linux-user: Fix stale tbs after mmap

If we execute linux-user code that does the following:

  * A = mmap()
  * execute code in A
  * munmap(A)
  * B = mmap(), but mmap returns the same address as A
  * execute code in B

we end up executing a stale cached tb that contains translated code
from A, while we want new code from B.

This patch adds a TB flush for mmap'ed regions, before we return them,
avoiding the whole issue. It also adds a flush for munmap, so that we
don't execute stale TBs instead of getting a segfault.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index 0607c9b..a0494c7 100644
--- a/exec.c
+++ b/exec.c
@@ -1075,6 +1075,23 @@ TranslationBlock *tb_gen_code(CPUArchState *env,
     return tb;
 }
 
+/*
+ * invalidate all TBs which intersect with the target physical pages
+ * starting in range [start;end[. NOTE: start and end may refer to
+ * different physical pages. 'is_cpu_write_access' should be true if called
+ * from a real cpu write access: the virtual CPU will exit the current
+ * TB if code is modified inside this TB.
+ */
+void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end,
+                              int is_cpu_write_access)
+{
+    while (start < end) {
+        tb_invalidate_phys_page_range(start, end, is_cpu_write_access);
+        start &= TARGET_PAGE_MASK;
+        start += TARGET_PAGE_SIZE;
+    }
+}
+
 /* invalidate all TBs which intersect with the target physical page
    starting in range [start;end[. NOTE: start and end must refer to
    the same physical page. 'is_cpu_write_access' should be true if called