Received: from eggs.gnu.org ([2001:4830:134:3::10]:51201) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gF94Q-0001I3-7W for qemu-devel@nongnu.org; Tue, 23 Oct 2018 22:38:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gF94N-00062n-0k for qemu-devel@nongnu.org; Tue, 23 Oct 2018 22:38:53 -0400 Received: from mail-lj1-x243.google.com ([2a00:1450:4864:20::243]:46559) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gF94M-00060G-LO for qemu-devel@nongnu.org; Tue, 23 Oct 2018 22:38:50 -0400 Received: by mail-lj1-x243.google.com with SMTP id x3-v6so3254808lji.13 for ; Tue, 23 Oct 2018 19:38:47 -0700 (PDT) From: Max Filippov Date: Tue, 23 Oct 2018 19:38:31 -0700 Message-Id: <20181024023831.2529-1-jcmvbkbc@gmail.com> Subject: [Qemu-devel] [PATCH] linux-user/flatload: fix initial stack pointer alignment List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Laurent Vivier , Max Filippov Stack pointer alignment code incorrectly adds stack_size to sp instead of subtracting it. It also does not take flat_argvp_envp_on_stack() into account when calculating stack_size. This results in initial stack pointer misalignment with certain set of command line arguments and environment variables and correct alignment for the same binary with a different set of arguments. This misalignment causes failures in the following tests in the testsuite of gcc built for xtensa uclinux: gcc.dg/torture/vshuf-v64qi.c gcc.dg/torture/vshuf-v8sf.c gcc.dg/torture/vshuf-v8si.c Signed-off-by: Max Filippov --- linux-user/flatload.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/linux-user/flatload.c b/linux-user/flatload.c index 2eefe55e5000..1893966b5b30 100644 --- a/linux-user/flatload.c +++ b/linux-user/flatload.c @@ -771,10 +771,12 @@ int load_flt_binary(struct linux_binprm *bprm, struct image_info *info) /* Enforce final stack alignment of 16 bytes. This is sufficient for all current targets, and excess alignment is harmless. */ stack_len = bprm->envc + bprm->argc + 2; - stack_len += 3; /* argc, arvg, argp */ + stack_len += flat_argvp_envp_on_stack() ? 2 : 0; /* arvg, argp */ + stack_len += 1; /* argc */ stack_len *= sizeof(abi_ulong); - if ((sp + stack_len) & 15) - sp -= 16 - ((sp + stack_len) & 15); + if ((sp - stack_len) & 15) { + sp -= ((sp - stack_len) & 15); + } sp = loader_build_argptr(bprm->envc, bprm->argc, sp, p, flat_argvp_envp_on_stack()); -- 2.11.0