Archipelago » qemu

/*

 *  virtual page mapping and translated block handling

 *

 *  Copyright (c) 2003 Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

#include "config.h"

#ifdef _WIN32

#include <windows.h>

#else

#include <sys/types.h>

#include <sys/mman.h>

#endif

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <inttypes.h>

#include "cpu.h"

#include "exec-all.h"

#include "qemu-common.h"

#include "tcg.h"

#include "hw/hw.h"

#include "osdep.h"

#include "kvm.h"

#if defined(CONFIG_USER_ONLY)

#include <qemu.h>

#include <signal.h>

#endif

//#define DEBUG_TB_INVALIDATE

//#define DEBUG_FLUSH

//#define DEBUG_TLB

//#define DEBUG_UNASSIGNED

/* make various TB consistency checks */

//#define DEBUG_TB_CHECK

//#define DEBUG_TLB_CHECK

//#define DEBUG_IOPORT

//#define DEBUG_SUBPAGE

#if !defined(CONFIG_USER_ONLY)

/* TB consistency checks only implemented for usermode emulation.  */

#undef DEBUG_TB_CHECK

#endif

#define SMC_BITMAP_USE_THRESHOLD 10

static TranslationBlock *tbs;

int code_gen_max_blocks;

TranslationBlock *tb_phys_hash[CODE_GEN_PHYS_HASH_SIZE];

static int nb_tbs;

/* any access to the tbs or the page table must use this lock */

spinlock_t tb_lock = SPIN_LOCK_UNLOCKED;

#if defined(__arm__) || defined(__sparc_v9__)

/* The prologue must be reachable with a direct jump. ARM and Sparc64

 have limited branch ranges (possibly also PPC) so place it in a

 section close to code segment. */

#define code_gen_section                                \

    __attribute__((__section__(".gen_code")))           \

    __attribute__((aligned (32)))

#elif defined(_WIN32)

/* Maximum alignment for Win32 is 16. */

#define code_gen_section                                \

    __attribute__((aligned (16)))

#else

#define code_gen_section                                \

    __attribute__((aligned (32)))

#endif

uint8_t code_gen_prologue[1024] code_gen_section;

static uint8_t *code_gen_buffer;

static unsigned long code_gen_buffer_size;

/* threshold to flush the translated code buffer */

static unsigned long code_gen_buffer_max_size;

uint8_t *code_gen_ptr;

#if !defined(CONFIG_USER_ONLY)

int phys_ram_fd;

uint8_t *phys_ram_dirty;

static int in_migration;

typedef struct RAMBlock {

    uint8_t *host;

    ram_addr_t offset;

    ram_addr_t length;

    struct RAMBlock *next;

} RAMBlock;

static RAMBlock *ram_blocks;

/* TODO: When we implement (and use) ram deallocation (e.g. for hotplug)

   then we can no longer assume contiguous ram offsets, and external uses

   of this variable will break.  */

ram_addr_t last_ram_offset;

#endif

CPUState *first_cpu;

/* current CPU in the current thread. It is only valid inside

   cpu_exec() */

CPUState *cpu_single_env;

/* 0 = Do not count executed instructions.

   1 = Precise instruction counting.

   2 = Adaptive rate instruction counting.  */

int use_icount = 0;

/* Current instruction counter.  While executing translated code this may

   include some instructions that have not yet been executed.  */

int64_t qemu_icount;

typedef struct PageDesc {

    /* list of TBs intersecting this ram page */

    TranslationBlock *first_tb;

    /* in order to optimize self modifying code, we count the number

       of lookups we do to a given page to use a bitmap */

    unsigned int code_write_count;

    uint8_t *code_bitmap;

#if defined(CONFIG_USER_ONLY)

    unsigned long flags;

#endif

} PageDesc;

/* In system mode we want L1_MAP to be based on ram offsets,

   while in user mode we want it to be based on virtual addresses.  */

#if !defined(CONFIG_USER_ONLY)

#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS

# define L1_MAP_ADDR_SPACE_BITS  HOST_LONG_BITS

#else

# define L1_MAP_ADDR_SPACE_BITS  TARGET_PHYS_ADDR_SPACE_BITS

#endif

#else

# define L1_MAP_ADDR_SPACE_BITS  TARGET_VIRT_ADDR_SPACE_BITS

#endif

/* Size of the L2 (and L3, etc) page tables.  */

#define L2_BITS 10

#define L2_SIZE (1 << L2_BITS)

/* The bits remaining after N lower levels of page tables.  */

#define P_L1_BITS_REM \

    ((TARGET_PHYS_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % L2_BITS)

#define V_L1_BITS_REM \

    ((L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % L2_BITS)

/* Size of the L1 page table.  Avoid silly small sizes.  */

#if P_L1_BITS_REM < 4

#define P_L1_BITS  (P_L1_BITS_REM + L2_BITS)

#else

#define P_L1_BITS  P_L1_BITS_REM

#endif

#if V_L1_BITS_REM < 4

#define V_L1_BITS  (V_L1_BITS_REM + L2_BITS)

#else

#define V_L1_BITS  V_L1_BITS_REM

#endif

#define P_L1_SIZE  ((target_phys_addr_t)1 << P_L1_BITS)

#define V_L1_SIZE  ((target_ulong)1 << V_L1_BITS)

#define P_L1_SHIFT (TARGET_PHYS_ADDR_SPACE_BITS - TARGET_PAGE_BITS - P_L1_BITS)

#define V_L1_SHIFT (L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS - V_L1_BITS)

unsigned long qemu_real_host_page_size;

unsigned long qemu_host_page_bits;

unsigned long qemu_host_page_size;

unsigned long qemu_host_page_mask;

/* This is a multi-level map on the virtual address space.

   The bottom level has pointers to PageDesc.  */

static void *l1_map[V_L1_SIZE];

#if !defined(CONFIG_USER_ONLY)

typedef struct PhysPageDesc {

    /* offset in host memory of the page + io_index in the low bits */

    ram_addr_t phys_offset;

    ram_addr_t region_offset;

} PhysPageDesc;

/* This is a multi-level map on the physical address space.

   The bottom level has pointers to PhysPageDesc.  */

static void *l1_phys_map[P_L1_SIZE];

static void io_mem_init(void);

/* io memory support */

CPUWriteMemoryFunc *io_mem_write[IO_MEM_NB_ENTRIES][4];

CPUReadMemoryFunc *io_mem_read[IO_MEM_NB_ENTRIES][4];

void *io_mem_opaque[IO_MEM_NB_ENTRIES];

static char io_mem_used[IO_MEM_NB_ENTRIES];

static int io_mem_watch;

#endif

/* log support */

#ifdef WIN32

static const char *logfilename = "qemu.log";

#else

static const char *logfilename = "/tmp/qemu.log";

#endif

FILE *logfile;

int loglevel;

static int log_append = 0;

/* statistics */

#if !defined(CONFIG_USER_ONLY)

static int tlb_flush_count;

#endif

static int tb_flush_count;

static int tb_phys_invalidate_count;

#ifdef _WIN32

static void map_exec(void *addr, long size)

{

    DWORD old_protect;

    VirtualProtect(addr, size,

                   PAGE_EXECUTE_READWRITE, &old_protect);

}

#else

static void map_exec(void *addr, long size)

{

    unsigned long start, end, page_size;

    page_size = getpagesize();

    start = (unsigned long)addr;

    start &= ~(page_size - 1);

    end = (unsigned long)addr + size;

    end += page_size - 1;

    end &= ~(page_size - 1);

    mprotect((void *)start, end - start,

             PROT_READ | PROT_WRITE | PROT_EXEC);

}

#endif

static void page_init(void)

{

    /* NOTE: we can always suppose that qemu_host_page_size >=

       TARGET_PAGE_SIZE */

#ifdef _WIN32

    {

        SYSTEM_INFO system_info;

        GetSystemInfo(&system_info);

        qemu_real_host_page_size = system_info.dwPageSize;

    }

#else

    qemu_real_host_page_size = getpagesize();

#endif

    if (qemu_host_page_size == 0)

        qemu_host_page_size = qemu_real_host_page_size;

    if (qemu_host_page_size < TARGET_PAGE_SIZE)

        qemu_host_page_size = TARGET_PAGE_SIZE;

    qemu_host_page_bits = 0;

    while ((1 << qemu_host_page_bits) < qemu_host_page_size)

        qemu_host_page_bits++;

    qemu_host_page_mask = ~(qemu_host_page_size - 1);

#if !defined(_WIN32) && defined(CONFIG_USER_ONLY)

    {

        FILE *f;

        last_brk = (unsigned long)sbrk(0);

        f = fopen("/proc/self/maps", "r");

        if (f) {

            mmap_lock();

            do {

                unsigned long startaddr, endaddr;

                int n;

                n = fscanf (f, "%lx-%lx %*[^\n]\n", &startaddr, &endaddr);

                if (n == 2 && h2g_valid(startaddr)) {

                    startaddr = h2g(startaddr) & TARGET_PAGE_MASK;

                    if (h2g_valid(endaddr)) {

                        endaddr = h2g(endaddr);

                    } else {

                        endaddr = ~0ul;

                    }

                    page_set_flags(startaddr, endaddr, PAGE_RESERVED);

                }

            } while (!feof(f));

            fclose(f);

            mmap_unlock();

        }

    }

#endif

}

static PageDesc *page_find_alloc(tb_page_addr_t index, int alloc)

{

    PageDesc *pd;

    void **lp;

    int i;

#if defined(CONFIG_USER_ONLY)

    /* We can't use qemu_malloc because it may recurse into a locked mutex.

       Neither can we record the new pages we reserve while allocating a

       given page because that may recurse into an unallocated page table

       entry.  Stuff the allocations we do make into a queue and process

       them after having completed one entire page table allocation.  */

    unsigned long reserve[2 * (V_L1_SHIFT / L2_BITS)];

    int reserve_idx = 0;

# define ALLOC(P, SIZE)                                 \

    do {                                                \

        P = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,    \

                 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);   \

        if (h2g_valid(P)) {                             \

            reserve[reserve_idx] = h2g(P);              \

            reserve[reserve_idx + 1] = SIZE;            \

            reserve_idx += 2;                           \

        }                                               \

    } while (0)

#else

# define ALLOC(P, SIZE) \

    do { P = qemu_mallocz(SIZE); } while (0)

#endif

    /* Level 1.  Always allocated.  */

    lp = l1_map + ((index >> V_L1_SHIFT) & (V_L1_SIZE - 1));

    /* Level 2..N-1.  */

    for (i = V_L1_SHIFT / L2_BITS - 1; i > 0; i--) {

        void **p = *lp;

        if (p == NULL) {

            if (!alloc) {

                return NULL;

            }

            ALLOC(p, sizeof(void *) * L2_SIZE);

            *lp = p;

        }

        lp = p + ((index >> (i * L2_BITS)) & (L2_SIZE - 1));

    }

    pd = *lp;

    if (pd == NULL) {

        if (!alloc) {

            return NULL;

        }

        ALLOC(pd, sizeof(PageDesc) * L2_SIZE);

        *lp = pd;

    }

#undef ALLOC

#if defined(CONFIG_USER_ONLY)

    for (i = 0; i < reserve_idx; i += 2) {

        unsigned long addr = reserve[i];

        unsigned long len = reserve[i + 1];

        page_set_flags(addr & TARGET_PAGE_MASK,

                       TARGET_PAGE_ALIGN(addr + len),

                       PAGE_RESERVED);

    }

#endif

    return pd + (index & (L2_SIZE - 1));

}

static inline PageDesc *page_find(tb_page_addr_t index)

{

    return page_find_alloc(index, 0);

}

#if !defined(CONFIG_USER_ONLY)

static PhysPageDesc *phys_page_find_alloc(target_phys_addr_t index, int alloc)

{

    PhysPageDesc *pd;

    void **lp;

    int i;

    /* Level 1.  Always allocated.  */

    lp = l1_phys_map + ((index >> P_L1_SHIFT) & (P_L1_SIZE - 1));

    /* Level 2..N-1.  */

    for (i = P_L1_SHIFT / L2_BITS - 1; i > 0; i--) {

        void **p = *lp;

        if (p == NULL) {

            if (!alloc) {

                return NULL;

            }

            *lp = p = qemu_mallocz(sizeof(void *) * L2_SIZE);

        }

        lp = p + ((index >> (i * L2_BITS)) & (L2_SIZE - 1));

    }

    pd = *lp;

    if (pd == NULL) {

        int i;

        if (!alloc) {

            return NULL;

        }

        *lp = pd = qemu_malloc(sizeof(PhysPageDesc) * L2_SIZE);

        for (i = 0; i < L2_SIZE; i++) {

            pd[i].phys_offset = IO_MEM_UNASSIGNED;

            pd[i].region_offset = (index + i) << TARGET_PAGE_BITS;

        }

    }

    return pd + (index & (L2_SIZE - 1));

}

static inline PhysPageDesc *phys_page_find(target_phys_addr_t index)

{

    return phys_page_find_alloc(index, 0);

}

static void tlb_protect_code(ram_addr_t ram_addr);

static void tlb_unprotect_code_phys(CPUState *env, ram_addr_t ram_addr,

                                    target_ulong vaddr);

#define mmap_lock() do { } while(0)

#define mmap_unlock() do { } while(0)

#endif

#define DEFAULT_CODE_GEN_BUFFER_SIZE (32 * 1024 * 1024)

#if defined(CONFIG_USER_ONLY)

/* Currently it is not recommended to allocate big chunks of data in

   user mode. It will change when a dedicated libc will be used */

#define USE_STATIC_CODE_GEN_BUFFER

#endif

#ifdef USE_STATIC_CODE_GEN_BUFFER

static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE];

#endif

static void code_gen_alloc(unsigned long tb_size)

{

#ifdef USE_STATIC_CODE_GEN_BUFFER

    code_gen_buffer = static_code_gen_buffer;

    code_gen_buffer_size = DEFAULT_CODE_GEN_BUFFER_SIZE;

    map_exec(code_gen_buffer, code_gen_buffer_size);

#else

    code_gen_buffer_size = tb_size;

    if (code_gen_buffer_size == 0) {

#if defined(CONFIG_USER_ONLY)

        /* in user mode, phys_ram_size is not meaningful */

        code_gen_buffer_size = DEFAULT_CODE_GEN_BUFFER_SIZE;

#else

        /* XXX: needs adjustments */

        code_gen_buffer_size = (unsigned long)(ram_size / 4);

#endif

    }

    if (code_gen_buffer_size < MIN_CODE_GEN_BUFFER_SIZE)

        code_gen_buffer_size = MIN_CODE_GEN_BUFFER_SIZE;

    /* The code gen buffer location may have constraints depending on

       the host cpu and OS */

#if defined(__linux__) 

    {

        int flags;

        void *start = NULL;

        flags = MAP_PRIVATE | MAP_ANONYMOUS;

#if defined(__x86_64__)

        flags |= MAP_32BIT;

        /* Cannot map more than that */

        if (code_gen_buffer_size > (800 * 1024 * 1024))

            code_gen_buffer_size = (800 * 1024 * 1024);

#elif defined(__sparc_v9__)

        // Map the buffer below 2G, so we can use direct calls and branches

        flags |= MAP_FIXED;

        start = (void *) 0x60000000UL;

        if (code_gen_buffer_size > (512 * 1024 * 1024))

            code_gen_buffer_size = (512 * 1024 * 1024);

#elif defined(__arm__)

        /* Map the buffer below 32M, so we can use direct calls and branches */

        flags |= MAP_FIXED;

        start = (void *) 0x01000000UL;

        if (code_gen_buffer_size > 16 * 1024 * 1024)

            code_gen_buffer_size = 16 * 1024 * 1024;

#endif

        code_gen_buffer = mmap(start, code_gen_buffer_size,

                               PROT_WRITE | PROT_READ | PROT_EXEC,

                               flags, -1, 0);

        if (code_gen_buffer == MAP_FAILED) {

            fprintf(stderr, "Could not allocate dynamic translator buffer\n");

            exit(1);

        }

    }

#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)

    {

        int flags;

        void *addr = NULL;

        flags = MAP_PRIVATE | MAP_ANONYMOUS;

#if defined(__x86_64__)

        /* FreeBSD doesn't have MAP_32BIT, use MAP_FIXED and assume

         * 0x40000000 is free */

        flags |= MAP_FIXED;

        addr = (void *)0x40000000;

        /* Cannot map more than that */

        if (code_gen_buffer_size > (800 * 1024 * 1024))

            code_gen_buffer_size = (800 * 1024 * 1024);

#endif

        code_gen_buffer = mmap(addr, code_gen_buffer_size,

                               PROT_WRITE | PROT_READ | PROT_EXEC, 

                               flags, -1, 0);

        if (code_gen_buffer == MAP_FAILED) {

            fprintf(stderr, "Could not allocate dynamic translator buffer\n");

            exit(1);

        }

    }

#else

    code_gen_buffer = qemu_malloc(code_gen_buffer_size);

    map_exec(code_gen_buffer, code_gen_buffer_size);

#endif

#endif /* !USE_STATIC_CODE_GEN_BUFFER */

    map_exec(code_gen_prologue, sizeof(code_gen_prologue));

    code_gen_buffer_max_size = code_gen_buffer_size - 

        code_gen_max_block_size();

    code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE;

    tbs = qemu_malloc(code_gen_max_blocks * sizeof(TranslationBlock));

}

/* Must be called before using the QEMU cpus. 'tb_size' is the size

   (in bytes) allocated to the translation buffer. Zero means default

   size. */

void cpu_exec_init_all(unsigned long tb_size)

{

    cpu_gen_init();

    code_gen_alloc(tb_size);

    code_gen_ptr = code_gen_buffer;

    page_init();

#if !defined(CONFIG_USER_ONLY)

    io_mem_init();

#endif

}

#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)

static int cpu_common_post_load(void *opaque, int version_id)

{

    CPUState *env = opaque;

    /* 0x01 was CPU_INTERRUPT_EXIT. This line can be removed when the

       version_id is increased. */

    env->interrupt_request &= ~0x01;

    tlb_flush(env, 1);

    return 0;

}

static const VMStateDescription vmstate_cpu_common = {

    .name = "cpu_common",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .post_load = cpu_common_post_load,

    .fields      = (VMStateField []) {

        VMSTATE_UINT32(halted, CPUState),

        VMSTATE_UINT32(interrupt_request, CPUState),

        VMSTATE_END_OF_LIST()

    }

};

#endif

CPUState *qemu_get_cpu(int cpu)

{

    CPUState *env = first_cpu;

    while (env) {

        if (env->cpu_index == cpu)

            break;

        env = env->next_cpu;

    }

    return env;

}

void cpu_exec_init(CPUState *env)

{

    CPUState **penv;

    int cpu_index;

#if defined(CONFIG_USER_ONLY)

    cpu_list_lock();

#endif

    env->next_cpu = NULL;

    penv = &first_cpu;

    cpu_index = 0;

    while (*penv != NULL) {

        penv = &(*penv)->next_cpu;

        cpu_index++;

    }

    env->cpu_index = cpu_index;

    env->numa_node = 0;

    QTAILQ_INIT(&env->breakpoints);

    QTAILQ_INIT(&env->watchpoints);

    *penv = env;

#if defined(CONFIG_USER_ONLY)

    cpu_list_unlock();

#endif

#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)

    vmstate_register(cpu_index, &vmstate_cpu_common, env);

    register_savevm("cpu", cpu_index, CPU_SAVE_VERSION,

                    cpu_save, cpu_load, env);

#endif

}

static inline void invalidate_page_bitmap(PageDesc *p)

{

    if (p->code_bitmap) {

        qemu_free(p->code_bitmap);

        p->code_bitmap = NULL;

    }

    p->code_write_count = 0;

}

/* Set to NULL all the 'first_tb' fields in all PageDescs. */

static void page_flush_tb_1 (int level, void **lp)

{

    int i;

    if (*lp == NULL) {

        return;

    }

    if (level == 0) {

        PageDesc *pd = *lp;

        for (i = 0; i < L2_SIZE; ++i) {

            pd[i].first_tb = NULL;

            invalidate_page_bitmap(pd + i);

        }

    } else {

        void **pp = *lp;

        for (i = 0; i < L2_SIZE; ++i) {

            page_flush_tb_1 (level - 1, pp + i);

        }

    }

}

static void page_flush_tb(void)

{

    int i;

    for (i = 0; i < V_L1_SIZE; i++) {

        page_flush_tb_1(V_L1_SHIFT / L2_BITS - 1, l1_map + i);

    }

}

/* flush all the translation blocks */

/* XXX: tb_flush is currently not thread safe */

void tb_flush(CPUState *env1)

{

    CPUState *env;

#if defined(DEBUG_FLUSH)

    printf("qemu: flush code_size=%ld nb_tbs=%d avg_tb_size=%ld\n",

           (unsigned long)(code_gen_ptr - code_gen_buffer),

           nb_tbs, nb_tbs > 0 ?

           ((unsigned long)(code_gen_ptr - code_gen_buffer)) / nb_tbs : 0);

#endif

    if ((unsigned long)(code_gen_ptr - code_gen_buffer) > code_gen_buffer_size)

        cpu_abort(env1, "Internal error: code buffer overflow\n");

    nb_tbs = 0;

    for(env = first_cpu; env != NULL; env = env->next_cpu) {

        memset (env->tb_jmp_cache, 0, TB_JMP_CACHE_SIZE * sizeof (void *));

    }

    memset (tb_phys_hash, 0, CODE_GEN_PHYS_HASH_SIZE * sizeof (void *));

    page_flush_tb();

    code_gen_ptr = code_gen_buffer;

    /* XXX: flush processor icache at this point if cache flush is

       expensive */

    tb_flush_count++;

}

#ifdef DEBUG_TB_CHECK

static void tb_invalidate_check(target_ulong address)

{

    TranslationBlock *tb;

    int i;

    address &= TARGET_PAGE_MASK;

    for(i = 0;i < CODE_GEN_PHYS_HASH_SIZE; i++) {

        for(tb = tb_phys_hash[i]; tb != NULL; tb = tb->phys_hash_next) {

            if (!(address + TARGET_PAGE_SIZE <= tb->pc ||

                  address >= tb->pc + tb->size)) {

                printf("ERROR invalidate: address=" TARGET_FMT_lx

                       " PC=%08lx size=%04x\n",

                       address, (long)tb->pc, tb->size);

            }

        }

    }

}

/* verify that all the pages have correct rights for code */

static void tb_page_check(void)

{

    TranslationBlock *tb;

    int i, flags1, flags2;

    for(i = 0;i < CODE_GEN_PHYS_HASH_SIZE; i++) {

        for(tb = tb_phys_hash[i]; tb != NULL; tb = tb->phys_hash_next) {

            flags1 = page_get_flags(tb->pc);

            flags2 = page_get_flags(tb->pc + tb->size - 1);

            if ((flags1 & PAGE_WRITE) || (flags2 & PAGE_WRITE)) {

                printf("ERROR page flags: PC=%08lx size=%04x f1=%x f2=%x\n",

                       (long)tb->pc, tb->size, flags1, flags2);

            }

        }

    }

}

#endif

/* invalidate one TB */

static inline void tb_remove(TranslationBlock **ptb, TranslationBlock *tb,

                             int next_offset)

{

    TranslationBlock *tb1;

    for(;;) {

        tb1 = *ptb;

        if (tb1 == tb) {

            *ptb = *(TranslationBlock **)((char *)tb1 + next_offset);

            break;

        }

        ptb = (TranslationBlock **)((char *)tb1 + next_offset);

    }

}

static inline void tb_page_remove(TranslationBlock **ptb, TranslationBlock *tb)

{

    TranslationBlock *tb1;

    unsigned int n1;

    for(;;) {

        tb1 = *ptb;

        n1 = (long)tb1 & 3;

        tb1 = (TranslationBlock *)((long)tb1 & ~3);

        if (tb1 == tb) {

            *ptb = tb1->page_next[n1];

            break;

        }

        ptb = &tb1->page_next[n1];

    }

}

static inline void tb_jmp_remove(TranslationBlock *tb, int n)

{

    TranslationBlock *tb1, **ptb;

    unsigned int n1;

    ptb = &tb->jmp_next[n];

    tb1 = *ptb;

    if (tb1) {

        /* find tb(n) in circular list */

        for(;;) {

            tb1 = *ptb;

            n1 = (long)tb1 & 3;

            tb1 = (TranslationBlock *)((long)tb1 & ~3);

            if (n1 == n && tb1 == tb)

                break;

            if (n1 == 2) {

                ptb = &tb1->jmp_first;

            } else {

                ptb = &tb1->jmp_next[n1];

            }

        }

        /* now we can suppress tb(n) from the list */

        *ptb = tb->jmp_next[n];

        tb->jmp_next[n] = NULL;

    }

}

/* reset the jump entry 'n' of a TB so that it is not chained to

   another TB */

static inline void tb_reset_jump(TranslationBlock *tb, int n)

{

    tb_set_jmp_target(tb, n, (unsigned long)(tb->tc_ptr + tb->tb_next_offset[n]));

}

void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)

{

    CPUState *env;

    PageDesc *p;

    unsigned int h, n1;

    tb_page_addr_t phys_pc;

    TranslationBlock *tb1, *tb2;

    /* remove the TB from the hash list */

    phys_pc = tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);

    h = tb_phys_hash_func(phys_pc);

    tb_remove(&tb_phys_hash[h], tb,

              offsetof(TranslationBlock, phys_hash_next));

    /* remove the TB from the page list */

    if (tb->page_addr[0] != page_addr) {

        p = page_find(tb->page_addr[0] >> TARGET_PAGE_BITS);

        tb_page_remove(&p->first_tb, tb);

        invalidate_page_bitmap(p);

    }

    if (tb->page_addr[1] != -1 && tb->page_addr[1] != page_addr) {

        p = page_find(tb->page_addr[1] >> TARGET_PAGE_BITS);

        tb_page_remove(&p->first_tb, tb);

        invalidate_page_bitmap(p);

    }

    tb_invalidated_flag = 1;

    /* remove the TB from the hash list */

    h = tb_jmp_cache_hash_func(tb->pc);

    for(env = first_cpu; env != NULL; env = env->next_cpu) {

        if (env->tb_jmp_cache[h] == tb)

            env->tb_jmp_cache[h] = NULL;

    }

    /* suppress this TB from the two jump lists */

    tb_jmp_remove(tb, 0);

    tb_jmp_remove(tb, 1);

    /* suppress any remaining jumps to this TB */

    tb1 = tb->jmp_first;

    for(;;) {

        n1 = (long)tb1 & 3;

        if (n1 == 2)

            break;

        tb1 = (TranslationBlock *)((long)tb1 & ~3);

        tb2 = tb1->jmp_next[n1];

        tb_reset_jump(tb1, n1);

        tb1->jmp_next[n1] = NULL;

        tb1 = tb2;

    }

    tb->jmp_first = (TranslationBlock *)((long)tb | 2); /* fail safe */

    tb_phys_invalidate_count++;

}

static inline void set_bits(uint8_t *tab, int start, int len)

{

    int end, mask, end1;

    end = start + len;

    tab += start >> 3;

    mask = 0xff << (start & 7);

    if ((start & ~7) == (end & ~7)) {

        if (start < end) {

            mask &= ~(0xff << (end & 7));

            *tab |= mask;

        }

    } else {

        *tab++ |= mask;

        start = (start + 8) & ~7;

        end1 = end & ~7;

        while (start < end1) {

            *tab++ = 0xff;

            start += 8;

        }

        if (start < end) {

            mask = ~(0xff << (end & 7));

            *tab |= mask;

        }

    }

}

static void build_page_bitmap(PageDesc *p)

{

    int n, tb_start, tb_end;

    TranslationBlock *tb;

    p->code_bitmap = qemu_mallocz(TARGET_PAGE_SIZE / 8);

    tb = p->first_tb;