cputlb.c

/*
 *  Common CPU TLB 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 "qemu/osdep.h"
#include "qemu/main-loop.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/memory.h"
#include "exec/address-spaces.h"
#include "exec/cpu_ldst.h"
#include "exec/cputlb.h"
#include "exec/memory-internal.h"
#include "exec/ram_addr.h"
#include "tcg/tcg.h"
#include "qemu/error-report.h"
#include "exec/log.h"
#include "exec/helper-proto.h"
#include "qemu/atomic.h"

/* DEBUG defines, enable DEBUG_TLB_LOG to log to the CPU_LOG_MMU target */
/* #define DEBUG_TLB */
/* #define DEBUG_TLB_LOG */

#ifdef DEBUG_TLB
# define DEBUG_TLB_GATE 1
# ifdef DEBUG_TLB_LOG
#  define DEBUG_TLB_LOG_GATE 1
# else
#  define DEBUG_TLB_LOG_GATE 0
# endif
#else
# define DEBUG_TLB_GATE 0
# define DEBUG_TLB_LOG_GATE 0
#endif

#define tlb_debug(fmt, ...) do { \
    if (DEBUG_TLB_LOG_GATE) { \
        qemu_log_mask(CPU_LOG_MMU, "%s: " fmt, __func__, \
                      ## __VA_ARGS__); \
    } else if (DEBUG_TLB_GATE) { \
        fprintf(stderr, "%s: " fmt, __func__, ## __VA_ARGS__); \
    } \
} while (0)

#define assert_cpu_is_self(this_cpu) do {                         \
        if (DEBUG_TLB_GATE) {                                     \
            g_assert(!cpu->created || qemu_cpu_is_self(cpu));     \
        }                                                         \
    } while (0)

/* run_on_cpu_data.target_ptr should always be big enough for a
 * target_ulong even on 32 bit builds */
QEMU_BUILD_BUG_ON(sizeof(target_ulong) > sizeof(run_on_cpu_data));

/* We currently can't handle more than 16 bits in the MMUIDX bitmask.
 */
QEMU_BUILD_BUG_ON(NB_MMU_MODES > 16);
#define ALL_MMUIDX_BITS ((1 << NB_MMU_MODES) - 1)

/* flush_all_helper: run fn across all cpus
 *
 * If the wait flag is set then the src cpu's helper will be queued as
 * "safe" work and the loop exited creating a synchronisation point
 * where all queued work will be finished before execution starts
 * again.
 */
static void flush_all_helper(CPUState *src, bool wait,
                             run_on_cpu_func fn, run_on_cpu_data d)
{
    CPUState *cpu;

    if (!wait) {
        CPU_FOREACH(cpu) {
            if (cpu != src) {
                async_run_on_cpu(cpu, fn, d);
            } else {
                g_assert(qemu_cpu_is_self(src));
                fn(src, d);
            }
        }
    } else {
        CPU_FOREACH(cpu) {
            if (cpu != src) {
                async_run_on_cpu(cpu, fn, d);
            } else {
                async_safe_run_on_cpu(cpu, fn, d);
            }

        }
        cpu_loop_exit(src);
    }
}

/* statistics */
int tlb_flush_count;

static void tlb_flush_nocheck(CPUState *cpu, int flush_global)
{
    CPUArchState *env = cpu->env_ptr;

    /* The QOM tests will trigger tlb_flushes without setting up TCG
     * so we bug out here in that case.
     */
    if (!tcg_enabled()) {
        return;
    }

    assert_cpu_is_self(cpu);
    tlb_debug("(%d)\n", flush_global);

    tb_lock();

    memset(env->tlb_table, -1, sizeof(env->tlb_table));
    memset(env->tlb_v_table, -1, sizeof(env->tlb_v_table));
    memset(cpu->tb_jmp_cache, 0, sizeof(cpu->tb_jmp_cache));

    env->vtlb_index = 0;
    env->tlb_flush_addr = -1;
    env->tlb_flush_mask = 0;
    tlb_flush_count++;

    tb_unlock();

    atomic_mb_set(&cpu->pending_tlb_flush, 0);
}

static void tlb_flush_global_async_work(CPUState *cpu, run_on_cpu_data data)
{
    tlb_flush_nocheck(cpu, data.host_int);
}

/* NOTE:
 * If flush_global is true (the usual case), flush all tlb entries.
 * If flush_global is false, flush (at least) all tlb entries not
 * marked global.
 *
 * Since QEMU doesn't currently implement a global/not-global flag
 * for tlb entries, at the moment tlb_flush() will also flush all
 * tlb entries in the flush_global == false case. This is OK because
 * CPU architectures generally permit an implementation to drop
 * entries from the TLB at any time, so flushing more entries than
 * required is only an efficiency issue, not a correctness issue.
 */
void tlb_flush(CPUState *cpu, int flush_global)
{
    if (cpu->created && !qemu_cpu_is_self(cpu)) {
        if (atomic_mb_read(&cpu->pending_tlb_flush) != ALL_MMUIDX_BITS) {
            atomic_mb_set(&cpu->pending_tlb_flush, ALL_MMUIDX_BITS);
            async_run_on_cpu(cpu, tlb_flush_global_async_work,
                             RUN_ON_CPU_HOST_INT(flush_global));
        }
    } else {
        tlb_flush_nocheck(cpu, flush_global);
    }
}

void tlb_flush_all_cpus(CPUState *src_cpu, bool wait)
{
    flush_all_helper(src_cpu, wait, tlb_flush_global_async_work, RUN_ON_CPU_NULL);
}

static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
{
    CPUArchState *env = cpu->env_ptr;
    unsigned long mmu_idx_bitmask = data.host_ulong;
    int mmu_idx;

    assert_cpu_is_self(cpu);

    tb_lock();

    tlb_debug("start: mmu_idx:0x%04lx\n", mmu_idx_bitmask);

    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {

        if (test_bit(mmu_idx, &mmu_idx_bitmask)) {
            tlb_debug("%d\n", mmu_idx);

            memset(env->tlb_table[mmu_idx], -1, sizeof(env->tlb_table[0]));
            memset(env->tlb_v_table[mmu_idx], -1, sizeof(env->tlb_v_table[0]));
        }
    }

    memset(cpu->tb_jmp_cache, 0, sizeof(cpu->tb_jmp_cache));

    tlb_debug("done\n");

    tb_unlock();
}

/* Helper function to slurp va_args list into a bitmap
 */
static inline unsigned long make_mmu_index_bitmap(va_list args)
{
    unsigned long bitmap = 0;
    int mmu_index = va_arg(args, int);

    /* An empty va_list would be a bad call */
    g_assert(mmu_index > 0);

    do {
        set_bit(mmu_index, &bitmap);
        mmu_index = va_arg(args, int);
    } while (mmu_index >= 0);

    return bitmap;
}

void tlb_flush_by_mmuidx(CPUState *cpu, ...)
{
    va_list argp;
    unsigned long mmu_idx_bitmap;

    va_start(argp, cpu);
    mmu_idx_bitmap = make_mmu_index_bitmap(argp);
    va_end(argp);

    tlb_debug("mmu_idx: 0x%04lx\n", mmu_idx_bitmap);

    if (!qemu_cpu_is_self(cpu)) {
        uint16_t pending_flushes =
            mmu_idx_bitmap & ~atomic_mb_read(&cpu->pending_tlb_flush);
        if (pending_flushes) {
            tlb_debug("reduced mmu_idx: 0x%" PRIx16 "\n", pending_flushes);

            atomic_or(&cpu->pending_tlb_flush, pending_flushes);
            async_run_on_cpu(cpu, tlb_flush_by_mmuidx_async_work,
                             RUN_ON_CPU_HOST_INT(pending_flushes));
        }
    } else {
        tlb_flush_by_mmuidx_async_work(cpu,
                                       RUN_ON_CPU_HOST_ULONG(mmu_idx_bitmap));
    }
}

/* This function affects all vCPUs are will ensure all work is
 * complete by the time the loop restarts
 */
void tlb_flush_by_mmuidx_all_cpus(CPUState *src_cpu, bool wait, ...)
{
    va_list argp;
    unsigned long mmu_idx_bitmap;

    va_start(argp, wait);
    mmu_idx_bitmap = make_mmu_index_bitmap(argp);
    va_end(argp);

    tlb_debug("mmu_idx: 0x%04lx\n", mmu_idx_bitmap);

    flush_all_helper(src_cpu, wait,
                     tlb_flush_by_mmuidx_async_work,
                     RUN_ON_CPU_HOST_ULONG(mmu_idx_bitmap));

    /* Will not return if wait == true */
    g_assert(!wait);
}


static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong addr)
{
    if (addr == (tlb_entry->addr_read &
                 (TARGET_PAGE_MASK | TLB_INVALID_MASK)) ||
        addr == (tlb_entry->addr_write &
                 (TARGET_PAGE_MASK | TLB_INVALID_MASK)) ||
        addr == (tlb_entry->addr_code &
                 (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
        memset(tlb_entry, -1, sizeof(*tlb_entry));
    }
}

static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data)
{
    CPUArchState *env = cpu->env_ptr;
    target_ulong addr = (target_ulong) data.target_ptr;
    int i;
    int mmu_idx;

    assert_cpu_is_self(cpu);

    tlb_debug("page :" TARGET_FMT_lx "\n", addr);

    /* Check if we need to flush due to large pages.  */
    if ((addr & env->tlb_flush_mask) == env->tlb_flush_addr) {
        tlb_debug("forcing full flush ("
                  TARGET_FMT_lx "/" TARGET_FMT_lx ")\n",
                  env->tlb_flush_addr, env->tlb_flush_mask);

        tlb_flush(cpu, 1);
        return;
    }

    addr &= TARGET_PAGE_MASK;
    i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr);
    }

    /* check whether there are entries that need to be flushed in the vtlb */
    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        int k;
        for (k = 0; k < CPU_VTLB_SIZE; k++) {
            tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], addr);
        }
    }

    tb_flush_jmp_cache(cpu, addr);
}

void tlb_flush_page(CPUState *cpu, target_ulong addr)
{
    tlb_debug("page :" TARGET_FMT_lx "\n", addr);

    if (!qemu_cpu_is_self(cpu)) {
        async_run_on_cpu(cpu, tlb_flush_page_async_work,
                         RUN_ON_CPU_TARGET_PTR(addr));
    } else {
        tlb_flush_page_async_work(cpu, RUN_ON_CPU_TARGET_PTR(addr));
    }
}

/* As we are going to hijack the bottom bits of the page address for a
 * mmuidx bit mask we need to fail to build if we can't do that
 */
QEMU_BUILD_BUG_ON(NB_MMU_MODES > TARGET_PAGE_BITS_MIN);

static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu,
                                                run_on_cpu_data data)
{
    CPUArchState *env = cpu->env_ptr;
    target_ulong addr_and_mmuidx = (target_ulong) data.target_ptr;
    target_ulong addr = addr_and_mmuidx & TARGET_PAGE_MASK;
    unsigned long mmu_idx_bitmap = addr_and_mmuidx & ALL_MMUIDX_BITS;
    int page = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    int mmu_idx;
    int i;

    assert_cpu_is_self(cpu);

    tlb_debug("page:%d addr:"TARGET_FMT_lx" mmu_idx:0x%lx\n",
              page, addr, mmu_idx_bitmap);

    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        if (test_bit(mmu_idx, &mmu_idx_bitmap)) {
            tlb_flush_entry(&env->tlb_table[mmu_idx][page], addr);

            /* check whether there are vltb entries that need to be flushed */
            for (i = 0; i < CPU_VTLB_SIZE; i++) {
                tlb_flush_entry(&env->tlb_v_table[mmu_idx][i], addr);
            }
        }
    }

    tb_flush_jmp_cache(cpu, addr);
}

static void tlb_check_page_and_flush_by_mmuidx_async_work(CPUState *cpu,
                                                          run_on_cpu_data data)
{
    CPUArchState *env = cpu->env_ptr;
    target_ulong addr_and_mmuidx = (target_ulong) data.target_ptr;
    target_ulong addr = addr_and_mmuidx & TARGET_PAGE_MASK;
    unsigned long mmu_idx_bitmap = addr_and_mmuidx & ALL_MMUIDX_BITS;

    tlb_debug("addr:"TARGET_FMT_lx" mmu_idx: %04lx\n", addr, mmu_idx_bitmap);

    /* Check if we need to flush due to large pages.  */
    if ((addr & env->tlb_flush_mask) == env->tlb_flush_addr) {
        tlb_debug("forced full flush ("
                  TARGET_FMT_lx "/" TARGET_FMT_lx ")\n",
                  env->tlb_flush_addr, env->tlb_flush_mask);

        tlb_flush_by_mmuidx_async_work(cpu, RUN_ON_CPU_HOST_ULONG(mmu_idx_bitmap));
    } else {
        tlb_flush_page_by_mmuidx_async_work(cpu, data);
    }
}

void tlb_flush_page_by_mmuidx(CPUState *cpu, target_ulong addr, ...)
{
    unsigned long mmu_idx_bitmap;
    target_ulong addr_and_mmu_idx;
    va_list argp;

    va_start(argp, addr);
    mmu_idx_bitmap = make_mmu_index_bitmap(argp);
    va_end(argp);

    tlb_debug("addr: "TARGET_FMT_lx" mmu_idx:%lx\n", addr, mmu_idx_bitmap);

    /* This should already be page aligned */
    addr_and_mmu_idx = addr & TARGET_PAGE_MASK;
    addr_and_mmu_idx |= mmu_idx_bitmap;

    if (!qemu_cpu_is_self(cpu)) {
        async_run_on_cpu(cpu, tlb_check_page_and_flush_by_mmuidx_async_work,
                         RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
    } else {
        tlb_check_page_and_flush_by_mmuidx_async_work(
            cpu, RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
    }
}

/* This function affects all vCPUs are will ensure all work is
 * complete by the time the loop restarts
 */
void tlb_flush_page_by_mmuidx_all_cpus(CPUState *src_cpu, bool wait,
                                       target_ulong addr, ...)
{
    unsigned long mmu_idx_bitmap;
    target_ulong addr_and_mmu_idx;
    va_list argp;

    va_start(argp, addr);
    mmu_idx_bitmap = make_mmu_index_bitmap(argp);
    va_end(argp);

    tlb_debug("addr: "TARGET_FMT_lx" mmu_idx:%lx\n", addr, mmu_idx_bitmap);

    /* This should already be page aligned */
    addr_and_mmu_idx = addr & TARGET_PAGE_MASK;
    addr_and_mmu_idx |= mmu_idx_bitmap;

    flush_all_helper(src_cpu, wait,
                     tlb_check_page_and_flush_by_mmuidx_async_work,
                     RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
    /* Will not return if wait == true */
    g_assert(!wait);
}

void tlb_flush_page_all_cpus(CPUState *src, bool wait, target_ulong addr)
{
    flush_all_helper(src, wait,
                     tlb_flush_page_async_work, RUN_ON_CPU_TARGET_PTR(addr));
    /* Will not return if wait == true */
    g_assert(!wait);
}

/* update the TLBs so that writes to code in the virtual page 'addr'
   can be detected */
void tlb_protect_code(ram_addr_t ram_addr)
{
    cpu_physical_memory_test_and_clear_dirty(ram_addr, TARGET_PAGE_SIZE,
                                             DIRTY_MEMORY_CODE);
}

/* update the TLB so that writes in physical page 'phys_addr' are no longer
   tested for self modifying code */
void tlb_unprotect_code(ram_addr_t ram_addr)
{
    cpu_physical_memory_set_dirty_flag(ram_addr, DIRTY_MEMORY_CODE);
}


/*
 * Dirty write flag handling
 *
 * When the TCG code writes to a location it looks up the address in
 * the TLB and uses that data to compute the final address. If any of
 * the lower bits of the address are set then the slow path is forced.
 * There are a number of reasons to do this but for normal RAM the
 * most usual is detecting writes to code regions which may invalidate
 * generated code.
 *
 * Because we want other vCPUs to respond to changes straight away we
 * update the te->addr_write field atomically. If the TLB entry has
 * been changed by the vCPU in the mean time we skip the update.
 */

static void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start,
                           uintptr_t length)
{
    /* paired with atomic_mb_set in tlb_set_page_with_attrs */
    uintptr_t orig_addr = atomic_mb_read(&tlb_entry->addr_write);
    uintptr_t addr = orig_addr;

    if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) {
        addr &= TARGET_PAGE_MASK;
        addr += atomic_read(&tlb_entry->addend);
        if ((addr - start) < length) {
            uintptr_t notdirty_addr = orig_addr | TLB_NOTDIRTY;
            atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, notdirty_addr);
        }
    }
}

/* This is a cross vCPU call (i.e. another vCPU resetting the flags of
 * the target vCPU). As such care needs to be taken that we don't
 * dangerously race with another vCPU update. The only thing actually
 * updated is the target TLB entry ->addr_write flags.
 */
void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length)
{
    CPUArchState *env;

    int mmu_idx;

    env = cpu->env_ptr;
    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        unsigned int i;

        for (i = 0; i < CPU_TLB_SIZE; i++) {
            tlb_reset_dirty_range(&env->tlb_table[mmu_idx][i],
                                  start1, length);
        }

        for (i = 0; i < CPU_VTLB_SIZE; i++) {
            tlb_reset_dirty_range(&env->tlb_v_table[mmu_idx][i],
                                  start1, length);
        }
    }
}

static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr)
{
    if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) {
        tlb_entry->addr_write = vaddr;
    }
}

/* update the TLB corresponding to virtual page vaddr
   so that it is no longer dirty */
void tlb_set_dirty(CPUState *cpu, target_ulong vaddr)
{
    CPUArchState *env = cpu->env_ptr;
    int i;
    int mmu_idx;

    assert_cpu_is_self(cpu);

    vaddr &= TARGET_PAGE_MASK;
    i = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        tlb_set_dirty1(&env->tlb_table[mmu_idx][i], vaddr);
    }

    for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
        int k;
        for (k = 0; k < CPU_VTLB_SIZE; k++) {
            tlb_set_dirty1(&env->tlb_v_table[mmu_idx][k], vaddr);
        }
    }
}

/* Our TLB does not support large pages, so remember the area covered by
   large pages and trigger a full TLB flush if these are invalidated.  */
static void tlb_add_large_page(CPUArchState *env, target_ulong vaddr,
                               target_ulong size)
{
    target_ulong mask = ~(size - 1);

    if (env->tlb_flush_addr == (target_ulong)-1) {
        env->tlb_flush_addr = vaddr & mask;
        env->tlb_flush_mask = mask;
        return;
    }
    /* Extend the existing region to include the new page.
       This is a compromise between unnecessary flushes and the cost
       of maintaining a full variable size TLB.  */
    mask &= env->tlb_flush_mask;
    while (((env->tlb_flush_addr ^ vaddr) & mask) != 0) {
        mask <<= 1;
    }
    env->tlb_flush_addr &= mask;
    env->tlb_flush_mask = mask;
}

/* Add a new TLB entry. At most one entry for a given virtual address
 * is permitted. Only a single TARGET_PAGE_SIZE region is mapped, the
 * supplied size is only used by tlb_flush_page.
 *
 * Called from TCG-generated code, which is under an RCU read-side
 * critical section.
 */
void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr,
                             hwaddr paddr, MemTxAttrs attrs, int prot,
                             int mmu_idx, target_ulong size)
{
    CPUArchState *env = cpu->env_ptr;
    MemoryRegionSection *section;
    unsigned int index;
    target_ulong address;
    target_ulong code_address, write_address;
    uintptr_t addend;
    CPUTLBEntry *te, *tv;
    hwaddr iotlb, xlat, sz;
    unsigned vidx = env->vtlb_index++ % CPU_VTLB_SIZE;
    int asidx = cpu_asidx_from_attrs(cpu, attrs);

    assert_cpu_is_self(cpu);
    assert(size >= TARGET_PAGE_SIZE);
    if (size != TARGET_PAGE_SIZE) {
        tlb_add_large_page(env, vaddr, size);
    }

    sz = size;
    section = address_space_translate_for_iotlb(cpu, asidx, paddr, &xlat, &sz);
    assert(sz >= TARGET_PAGE_SIZE);

    tlb_debug("vaddr=" TARGET_FMT_lx " paddr=0x" TARGET_FMT_plx
              " prot=%x idx=%d\n",
              vaddr, paddr, prot, mmu_idx);

    address = vaddr;
    if (!memory_region_is_ram(section->mr) && !memory_region_is_romd(section->mr)) {
        /* IO memory case */
        address |= TLB_MMIO;
        addend = 0;
    } else {
        /* TLB_MMIO for rom/romd handled below */
        addend = (uintptr_t)memory_region_get_ram_ptr(section->mr) + xlat;
    }

    code_address = address;
    iotlb = memory_region_section_get_iotlb(cpu, section, vaddr, paddr, xlat,
                                            prot, &address);

    index = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    te = &env->tlb_table[mmu_idx][index];
    /* do not discard the translation in te, evict it into a victim tlb */
    tv = &env->tlb_v_table[mmu_idx][vidx];

    /* addr_write can race with tlb_reset_dirty_range_all */
    tv->addr_read = te->addr_read;
    atomic_set(&tv->addr_write, atomic_read(&te->addr_write));
    tv->addr_code = te->addr_code;
    atomic_set(&tv->addend, atomic_read(&te->addend));

    env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index];

    /* refill the tlb */
    env->iotlb[mmu_idx][index].addr = iotlb - vaddr;
    env->iotlb[mmu_idx][index].attrs = attrs;
    atomic_set(&te->addend, addend - vaddr);
    if (prot & PAGE_READ) {
        te->addr_read = address;
    } else {
        te->addr_read = -1;
    }

    if (prot & PAGE_EXEC) {
        te->addr_code = code_address;
    } else {
        te->addr_code = -1;
    }

    write_address = -1;
    if (prot & PAGE_WRITE) {
        if ((memory_region_is_ram(section->mr) && section->readonly)
            || memory_region_is_romd(section->mr)) {
            /* Write access calls the I/O callback.  */
            write_address = address | TLB_MMIO;
        } else if (memory_region_is_ram(section->mr)
                   && cpu_physical_memory_is_clean(
                        memory_region_get_ram_addr(section->mr) + xlat)) {
            write_address = address | TLB_NOTDIRTY;
        } else {
            write_address = address;
        }
    }

    /* Pairs with flag setting in tlb_reset_dirty_range */
    atomic_mb_set(&te->addr_write, write_address);
}

/* Add a new TLB entry, but without specifying the memory
 * transaction attributes to be used.
 */
void tlb_set_page(CPUState *cpu, target_ulong vaddr,
                  hwaddr paddr, int prot,
                  int mmu_idx, target_ulong size)
{
    tlb_set_page_with_attrs(cpu, vaddr, paddr, MEMTXATTRS_UNSPECIFIED,
                            prot, mmu_idx, size);
}

static void report_bad_exec(CPUState *cpu, target_ulong addr)
{
    /* Accidentally executing outside RAM or ROM is quite common for
     * several user-error situations, so report it in a way that
     * makes it clear that this isn't a QEMU bug and provide suggestions
     * about what a user could do to fix things.
     */
    error_report("Trying to execute code outside RAM or ROM at 0x"
                 TARGET_FMT_lx, addr);
    error_printf("This usually means one of the following happened:\n\n"
                 "(1) You told QEMU to execute a kernel for the wrong machine "
                 "type, and it crashed on startup (eg trying to run a "
                 "raspberry pi kernel on a versatilepb QEMU machine)\n"
                 "(2) You didn't give QEMU a kernel or BIOS filename at all, "
                 "and QEMU executed a ROM full of no-op instructions until "
                 "it fell off the end\n"
                 "(3) Your guest kernel has a bug and crashed by jumping "
                 "off into nowhere\n\n"
                 "This is almost always one of the first two, so check your "
                 "command line and that you are using the right type of kernel "
                 "for this machine.\n"
                 "If you think option (3) is likely then you can try debugging "
                 "your guest with the -d debug options; in particular "
                 "-d guest_errors will cause the log to include a dump of the "
                 "guest register state at this point.\n\n"
                 "Execution cannot continue; stopping here.\n\n");

    /* Report also to the logs, with more detail including register dump */
    qemu_log_mask(LOG_GUEST_ERROR, "qemu: fatal: Trying to execute code "
                  "outside RAM or ROM at 0x" TARGET_FMT_lx "\n", addr);
    log_cpu_state_mask(LOG_GUEST_ERROR, cpu, CPU_DUMP_FPU | CPU_DUMP_CCOP);
}

static inline ram_addr_t qemu_ram_addr_from_host_nofail(void *ptr)
{
    ram_addr_t ram_addr;

    ram_addr = qemu_ram_addr_from_host(ptr);
    if (ram_addr == RAM_ADDR_INVALID) {
        error_report("Bad ram pointer %p", ptr);
        abort();
    }
    return ram_addr;
}

/* NOTE: this function can trigger an exception */
/* NOTE2: the returned address is not exactly the physical address: it
 * is actually a ram_addr_t (in system mode; the user mode emulation
 * version of this function returns a guest virtual address).
 */
tb_page_addr_t get_page_addr_code(CPUArchState *env1, target_ulong addr)
{
    int mmu_idx, page_index, pd;
    void *p;
    MemoryRegion *mr;
    CPUState *cpu = ENV_GET_CPU(env1);
    CPUIOTLBEntry *iotlbentry;

    page_index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    mmu_idx = cpu_mmu_index(env1, true);
    if (unlikely(env1->tlb_table[mmu_idx][page_index].addr_code !=
                 (addr & TARGET_PAGE_MASK))) {
        cpu_ldub_code(env1, addr);
    }
    iotlbentry = &env1->iotlb[mmu_idx][page_index];
    pd = iotlbentry->addr & ~TARGET_PAGE_MASK;
    mr = iotlb_to_region(cpu, pd, iotlbentry->attrs);
    if (memory_region_is_unassigned(mr)) {
        CPUClass *cc = CPU_GET_CLASS(cpu);

        if (cc->do_unassigned_access) {
            cc->do_unassigned_access(cpu, addr, false, true, 0, 4);
        } else {
            report_bad_exec(cpu, addr);
            exit(1);
        }
    }
    p = (void *)((uintptr_t)addr + env1->tlb_table[mmu_idx][page_index].addend);
    return qemu_ram_addr_from_host_nofail(p);
}

static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry,
                         target_ulong addr, uintptr_t retaddr, int size)
{
    CPUState *cpu = ENV_GET_CPU(env);
    hwaddr physaddr = iotlbentry->addr;
    MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs);
    uint64_t val;
    bool locked = false;

    physaddr = (physaddr & TARGET_PAGE_MASK) + addr;
    cpu->mem_io_pc = retaddr;
    if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) {
        cpu_io_recompile(cpu, retaddr);
    }

    cpu->mem_io_vaddr = addr;

    if (mr->global_locking) {
        qemu_mutex_lock_iothread();
        locked = true;
    }
    memory_region_dispatch_read(mr, physaddr, &val, size, iotlbentry->attrs);
    if (locked) {
        qemu_mutex_unlock_iothread();
    }

    return val;
}

static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry,
                      uint64_t val, target_ulong addr,
                      uintptr_t retaddr, int size)
{
    CPUState *cpu = ENV_GET_CPU(env);
    hwaddr physaddr = iotlbentry->addr;
    MemoryRegion *mr = iotlb_to_region(cpu, physaddr, iotlbentry->attrs);
    bool locked = false;

    physaddr = (physaddr & TARGET_PAGE_MASK) + addr;
    if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) {
        cpu_io_recompile(cpu, retaddr);
    }
    cpu->mem_io_vaddr = addr;
    cpu->mem_io_pc = retaddr;

    if (mr->global_locking) {
        qemu_mutex_lock_iothread();
        locked = true;
    }
    memory_region_dispatch_write(mr, physaddr, val, size, iotlbentry->attrs);
    if (locked) {
        qemu_mutex_unlock_iothread();
    }
}

/* Return true if ADDR is present in the victim tlb, and has been copied
   back to the main tlb.  */
static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index,
                           size_t elt_ofs, target_ulong page)
{
    size_t vidx;
    for (vidx = 0; vidx < CPU_VTLB_SIZE; ++vidx) {
        CPUTLBEntry *vtlb = &env->tlb_v_table[mmu_idx][vidx];
        target_ulong cmp = *(target_ulong *)((uintptr_t)vtlb + elt_ofs);

        if (cmp == page) {
            /* Found entry in victim tlb, swap tlb and iotlb.  */
            CPUTLBEntry tmptlb, *tlb = &env->tlb_table[mmu_idx][index];

            /* tmptlb = *tlb; */
            /* addr_write can race with tlb_reset_dirty_range_all */
            tmptlb.addr_read = tlb->addr_read;
            tmptlb.addr_write = atomic_read(&tlb->addr_write);
            tmptlb.addr_code = tlb->addr_code;
            tmptlb.addend = atomic_read(&tlb->addend);

            /* *tlb = *vtlb; */
            tlb->addr_read = vtlb->addr_read;
            atomic_set(&tlb->addr_write, atomic_read(&vtlb->addr_write));
            tlb->addr_code = vtlb->addr_code;
            atomic_set(&tlb->addend, atomic_read(&vtlb->addend));

            /* *vtlb = tmptlb; */
            vtlb->addr_read = tmptlb.addr_read;
            atomic_set(&vtlb->addr_write, tmptlb.addr_write);
            vtlb->addr_code = tmptlb.addr_code;
            atomic_set(&vtlb->addend, tmptlb.addend);

            CPUIOTLBEntry tmpio, *io = &env->iotlb[mmu_idx][index];
            CPUIOTLBEntry *vio = &env->iotlb_v[mmu_idx][vidx];
            tmpio = *io; *io = *vio; *vio = tmpio;
            return true;
        }
    }
    return false;
}

/* Macro to call the above, with local variables from the use context.  */
#define VICTIM_TLB_HIT(TY, ADDR) \
  victim_tlb_hit(env, mmu_idx, index, offsetof(CPUTLBEntry, TY), \
                 (ADDR) & TARGET_PAGE_MASK)

/* Probe for whether the specified guest write access is permitted.
 * If it is not permitted then an exception will be taken in the same
 * way as if this were a real write access (and we will not return).
 * Otherwise the function will return, and there will be a valid
 * entry in the TLB for this access.
 */
void probe_write(CPUArchState *env, target_ulong addr, int mmu_idx,
                 uintptr_t retaddr)
{
    int index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    target_ulong tlb_addr = env->tlb_table[mmu_idx][index].addr_write;

    if ((addr & TARGET_PAGE_MASK)
        != (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
        /* TLB entry is for a different page */
        if (!VICTIM_TLB_HIT(addr_write, addr)) {
            tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, retaddr);
        }
    }
}

/* Probe for a read-modify-write atomic operation.  Do not allow unaligned
 * operations, or io operations to proceed.  Return the host address.  */
static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
                               TCGMemOpIdx oi, uintptr_t retaddr)
{
    size_t mmu_idx = get_mmuidx(oi);
    size_t index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    CPUTLBEntry *tlbe = &env->tlb_table[mmu_idx][index];
    target_ulong tlb_addr = tlbe->addr_write;
    TCGMemOp mop = get_memop(oi);
    int a_bits = get_alignment_bits(mop);
    int s_bits = mop & MO_SIZE;

    /* Adjust the given return address.  */
    retaddr -= GETPC_ADJ;

    /* Enforce guest required alignment.  */
    if (unlikely(a_bits > 0 && (addr & ((1 << a_bits) - 1)))) {
        /* ??? Maybe indicate atomic op to cpu_unaligned_access */
        cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
                             mmu_idx, retaddr);
    }

    /* Enforce qemu required alignment.  */
    if (unlikely(addr & ((1 << s_bits) - 1))) {
        /* We get here if guest alignment was not requested,
           or was not enforced by cpu_unaligned_access above.
           We might widen the access and emulate, but for now
           mark an exception and exit the cpu loop.  */
        goto stop_the_world;
    }

    /* Check TLB entry and enforce page permissions.  */
    if ((addr & TARGET_PAGE_MASK)
        != (tlb_addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
        if (!VICTIM_TLB_HIT(addr_write, addr)) {
            tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, retaddr);
        }
        tlb_addr = tlbe->addr_write;
    }

    /* Notice an IO access, or a notdirty page.  */
    if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
        /* There's really nothing that can be done to
           support this apart from stop-the-world.  */
        goto stop_the_world;
    }

    /* Let the guest notice RMW on a write-only page.  */
    if (unlikely(tlbe->addr_read != tlb_addr)) {
        tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_LOAD, mmu_idx, retaddr);
        /* Since we don't support reads and writes to different addresses,
           and we do have the proper page loaded for write, this shouldn't
           ever return.  But just in case, handle via stop-the-world.  */
        goto stop_the_world;
    }

    return (void *)((uintptr_t)addr + tlbe->addend);

 stop_the_world:
    cpu_loop_exit_atomic(ENV_GET_CPU(env), retaddr);
}

#ifdef TARGET_WORDS_BIGENDIAN
# define TGT_BE(X)  (X)
# define TGT_LE(X)  BSWAP(X)
#else
# define TGT_BE(X)  BSWAP(X)
# define TGT_LE(X)  (X)
#endif

#define MMUSUFFIX _mmu

#define DATA_SIZE 1
#include "softmmu_template.h"

#define DATA_SIZE 2
#include "softmmu_template.h"

#define DATA_SIZE 4
#include "softmmu_template.h"

#define DATA_SIZE 8
#include "softmmu_template.h"

/* First set of helpers allows passing in of OI and RETADDR.  This makes
   them callable from other helpers.  */

#define EXTRA_ARGS     , TCGMemOpIdx oi, uintptr_t retaddr
#define ATOMIC_NAME(X) \
    HELPER(glue(glue(glue(atomic_ ## X, SUFFIX), END), _mmu))
#define ATOMIC_MMU_LOOKUP  atomic_mmu_lookup(env, addr, oi, retaddr)

#define DATA_SIZE 1
#include "atomic_template.h"

#define DATA_SIZE 2
#include "atomic_template.h"

#define DATA_SIZE 4
#include "atomic_template.h"

#ifdef CONFIG_ATOMIC64
#define DATA_SIZE 8
#include "atomic_template.h"
#endif

#ifdef CONFIG_ATOMIC128
#define DATA_SIZE 16
#include "atomic_template.h"
#endif

/* Second set of helpers are directly callable from TCG as helpers.  */

#undef EXTRA_ARGS
#undef ATOMIC_NAME
#undef ATOMIC_MMU_LOOKUP
#define EXTRA_ARGS         , TCGMemOpIdx oi
#define ATOMIC_NAME(X)     HELPER(glue(glue(atomic_ ## X, SUFFIX), END))
#define ATOMIC_MMU_LOOKUP  atomic_mmu_lookup(env, addr, oi, GETPC())

#define DATA_SIZE 1
#include "atomic_template.h"

#define DATA_SIZE 2
#include "atomic_template.h"

#define DATA_SIZE 4
#include "atomic_template.h"

#ifdef CONFIG_ATOMIC64
#define DATA_SIZE 8
#include "atomic_template.h"
#endif

/* Code access functions.  */

#undef MMUSUFFIX
#define MMUSUFFIX _cmmu
#undef GETPC
#define GETPC() ((uintptr_t)0)
#define SOFTMMU_CODE_ACCESS

#define DATA_SIZE 1
#include "softmmu_template.h"

#define DATA_SIZE 2
#include "softmmu_template.h"

#define DATA_SIZE 4
#include "softmmu_template.h"

#define DATA_SIZE 8
#include "softmmu_template.h"