Remove PAGE_RESERVED

The usermode PAGE_RESERVED code is not required by the current mmap
implementation, and is already broken when guest_base != 0.
Unfortunately the bsd emulation still uses the old mmap implementation,
so we can't rip it out altogether.

Signed-off-by: Paul Brook <paul@codesourcery.com>

cpu-all.h

@@ -742,7 +742,10 @@ extern unsigned long qemu_host_page_mask;
 /* original state of the write flag (used when tracking self-modifying
    code */
 #define PAGE_WRITE_ORG 0x0010
+#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
+/* FIXME: Code that sets/uses this is broken and needs to go away.  */
 #define PAGE_RESERVED  0x0020
+#endif
 
 #if defined(CONFIG_USER_ONLY)
 void page_dump(FILE *f);

exec.c

@@ -288,7 +288,7 @@ static void page_init(void)
         qemu_host_page_bits++;
     qemu_host_page_mask = ~(qemu_host_page_size - 1);
 
-#if !defined(_WIN32) && defined(CONFIG_USER_ONLY)
+#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
     {
 #ifdef HAVE_KINFO_GETVMMAP
         struct kinfo_vmentry *freep;
@@ -324,11 +324,7 @@ static void page_init(void)
 
         last_brk = (unsigned long)sbrk(0);
 
-#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
         f = fopen("/compat/linux/proc/self/maps", "r");
-#else
-        f = fopen("/proc/self/maps", "r");
-#endif
         if (f) {
             mmap_lock();
 
@@ -365,24 +361,11 @@ static PageDesc *page_find_alloc(tb_page_addr_t index, int alloc)
     int i;
 
 #if defined(CONFIG_USER_ONLY)
-    /* We can't use qemu_malloc because it may recurse into a locked mutex.
+    /* We can't use qemu_malloc because it may recurse into a locked mutex. */
-       Neither can we record the new pages we reserve while allocating a
-       given page because that may recurse into an unallocated page table
-       entry.  Stuff the allocations we do make into a queue and process
-       them after having completed one entire page table allocation.  */
-
-    unsigned long reserve[2 * (V_L1_SHIFT / L2_BITS)];
-    int reserve_idx = 0;
-
 # define ALLOC(P, SIZE)                                 \
     do {                                                \
         P = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,    \
                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);   \
-        if (h2g_valid(P)) {                             \
-            reserve[reserve_idx] = h2g(P);              \
-            reserve[reserve_idx + 1] = SIZE;            \
-            reserve_idx += 2;                           \
-        }                                               \
     } while (0)
 #else
 # define ALLOC(P, SIZE) \
@@ -417,16 +400,6 @@ static PageDesc *page_find_alloc(tb_page_addr_t index, int alloc)
     }
 
 #undef ALLOC
-#if defined(CONFIG_USER_ONLY)
-    for (i = 0; i < reserve_idx; i += 2) {
-        unsigned long addr = reserve[i];
-        unsigned long len = reserve[i + 1];
-
-        page_set_flags(addr & TARGET_PAGE_MASK,
-                       TARGET_PAGE_ALIGN(addr + len),
-                       PAGE_RESERVED);
-    }
-#endif
 
     return pd + (index & (L2_SIZE - 1));
 }

linux-user/elfload.c

@@ -2159,12 +2159,6 @@ static int vma_walker(void *priv, abi_ulong start, abi_ulong end,
 {
     struct mm_struct *mm = (struct mm_struct *)priv;
 
-    /*
-     * Don't dump anything that qemu has reserved for internal use.
-     */
-    if (flags & PAGE_RESERVED)
-        return (0);
-
     vma_add_mapping(mm, start, end, flags);
     return (0);
 }

linux-user/mmap.c

@@ -85,14 +85,6 @@ void *qemu_vmalloc(size_t size)
     /* Use map and mark the pages as used.  */
     p = mmap(NULL, size, PROT_READ | PROT_WRITE,
              MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-
-    if (h2g_valid(p)) {
-        /* Allocated region overlaps guest address space. This may recurse.  */
-        abi_ulong addr = h2g(p);
-        page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr + size),
-                       PAGE_RESERVED);
-    }
-
     mmap_unlock();
     return p;
 }
@@ -484,9 +476,6 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
         }
         start = h2g(host_start);
     } else {
-        int flg;
-        target_ulong addr;
-
         if (start & ~TARGET_PAGE_MASK) {
             errno = EINVAL;
             goto fail;
@@ -504,14 +493,6 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
             goto fail;
         }
 
-        for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
-            flg = page_get_flags(addr);
-            if (flg & PAGE_RESERVED) {
-                errno = ENXIO;
-                goto fail;
-            }
-        }
-
         /* worst case: we cannot map the file because the offset is not
            aligned, so we read it */
         if (!(flags & MAP_ANONYMOUS) &&