Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-2.13-pull-request' into staging

# gpg: Signature made Mon 30 Apr 2018 10:05:56 BST
# gpg:                using RSA key F30C38BD3F2FBE3C
# 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-2.13-pull-request: (42 commits)
  linux-user: Add ARM get_tls syscall support
  linux-user: move xtensa cpu loop to xtensa directory
  linux-user: move hppa cpu loop to hppa directory
  linux-user: move riscv cpu loop to riscv directory
  linux-user: move tilegx cpu loop to tilegx directory
  linux-user: move s390x cpu loop to s390x directory
  linux-user: move alpha cpu loop to alpha directory
  linux-user: move m68k cpu loop to m68k directory
  linux-user: move microblaze cpu loop to microblaze directory
  linux-user: move cris cpu loop to cris directory
  linux-user: move sh4 cpu loop to sh4 directory
  linux-user: move openrisc cpu loop to openrisc directory
  linux-user: move nios2 cpu loop to nios2 directory
  linux-user: move mips/mips64 cpu loop to mips directory
  linux-user: move ppc/ppc64 cpu loop to ppc directory
  linux-user: move sparc/sparc64 cpu loop to sparc directory
  linux-user: move arm cpu loop to arm directory
  linux-user: move aarch64 cpu loop to aarch64 directory
  linux-user: move i386/x86_64 cpu loop to i386 directory
  linux-user: create a dummy per arch cpu_loop.c
  ...

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

1 files changed, 15 insertions, 3 deletions

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 643b8833de..404be44ad5 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -259,10 +259,22 @@ static int gettid(void) {
     return -ENOSYS;
 }
 #endif
-#if defined(TARGET_NR_getdents) && defined(__NR_getdents)
+
+/* For the 64-bit guest on 32-bit host case we must emulate
+ * getdents using getdents64, because otherwise the host
+ * might hand us back more dirent records than we can fit
+ * into the guest buffer after structure format conversion.
+ * Otherwise we emulate getdents with getdents if the host has it.
+ */
+#if defined(__NR_getdents) && HOST_LONG_BITS >= TARGET_ABI_BITS
+#define EMULATE_GETDENTS_WITH_GETDENTS
+#endif
+
+#if defined(TARGET_NR_getdents) && defined(EMULATE_GETDENTS_WITH_GETDENTS)
 _syscall3(int, sys_getdents, uint, fd, struct linux_dirent *, dirp, uint, count);
 #endif
-#if !defined(__NR_getdents) || \
+#if (defined(TARGET_NR_getdents) && \
+      !defined(EMULATE_GETDENTS_WITH_GETDENTS)) || \
     (defined(TARGET_NR_getdents64) && defined(__NR_getdents64))
 _syscall3(int, sys_getdents64, uint, fd, struct linux_dirent64 *, dirp, uint, count);
 #endif
@@ -10163,7 +10175,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_getdents
     case TARGET_NR_getdents:
-#ifdef __NR_getdents
+#ifdef EMULATE_GETDENTS_WITH_GETDENTS
 #if TARGET_ABI_BITS == 32 && HOST_LONG_BITS == 64
         {
             struct target_dirent *target_dirp;