mmap emulation

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@158 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 148 insertions, 0 deletions

diff --git a/exec.c b/exec.c
new file mode 100644
index 0000000000..a917143d60
--- /dev/null
+++ b/exec.c
@@ -0,0 +1,148 @@
+/*
+ *  virtual page mapping
+ * 
+ *  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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include "cpu-i386.h"
+
+/* XXX: pack the flags in the low bits of the pointer ? */
+typedef struct PageDesc {
+    struct TranslationBlock *first_tb;
+    unsigned long flags;
+} PageDesc;
+
+#define L2_BITS 10
+#define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS)
+
+#define L1_SIZE (1 << L1_BITS)
+#define L2_SIZE (1 << L2_BITS)
+
+unsigned long real_host_page_size;
+unsigned long host_page_bits;
+unsigned long host_page_size;
+unsigned long host_page_mask;
+
+static PageDesc *l1_map[L1_SIZE];
+
+void page_init(void)
+{
+    /* NOTE: we can always suppose that host_page_size >=
+       TARGET_PAGE_SIZE */
+    real_host_page_size = getpagesize();
+    if (host_page_size == 0)
+        host_page_size = real_host_page_size;
+    if (host_page_size < TARGET_PAGE_SIZE)
+        host_page_size = TARGET_PAGE_SIZE;
+    host_page_bits = 0;
+    while ((1 << host_page_bits) < host_page_size)
+        host_page_bits++;
+    host_page_mask = ~(host_page_size - 1);
+}
+
+/* dump memory mappings */
+void page_dump(FILE *f)
+{
+    unsigned long start, end;
+    int i, j, prot, prot1;
+    PageDesc *p;
+
+    fprintf(f, "%-8s %-8s %-8s %s\n",
+            "start", "end", "size", "prot");
+    start = -1;
+    end = -1;
+    prot = 0;
+    for(i = 0; i <= L1_SIZE; i++) {
+        if (i < L1_SIZE)
+            p = l1_map[i];
+        else
+            p = NULL;
+        for(j = 0;j < L2_SIZE; j++) {
+            if (!p)
+                prot1 = 0;
+            else
+                prot1 = p[j].flags;
+            if (prot1 != prot) {
+                end = (i << (32 - L1_BITS)) | (j << TARGET_PAGE_BITS);
+                if (start != -1) {
+                    fprintf(f, "%08lx-%08lx %08lx %c%c%c\n",
+                            start, end, end - start, 
+                            prot & PAGE_READ ? 'r' : '-',
+                            prot & PAGE_WRITE ? 'w' : '-',
+                            prot & PAGE_EXEC ? 'x' : '-');
+                }
+                if (prot1 != 0)
+                    start = end;
+                else
+                    start = -1;
+                prot = prot1;
+            }
+            if (!p)
+                break;
+        }
+    }
+}
+
+
+static inline PageDesc *page_find_alloc(unsigned long address)
+{
+    unsigned int index;
+    PageDesc **lp, *p;
+
+    index = address >> TARGET_PAGE_BITS;
+    lp = &l1_map[index >> L2_BITS];
+    p = *lp;
+    if (!p) {
+        /* allocate if not found */
+        p = malloc(sizeof(PageDesc) * L2_SIZE);
+        memset(p, 0, sizeof(sizeof(PageDesc) * L2_SIZE));
+        *lp = p;
+    }
+    return p + (index & (L2_SIZE - 1));
+}
+
+int page_get_flags(unsigned long address)
+{
+    unsigned int index;
+    PageDesc *p;
+
+    index = address >> TARGET_PAGE_BITS;
+    p = l1_map[index >> L2_BITS];
+    if (!p)
+        return 0;
+    return p[index & (L2_SIZE - 1)].flags;
+}
+
+void page_set_flags(unsigned long start, unsigned long end, int flags)
+{
+    PageDesc *p;
+    unsigned long addr;
+
+    start = start & TARGET_PAGE_MASK;
+    end = TARGET_PAGE_ALIGN(end);
+    for(addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
+        p = page_find_alloc(addr);
+        p->flags = flags;
+    }
+}