exec: move TB handling to translate-all.c

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 1719 insertions, 0 deletions

diff --git a/translate-all.c b/translate-all.c
index f22e3eedd2..b958342a99 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -16,6 +16,12 @@
  * 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/>.
  */
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <sys/types.h>
+#include <sys/mman.h>
+#endif
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -24,15 +30,119 @@
 
 #include "config.h"
 
+#include "qemu-common.h"
 #define NO_CPU_IO_DEFS
 #include "cpu.h"
 #include "disas.h"
 #include "tcg.h"
 #include "qemu-timer.h"
+#include "memory.h"
+#include "exec-memory.h"
+#if defined(CONFIG_USER_ONLY)
+#include "qemu.h"
+#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+#include <sys/param.h>
+#if __FreeBSD_version >= 700104
+#define HAVE_KINFO_GETVMMAP
+#define sigqueue sigqueue_freebsd  /* avoid redefinition */
+#include <sys/time.h>
+#include <sys/proc.h>
+#include <machine/profile.h>
+#define _KERNEL
+#include <sys/user.h>
+#undef _KERNEL
+#undef sigqueue
+#include <libutil.h>
+#endif
+#endif
+#endif
+
+#include "cputlb.h"
+#include "translate-all.h"
+
+//#define DEBUG_TB_INVALIDATE
+//#define DEBUG_FLUSH
+/* make various TB consistency checks */
+//#define DEBUG_TB_CHECK
+
+#if !defined(CONFIG_USER_ONLY)
+/* TB consistency checks only implemented for usermode emulation.  */
+#undef DEBUG_TB_CHECK
+#endif
+
+#define SMC_BITMAP_USE_THRESHOLD 10
+
+/* Code generation and translation blocks */
+static TranslationBlock *tbs;
+static 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;
+
+uint8_t *code_gen_prologue;
+static uint8_t *code_gen_buffer;
+static size_t code_gen_buffer_size;
+/* threshold to flush the translated code buffer */
+static size_t code_gen_buffer_max_size;
+static uint8_t *code_gen_ptr;
+
+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
+
+/* The bits remaining after N lower levels of page tables.  */
+#define V_L1_BITS_REM \
+    ((L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS) % L2_BITS)
+
+#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 V_L1_SIZE  ((target_ulong)1 << V_L1_BITS)
+
+#define V_L1_SHIFT (L1_MAP_ADDR_SPACE_BITS - TARGET_PAGE_BITS - V_L1_BITS)
+
+uintptr_t qemu_real_host_page_size;
+uintptr_t qemu_host_page_size;
+uintptr_t 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];
+
+/* statistics */
+static int tb_flush_count;
+static int tb_phys_invalidate_count;
 
 /* code generation context */
 TCGContext tcg_ctx;
 
+static void tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc,
+                         tb_page_addr_t phys_page2);
+
 void cpu_gen_init(void)
 {
     tcg_context_init(&tcg_ctx); 
@@ -155,3 +265,1612 @@ int cpu_restore_state(TranslationBlock *tb,
 #endif
     return 0;
 }
+
+#ifdef _WIN32
+static inline void map_exec(void *addr, long size)
+{
+    DWORD old_protect;
+    VirtualProtect(addr, size,
+                   PAGE_EXECUTE_READWRITE, &old_protect);
+}
+#else
+static inline 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_mask = ~(qemu_host_page_size - 1);
+
+#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
+    {
+#ifdef HAVE_KINFO_GETVMMAP
+        struct kinfo_vmentry *freep;
+        int i, cnt;
+
+        freep = kinfo_getvmmap(getpid(), &cnt);
+        if (freep) {
+            mmap_lock();
+            for (i = 0; i < cnt; i++) {
+                unsigned long startaddr, endaddr;
+
+                startaddr = freep[i].kve_start;
+                endaddr = freep[i].kve_end;
+                if (h2g_valid(startaddr)) {
+                    startaddr = h2g(startaddr) & TARGET_PAGE_MASK;
+
+                    if (h2g_valid(endaddr)) {
+                        endaddr = h2g(endaddr);
+                        page_set_flags(startaddr, endaddr, PAGE_RESERVED);
+                    } else {
+#if TARGET_ABI_BITS <= L1_MAP_ADDR_SPACE_BITS
+                        endaddr = ~0ul;
+                        page_set_flags(startaddr, endaddr, PAGE_RESERVED);
+#endif
+                    }
+                }
+            }
+            free(freep);
+            mmap_unlock();
+        }
+#else
+        FILE *f;
+
+        last_brk = (unsigned long)sbrk(0);
+
+        f = fopen("/compat/linux/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
+    }
+#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 g_malloc because it may recurse into a locked mutex. */
+# define ALLOC(P, SIZE)                                 \
+    do {                                                \
+        P = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,    \
+                 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);   \
+    } while (0)
+#else
+# define ALLOC(P, SIZE) \
+    do { P = g_malloc0(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
+
+    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)
+#define mmap_lock() do { } while (0)
+#define mmap_unlock() do { } while (0)
+#endif
+
+#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.  */
+/* ??? 64-bit hosts ought to have no problem mmaping data outside the
+   region in which the guest needs to run.  Revisit this.  */
+#define USE_STATIC_CODE_GEN_BUFFER
+#endif
+
+/* ??? Should configure for this, not list operating systems here.  */
+#if (defined(__linux__) \
+    || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) \
+    || defined(__DragonFly__) || defined(__OpenBSD__) \
+    || defined(__NetBSD__))
+# define USE_MMAP
+#endif
+
+/* Minimum size of the code gen buffer.  This number is randomly chosen,
+   but not so small that we can't have a fair number of TB's live.  */
+#define MIN_CODE_GEN_BUFFER_SIZE     (1024u * 1024)
+
+/* Maximum size of the code gen buffer we'd like to use.  Unless otherwise
+   indicated, this is constrained by the range of direct branches on the
+   host cpu, as used by the TCG implementation of goto_tb.  */
+#if defined(__x86_64__)
+# define MAX_CODE_GEN_BUFFER_SIZE  (2ul * 1024 * 1024 * 1024)
+#elif defined(__sparc__)
+# define MAX_CODE_GEN_BUFFER_SIZE  (2ul * 1024 * 1024 * 1024)
+#elif defined(__arm__)
+# define MAX_CODE_GEN_BUFFER_SIZE  (16u * 1024 * 1024)
+#elif defined(__s390x__)
+  /* We have a +- 4GB range on the branches; leave some slop.  */
+# define MAX_CODE_GEN_BUFFER_SIZE  (3ul * 1024 * 1024 * 1024)
+#else
+# define MAX_CODE_GEN_BUFFER_SIZE  ((size_t)-1)
+#endif
+
+#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (32u * 1024 * 1024)
+
+#define DEFAULT_CODE_GEN_BUFFER_SIZE \
+  (DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \
+   ? DEFAULT_CODE_GEN_BUFFER_SIZE_1 : MAX_CODE_GEN_BUFFER_SIZE)
+
+static inline size_t size_code_gen_buffer(size_t tb_size)
+{
+    /* Size the buffer.  */
+    if (tb_size == 0) {
+#ifdef USE_STATIC_CODE_GEN_BUFFER
+        tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
+#else
+        /* ??? Needs adjustments.  */
+        /* ??? If we relax the requirement that CONFIG_USER_ONLY use the
+           static buffer, we could size this on RESERVED_VA, on the text
+           segment size of the executable, or continue to use the default.  */
+        tb_size = (unsigned long)(ram_size / 4);
+#endif
+    }
+    if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {
+        tb_size = MIN_CODE_GEN_BUFFER_SIZE;
+    }
+    if (tb_size > MAX_CODE_GEN_BUFFER_SIZE) {
+        tb_size = MAX_CODE_GEN_BUFFER_SIZE;
+    }
+    code_gen_buffer_size = tb_size;
+    return tb_size;
+}
+
+#ifdef USE_STATIC_CODE_GEN_BUFFER
+static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE]
+    __attribute__((aligned(CODE_GEN_ALIGN)));
+
+static inline void *alloc_code_gen_buffer(void)
+{
+    map_exec(static_code_gen_buffer, code_gen_buffer_size);
+    return static_code_gen_buffer;
+}
+#elif defined(USE_MMAP)
+static inline void *alloc_code_gen_buffer(void)
+{
+    int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+    uintptr_t start = 0;
+    void *buf;
+
+    /* Constrain the position of the buffer based on the host cpu.
+       Note that these addresses are chosen in concert with the
+       addresses assigned in the relevant linker script file.  */
+# if defined(__PIE__) || defined(__PIC__)
+    /* Don't bother setting a preferred location if we're building
+       a position-independent executable.  We're more likely to get
+       an address near the main executable if we let the kernel
+       choose the address.  */
+# elif defined(__x86_64__) && defined(MAP_32BIT)
+    /* Force the memory down into low memory with the executable.
+       Leave the choice of exact location with the kernel.  */
+    flags |= MAP_32BIT;
+    /* Cannot expect to map more than 800MB in low memory.  */
+    if (code_gen_buffer_size > 800u * 1024 * 1024) {
+        code_gen_buffer_size = 800u * 1024 * 1024;
+    }
+# elif defined(__sparc__)
+    start = 0x40000000ul;
+# elif defined(__s390x__)
+    start = 0x90000000ul;
+# endif
+
+    buf = mmap((void *)start, code_gen_buffer_size,
+               PROT_WRITE | PROT_READ | PROT_EXEC, flags, -1, 0);
+    return buf == MAP_FAILED ? NULL : buf;
+}
+#else
+static inline void *alloc_code_gen_buffer(void)
+{
+    void *buf = g_malloc(code_gen_buffer_size);
+
+    if (buf) {
+        map_exec(buf, code_gen_buffer_size);
+    }
+    return buf;
+}
+#endif /* USE_STATIC_CODE_GEN_BUFFER, USE_MMAP */
+
+static inline void code_gen_alloc(size_t tb_size)
+{
+    code_gen_buffer_size = size_code_gen_buffer(tb_size);
+    code_gen_buffer = alloc_code_gen_buffer();
+    if (code_gen_buffer == NULL) {
+        fprintf(stderr, "Could not allocate dynamic translator buffer\n");
+        exit(1);
+    }
+
+    qemu_madvise(code_gen_buffer, code_gen_buffer_size, QEMU_MADV_HUGEPAGE);
+
+    /* Steal room for the prologue at the end of the buffer.  This ensures
+       (via the MAX_CODE_GEN_BUFFER_SIZE limits above) that direct branches
+       from TB's to the prologue are going to be in range.  It also means
+       that we don't need to mark (additional) portions of the data segment
+       as executable.  */
+    code_gen_prologue = code_gen_buffer + code_gen_buffer_size - 1024;
+    code_gen_buffer_size -= 1024;
+
+    code_gen_buffer_max_size = code_gen_buffer_size -
+        (TCG_MAX_OP_SIZE * OPC_BUF_SIZE);
+    code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE;
+    tbs = g_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 tcg_exec_init(unsigned long tb_size)
+{
+    cpu_gen_init();
+    code_gen_alloc(tb_size);
+    code_gen_ptr = code_gen_buffer;
+    tcg_register_jit(code_gen_buffer, code_gen_buffer_size);
+    page_init();
+#if !defined(CONFIG_USER_ONLY) || !defined(CONFIG_USE_GUEST_BASE)
+    /* There's no guest base to take into account, so go ahead and
+       initialize the prologue now.  */
+    tcg_prologue_init(&tcg_ctx);
+#endif
+}
+
+bool tcg_enabled(void)
+{
+    return code_gen_buffer != NULL;
+}
+
+/* Allocate a new translation block. Flush the translation buffer if
+   too many translation blocks or too much generated code. */
+static TranslationBlock *tb_alloc(target_ulong pc)
+{
+    TranslationBlock *tb;
+
+    if (nb_tbs >= code_gen_max_blocks ||
+        (code_gen_ptr - code_gen_buffer) >= code_gen_buffer_max_size) {
+        return NULL;
+    }
+    tb = &tbs[nb_tbs++];
+    tb->pc = pc;
+    tb->cflags = 0;
+    return tb;
+}
+
+void tb_free(TranslationBlock *tb)
+{
+    /* In practice this is mostly used for single use temporary TB
+       Ignore the hard cases and just back up if this TB happens to
+       be the last one generated.  */
+    if (nb_tbs > 0 && tb == &tbs[nb_tbs - 1]) {
+        code_gen_ptr = tb->tc_ptr;
+        nb_tbs--;
+    }
+}
+
+static inline void invalidate_page_bitmap(PageDesc *p)
+{
+    if (p->code_bitmap) {
+        g_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(CPUArchState *env1)
+{
+    CPUArchState *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 = (uintptr_t)tb1 & 3;
+        tb1 = (TranslationBlock *)((uintptr_t)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 = (uintptr_t)tb1 & 3;
+            tb1 = (TranslationBlock *)((uintptr_t)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, (uintptr_t)(tb->tc_ptr + tb->tb_next_offset[n]));
+}
+
+void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr)
+{
+    CPUArchState *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 = (uintptr_t)tb1 & 3;
+        if (n1 == 2) {
+            break;
+        }
+        tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
+        tb2 = tb1->jmp_next[n1];
+        tb_reset_jump(tb1, n1);
+        tb1->jmp_next[n1] = NULL;
+        tb1 = tb2;
+    }
+    tb->jmp_first = (TranslationBlock *)((uintptr_t)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 = g_malloc0(TARGET_PAGE_SIZE / 8);
+
+    tb = p->first_tb;
+    while (tb != NULL) {
+        n = (uintptr_t)tb & 3;
+        tb = (TranslationBlock *)((uintptr_t)tb & ~3);
+        /* NOTE: this is subtle as a TB may span two physical pages */
+        if (n == 0) {
+            /* NOTE: tb_end may be after the end of the page, but
+               it is not a problem */
+            tb_start = tb->pc & ~TARGET_PAGE_MASK;
+            tb_end = tb_start + tb->size;
+            if (tb_end > TARGET_PAGE_SIZE) {
+                tb_end = TARGET_PAGE_SIZE;
+            }
+        } else {
+            tb_start = 0;
+            tb_end = ((tb->pc + tb->size) & ~TARGET_PAGE_MASK);
+        }
+        set_bits(p->code_bitmap, tb_start, tb_end - tb_start);
+        tb = tb->page_next[n];
+    }
+}
+
+TranslationBlock *tb_gen_code(CPUArchState *env,
+                              target_ulong pc, target_ulong cs_base,
+                              int flags, int cflags)
+{
+    TranslationBlock *tb;
+    uint8_t *tc_ptr;
+    tb_page_addr_t phys_pc, phys_page2;
+    target_ulong virt_page2;
+    int code_gen_size;
+
+    phys_pc = get_page_addr_code(env, pc);
+    tb = tb_alloc(pc);
+    if (!tb) {
+        /* flush must be done */
+        tb_flush(env);
+        /* cannot fail at this point */
+        tb = tb_alloc(pc);
+        /* Don't forget to invalidate previous TB info.  */
+        tb_invalidated_flag = 1;
+    }
+    tc_ptr = code_gen_ptr;
+    tb->tc_ptr = tc_ptr;
+    tb->cs_base = cs_base;
+    tb->flags = flags;
+    tb->cflags = cflags;
+    cpu_gen_code(env, tb, &code_gen_size);
+    code_gen_ptr = (void *)(((uintptr_t)code_gen_ptr + code_gen_size +
+                             CODE_GEN_ALIGN - 1) & ~(CODE_GEN_ALIGN - 1));
+
+    /* check next page if needed */
+    virt_page2 = (pc + tb->size - 1) & TARGET_PAGE_MASK;
+    phys_page2 = -1;
+    if ((pc & TARGET_PAGE_MASK) != virt_page2) {
+        phys_page2 = get_page_addr_code(env, virt_page2);
+    }
+    tb_link_page(tb, phys_pc, phys_page2);
+    return tb;
+}
+
+/*
+ * Invalidate all TBs which intersect with the target physical address range
+ * [start;end[. NOTE: start and end may refer to *different* physical pages.
+ * 'is_cpu_write_access' should be true if called from a real cpu write
+ * access: the virtual CPU will exit the current TB if code is modified inside
+ * this TB.
+ */
+void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end,
+                              int is_cpu_write_access)
+{
+    while (start < end) {
+        tb_invalidate_phys_page_range(start, end, is_cpu_write_access);
+        start &= TARGET_PAGE_MASK;
+        start += TARGET_PAGE_SIZE;
+    }
+}
+
+/*
+ * Invalidate all TBs which intersect with the target physical address range
+ * [start;end[. NOTE: start and end must refer to the *same* physical page.
+ * 'is_cpu_write_access' should be true if called from a real cpu write
+ * access: the virtual CPU will exit the current TB if code is modified inside
+ * this TB.
+ */
+void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
+                                   int is_cpu_write_access)
+{
+    TranslationBlock *tb, *tb_next, *saved_tb;
+    CPUArchState *env = cpu_single_env;
+    tb_page_addr_t tb_start, tb_end;
+    PageDesc *p;
+    int n;
+#ifdef TARGET_HAS_PRECISE_SMC
+    int current_tb_not_found = is_cpu_write_access;
+    TranslationBlock *current_tb = NULL;
+    int current_tb_modified = 0;
+    target_ulong current_pc = 0;
+    target_ulong current_cs_base = 0;
+    int current_flags = 0;
+#endif /* TARGET_HAS_PRECISE_SMC */
+
+    p = page_find(start >> TARGET_PAGE_BITS);
+    if (!p) {
+        return;
+    }
+    if (!p->code_bitmap &&
+        ++p->code_write_count >= SMC_BITMAP_USE_THRESHOLD &&
+        is_cpu_write_access) {
+        /* build code bitmap */
+        build_page_bitmap(p);
+    }
+
+    /* we remove all the TBs in the range [start, end[ */
+    /* XXX: see if in some cases it could be faster to invalidate all
+       the code */
+    tb = p->first_tb;
+    while (tb != NULL) {
+        n = (uintptr_t)tb & 3;
+        tb = (TranslationBlock *)((uintptr_t)tb & ~3);
+        tb_next = tb->page_next[n];
+        /* NOTE: this is subtle as a TB may span two physical pages */
+        if (n == 0) {
+            /* NOTE: tb_end may be after the end of the page, but
+               it is not a problem */
+            tb_start = tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);
+            tb_end = tb_start + tb->size;
+        } else {
+            tb_start = tb->page_addr[1];
+            tb_end = tb_start + ((tb->pc + tb->size) & ~TARGET_PAGE_MASK);
+        }
+        if (!(tb_end <= start || tb_start >= end)) {
+#ifdef TARGET_HAS_PRECISE_SMC
+            if (current_tb_not_found) {
+                current_tb_not_found = 0;
+                current_tb = NULL;
+                if (env->mem_io_pc) {
+                    /* now we have a real cpu fault */
+                    current_tb = tb_find_pc(env->mem_io_pc);
+                }
+            }
+            if (current_tb == tb &&
+                (current_tb->cflags & CF_COUNT_MASK) != 1) {
+                /* If we are modifying the current TB, we must stop
+                its execution. We could be more precise by checking
+                that the modification is after the current PC, but it
+                would require a specialized function to partially
+                restore the CPU state */
+
+                current_tb_modified = 1;
+                cpu_restore_state(current_tb, env, env->mem_io_pc);
+                cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
+                                     &current_flags);
+            }
+#endif /* TARGET_HAS_PRECISE_SMC */
+            /* we need to do that to handle the case where a signal
+               occurs while doing tb_phys_invalidate() */
+            saved_tb = NULL;
+            if (env) {
+                saved_tb = env->current_tb;
+                env->current_tb = NULL;
+            }
+            tb_phys_invalidate(tb, -1);
+            if (env) {
+                env->current_tb = saved_tb;
+                if (env->interrupt_request && env->current_tb) {
+                    cpu_interrupt(env, env->interrupt_request);
+                }
+            }
+        }
+        tb = tb_next;
+    }
+#if !defined(CONFIG_USER_ONLY)
+    /* if no code remaining, no need to continue to use slow writes */
+    if (!p->first_tb) {
+        invalidate_page_bitmap(p);
+        if (is_cpu_write_access) {
+            tlb_unprotect_code_phys(env, start, env->mem_io_vaddr);
+        }
+    }
+#endif
+#ifdef TARGET_HAS_PRECISE_SMC
+    if (current_tb_modified) {
+        /* we generate a block containing just the instruction
+           modifying the memory. It will ensure that it cannot modify
+           itself */
+        env->current_tb = NULL;
+        tb_gen_code(env, current_pc, current_cs_base, current_flags, 1);
+        cpu_resume_from_signal(env, NULL);
+    }
+#endif
+}
+
+/* len must be <= 8 and start must be a multiple of len */
+void tb_invalidate_phys_page_fast(tb_page_addr_t start, int len)
+{
+    PageDesc *p;
+    int offset, b;
+
+#if 0
+    if (1) {
+        qemu_log("modifying code at 0x%x size=%d EIP=%x PC=%08x\n",
+                  cpu_single_env->mem_io_vaddr, len,
+                  cpu_single_env->eip,
+                  cpu_single_env->eip +
+                  (intptr_t)cpu_single_env->segs[R_CS].base);
+    }
+#endif
+    p = page_find(start >> TARGET_PAGE_BITS);
+    if (!p) {
+        return;
+    }
+    if (p->code_bitmap) {
+        offset = start & ~TARGET_PAGE_MASK;
+        b = p->code_bitmap[offset >> 3] >> (offset & 7);
+        if (b & ((1 << len) - 1)) {
+            goto do_invalidate;
+        }
+    } else {
+    do_invalidate:
+        tb_invalidate_phys_page_range(start, start + len, 1);
+    }
+}
+
+#if !defined(CONFIG_SOFTMMU)
+static void tb_invalidate_phys_page(tb_page_addr_t addr,
+                                    uintptr_t pc, void *puc)
+{
+    TranslationBlock *tb;
+    PageDesc *p;
+    int n;
+#ifdef TARGET_HAS_PRECISE_SMC
+    TranslationBlock *current_tb = NULL;
+    CPUArchState *env = cpu_single_env;
+    int current_tb_modified = 0;
+    target_ulong current_pc = 0;
+    target_ulong current_cs_base = 0;
+    int current_flags = 0;
+#endif
+
+    addr &= TARGET_PAGE_MASK;
+    p = page_find(addr >> TARGET_PAGE_BITS);
+    if (!p) {
+        return;
+    }
+    tb = p->first_tb;
+#ifdef TARGET_HAS_PRECISE_SMC
+    if (tb && pc != 0) {
+        current_tb = tb_find_pc(pc);
+    }
+#endif
+    while (tb != NULL) {
+        n = (uintptr_t)tb & 3;
+        tb = (TranslationBlock *)((uintptr_t)tb & ~3);
+#ifdef TARGET_HAS_PRECISE_SMC
+        if (current_tb == tb &&
+            (current_tb->cflags & CF_COUNT_MASK) != 1) {
+                /* If we are modifying the current TB, we must stop
+                   its execution. We could be more precise by checking
+                   that the modification is after the current PC, but it
+                   would require a specialized function to partially
+                   restore the CPU state */
+
+            current_tb_modified = 1;
+            cpu_restore_state(current_tb, env, pc);
+            cpu_get_tb_cpu_state(env, &current_pc, &current_cs_base,
+                                 &current_flags);
+        }
+#endif /* TARGET_HAS_PRECISE_SMC */
+        tb_phys_invalidate(tb, addr);
+        tb = tb->page_next[n];
+    }
+    p->first_tb = NULL;
+#ifdef TARGET_HAS_PRECISE_SMC
+    if (current_tb_modified) {
+        /* we generate a block containing just the instruction
+           modifying the memory. It will ensure that it cannot modify
+           itself */
+        env->current_tb = NULL;
+        tb_gen_code(env, current_pc, current_cs_base, current_flags, 1);
+        cpu_resume_from_signal(env, puc);
+    }
+#endif
+}
+#endif
+
+/* add the tb in the target page and protect it if necessary */
+static inline void tb_alloc_page(TranslationBlock *tb,
+                                 unsigned int n, tb_page_addr_t page_addr)
+{
+    PageDesc *p;
+#ifndef CONFIG_USER_ONLY
+    bool page_already_protected;
+#endif
+
+    tb->page_addr[n] = page_addr;
+    p = page_find_alloc(page_addr >> TARGET_PAGE_BITS, 1);
+    tb->page_next[n] = p->first_tb;
+#ifndef CONFIG_USER_ONLY
+    page_already_protected = p->first_tb != NULL;
+#endif
+    p->first_tb = (TranslationBlock *)((uintptr_t)tb | n);
+    invalidate_page_bitmap(p);
+
+#if defined(TARGET_HAS_SMC) || 1
+
+#if defined(CONFIG_USER_ONLY)
+    if (p->flags & PAGE_WRITE) {
+        target_ulong addr;
+        PageDesc *p2;
+        int prot;
+
+        /* force the host page as non writable (writes will have a
+           page fault + mprotect overhead) */
+        page_addr &= qemu_host_page_mask;
+        prot = 0;
+        for (addr = page_addr; addr < page_addr + qemu_host_page_size;
+            addr += TARGET_PAGE_SIZE) {
+
+            p2 = page_find(addr >> TARGET_PAGE_BITS);
+            if (!p2) {
+                continue;
+            }
+            prot |= p2->flags;
+            p2->flags &= ~PAGE_WRITE;
+          }
+        mprotect(g2h(page_addr), qemu_host_page_size,
+                 (prot & PAGE_BITS) & ~PAGE_WRITE);
+#ifdef DEBUG_TB_INVALIDATE
+        printf("protecting code page: 0x" TARGET_FMT_lx "\n",
+               page_addr);
+#endif
+    }
+#else
+    /* if some code is already present, then the pages are already
+       protected. So we handle the case where only the first TB is
+       allocated in a physical page */
+    if (!page_already_protected) {
+        tlb_protect_code(page_addr);
+    }
+#endif
+
+#endif /* TARGET_HAS_SMC */
+}
+
+/* add a new TB and link it to the physical page tables. phys_page2 is
+   (-1) to indicate that only one page contains the TB. */
+static void tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc,
+                         tb_page_addr_t phys_page2)
+{
+    unsigned int h;
+    TranslationBlock **ptb;
+
+    /* Grab the mmap lock to stop another thread invalidating this TB
+       before we are done.  */
+    mmap_lock();
+    /* add in the physical hash table */
+    h = tb_phys_hash_func(phys_pc);
+    ptb = &tb_phys_hash[h];
+    tb->phys_hash_next = *ptb;
+    *ptb = tb;
+
+    /* add in the page list */
+    tb_alloc_page(tb, 0, phys_pc & TARGET_PAGE_MASK);
+    if (phys_page2 != -1) {
+        tb_alloc_page(tb, 1, phys_page2);
+    } else {
+        tb->page_addr[1] = -1;
+    }
+
+    tb->jmp_first = (TranslationBlock *)((uintptr_t)tb | 2);
+    tb->jmp_next[0] = NULL;
+    tb->jmp_next[1] = NULL;
+
+    /* init original jump addresses */
+    if (tb->tb_next_offset[0] != 0xffff) {
+        tb_reset_jump(tb, 0);
+    }
+    if (tb->tb_next_offset[1] != 0xffff) {
+        tb_reset_jump(tb, 1);
+    }
+
+#ifdef DEBUG_TB_CHECK
+    tb_page_check();
+#endif
+    mmap_unlock();
+}
+
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+/* check whether the given addr is in TCG generated code buffer or not */
+bool is_tcg_gen_code(uintptr_t tc_ptr)
+{
+    /* This can be called during code generation, code_gen_buffer_max_size
+       is used instead of code_gen_ptr for upper boundary checking */
+    return (tc_ptr >= (uintptr_t)code_gen_buffer &&
+            tc_ptr < (uintptr_t)(code_gen_buffer + code_gen_buffer_max_size));
+}
+#endif
+
+/* find the TB 'tb' such that tb[0].tc_ptr <= tc_ptr <
+   tb[1].tc_ptr. Return NULL if not found */
+TranslationBlock *tb_find_pc(uintptr_t tc_ptr)
+{
+    int m_min, m_max, m;
+    uintptr_t v;
+    TranslationBlock *tb;
+
+    if (nb_tbs <= 0) {
+        return NULL;
+    }
+    if (tc_ptr < (uintptr_t)code_gen_buffer ||
+        tc_ptr >= (uintptr_t)code_gen_ptr) {
+        return NULL;
+    }
+    /* binary search (cf Knuth) */
+    m_min = 0;
+    m_max = nb_tbs - 1;
+    while (m_min <= m_max) {
+        m = (m_min + m_max) >> 1;
+        tb = &tbs[m];
+        v = (uintptr_t)tb->tc_ptr;
+        if (v == tc_ptr) {
+            return tb;
+        } else if (tc_ptr < v) {
+            m_max = m - 1;
+        } else {
+            m_min = m + 1;
+        }
+    }
+    return &tbs[m_max];
+}
+
+static void tb_reset_jump_recursive(TranslationBlock *tb);
+
+static inline void tb_reset_jump_recursive2(TranslationBlock *tb, int n)
+{
+    TranslationBlock *tb1, *tb_next, **ptb;
+    unsigned int n1;
+
+    tb1 = tb->jmp_next[n];
+    if (tb1 != NULL) {
+        /* find head of list */
+        for (;;) {
+            n1 = (uintptr_t)tb1 & 3;
+            tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
+            if (n1 == 2) {
+                break;
+            }
+            tb1 = tb1->jmp_next[n1];
+        }
+        /* we are now sure now that tb jumps to tb1 */
+        tb_next = tb1;
+
+        /* remove tb from the jmp_first list */
+        ptb = &tb_next->jmp_first;
+        for (;;) {
+            tb1 = *ptb;
+            n1 = (uintptr_t)tb1 & 3;
+            tb1 = (TranslationBlock *)((uintptr_t)tb1 & ~3);
+            if (n1 == n && tb1 == tb) {
+                break;
+            }
+            ptb = &tb1->jmp_next[n1];
+        }
+        *ptb = tb->jmp_next[n];
+        tb->jmp_next[n] = NULL;
+
+        /* suppress the jump to next tb in generated code */
+        tb_reset_jump(tb, n);
+
+        /* suppress jumps in the tb on which we could have jumped */
+        tb_reset_jump_recursive(tb_next);
+    }
+}
+
+static void tb_reset_jump_recursive(TranslationBlock *tb)
+{
+    tb_reset_jump_recursive2(tb, 0);
+    tb_reset_jump_recursive2(tb, 1);
+}
+
+#if defined(TARGET_HAS_ICE) && !defined(CONFIG_USER_ONLY)
+void tb_invalidate_phys_addr(hwaddr addr)
+{
+    ram_addr_t ram_addr;
+    MemoryRegionSection *section;
+
+    section = phys_page_find(address_space_memory.dispatch,
+                             addr >> TARGET_PAGE_BITS);
+    if (!(memory_region_is_ram(section->mr)
+          || (section->mr->rom_device && section->mr->readable))) {
+        return;
+    }
+    ram_addr = (memory_region_get_ram_addr(section->mr) & TARGET_PAGE_MASK)
+        + memory_region_section_addr(section, addr);
+    tb_invalidate_phys_page_range(ram_addr, ram_addr + 1, 0);
+}
+#endif /* TARGET_HAS_ICE && !defined(CONFIG_USER_ONLY) */
+
+void cpu_unlink_tb(CPUArchState *env)
+{
+    /* FIXME: TB unchaining isn't SMP safe.  For now just ignore the
+       problem and hope the cpu will stop of its own accord.  For userspace
+       emulation this often isn't actually as bad as it sounds.  Often
+       signals are used primarily to interrupt blocking syscalls.  */
+    TranslationBlock *tb;
+    static spinlock_t interrupt_lock = SPIN_LOCK_UNLOCKED;
+
+    spin_lock(&interrupt_lock);
+    tb = env->current_tb;
+    /* if the cpu is currently executing code, we must unlink it and
+       all the potentially executing TB */
+    if (tb) {
+        env->current_tb = NULL;
+        tb_reset_jump_recursive(tb);
+    }
+    spin_unlock(&interrupt_lock);
+}
+
+void tb_check_watchpoint(CPUArchState *env)
+{
+    TranslationBlock *tb;
+
+    tb = tb_find_pc(env->mem_io_pc);
+    if (!tb) {
+        cpu_abort(env, "check_watchpoint: could not find TB for pc=%p",
+                  (void *)env->mem_io_pc);
+    }
+    cpu_restore_state(tb, env, env->mem_io_pc);
+    tb_phys_invalidate(tb, -1);
+}
+
+#ifndef CONFIG_USER_ONLY
+/* mask must never be zero, except for A20 change call */
+static void tcg_handle_interrupt(CPUArchState *env, int mask)
+{
+    CPUState *cpu = ENV_GET_CPU(env);
+    int old_mask;
+
+    old_mask = env->interrupt_request;
+    env->interrupt_request |= mask;
+
+    /*
+     * If called from iothread context, wake the target cpu in
+     * case its halted.
+     */
+    if (!qemu_cpu_is_self(cpu)) {
+        qemu_cpu_kick(cpu);
+        return;
+    }
+
+    if (use_icount) {
+        env->icount_decr.u16.high = 0xffff;
+        if (!can_do_io(env)
+            && (mask & ~old_mask) != 0) {
+            cpu_abort(env, "Raised interrupt while not in I/O function");
+        }
+    } else {
+        cpu_unlink_tb(env);
+    }
+}
+
+CPUInterruptHandler cpu_interrupt_handler = tcg_handle_interrupt;
+
+/* in deterministic execution mode, instructions doing device I/Os
+   must be at the end of the TB */
+void cpu_io_recompile(CPUArchState *env, uintptr_t retaddr)
+{
+    TranslationBlock *tb;
+    uint32_t n, cflags;
+    target_ulong pc, cs_base;
+    uint64_t flags;
+
+    tb = tb_find_pc(retaddr);
+    if (!tb) {
+        cpu_abort(env, "cpu_io_recompile: could not find TB for pc=%p",
+                  (void *)retaddr);
+    }
+    n = env->icount_decr.u16.low + tb->icount;
+    cpu_restore_state(tb, env, retaddr);
+    /* Calculate how many instructions had been executed before the fault
+       occurred.  */
+    n = n - env->icount_decr.u16.low;
+    /* Generate a new TB ending on the I/O insn.  */
+    n++;
+    /* On MIPS and SH, delay slot instructions can only be restarted if
+       they were already the first instruction in the TB.  If this is not
+       the first instruction in a TB then re-execute the preceding
+       branch.  */
+#if defined(TARGET_MIPS)
+    if ((env->hflags & MIPS_HFLAG_BMASK) != 0 && n > 1) {
+        env->active_tc.PC -= 4;
+        env->icount_decr.u16.low++;
+        env->hflags &= ~MIPS_HFLAG_BMASK;
+    }
+#elif defined(TARGET_SH4)
+    if ((env->flags & ((DELAY_SLOT | DELAY_SLOT_CONDITIONAL))) != 0
+            && n > 1) {
+        env->pc -= 2;
+        env->icount_decr.u16.low++;
+        env->flags &= ~(DELAY_SLOT | DELAY_SLOT_CONDITIONAL);
+    }
+#endif
+    /* This should never happen.  */
+    if (n > CF_COUNT_MASK) {
+        cpu_abort(env, "TB too big during recompile");
+    }
+
+    cflags = n | CF_LAST_IO;
+    pc = tb->pc;
+    cs_base = tb->cs_base;
+    flags = tb->flags;
+    tb_phys_invalidate(tb, -1);
+    /* FIXME: In theory this could raise an exception.  In practice
+       we have already translated the block once so it's probably ok.  */
+    tb_gen_code(env, pc, cs_base, flags, cflags);
+    /* TODO: If env->pc != tb->pc (i.e. the faulting instruction was not
+       the first in the TB) then we end up generating a whole new TB and
+       repeating the fault, which is horribly inefficient.
+       Better would be to execute just this insn uncached, or generate a
+       second new TB.  */
+    cpu_resume_from_signal(env, NULL);
+}
+
+void tb_flush_jmp_cache(CPUArchState *env, target_ulong addr)
+{
+    unsigned int i;
+
+    /* Discard jump cache entries for any tb which might potentially
+       overlap the flushed page.  */
+    i = tb_jmp_cache_hash_page(addr - TARGET_PAGE_SIZE);
+    memset(&env->tb_jmp_cache[i], 0,
+           TB_JMP_PAGE_SIZE * sizeof(TranslationBlock *));
+
+    i = tb_jmp_cache_hash_page(addr);
+    memset(&env->tb_jmp_cache[i], 0,
+           TB_JMP_PAGE_SIZE * sizeof(TranslationBlock *));
+}
+
+void dump_exec_info(FILE *f, fprintf_function cpu_fprintf)
+{
+    int i, target_code_size, max_target_code_size;
+    int direct_jmp_count, direct_jmp2_count, cross_page;
+    TranslationBlock *tb;
+
+    target_code_size = 0;
+    max_target_code_size = 0;
+    cross_page = 0;
+    direct_jmp_count = 0;
+    direct_jmp2_count = 0;
+    for (i = 0; i < nb_tbs; i++) {
+        tb = &tbs[i];
+        target_code_size += tb->size;
+        if (tb->size > max_target_code_size) {
+            max_target_code_size = tb->size;
+        }
+        if (tb->page_addr[1] != -1) {
+            cross_page++;
+        }
+        if (tb->tb_next_offset[0] != 0xffff) {
+            direct_jmp_count++;
+            if (tb->tb_next_offset[1] != 0xffff) {
+                direct_jmp2_count++;
+            }
+        }
+    }
+    /* XXX: avoid using doubles ? */
+    cpu_fprintf(f, "Translation buffer state:\n");
+    cpu_fprintf(f, "gen code size       %td/%zd\n",
+                code_gen_ptr - code_gen_buffer, code_gen_buffer_max_size);
+    cpu_fprintf(f, "TB count            %d/%d\n",
+                nb_tbs, code_gen_max_blocks);
+    cpu_fprintf(f, "TB avg target size  %d max=%d bytes\n",
+                nb_tbs ? target_code_size / nb_tbs : 0,
+                max_target_code_size);
+    cpu_fprintf(f, "TB avg host size    %td bytes (expansion ratio: %0.1f)\n",
+                nb_tbs ? (code_gen_ptr - code_gen_buffer) / nb_tbs : 0,
+                target_code_size ? (double) (code_gen_ptr - code_gen_buffer)
+                / target_code_size : 0);
+    cpu_fprintf(f, "cross page TB count %d (%d%%)\n",
+            cross_page,
+            nb_tbs ? (cross_page * 100) / nb_tbs : 0);
+    cpu_fprintf(f, "direct jump count   %d (%d%%) (2 jumps=%d %d%%)\n",
+                direct_jmp_count,
+                nb_tbs ? (direct_jmp_count * 100) / nb_tbs : 0,
+                direct_jmp2_count,
+                nb_tbs ? (direct_jmp2_count * 100) / nb_tbs : 0);
+    cpu_fprintf(f, "\nStatistics:\n");
+    cpu_fprintf(f, "TB flush count      %d\n", tb_flush_count);
+    cpu_fprintf(f, "TB invalidate count %d\n", tb_phys_invalidate_count);
+    cpu_fprintf(f, "TLB flush count     %d\n", tlb_flush_count);
+    tcg_dump_info(f, cpu_fprintf);
+}
+
+#else /* CONFIG_USER_ONLY */
+
+void cpu_interrupt(CPUArchState *env, int mask)
+{
+    env->interrupt_request |= mask;
+    cpu_unlink_tb(env);
+}
+
+/*
+ * Walks guest process memory "regions" one by one
+ * and calls callback function 'fn' for each region.
+ */
+struct walk_memory_regions_data {
+    walk_memory_regions_fn fn;
+    void *priv;
+    uintptr_t start;
+    int prot;
+};
+
+static int walk_memory_regions_end(struct walk_memory_regions_data *data,
+                                   abi_ulong end, int new_prot)
+{
+    if (data->start != -1ul) {
+        int rc = data->fn(data->priv, data->start, end, data->prot);
+        if (rc != 0) {
+            return rc;
+        }
+    }
+
+    data->start = (new_prot ? end : -1ul);
+    data->prot = new_prot;
+
+    return 0;
+}
+
+static int walk_memory_regions_1(struct walk_memory_regions_data *data,
+                                 abi_ulong base, int level, void **lp)
+{
+    abi_ulong pa;
+    int i, rc;
+
+    if (*lp == NULL) {
+        return walk_memory_regions_end(data, base, 0);
+    }
+
+    if (level == 0) {
+        PageDesc *pd = *lp;
+
+        for (i = 0; i < L2_SIZE; ++i) {
+            int prot = pd[i].flags;
+
+            pa = base | (i << TARGET_PAGE_BITS);
+            if (prot != data->prot) {
+                rc = walk_memory_regions_end(data, pa, prot);
+                if (rc != 0) {
+                    return rc;
+                }
+            }
+        }
+    } else {
+        void **pp = *lp;
+
+        for (i = 0; i < L2_SIZE; ++i) {
+            pa = base | ((abi_ulong)i <<
+                (TARGET_PAGE_BITS + L2_BITS * level));
+            rc = walk_memory_regions_1(data, pa, level - 1, pp + i);
+            if (rc != 0) {
+                return rc;
+            }
+        }
+    }
+
+    return 0;
+}
+
+int walk_memory_regions(void *priv, walk_memory_regions_fn fn)
+{
+    struct walk_memory_regions_data data;
+    uintptr_t i;
+
+    data.fn = fn;
+    data.priv = priv;
+    data.start = -1ul;
+    data.prot = 0;
+
+    for (i = 0; i < V_L1_SIZE; i++) {
+        int rc = walk_memory_regions_1(&data, (abi_ulong)i << V_L1_SHIFT,
+                                       V_L1_SHIFT / L2_BITS - 1, l1_map + i);
+
+        if (rc != 0) {
+            return rc;
+        }
+    }
+
+    return walk_memory_regions_end(&data, 0, 0);
+}
+
+static int dump_region(void *priv, abi_ulong start,
+    abi_ulong end, unsigned long prot)
+{
+    FILE *f = (FILE *)priv;
+
+    (void) fprintf(f, TARGET_ABI_FMT_lx"-"TARGET_ABI_FMT_lx
+        " "TARGET_ABI_FMT_lx" %c%c%c\n",
+        start, end, end - start,
+        ((prot & PAGE_READ) ? 'r' : '-'),
+        ((prot & PAGE_WRITE) ? 'w' : '-'),
+        ((prot & PAGE_EXEC) ? 'x' : '-'));
+
+    return 0;
+}
+
+/* dump memory mappings */
+void page_dump(FILE *f)
+{
+    (void) fprintf(f, "%-8s %-8s %-8s %s\n",
+            "start", "end", "size", "prot");
+    walk_memory_regions(f, dump_region);
+}
+
+int page_get_flags(target_ulong address)
+{
+    PageDesc *p;
+
+    p = page_find(address >> TARGET_PAGE_BITS);
+    if (!p) {
+        return 0;
+    }
+    return p->flags;
+}
+
+/* Modify the flags of a page and invalidate the code if necessary.
+   The flag PAGE_WRITE_ORG is positioned automatically depending
+   on PAGE_WRITE.  The mmap_lock should already be held.  */
+void page_set_flags(target_ulong start, target_ulong end, int flags)
+{
+    target_ulong addr, len;
+
+    /* This function should never be called with addresses outside the
+       guest address space.  If this assert fires, it probably indicates
+       a missing call to h2g_valid.  */
+#if TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS
+    assert(end < ((abi_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
+#endif
+    assert(start < end);
+
+    start = start & TARGET_PAGE_MASK;
+    end = TARGET_PAGE_ALIGN(end);
+
+    if (flags & PAGE_WRITE) {
+        flags |= PAGE_WRITE_ORG;
+    }
+
+    for (addr = start, len = end - start;
+         len != 0;
+         len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
+        PageDesc *p = page_find_alloc(addr >> TARGET_PAGE_BITS, 1);
+
+        /* If the write protection bit is set, then we invalidate
+           the code inside.  */
+        if (!(p->flags & PAGE_WRITE) &&
+            (flags & PAGE_WRITE) &&
+            p->first_tb) {
+            tb_invalidate_phys_page(addr, 0, NULL);
+        }
+        p->flags = flags;
+    }
+}
+
+int page_check_range(target_ulong start, target_ulong len, int flags)
+{
+    PageDesc *p;
+    target_ulong end;
+    target_ulong addr;
+
+    /* This function should never be called with addresses outside the
+       guest address space.  If this assert fires, it probably indicates
+       a missing call to h2g_valid.  */
+#if TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS
+    assert(start < ((abi_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
+#endif
+
+    if (len == 0) {
+        return 0;
+    }
+    if (start + len - 1 < start) {
+        /* We've wrapped around.  */
+        return -1;
+    }
+
+    /* must do before we loose bits in the next step */
+    end = TARGET_PAGE_ALIGN(start + len);
+    start = start & TARGET_PAGE_MASK;
+
+    for (addr = start, len = end - start;
+         len != 0;
+         len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
+        p = page_find(addr >> TARGET_PAGE_BITS);
+        if (!p) {
+            return -1;
+        }
+        if (!(p->flags & PAGE_VALID)) {
+            return -1;
+        }
+
+        if ((flags & PAGE_READ) && !(p->flags & PAGE_READ)) {
+            return -1;
+        }
+        if (flags & PAGE_WRITE) {
+            if (!(p->flags & PAGE_WRITE_ORG)) {
+                return -1;
+            }
+            /* unprotect the page if it was put read-only because it
+               contains translated code */
+            if (!(p->flags & PAGE_WRITE)) {
+                if (!page_unprotect(addr, 0, NULL)) {
+                    return -1;
+                }
+            }
+            return 0;
+        }
+    }
+    return 0;
+}
+
+/* called from signal handler: invalidate the code and unprotect the
+   page. Return TRUE if the fault was successfully handled. */
+int page_unprotect(target_ulong address, uintptr_t pc, void *puc)
+{
+    unsigned int prot;
+    PageDesc *p;
+    target_ulong host_start, host_end, addr;
+
+    /* Technically this isn't safe inside a signal handler.  However we
+       know this only ever happens in a synchronous SEGV handler, so in
+       practice it seems to be ok.  */
+    mmap_lock();
+
+    p = page_find(address >> TARGET_PAGE_BITS);
+    if (!p) {
+        mmap_unlock();
+        return 0;
+    }
+
+    /* if the page was really writable, then we change its
+       protection back to writable */
+    if ((p->flags & PAGE_WRITE_ORG) && !(p->flags & PAGE_WRITE)) {
+        host_start = address & qemu_host_page_mask;
+        host_end = host_start + qemu_host_page_size;
+
+        prot = 0;
+        for (addr = host_start ; addr < host_end ; addr += TARGET_PAGE_SIZE) {
+            p = page_find(addr >> TARGET_PAGE_BITS);
+            p->flags |= PAGE_WRITE;
+            prot |= p->flags;
+
+            /* and since the content will be modified, we must invalidate
+               the corresponding translated code. */
+            tb_invalidate_phys_page(addr, pc, puc);
+#ifdef DEBUG_TB_CHECK
+            tb_invalidate_check(addr);
+#endif
+        }
+        mprotect((void *)g2h(host_start), qemu_host_page_size,
+                 prot & PAGE_BITS);
+
+        mmap_unlock();
+        return 1;
+    }
+    mmap_unlock();
+    return 0;
+}
+#endif /* CONFIG_USER_ONLY */