Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.12-pull-request' into staging

# gpg: Signature made Tue 23 Jan 2018 14:47:41 GMT
# gpg:                using RSA key 0xF30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-2.12-pull-request:
  linux-user: implement renameat2
  page_unprotect(): handle calls to pages that are PAGE_WRITE
  linux-user: Propagate siginfo_t through to handle_cpu_signal()
  linux-user: remove nmi.c and fw-path-provider.c
  linux-user: Add getcpu() support
  linux-user: Add AT_SECURE auxval
  linux-user: Fix sched_get/setaffinity conversion
  linux-user/mmap.c: Avoid choosing NULL as start address
  linux-user: Translate flags argument to dup3 syscall
  linux-user: Don't use CMSG_ALIGN(sizeof struct cmsghdr)
  linux-user: Fix length calculations in host_to_target_cmsg()
  linux-user: wrap fork() in a start/end exclusive section
  linux-user: Fix locking order in fork_start()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 31 insertions, 19 deletions

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 7736257085..67795cd78c 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -2181,29 +2181,41 @@ int page_unprotect(target_ulong address, uintptr_t pc)
 
     /* if the page was really writable, then we change its
        protection back to writable */
-    if ((p->flags & PAGE_WRITE_ORG) && !(p->flags & PAGE_WRITE)) {
-        host_start = address & qemu_host_page_mask;
-        host_end = host_start + qemu_host_page_size;
-
-        prot = 0;
+    if (p->flags & PAGE_WRITE_ORG) {
         current_tb_invalidated = false;
-        for (addr = host_start ; addr < host_end ; addr += TARGET_PAGE_SIZE) {
-            p = page_find(addr >> TARGET_PAGE_BITS);
-            p->flags |= PAGE_WRITE;
-            prot |= p->flags;
-
-            /* and since the content will be modified, we must invalidate
-               the corresponding translated code. */
-            current_tb_invalidated |= tb_invalidate_phys_page(addr, pc);
-#ifdef CONFIG_USER_ONLY
-            if (DEBUG_TB_CHECK_GATE) {
-                tb_invalidate_check(addr);
+        if (p->flags & PAGE_WRITE) {
+            /* If the page is actually marked WRITE then assume this is because
+             * this thread raced with another one which got here first and
+             * set the page to PAGE_WRITE and did the TB invalidate for us.
+             */
+#ifdef TARGET_HAS_PRECISE_SMC
+            TranslationBlock *current_tb = tb_find_pc(pc);
+            if (current_tb) {
+                current_tb_invalidated = tb_cflags(current_tb) & CF_INVALID;
             }
 #endif
+        } else {
+            host_start = address & qemu_host_page_mask;
+            host_end = host_start + qemu_host_page_size;
+
+            prot = 0;
+            for (addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) {
+                p = page_find(addr >> TARGET_PAGE_BITS);
+                p->flags |= PAGE_WRITE;
+                prot |= p->flags;
+
+                /* and since the content will be modified, we must invalidate
+                   the corresponding translated code. */
+                current_tb_invalidated |= tb_invalidate_phys_page(addr, pc);
+#ifdef CONFIG_USER_ONLY
+                if (DEBUG_TB_CHECK_GATE) {
+                    tb_invalidate_check(addr);
+                }
+#endif
+            }
+            mprotect((void *)g2h(host_start), qemu_host_page_size,
+                     prot & PAGE_BITS);
         }
-        mprotect((void *)g2h(host_start), qemu_host_page_size,
-                 prot & PAGE_BITS);
-
         mmap_unlock();
         /* If current TB was invalidated return to main loop */
         return current_tb_invalidated ? 2 : 1;