qemu/0051-linux-user-Fix-stale-tbs-after-mmap.patch

From 43526150fac8e7d36739e948cb3ca2f433e4e607 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Mon, 7 May 2012 11:23:02 +0200
Subject: [PATCH] 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.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 exec-all.h        |    2 ++
 exec.c            |   17 +++++++++++++++++
 linux-user/mmap.c |    2 ++
 3 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/exec-all.h b/exec-all.h
index c211242..7fcd76f 100644
--- a/exec-all.h
+++ b/exec-all.h
@@ -96,6 +96,8 @@ void QEMU_NORETURN cpu_loop_exit(CPUState *env1);
 int page_unprotect(target_ulong address, unsigned long pc, void *puc);
 void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end,
                                    int is_cpu_write_access);
+void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end,
+                              int is_cpu_write_access);
 void tlb_flush_page(CPUState *env, target_ulong addr);
 void tlb_flush(CPUState *env, int flush_global);
 #if !defined(CONFIG_USER_ONLY)
diff --git a/exec.c b/exec.c
index e71a82d..532b00c 100644
--- a/exec.c
+++ b/exec.c
@@ -1016,6 +1016,23 @@ TranslationBlock *tb_gen_code(CPUState *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
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 2620f88..3611deb 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -587,6 +587,7 @@ 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, 0);
     mmap_unlock();
     return start;
 fail:
@@ -768,6 +769,7 @@ 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, 0);
     mmap_unlock();
     return new_addr;
 }