From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82FC2C63697 for ; Fri, 13 Nov 2020 23:32:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F21422256 for ; Fri, 13 Nov 2020 23:32:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="jSNVZO0K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726221AbgKMXbs (ORCPT ); Fri, 13 Nov 2020 18:31:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726039AbgKMXbr (ORCPT ); Fri, 13 Nov 2020 18:31:47 -0500 Received: from mail-vs1-xe42.google.com (mail-vs1-xe42.google.com [IPv6:2607:f8b0:4864:20::e42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F958C0617A6 for ; Fri, 13 Nov 2020 15:31:47 -0800 (PST) Received: by mail-vs1-xe42.google.com with SMTP id m16so6097107vsl.8 for ; Fri, 13 Nov 2020 15:31:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=AJStHOY5Qh2DGFTroegyQhWYQ1MmCmTEUHWIJvas+7M=; b=jSNVZO0K7wzWNgivPRsTS23unTlL5xu3JAtfH6tP3wTtqKXHTFxKLDpXglVNKVogCS 6GN3EBqfM/ZUBQPh9/KXRac8yN3VH0HlBG3quWK6QtaxtiL1rK8O5VK7VVHqo6J7Rt/X pLPxkZTYuxt9e7KMQUlSjLI7JuuwGE0+gzwfrHa+KQQiFj8lluSMbarMau3hHsSH1/Ly I1ayeKXU+HZyBmmdWsN2DNObwSk0A53WftOV1KjCprrJHCY1GRvxqs5hu+HPHBc4Mr91 nRjSltnInqcTuCWkLRcwZA5Rf8Mmi9P0lK2FChkaNPICHq6O3gumsgzJMmBvO66F5HQu PNWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=AJStHOY5Qh2DGFTroegyQhWYQ1MmCmTEUHWIJvas+7M=; b=WtMVs2voR/dSphTx0NARMdldh4FT6kfu5Zn67KFqdpzf8nK/p1Hv/xRnPekOfcU7EQ HAMB1aoZCsLDzeWaSzT5Et7t5O2uzUm0VSAkh5y/mpYwuGOgupFfz1Q20vCZ7/bdM7zk kB1XpVrL0OMD1CGNInlCpSA0VrYTxJMWv8Jhvtobw+jRy7x7G+GM2ZAJkcGYAmHhDwQC ATxP8AHe4kuxRzFKGHtLG4v6DYLludszjf48zht6uRykpTdtr1uYefY7rYR2F7TB6m33 45QiX3nlrMO7/goz3qkloWIk4rozkkjiBqGa6sW820VMdu2DPADjov/YZAhbrKLejR0m BNUw== X-Gm-Message-State: AOAM532jU2IrbFKe7CHcWEhYcISIVUfOFm8kNn7G0tthhbPw9J7+5BTT b7GFgbC8Vq5/qVy1dZ7xUjlQzCLpqmJ/bsq7Dv28jg== X-Google-Smtp-Source: ABdhPJxSW9RODWqSRFIxVh02sljFGIxaFmVwff0K0MDsmxDUSocAvDQCNoKIe2vb8EcMsPSHfR3I4Mur2BV/pt3dnso= X-Received: by 2002:a67:ee93:: with SMTP id n19mr3267175vsp.36.1605310306224; Fri, 13 Nov 2020 15:31:46 -0800 (PST) MIME-Version: 1.0 References: <20201021085606.GZ2628@hirez.programming.kicks-ass.net> <20201023173617.GA3021099@google.com> <20201110022924.tekltjo25wtrao7z@treble> <20201110174606.mp5m33lgqksks4mt@treble> <20201113195408.atbpjizijnhuinzy@treble> <20201113223412.inono2ekrs7ky7rm@treble> In-Reply-To: <20201113223412.inono2ekrs7ky7rm@treble> From: Sami Tolvanen Date: Fri, 13 Nov 2020 15:31:34 -0800 Message-ID: Subject: Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps To: Josh Poimboeuf Cc: Peter Zijlstra , Jann Horn , "the arch/x86 maintainers" , Masahiro Yamada , Steven Rostedt , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , linux-kbuild , kernel list , linux-pci@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Fri, Nov 13, 2020 at 2:34 PM Josh Poimboeuf wrote: > > On Fri, Nov 13, 2020 at 12:24:32PM -0800, Sami Tolvanen wrote: > > > I still don't see this warning for some reason. > > > > Do you have CONFIG_XEN enabled? I can reproduce this on ToT master as follows: > > > > $ git rev-parse HEAD > > 585e5b17b92dead8a3aca4e3c9876fbca5f7e0ba > > $ make defconfig && \ > > ./scripts/config -e HYPERVISOR_GUEST -e PARAVIRT -e XEN && \ > > make olddefconfig && \ > > make -j110 > > ... > > $ ./tools/objtool/objtool check -arfld vmlinux.o 2>&1 | grep secondary > > vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with > > modified stack frame > > > > > Is it fixed by adding cpu_bringup_and_idle() to global_noreturns[] in > > > tools/objtool/check.c? > > > > No, that didn't fix the warning. Here's what I tested: > > I think this fixes it: > > From: Josh Poimboeuf > Subject: [PATCH] x86/xen: Fix objtool vmlinux.o validation of xen hypercalls > > Objtool vmlinux.o validation is showing warnings like the following: > > # tools/objtool/objtool check -barfld vmlinux.o > vmlinux.o: warning: objtool: __startup_secondary_64()+0x2: return with modified stack frame > vmlinux.o: warning: objtool: xen_hypercall_set_trap_table()+0x0: <=== (sym) > > Objtool falls through all the empty hypercall text and gets confused > when it encounters the first real function afterwards. The empty unwind > hints in the hypercalls aren't working for some reason. Replace them > with a more straightforward use of STACK_FRAME_NON_STANDARD. > > Reported-by: Sami Tolvanen > Signed-off-by: Josh Poimboeuf > --- > arch/x86/xen/xen-head.S | 9 ++++----- > include/linux/objtool.h | 8 ++++++++ > 2 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S > index 2d7c8f34f56c..3c538b1ff4a6 100644 > --- a/arch/x86/xen/xen-head.S > +++ b/arch/x86/xen/xen-head.S > @@ -6,6 +6,7 @@ > > #include > #include > +#include > > #include > #include > @@ -67,14 +68,12 @@ SYM_CODE_END(asm_cpu_bringup_and_idle) > .pushsection .text > .balign PAGE_SIZE > SYM_CODE_START(hypercall_page) > - .rept (PAGE_SIZE / 32) > - UNWIND_HINT_EMPTY > - .skip 32 > - .endr > + .skip PAGE_SIZE > > #define HYPERCALL(n) \ > .equ xen_hypercall_##n, hypercall_page + __HYPERVISOR_##n * 32; \ > - .type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32 > + .type xen_hypercall_##n, @function; .size xen_hypercall_##n, 32; \ > + STACK_FRAME_NON_STANDARD xen_hypercall_##n > #include > #undef HYPERCALL > SYM_CODE_END(hypercall_page) > diff --git a/include/linux/objtool.h b/include/linux/objtool.h > index 577f51436cf9..746617265236 100644 > --- a/include/linux/objtool.h > +++ b/include/linux/objtool.h > @@ -109,6 +109,12 @@ struct unwind_hint { > .popsection > .endm > > +.macro STACK_FRAME_NON_STANDARD func:req > + .pushsection .discard.func_stack_frame_non_standard > + .long \func - . > + .popsection > +.endm > + > #endif /* __ASSEMBLY__ */ > > #else /* !CONFIG_STACK_VALIDATION */ > @@ -123,6 +129,8 @@ struct unwind_hint { > .macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0 > .endm > #endif > +.macro STACK_FRAME_NON_STANDARD func:req > +.endm This macro needs to be before the #endif, so it's defined only for assembly code. This breaks my arm64 builds even though x86 curiously worked just fine. Sami