latent_entropy: fix ARM build error on earlier gcc

commit 9988f4d577f42f43b7612d755477585f35424af7 upstream.

This fixes build errors seen on gcc-4.9.3 or gcc-5.3.1 for an ARM:

arm-soc/init/initramfs.c: In function 'error':
arm-soc/init/initramfs.c:50:1: error: unrecognizable insn:
 }
 ^
(insn 26 25 27 5 (set (reg:SI 111 [ local_entropy.243 ])
        (rotatert:SI (reg:SI 116 [ local_entropy.243 ])
            (const_int -30 [0xffffffffffffffe2]))) -1
     (nil))

Patch from PaX Team <pageexec@freemail.hu>

Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index 8160f1c1b56ed941a6e15f7c906f8fb990edcdd3..dff390f692a2c61e3117d2075dca40c13bef66b0 100644 (file)
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -328,9 +328,9 @@ static enum tree_code get_op(tree *rhs)
                        op = LROTATE_EXPR;
                        /*
                         * This code limits the value of random_const to
-                        * the size of a wide int for the rotation
+                        * the size of a long for the rotation
                         */
-                       random_const &= HOST_BITS_PER_WIDE_INT - 1;
+                       random_const %= TYPE_PRECISION(long_unsigned_type_node);
                        break;
                }