LXR qemu/semihosting/uaccess.c

   1/*
   2 * Helper routines to provide target memory access for semihosting
   3 * syscalls in system emulation mode.
   4 *
   5 * Copyright (c) 2007 CodeSourcery.
   6 *
   7 * This code is licensed under the GPL
   8 */
   9
  10#include "qemu/osdep.h"
  11#include "exec/exec-all.h"
  12#include "semihosting/softmmu-uaccess.h"
  13
  14void *softmmu_lock_user(CPUArchState *env, target_ulong addr,
  15                        target_ulong len, bool copy)
  16{
  17    void *p = malloc(len);
  18    if (p && copy) {
  19        if (cpu_memory_rw_debug(env_cpu(env), addr, p, len, 0)) {
  20            free(p);
  21            p = NULL;
  22        }
  23    }
  24    return p;
  25}
  26
  27ssize_t softmmu_strlen_user(CPUArchState *env, target_ulong addr)
  28{
  29    int mmu_idx = cpu_mmu_index(env, false);
  30    size_t len = 0;
  31
  32    while (1) {
  33        size_t left_in_page;
  34        int flags;
  35        void *h;
  36
  37        /* Find the number of bytes remaining in the page. */
  38        left_in_page = TARGET_PAGE_SIZE - (addr & ~TARGET_PAGE_MASK);
  39
  40        flags = probe_access_flags(env, addr, 0, MMU_DATA_LOAD,
  41                                   mmu_idx, true, &h, 0);
  42        if (flags & TLB_INVALID_MASK) {
  43            return -1;
  44        }
  45        if (flags & TLB_MMIO) {
  46            do {
  47                uint8_t c;
  48                if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
  49                    return -1;
  50                }
  51                if (c == 0) {
  52                    return len;
  53                }
  54                addr++;
  55                len++;
  56                if (len > INT32_MAX) {
  57                    return -1;
  58                }
  59            } while (--left_in_page != 0);
  60        } else {
  61            char *p = memchr(h, 0, left_in_page);
  62            if (p) {
  63                len += p - (char *)h;
  64                return len <= INT32_MAX ? (ssize_t)len : -1;
  65            }
  66            addr += left_in_page;
  67            len += left_in_page;
  68            if (len > INT32_MAX) {
  69                return -1;
  70            }
  71        }
  72    }
  73}
  74
  75char *softmmu_lock_user_string(CPUArchState *env, target_ulong addr)
  76{
  77    ssize_t len = softmmu_strlen_user(env, addr);
  78    if (len < 0) {
  79        return NULL;
  80    }
  81    return softmmu_lock_user(env, addr, len + 1, true);
  82}
  83
  84void softmmu_unlock_user(CPUArchState *env, void *p,
  85                         target_ulong addr, target_ulong len)
  86{
  87    if (len) {
  88        cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1);
  89    }
  90    free(p);
  91}
  92