1 files changed, 91 insertions, 0 deletions
diff --git a/semihosting/uaccess.c b/semihosting/uaccess.c
new file mode 100644
index 0000000000..8018828069
--- /dev/null
+++ b/semihosting/uaccess.c
@@ -0,0 +1,91 @@
+/*
+ * Helper routines to provide target memory access for semihosting
+ * syscalls in system emulation mode.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ * This code is licensed under the GPL
+ */
+
+#include "qemu/osdep.h"
+#include "exec/exec-all.h"
+#include "semihosting/softmmu-uaccess.h"
+
+void *softmmu_lock_user(CPUArchState *env, target_ulong addr,
+                        target_ulong len, bool copy)
+{
+    void *p = malloc(len);
+    if (p && copy) {
+        if (cpu_memory_rw_debug(env_cpu(env), addr, p, len, 0)) {
+            free(p);
+            p = NULL;
+        }
+    }
+    return p;
+}
+
+ssize_t softmmu_strlen_user(CPUArchState *env, target_ulong addr)
+{
+    int mmu_idx = cpu_mmu_index(env, false);
+    size_t len = 0;
+
+    while (1) {
+        size_t left_in_page;
+        int flags;
+        void *h;
+
+        /* Find the number of bytes remaining in the page. */
+        left_in_page = TARGET_PAGE_SIZE - (addr & ~TARGET_PAGE_MASK);
+
+        flags = probe_access_flags(env, addr, MMU_DATA_LOAD,
+                                   mmu_idx, true, &h, 0);
+        if (flags & TLB_INVALID_MASK) {
+            return -1;
+        }
+        if (flags & TLB_MMIO) {
+            do {
+                uint8_t c;
+                if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
+                    return -1;
+                }
+                if (c == 0) {
+                    return len;
+                }
+                addr++;
+                len++;
+                if (len > INT32_MAX) {
+                    return -1;
+                }
+            } while (--left_in_page != 0);
+        } else {
+            char *p = memchr(h, 0, left_in_page);
+            if (p) {
+                len += p - (char *)h;
+                return len <= INT32_MAX ? (ssize_t)len : -1;
+            }
+            addr += left_in_page;
+            len += left_in_page;
+            if (len > INT32_MAX) {
+                return -1;
+            }
+        }
+    }
+}
+
+char *softmmu_lock_user_string(CPUArchState *env, target_ulong addr)
+{
+    ssize_t len = softmmu_strlen_user(env, addr);
+    if (len < 0) {
+        return NULL;
+    }
+    return softmmu_lock_user(env, addr, len + 1, true);
+}
+
+void softmmu_unlock_user(CPUArchState *env, void *p,
+                         target_ulong addr, target_ulong len)
+{
+    if (len) {
+        cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1);
+    }
+    free(p);
+}