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 "config.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/cputlb.h"

#ifdef CONFIG_MEMCHECK
#include "memcheck/memcheck_api.h"
#endif

/* statistics */
int tlb_flush_count;

static const CPUTLBEntry s_cputlb_empty_entry = {
    .addr_read  = -1,
    .addr_write = -1,
    .addr_code  = -1,
    .addend     = -1,
};

/* 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(CPUArchState *env, int flush_global)
{
    int i;

#if defined(DEBUG_TLB)
    printf("tlb_flush:\n");
#endif
    /* must reset current TB so that interrupts cannot modify the
       links while we are modifying them */
    env->current_tb = NULL;

    for (i = 0; i < CPU_TLB_SIZE; i++) {
        int mmu_idx;

        for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
            env->tlb_table[mmu_idx][i] = s_cputlb_empty_entry;
        }
    }

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

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))) {
        *tlb_entry = s_cputlb_empty_entry;
    }
}

void tlb_flush_page(CPUArchState *env, target_ulong addr)
{
    int i;
    int mmu_idx;

#if defined(DEBUG_TLB)
    printf("tlb_flush_page: " TARGET_FMT_lx "\n", addr);
#endif
    /* must reset current TB so that interrupts cannot modify the
       links while we are modifying them */
    env->current_tb = NULL;

    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);
    }

    tb_flush_jmp_cache(env, addr);
}

/* 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_reset_dirty(ram_addr,
                                    ram_addr + TARGET_PAGE_SIZE,
                                    CODE_DIRTY_FLAG);
}

/* update the TLB so that writes in physical page 'phys_addr' are no longer
   tested for self modifying code */
void tlb_unprotect_code_phys(CPUArchState *env, ram_addr_t ram_addr,
                             target_ulong vaddr)
{
    cpu_physical_memory_set_dirty_flags(ram_addr, CODE_DIRTY_FLAG);
}

static bool tlb_is_dirty_ram(CPUTLBEntry *tlbe)
{
    return (tlbe->addr_write & ~TARGET_PAGE_MASK) == IO_MEM_RAM;
}

void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start,
                           uintptr_t length)
{
    uintptr_t addr;

    if (tlb_is_dirty_ram(tlb_entry)) {
        addr = (tlb_entry->addr_write & TARGET_PAGE_MASK) + tlb_entry->addend;
        if ((addr - start) < length) {
            tlb_entry->addr_write &= TARGET_PAGE_MASK;
            tlb_entry->addr_write |= TLB_NOTDIRTY;
        }
    }
}

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(CPUArchState *env, target_ulong vaddr)
{
    int i;
    int mmu_idx;

    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);
    }
}

/* add a new TLB entry. At most one entry for a given virtual address
   is permitted. Return 0 if OK or 2 if the page could not be mapped
   (can only happen in non SOFTMMU mode for I/O pages or pages
   conflicting with the host address space). */
int tlb_set_page_exec(CPUArchState *env, target_ulong vaddr,
                      hwaddr paddr, int prot,
                      int mmu_idx, int is_softmmu)
{
    PhysPageDesc *p;
    unsigned long pd;
    unsigned int index;
    target_ulong address;
    target_ulong code_address;
    ptrdiff_t addend;
    int ret;
    CPUTLBEntry *te;
    CPUWatchpoint *wp;
    hwaddr iotlb;

    p = phys_page_find(paddr >> TARGET_PAGE_BITS);
    if (!p) {
        pd = IO_MEM_UNASSIGNED;
    } else {
        pd = p->phys_offset;
    }
#if defined(DEBUG_TLB)
    printf("tlb_set_page: vaddr=" TARGET_FMT_lx " paddr=0x" TARGET_FMT_plx
           " prot=%x idx=%d smmu=%d pd=0x%08lx\n",
           vaddr, paddr, prot, mmu_idx, is_softmmu, pd);
#endif

    ret = 0;
    address = vaddr;
    if ((pd & ~TARGET_PAGE_MASK) > IO_MEM_ROM && !(pd & IO_MEM_ROMD)) {
        /* IO memory case (romd handled later) */
        address |= TLB_MMIO;
    }
    addend = (ptrdiff_t)qemu_get_ram_ptr(pd & TARGET_PAGE_MASK);
    if ((pd & ~TARGET_PAGE_MASK) <= IO_MEM_ROM) {
        /* Normal RAM.  */
        iotlb = pd & TARGET_PAGE_MASK;
        if ((pd & ~TARGET_PAGE_MASK) == IO_MEM_RAM)
            iotlb |= IO_MEM_NOTDIRTY;
        else
            iotlb |= IO_MEM_ROM;
    } else {
        /* IO handlers are currently passed a physical address.
           It would be nice to pass an offset from the base address
           of that region.  This would avoid having to special case RAM,
           and avoid full address decoding in every device.
           We can't use the high bits of pd for this because
           IO_MEM_ROMD uses these as a ram address.  */
        iotlb = (pd & ~TARGET_PAGE_MASK);
        if (p) {
            iotlb += p->region_offset;
        } else {
            iotlb += paddr;
        }
    }

    code_address = address;
    /* Make accesses to pages with watchpoints go via the
       watchpoint trap routines.  */
    QTAILQ_FOREACH(wp, &env->watchpoints, entry) {
        if (vaddr == (wp->vaddr & TARGET_PAGE_MASK)) {
            iotlb = io_mem_watch + paddr;
            /* TODO: The memory case can be optimized by not trapping
               reads of pages with a write breakpoint.  */
            address |= TLB_MMIO;
        }
    }

    index = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
    env->iotlb[mmu_idx][index] = iotlb - vaddr;
    te = &env->tlb_table[mmu_idx][index];
    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;
    }
    if (prot & PAGE_WRITE) {
        if ((pd & ~TARGET_PAGE_MASK) == IO_MEM_ROM ||
            (pd & IO_MEM_ROMD)) {
            /* Write access calls the I/O callback.  */
            te->addr_write = address | TLB_MMIO;
        } else if ((pd & ~TARGET_PAGE_MASK) == IO_MEM_RAM &&
                   !cpu_physical_memory_is_dirty(pd)) {
            te->addr_write = address | TLB_NOTDIRTY;
        } else {
            te->addr_write = address;
        }
    } else {
        te->addr_write = -1;
    }

#ifdef CONFIG_MEMCHECK
    /*
     * If we have memchecker running, we need to make sure that page, cached
     * into TLB as the result of this operation will comply with our requirement
     * to cause __ld/__stx_mmu being called for memory access on the pages
     * containing memory blocks that require access violation checks.
     *
     * We need to check with memory checker if we should invalidate this page
     * iff:
     *  - Memchecking is enabled.
     *  - Page that's been cached belongs to the user space.
     *  - Request to cache this page didn't come from softmmu. We're covered
     *    there, because after page was cached here we will invalidate it in
     *    the __ld/__stx_mmu wrapper.
     *  - Cached page belongs to RAM, not I/O area.
     *  - Page is cached for read, or write access.
     */
    if (memcheck_instrument_mmu && mmu_idx == 1 && !is_softmmu &&
        (pd & ~TARGET_PAGE_MASK) == IO_MEM_RAM &&
        (prot & (PAGE_READ | PAGE_WRITE)) &&
        memcheck_is_checked(vaddr & TARGET_PAGE_MASK, TARGET_PAGE_SIZE)) {
        if (prot & PAGE_READ) {
            te->addr_read ^= TARGET_PAGE_MASK;
        }
        if (prot & PAGE_WRITE) {
            te->addr_write ^= TARGET_PAGE_MASK;
        }
    }
#endif  // CONFIG_MEMCHECK

    return ret;
}

int tlb_set_page(CPUArchState *env1, target_ulong vaddr,
                 hwaddr paddr, int prot,
                 int mmu_idx, int is_softmmu)
{
    if (prot & PAGE_READ)
        prot |= PAGE_EXEC;
    return tlb_set_page_exec(env1, vaddr, paddr, prot, mmu_idx, is_softmmu);
}

#define MMUSUFFIX _cmmu
#define GETPC() NULL
#define env cpu_single_env
#define SOFTMMU_CODE_ACCESS

#define SHIFT 0
#include "exec/softmmu_template.h"

#define SHIFT 1
#include "exec/softmmu_template.h"

#define SHIFT 2
#include "exec/softmmu_template.h"

#define SHIFT 3
#include "exec/softmmu_template.h"

#undef env