Fix mmap to handle differing host/target page sizes, by Edgar E. Iglesias.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3291 c046a42c-6fe2-441c-8c8c-71466251a162

linux-user/mmap.c

@@ -36,7 +36,8 @@ int target_mprotect(target_ulong start, target_ulong len, int prot)
     int prot1, ret;
 
 #ifdef DEBUG_MMAP
-    printf("mprotect: start=0x%lx len=0x%lx prot=%c%c%c\n", start, len,
+    printf("mprotect: start=0x" TARGET_FMT_lx
+	   "len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len,
            prot & PROT_READ ? 'r' : '-',
            prot & PROT_WRITE ? 'w' : '-',
            prot & PROT_EXEC ? 'x' : '-');
@@ -151,11 +152,11 @@ static int mmap_frag(target_ulong real_start,
 }
 
 /* NOTE: all the constants are the HOST ones */
-long target_mmap(target_ulong start, target_ulong len, int prot,
+target_long target_mmap(target_ulong start, target_ulong len, int prot,
                  int flags, int fd, target_ulong offset)
 {
     target_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
-    long host_start;
+    unsigned long host_start;
 #if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
         defined(__ia64) || defined(__mips__)
     static target_ulong last_start = 0x40000000;
@@ -166,7 +167,8 @@ long target_mmap(target_ulong start, target_ulong len, int prot,
 
 #ifdef DEBUG_MMAP
     {
-        printf("mmap: start=0x%lx len=0x%lx prot=%c%c%c flags=",
+        printf("mmap: start=0x" TARGET_FMT_lx
+	       " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=",
                start, len,
                prot & PROT_READ ? 'r' : '-',
                prot & PROT_WRITE ? 'w' : '-',
@@ -186,7 +188,7 @@ long target_mmap(target_ulong start, target_ulong len, int prot,
             printf("[MAP_TYPE=0x%x] ", flags & MAP_TYPE);
             break;
         }
-        printf("fd=%d offset=%lx\n", fd, offset);
+        printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset);
     }
 #endif
 
@@ -209,34 +211,59 @@ long target_mmap(target_ulong start, target_ulong len, int prot,
             last_start += HOST_PAGE_ALIGN(len);
         }
 #endif
-        if (0 && qemu_host_page_size != qemu_real_host_page_size) {
-            /* NOTE: this code is only for debugging with '-p' option */
-            /* ??? Can also occur when TARGET_PAGE_SIZE > host page size.  */
-            /* reserve a memory area */
-            /* ??? This needs fixing for remapping.  */
-abort();
-            host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
-            real_start = (long)mmap(g2h(real_start), host_len, PROT_NONE,
-                                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-            if (real_start == -1)
-                return real_start;
-            real_end = real_start + host_len;
-            start = HOST_PAGE_ALIGN(real_start);
-            end = start + HOST_PAGE_ALIGN(len);
-            if (start > real_start)
-                munmap((void *)g2h(real_start), start - real_start);
-            if (end < real_end)
-                munmap((void *)g2h(end), real_end - end);
-            /* use it as a fixed mapping */
-            flags |= MAP_FIXED;
-        } else {
-            /* if not fixed, no need to do anything */
             host_offset = offset & qemu_host_page_mask;
             host_len = len + offset - host_offset;
+
+        if (qemu_host_page_size > qemu_real_host_page_size) {
+            /*
+             * The guest expects to see mmapped areas aligned to it's pagesize.
+             * If the host's real page size is smaller than the guest's, we need
+             * to fixup the maps. It is done by allocating a larger area,
+             * displacing the map (if needed) and finally chopping off the spare
+             * room at the edges.
+             */
+
+            /*
+             * We assume qemu_host_page_size is always the same as
+             * TARGET_PAGE_SIZE, see exec.c. qemu_real_host_page_size is the
+             * hosts real page size.
+             */
+            target_ulong host_end;
+            unsigned long host_aligned_start;
+
+            host_len = HOST_PAGE_ALIGN(host_len + qemu_host_page_size
+                                       - qemu_real_host_page_size);
+            host_start = (unsigned long) mmap(real_start ?
+					      g2h(real_start) : NULL,
+					      host_len, prot, flags,
+					      fd, host_offset);
+            if (host_start == -1)
+                return -1;
+
+            host_end = host_start + host_len;
+
+            /* Find start and end, aligned to the targets pagesize with-in the
+               large mmaped area.  */
+            host_aligned_start = TARGET_PAGE_ALIGN(host_start);
+            if (!(flags & MAP_ANONYMOUS))
+                host_aligned_start += offset - host_offset;
+
+            start = h2g(host_aligned_start);
+            end = start + TARGET_PAGE_ALIGN(len);
+
+            /* Chop off the leftovers, if any.  */
+            if (host_aligned_start > host_start)
+                munmap((void *)host_start, host_aligned_start - host_start);
+            if (end < host_end)
+                munmap((void *)g2h(end), host_end - end);
+
+            goto the_end1;
+        } else {
+            /* if not fixed, no need to do anything */
             host_start = (long)mmap(real_start ? g2h(real_start) : NULL,
                                     host_len, prot, flags, fd, host_offset);
             if (host_start == -1)
-                return host_start;
+                return -1;
             /* update start so that it points to the file position at 'offset' */
             if (!(flags & MAP_ANONYMOUS))
                 host_start += offset - host_offset;
@@ -267,7 +294,7 @@ abort();
                               MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
                               -1, 0);
         if (retaddr == -1)
-            return retaddr;
+            return -1;
         pread(fd, g2h(start), len, offset);
         if (!(prot & PROT_WRITE)) {
             ret = target_mprotect(start, len, prot);
@@ -300,7 +327,7 @@ abort();
                         prot, flags, fd,
                         offset + real_end - qemu_host_page_size - start);
         if (ret == -1)
-            return ret;
+            return -1;
         real_end -= qemu_host_page_size;
     }
 
@@ -314,13 +341,13 @@ abort();
         ret = (long)mmap(g2h(real_start), real_end - real_start,
                          prot, flags, fd, offset1);
         if (ret == -1)
-            return ret;
+            return -1;
     }
  the_end1:
     page_set_flags(start, start + len, prot | PAGE_VALID);
  the_end:
 #ifdef DEBUG_MMAP
-    printf("ret=0x%lx\n", (long)start);
+    printf("ret=0x%llx\n", start);
     page_dump(stdout);
     printf("\n");
 #endif
@@ -381,17 +408,18 @@ int target_munmap(target_ulong start, target_ulong len)
 
 /* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
    blocks which have been allocated starting on a host page */
-long target_mremap(target_ulong old_addr, target_ulong old_size,
+target_long target_mremap(target_ulong old_addr, target_ulong old_size,
                    target_ulong new_size, unsigned long flags,
                    target_ulong new_addr)
 {
     int prot;
+    unsigned long host_addr;
 
     /* XXX: use 5 args syscall */
-    new_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
-    if (new_addr == -1)
-        return new_addr;
-    new_addr = h2g(new_addr);
+    host_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
+    if (host_addr == -1)
+        return -1;
+    new_addr = h2g(host_addr);
     prot = page_get_flags(old_addr);
     page_set_flags(old_addr, old_addr + old_size, 0);
     page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);

linux-user/qemu.h

@@ -164,10 +164,10 @@ int do_vm86(CPUX86State *env, long subfunction, target_ulong v86_addr);
 
 /* mmap.c */
 int target_mprotect(target_ulong start, target_ulong len, int prot);
-long target_mmap(target_ulong start, target_ulong len, int prot,
+target_long target_mmap(target_ulong start, target_ulong len, int prot,
                  int flags, int fd, target_ulong offset);
 int target_munmap(target_ulong start, target_ulong len);
-long target_mremap(target_ulong old_addr, target_ulong old_size,
+target_long target_mremap(target_ulong old_addr, target_ulong old_size,
                    target_ulong new_size, unsigned long flags,
                    target_ulong new_addr);
 int target_msync(target_ulong start, target_ulong len, int flags);