X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/680c877af48cf5f2fb4586f34c13fd21ce33bfec..e4baa9f00b9ddf47ac2811eb58a3931434b848f7:/linux-user/mmap.c

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index fd315aaabb..4888f53139 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -16,24 +16,14 @@
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
-#include <stdlib.h>
-#include <stdio.h>
-#include <stdarg.h>
-#include <string.h>
-#include <unistd.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <linux/mman.h>
-#include <linux/unistd.h>
+#include "qemu/osdep.h"
 
 #include "qemu.h"
 #include "qemu-common.h"
+#include "translate-all.h"
 
 //#define DEBUG_MMAP
 
-#if defined(CONFIG_USE_NPTL)
 static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
 static __thread int mmap_lock_count;
 
@@ -51,6 +41,11 @@ void mmap_unlock(void)
     }
 }
 
+bool have_mmap_lock(void)
+{
+    return mmap_lock_count > 0 ? true : false;
+}
+
 /* Grab lock to make sure things are in a consistent state after fork().  */
 void mmap_fork_start(void)
 {
@@ -66,16 +61,6 @@ void mmap_fork_end(int child)
     else
         pthread_mutex_unlock(&mmap_mutex);
 }
-#else
-/* We aren't threadsafe to start with, so no need to worry about locking.  */
-void mmap_lock(void)
-{
-}
-
-void mmap_unlock(void)
-{
-}
-#endif
 
 /* NOTE: all the constants are the HOST ones, but addresses are target. */
 int target_mprotect(abi_ulong start, abi_ulong len, int prot)
@@ -196,26 +181,72 @@ static int mmap_frag(abi_ulong real_start,
         if (prot_new != (prot1 | PROT_WRITE))
             mprotect(host_start, qemu_host_page_size, prot_new);
     } else {
-        /* just update the protection */
         if (prot_new != prot1) {
             mprotect(host_start, qemu_host_page_size, prot_new);
         }
+        if (prot_new & PROT_WRITE) {
+            memset(g2h(start), 0, end - start);
+        }
     }
     return 0;
 }
 
 #if HOST_LONG_BITS == 64 && TARGET_ABI_BITS == 64
 # define TASK_UNMAPPED_BASE  (1ul << 38)
-#elif defined(__CYGWIN__)
-/* Cygwin doesn't have a whole lot of address space.  */
-# define TASK_UNMAPPED_BASE  0x18000000
 #else
 # define TASK_UNMAPPED_BASE  0x40000000
 #endif
-static abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
+abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
 
 unsigned long last_brk;
 
+/* Subroutine of mmap_find_vma, used when we have pre-allocated a chunk
+   of guest address space.  */
+static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size)
+{
+    abi_ulong addr;
+    abi_ulong end_addr;
+    int prot;
+    int looped = 0;
+
+    if (size > reserved_va) {
+        return (abi_ulong)-1;
+    }
+
+    size = HOST_PAGE_ALIGN(size);
+    end_addr = start + size;
+    if (end_addr > reserved_va) {
+        end_addr = reserved_va;
+    }
+    addr = end_addr - qemu_host_page_size;
+
+    while (1) {
+        if (addr > end_addr) {
+            if (looped) {
+                return (abi_ulong)-1;
+            }
+            end_addr = reserved_va;
+            addr = end_addr - qemu_host_page_size;
+            looped = 1;
+            continue;
+        }
+        prot = page_get_flags(addr);
+        if (prot) {
+            end_addr = addr;
+        }
+        if (addr + size == end_addr) {
+            break;
+        }
+        addr -= qemu_host_page_size;
+    }
+
+    if (start == mmap_next_start) {
+        mmap_next_start = addr;
+    }
+
+    return addr;
+}
+
 /*
  * Find and reserve a free memory area of size 'size'. The search
  * starts at 'start'.
@@ -237,6 +268,10 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
 
     size = HOST_PAGE_ALIGN(size);
 
+    if (reserved_va) {
+        return mmap_find_vma_reserved(start, size);
+    }
+
     addr = start;
     wrapped = repeat = 0;
     prev = 0;
@@ -304,7 +339,7 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
         munmap(ptr, size);
 
         /* ENOMEM if we checked the whole of the target address space.  */
-        if (addr == -1ul) {
+        if (addr == (abi_ulong)-1) {
             return (abi_ulong)-1;
         } else if (addr == 0) {
             if (wrapped) {
@@ -312,7 +347,7 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
             }
             wrapped = 1;
             /* Don't actually use 0 when wrapping, instead indicate
-               that we'd truely like an allocation in low memory.  */
+               that we'd truly like an allocation in low memory.  */
             addr = (mmap_min_addr > TARGET_PAGE_SIZE
                      ? TARGET_PAGE_ALIGN(mmap_min_addr)
                      : TARGET_PAGE_SIZE);
@@ -327,7 +362,6 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                      int flags, int fd, abi_ulong offset)
 {
     abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
-    unsigned long host_start;
 
     mmap_lock();
 #ifdef DEBUG_MMAP
@@ -366,6 +400,19 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
     if (len == 0)
         goto the_end;
     real_start = start & qemu_host_page_mask;
+    host_offset = offset & qemu_host_page_mask;
+
+    /* If the user is asking for the kernel to find a location, do that
+       before we truncate the length for mapping files below.  */
+    if (!(flags & MAP_FIXED)) {
+        host_len = len + offset - host_offset;
+        host_len = HOST_PAGE_ALIGN(host_len);
+        start = mmap_find_vma(real_start, host_len);
+        if (start == (abi_ulong)-1) {
+            errno = ENOMEM;
+            goto fail;
+        }
+    }
 
     /* When mapping files into a memory area larger than the file, accesses
        to pages beyond the file size will cause a SIGBUS. 
@@ -379,9 +426,9 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
        may need to truncate file maps at EOF and add extra anonymous pages
        up to the targets page boundary.  */
 
-    if ((qemu_real_host_page_size < TARGET_PAGE_SIZE)
-        && !(flags & MAP_ANONYMOUS)) {
-       struct stat sb;
+    if ((qemu_real_host_page_size < qemu_host_page_size) &&
+        !(flags & MAP_ANONYMOUS)) {
+        struct stat sb;
 
        if (fstat (fd, &sb) == -1)
            goto fail;
@@ -391,35 +438,33 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
            /* If so, truncate the file map at eof aligned with 
               the hosts real pagesize. Additional anonymous maps
               will be created beyond EOF.  */
-           len = (sb.st_size - offset);
-           len += qemu_real_host_page_size - 1;
-           len &= ~(qemu_real_host_page_size - 1);
+           len = REAL_HOST_PAGE_ALIGN(sb.st_size - offset);
        }
     }
 
     if (!(flags & MAP_FIXED)) {
-        abi_ulong mmap_start;
+        unsigned long host_start;
         void *p;
-        host_offset = offset & qemu_host_page_mask;
+
         host_len = len + offset - host_offset;
         host_len = HOST_PAGE_ALIGN(host_len);
-        mmap_start = mmap_find_vma(real_start, host_len);
-        if (mmap_start == (abi_ulong)-1) {
-            errno = ENOMEM;
-            goto fail;
-        }
+
         /* Note: we prefer to control the mapping address. It is
            especially important if qemu_host_page_size >
            qemu_real_host_page_size */
-        p = mmap(g2h(mmap_start),
-                 host_len, prot, flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
+        p = mmap(g2h(start), host_len, prot,
+                 flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
         if (p == MAP_FAILED)
             goto fail;
         /* update start so that it points to the file position at 'offset' */
         host_start = (unsigned long)p;
         if (!(flags & MAP_ANONYMOUS)) {
-            p = mmap(g2h(mmap_start), len, prot, 
+            p = mmap(g2h(start), len, prot,
                      flags | MAP_FIXED, fd, host_offset);
+            if (p == MAP_FAILED) {
+                munmap(g2h(start), host_len);
+                goto fail;
+            }
             host_start += offset - host_offset;
         }
         start = h2g(host_start);
@@ -461,10 +506,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                 goto fail;
             if (!(prot & PROT_WRITE)) {
                 ret = target_mprotect(start, len, prot);
-                if (ret != 0) {
-                    start = ret;
-                    goto the_end;
-                }
+                assert(ret == 0);
             }
             goto the_end;
         }
@@ -488,7 +530,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
         /* handle the end of the mapping */
         if (end < real_end) {
             ret = mmap_frag(real_end - qemu_host_page_size,
-                            real_end - qemu_host_page_size, real_end,
+                            real_end - qemu_host_page_size, end,
                             prot, flags, fd,
                             offset + real_end - qemu_host_page_size - start);
             if (ret == -1)
@@ -518,6 +560,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
     page_dump(stdout);
     printf("\n");
 #endif
+    tb_invalidate_phys_range(start, start + len);
     mmap_unlock();
     return start;
 fail:
@@ -525,6 +568,47 @@ fail:
     return -1;
 }
 
+static void mmap_reserve(abi_ulong start, abi_ulong size)
+{
+    abi_ulong real_start;
+    abi_ulong real_end;
+    abi_ulong addr;
+    abi_ulong end;
+    int prot;
+
+    real_start = start & qemu_host_page_mask;
+    real_end = HOST_PAGE_ALIGN(start + size);
+    end = start + size;
+    if (start > real_start) {
+        /* handle host page containing start */
+        prot = 0;
+        for (addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
+            prot |= page_get_flags(addr);
+        }
+        if (real_end == real_start + qemu_host_page_size) {
+            for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+                prot |= page_get_flags(addr);
+            }
+            end = real_end;
+        }
+        if (prot != 0)
+            real_start += qemu_host_page_size;
+    }
+    if (end < real_end) {
+        prot = 0;
+        for (addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+            prot |= page_get_flags(addr);
+        }
+        if (prot != 0)
+            real_end -= qemu_host_page_size;
+    }
+    if (real_start != real_end) {
+        mmap(g2h(real_start), real_end - real_start, PROT_NONE,
+                 MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE,
+                 -1, 0);
+    }
+}
+
 int target_munmap(abi_ulong start, abi_ulong len)
 {
     abi_ulong end, real_start, real_end, addr;
@@ -572,11 +656,17 @@ int target_munmap(abi_ulong start, abi_ulong len)
     ret = 0;
     /* unmap what we can */
     if (real_start < real_end) {
-        ret = munmap(g2h(real_start), real_end - real_start);
+        if (reserved_va) {
+            mmap_reserve(real_start, real_end - real_start);
+        } else {
+            ret = munmap(g2h(real_start), real_end - real_start);
+        }
     }
 
-    if (ret == 0)
+    if (ret == 0) {
         page_set_flags(start, start + len, 0);
+        tb_invalidate_phys_range(start, start + len);
+    }
     mmap_unlock();
     return ret;
 }
@@ -590,12 +680,16 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
 
     mmap_lock();
 
-    if (flags & MREMAP_FIXED)
-        host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
-                                     old_size, new_size,
-                                     flags,
-                                     new_addr);
-    else if (flags & MREMAP_MAYMOVE) {
+    if (flags & MREMAP_FIXED) {
+        host_addr = mremap(g2h(old_addr), old_size, new_size,
+                           flags, g2h(new_addr));
+
+        if (reserved_va && host_addr != MAP_FAILED) {
+            /* If new and old addresses overlap then the above mremap will
+               already have failed with EINVAL.  */
+            mmap_reserve(old_addr, old_size);
+        }
+    } else if (flags & MREMAP_MAYMOVE) {
         abi_ulong mmap_start;
 
         mmap_start = mmap_find_vma(0, new_size);
@@ -603,13 +697,32 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
         if (mmap_start == -1) {
             errno = ENOMEM;
             host_addr = MAP_FAILED;
-        } else
-            host_addr = (void *) syscall(__NR_mremap, g2h(old_addr),
-                                         old_size, new_size,
-                                         flags | MREMAP_FIXED,
-                                         g2h(mmap_start));
+        } else {
+            host_addr = mremap(g2h(old_addr), old_size, new_size,
+                               flags | MREMAP_FIXED, g2h(mmap_start));
+            if (reserved_va) {
+                mmap_reserve(old_addr, old_size);
+            }
+        }
     } else {
-        host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
+        int prot = 0;
+        if (reserved_va && old_size < new_size) {
+            abi_ulong addr;
+            for (addr = old_addr + old_size;
+                 addr < old_addr + new_size;
+                 addr++) {
+                prot |= page_get_flags(addr);
+            }
+        }
+        if (prot == 0) {
+            host_addr = mremap(g2h(old_addr), old_size, new_size, flags);
+            if (host_addr != MAP_FAILED && reserved_va && old_size > new_size) {
+                mmap_reserve(old_addr + old_size, new_size - old_size);
+            }
+        } else {
+            errno = ENOMEM;
+            host_addr = MAP_FAILED;
+        }
         /* Check if address fits target address space */
         if ((unsigned long)host_addr + new_size > (abi_ulong)-1) {
             /* Revert mremap() changes */
@@ -627,6 +740,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
         page_set_flags(old_addr, old_addr + old_size, 0);
         page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
     }
+    tb_invalidate_phys_range(new_addr, new_addr + new_size);
     mmap_unlock();
     return new_addr;
 }