG_TYPE; DHCPHeader->Options[1] = 1; DHCPHeader->Options[2] = DHCPMessageType; DHCPHeader->Options[3] = DHCP_OPTION_END; /* Calculate the total number of bytes added to the outgoing packet */ return (sizeof(DHCP_Header_t) + 4); } /** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the * end of options terminator past the new option in the options list. * * \param[in,out] DHCPOptionList Pointer to the start of the DHCP packet's options list * \param[in] Option DHCP option to add to the list * \param[in] DataLen Size in bytes of the option data to add * \param[in] OptionData Buffer where the option's data is to be sourced from * * \return Number of bytes added to the DHCP packet */ static uint8_t DHCPClientApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* OptionData) { /* Skip through the DHCP options list until the terminator option is found */ while (*DHCPOptionList != DHCP_OPTION_END) DHCPOptionList += (DHCPOptionList[1] + 2); /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */ DHCPOptionList[0] = Option; DHCPOptionList[1] = DataLen; memcpy(&DHCPOptionList[2], OptionData, DataLen); DHCPOptionList[2 + DataLen] = DHCP_OPTION_END; /* Calculate the total number of bytes added to the outgoing packet */ return (2 + DataLen); } /** Retrieves the given option's data (if present) from the DHCP packet's options list. * * \param[in,out] DHCPOptionList Pointer to the start of the DHCP packet's options list * \param[in] Option DHCP option to retrieve to the list * \param[out] Destination Buffer where the option's data is to be written to if found * * \return Boolean true if the option was found in the DHCP packet's options list, false otherwise */ static bool DHCPClientApp_GetOption(const uint8_t* DHCPOptionList, const uint8_t Option, void* const Destination) { /* Look through the incoming DHCP packet's options list for the requested option */ while (*DHCPOptionList != DHCP_OPTION_END) { /* Check if the current DHCP option in the packet is the one requested */ if (DHCPOptionList[0] == Option) { /* Copy request option's data to the destination buffer */ memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]); /* Indicate that the requested option data was successfully retrieved */ return true; } /* Skip to next DHCP option in the options list */ DHCPOptionList += (DHCPOptionList[1] + 2); } /* Requested option not found in the incoming packet's DHCP options list */ return false; } #endif 42' href='#n242'>242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 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/*
 * linux/mm/slab.c
 * Written by Mark Hemment, 1996/97.
 * (markhe@nextd.demon.co.uk)
 *
 * xmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
 *
 * Major cleanup, different bufctl logic, per-cpu arrays
 *	(c) 2000 Manfred Spraul
 *
 * An implementation of the Slab Allocator as described in outline in;
 *	UNIX Internals: The New Frontiers by Uresh Vahalia
 *	Pub: Prentice Hall	ISBN 0-13-101908-2
 * or with a little more detail in;
 *	The Slab Allocator: An Object-Caching Kernel Memory Allocator
 *	Jeff Bonwick (Sun Microsystems).
 *	Presented at: USENIX Summer 1994 Technical Conference
 *
 *
 * The memory is organized in caches, one cache for each object type.
 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
 * Each cache consists out of many slabs (they are small (usually one
 * page long) and always contiguous), and each slab contains multiple
 * initialized objects.
 *
 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
 *   full slabs with 0 free objects
 *   partial slabs
 *   empty slabs with no allocated objects
 *
 * If partial slabs exist, then new allocations come from these slabs,
 * otherwise from empty slabs or new slabs are allocated.
 *
 * xmem_cache_destroy() CAN CRASH if you try to allocate from the cache
 * during xmem_cache_destroy(). The caller must prevent concurrent allocs.
 *
 * On SMP systems, each cache has a short per-cpu head array, most allocs
 * and frees go into that array, and if that array overflows, then 1/2
 * of the entries in the array are given back into the global cache.
 * This reduces the number of spinlock operations.
 *
 * The c_cpuarray may not be read with enabled local interrupts.
 *
 * SMP synchronization:
 *  constructors and destructors are called without any locking.
 *  Several members in xmem_cache_t and slab_t never change, they
 *	are accessed without any locking.
 *  The per-cpu arrays are never accessed from the wrong cpu, no locking.
 *  The non-constant members are protected with a per-cache irq spinlock.
 */

#include <xen/config.h>
#include <xen/init.h>
#include <xen/types.h>
#include <xen/lib.h>
#include <xen/slab.h>
#include <xen/list.h>
#include <xen/spinlock.h>
#include <xen/errno.h>
#include <xen/smp.h>
#include <xen/sched.h>

/*
 * DEBUG  - 1 for xmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
 *	    SLAB_RED_ZONE & SLAB_POISON.
 *	    0 for faster, smaller code (especially in the critical paths).
 *
 * STATS  - 1 to collect stats for /proc/slabinfo.
 *	    0 for faster, smaller code (especially in the critical paths).
 *
 * FORCED_DEBUG	- 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
 */
#ifdef CONFIG_DEBUG_SLAB
#define	DEBUG		1
#define	STATS		1
#define	FORCED_DEBUG	1
#else
#define	DEBUG		0
#define	STATS		0
#define	FORCED_DEBUG	0
#endif

/*
 * Parameters for xmem_cache_reap
 */
#define REAP_SCANLEN	10
#define REAP_PERFECT	10

/* Shouldn't this be in a header file somewhere? */
#define	BYTES_PER_WORD		sizeof(void *)

/* Legal flag mask for xmem_cache_create(). */
#if DEBUG
#define CREATE_MASK	(SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
			 SLAB_NO_REAP)
#else
#define CREATE_MASK	(SLAB_HWCACHE_ALIGN | SLAB_NO_REAP)
#endif

/*
 * xmem_bufctl_t:
 *
 * Bufctl's are used for linking objs within a slab
 * linked offsets.
 *
 * This implementaion relies on "struct page" for locating the cache &
 * slab an object belongs to.
 * This allows the bufctl structure to be small (one int), but limits
 * the number of objects a slab (not a cache) can contain when off-slab
 * bufctls are used. The limit is the size of the largest general cache
 * that does not use off-slab slabs.
 * For 32bit archs with 4 kB pages, is this 56.
 * This is not serious, as it is only for large objects, when it is unwise
 * to have too many per slab.
 * Note: This limit can be raised by introducing a general cache whose size
 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
 */

#define BUFCTL_END	(((xmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE	(((xmem_bufctl_t)(~0U))-1)
#define	SLAB_LIMIT	(((xmem_bufctl_t)(~0U))-2)

/* Max number of objs-per-slab for caches which use off-slab slabs.
 * Needed to avoid a possible looping condition in xmem_cache_grow().
 */
static unsigned long offslab_limit;

/*
 * slab_t
 *
 * Manages the objs in a slab. Placed either at the beginning of mem allocated
 * for a slab, or allocated from an general cache.
 * Slabs are chained into three list: fully used, partial, fully free slabs.
 */
typedef struct slab_s {
    struct list_head list;
    unsigned long    colouroff;
    void            *s_mem;    /* including colour offset */
    unsigned int     inuse;    /* num of objs active in slab */
    xmem_bufctl_t    free;
} slab_t;

#define slab_bufctl(slabp) \
	((xmem_bufctl_t *)(((slab_t*)slabp)+1))

/*
 * cpucache_t
 *
 * Per cpu structures
 * The limit is stored in the per-cpu structure to reduce the data cache
 * footprint.
 */
typedef struct cpucache_s {
    unsigned int avail;
    unsigned int limit;
} cpucache_t;

#define cc_entry(cpucache) \
	((void **)(((cpucache_t*)(cpucache))+1))
#define cc_data(cachep) \
	((cachep)->cpudata[smp_processor_id()])
/*
 * xmem_cache_t
 *
 * manages a cache.
 */

#define CACHE_NAMELEN	20	/* max name length for a slab cache */

struct xmem_cache_s {
/* 1) each alloc & free */
    /* full, partial first, then free */
    struct list_head	slabs_full;
    struct list_head	slabs_partial;
    struct list_head	slabs_free;
    unsigned int		objsize;
    unsigned int	 	flags;	/* constant flags */
    unsigned int		num;	/* # of objs per slab */
    spinlock_t		spinlock;
#ifdef CONFIG_SMP
    unsigned int		batchcount;
#endif

/* 2) slab additions /removals */
    /* order of pgs per slab (2^n) */
    unsigned int		gfporder;
    size_t			colour;		/* cache colouring range */
    unsigned int		colour_off;	/* colour offset */
    unsigned int		colour_next;	/* cache colouring */
    xmem_cache_t		*slabp_cache;
    unsigned int		growing;
    unsigned int		dflags;		/* dynamic flags */

    /* constructor func */
    void (*ctor)(void *, xmem_cache_t *, unsigned long);

    /* de-constructor func */
    void (*dtor)(void *, xmem_cache_t *, unsigned long);

    unsigned long		failures;

/* 3) cache creation/removal */
    char			name[CACHE_NAMELEN];
    struct list_head	next;
#ifdef CONFIG_SMP
/* 4) per-cpu data */
    cpucache_t		*cpudata[NR_CPUS];
#endif
#if STATS
    unsigned long		num_active;
    unsigned long		num_allocations;
    unsigned long		high_mark;
    unsigned long		grown;
    unsigned long		reaped;
    unsigned long 		errors;
#ifdef CONFIG_SMP
    atomic_t		allochit;
    atomic_t		allocmiss;
    atomic_t		freehit;
    atomic_t		freemiss;
#endif
#endif
};

/* internal c_flags */
#define	CFLGS_OFF_SLAB	0x010000UL	/* slab management in own cache */
#define	CFLGS_OPTIMIZE	0x020000UL	/* optimized slab lookup */

/* c_dflags (dynamic flags). Need to hold the spinlock to access this member */
#define	DFLGS_GROWN	0x000001UL	/* don't reap a recently grown */

#define	OFF_SLAB(x)	((x)->flags & CFLGS_OFF_SLAB)
#define	OPTIMIZE(x)	((x)->flags & CFLGS_OPTIMIZE)
#define	GROWN(x)	((x)->dlags & DFLGS_GROWN)

#if STATS
#define	STATS_INC_ACTIVE(x)	((x)->num_active++)
#define	STATS_DEC_ACTIVE(x)	((x)->num_active--)
#define	STATS_INC_ALLOCED(x)	((x)->num_allocations++)
#define	STATS_INC_GROWN(x)	((x)->grown++)
#define	STATS_INC_REAPED(x)	((x)->reaped++)
#define	STATS_SET_HIGH(x)	do { if ((x)->num_active > (x)->high_mark) \
					(x)->high_mark = (x)->num_active; \
				} while (0)
#define	STATS_INC_ERR(x)	((x)->errors++)
#else
#define	STATS_INC_ACTIVE(x)	do { } while (0)
#define	STATS_DEC_ACTIVE(x)	do { } while (0)
#define	STATS_INC_ALLOCED(x)	do { } while (0)
#define	STATS_INC_GROWN(x)	do { } while (0)
#define	STATS_INC_REAPED(x)	do { } while (0)
#define	STATS_SET_HIGH(x)	do { } while (0)
#define	STATS_INC_ERR(x)	do { } while (0)
#endif

#if STATS && defined(CONFIG_SMP)
#define STATS_INC_ALLOCHIT(x)	atomic_inc(&(x)->allochit)
#define STATS_INC_ALLOCMISS(x)	atomic_inc(&(x)->allocmiss)
#define STATS_INC_FREEHIT(x)	atomic_inc(&(x)->freehit)
#define STATS_INC_FREEMISS(x)	atomic_inc(&(x)->freemiss)
#else
#define STATS_INC_ALLOCHIT(x)	do { } while (0)
#define STATS_INC_ALLOCMISS(x)	do { } while (0)
#define STATS_INC_FREEHIT(x)	do { } while (0)
#define STATS_INC_FREEMISS(x)	do { } while (0)
#endif

#if DEBUG
/* Magic nums for obj red zoning.
 * Placed in the first word before and the first word after an obj.
 */
#define	RED_MAGIC1	0x5A2CF071UL	/* when obj is active */
#define	RED_MAGIC2	0x170FC2A5UL	/* when obj is inactive */

/* ...and for poisoning */
#define	POISON_BYTE	0x5a		/* byte value for poisoning */
#define	POISON_END	0xa5		/* end-byte of poisoning */

#endif

/* maximum size of an obj (in 2^order pages) */
#define	MAX_OBJ_ORDER	5	/* 32 pages */

/*
 * Do not go above this order unless 0 objects fit into the slab.
 */
#define	BREAK_GFP_ORDER_HI	2
#define	BREAK_GFP_ORDER_LO	1
static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;

/*
 * Absolute limit for the gfp order
 */
#define	MAX_GFP_ORDER	5	/* 32 pages */


/* Macros for storing/retrieving the cachep and or slab from the
 * global 'mem_map'. These are used to find the slab an obj belongs to.
 * With xfree(), these are used to find the cache which an obj belongs to.
 */
#define	SET_PAGE_CACHE(pg,x)  ((pg)->list.next = (struct list_head *)(x))
#define	GET_PAGE_CACHE(pg)    ((xmem_cache_t *)(pg)->list.next)
#define	SET_PAGE_SLAB(pg,x)   ((pg)->list.prev = (struct list_head *)(x))
#define	GET_PAGE_SLAB(pg)     ((slab_t *)(pg)->list.prev)

/* Size description struct for general caches. */
typedef struct cache_sizes {
    size_t		 cs_size;
    xmem_cache_t	*cs_cachep;
} cache_sizes_t;

static cache_sizes_t cache_sizes[] = {
    {    32,	NULL},
    {    64,	NULL},
    {   128,	NULL},
    {   256,	NULL},
    {   512,	NULL},
    {  1024,	NULL},
    {  2048,	NULL},
    {  4096,	NULL},
    {  8192,	NULL},
    { 16384,	NULL},
    {     0,	NULL}
};

/* internal cache of cache description objs */
static xmem_cache_t cache_cache = {
    slabs_full:    LIST_HEAD_INIT(cache_cache.slabs_full),
    slabs_partial: LIST_HEAD_INIT(cache_cache.slabs_partial),
    slabs_free:    LIST_HEAD_INIT(cache_cache.slabs_free),
    objsize:       sizeof(xmem_cache_t),
    flags:         SLAB_NO_REAP,
    spinlock:      SPIN_LOCK_UNLOCKED,
    colour_off:    L1_CACHE_BYTES,
    name:          "xmem_cache"
};

/* Guard access to the cache-chain. */
/* KAF: No semaphores, as we'll never wait around for I/O. */
static spinlock_t cache_chain_sem;
#define init_MUTEX(_m)   spin_lock_init(_m)
#define down(_m)         spin_lock_irqsave(_m,spin_flags)
#define up(_m)           spin_unlock_irqrestore(_m,spin_flags)

/* Place maintainer for reaping. */
static xmem_cache_t *clock_searchp = &cache_cache;

#define cache_chain (cache_cache.next)

#ifdef CONFIG_SMP
/*
 * chicken and egg problem: delay the per-cpu array allocation
 * until the general caches are up.
 */
static int g_cpucache_up;

static void enable_cpucache (xmem_cache_t *cachep);
static void enable_all_cpucaches (void);
#endif

/* Cal the num objs, wastage, and bytes left over for a given slab size. */
static void xmem_cache_estimate (unsigned long gfporder, size_t size,
                                 int flags, size_t *left_over, unsigned int *num)
{
    int i;
    size_t wastage = PAGE_SIZE<<gfporder;
    size_t extra = 0;
    size_t base = 0;

    if (!(flags & CFLGS_OFF_SLAB)) {
        base = sizeof(slab_t);
        extra = sizeof(xmem_bufctl_t);
    }
    i = 0;
    while (i*size + L1_CACHE_ALIGN(base+i*extra) <= wastage)
        i++;
    if (i > 0)
        i--;

    if (i > SLAB_LIMIT)
        i = SLAB_LIMIT;

    *num = i;
    wastage -= i*size;
    wastage -= L1_CACHE_ALIGN(base+i*extra);
    *left_over = wastage;
}

/* Initialisation - setup the `cache' cache. */
void __init xmem_cache_init(void)
{
    size_t left_over;

    init_MUTEX(&cache_chain_sem);
    INIT_LIST_HEAD(&cache_chain);

    xmem_cache_estimate(0, cache_cache.objsize, 0,
			&left_over, &cache_cache.num);
    if (!cache_cache.num)
        BUG();

    cache_cache.colour = left_over/cache_cache.colour_off;
    cache_cache.colour_next = 0;
}


/* Initialisation - setup remaining internal and general caches.
 * Called after the gfp() functions have been enabled, and before smp_init().
 */
void __init xmem_cache_sizes_init(unsigned long num_physpages)
{
    cache_sizes_t *sizes = cache_sizes;
    char name[20];
    /*
     * Fragmentation resistance on low memory - only use bigger
     * page orders on machines with more than 32MB of memory.
     */
    if (num_physpages > (32 << 20) >> PAGE_SHIFT)
        slab_break_gfp_order = BREAK_GFP_ORDER_HI;
    do {
        /* For performance, all the general caches are L1 aligned.
         * This should be particularly beneficial on SMP boxes, as it
         * eliminates "false sharing".
         * Note for systems short on memory removing the alignment will
         * allow tighter packing of the smaller caches. */
        sprintf(name,"size-%Zd",sizes->cs_size);
        if (!(sizes->cs_cachep =
              xmem_cache_create(name, sizes->cs_size,
                                0, SLAB_HWCACHE_ALIGN, NULL, NULL))) {
            BUG();
        }

        /* Inc off-slab bufctl limit until the ceiling is hit. */
        if (!(OFF_SLAB(sizes->cs_cachep))) {
            offslab_limit = sizes->cs_size-sizeof(slab_t);
            offslab_limit /= 2;
        }
        sizes++;
    } while (sizes->cs_size);
}

int __init xmem_cpucache_init(void)
{
#ifdef CONFIG_SMP
    g_cpucache_up = 1;
    enable_all_cpucaches();
#endif
    return 0;
}

/*__initcall(xmem_cpucache_init);*/

/* Interface to system's page allocator. No need to hold the cache-lock.
 */
static inline void *xmem_getpages(xmem_cache_t *cachep)
{
    void *addr;

    addr = (void*) alloc_xenheap_pages(cachep->gfporder);
    /* Assume that now we have the pages no one else can legally
     * messes with the 'struct page's.
     * However vm_scan() might try to test the structure to see if
     * it is a named-page or buffer-page.  The members it tests are
     * of no interest here.....
     */
    return addr;
}

/* Interface to system's page release. */
static inline void xmem_freepages (xmem_cache_t *cachep, void *addr)
{
    unsigned long i = (1<<cachep->gfporder);
    struct pfn_info *page = virt_to_page(addr);

    /* free_xenheap_pages() does not clear the type bit - we do that.
     * The pages have been unlinked from their cache-slab,
     * but their 'struct page's might be accessed in
     * vm_scan(). Shouldn't be a worry.
     */
    while (i--) {
        PageClearSlab(page);
        page++;
    }

    free_xenheap_pages((unsigned long)addr, cachep->gfporder);
}

#if DEBUG
static inline void xmem_poison_obj (xmem_cache_t *cachep, void *addr)
{
    int size = cachep->objsize;
    if (cachep->flags & SLAB_RED_ZONE) {
        addr += BYTES_PER_WORD;
        size -= 2*BYTES_PER_WORD;
    }
    memset(addr, POISON_BYTE, size);
    *(unsigned char *)(addr+size-1) = POISON_END;
}

static inline int xmem_check_poison_obj (xmem_cache_t *cachep, void *addr)
{
    int size = cachep->objsize;
    void *end;
    if (cachep->flags & SLAB_RED_ZONE) {
        addr += BYTES_PER_WORD;
        size -= 2*BYTES_PER_WORD;
    }
    end = memchr(addr, POISON_END, size);