From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936455AbdEXHBS (ORCPT ); Wed, 24 May 2017 03:01:18 -0400 Received: from b.ns.miles-group.at ([95.130.255.144]:44723 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934256AbdEXHBQ (ORCPT ); Wed, 24 May 2017 03:01:16 -0400 Subject: Re: [PATCH] um: Allow building and running on older hosts To: Florian Fainelli , linux-kernel@vger.kernel.org References: <20170524010858.16134-1-f.fainelli@gmail.com> Cc: elicooper@gmx.com, Jeff Dike , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "open list:USER-MODE LINUX (UML)" , "open list:USER-MODE LINUX (UML)" , Thomas Meyer From: Richard Weinberger Message-ID: Date: Wed, 24 May 2017 09:01:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20170524010858.16134-1-f.fainelli@gmail.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CC'ing Thomas. We is also facing issues with these commits. Am 24.05.2017 um 03:08 schrieb Florian Fainelli: > Commit a78ff1112263 ("um: add extended processor state save/restore > support") and b6024b21fec8 ("um: extend fpstate to _xstate to support > YMM registers") forced the use of the x86 FP _xstate and > PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to > build UML nor run it anymore with these two commits applied because we > don't have definitions for struct _xstate nor these two ptrace requests. > > We can determine at build time which fp context structure to check > against, just like we can keep using the old i387 fp save/restore if > PTRACE_GETRESET/SETREGSET are not defined. > > Fixes: a78ff1112263 ("um: add extended processor state save/restore support") > Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers") > Signed-off-by: Florian Fainelli > --- > arch/x86/um/os-Linux/registers.c | 13 +++++++++---- > arch/x86/um/user-offsets.c | 4 ++++ > 2 files changed, 13 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c > index 00f54a91bb4b..502bd642e5c2 100644 > --- a/arch/x86/um/os-Linux/registers.c > +++ b/arch/x86/um/os-Linux/registers.c > @@ -26,13 +26,14 @@ int save_i387_registers(int pid, unsigned long *fp_regs) > > int save_fp_registers(int pid, unsigned long *fp_regs) > { > - struct iovec iov; > - > if (have_xstate_support) { > +#ifdef PTRACE_GETREGSET > + struct iovec iov; > iov.iov_base = fp_regs; > iov.iov_len = sizeof(struct _xstate); > if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0) > return -errno; > +#endif > return 0; > } else { > return save_i387_registers(pid, fp_regs); > @@ -48,13 +49,15 @@ int restore_i387_registers(int pid, unsigned long *fp_regs) > > int restore_fp_registers(int pid, unsigned long *fp_regs) > { > - struct iovec iov; > - > if (have_xstate_support) { > +#ifdef PTRACE_SETREGSET > + struct iovec iov; > + > iov.iov_base = fp_regs; > iov.iov_len = sizeof(struct _xstate); > if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0) > return -errno; > +#endif > return 0; > } else { > return restore_i387_registers(pid, fp_regs); > @@ -127,8 +130,10 @@ void arch_init_registers(int pid) > > iov.iov_base = &fp_regs; > iov.iov_len = sizeof(struct _xstate); > +#ifdef PTRACE_GETREGSET > if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0) > have_xstate_support = 1; > +#endif > } > #endif > > diff --git a/arch/x86/um/user-offsets.c b/arch/x86/um/user-offsets.c > index cb3c22370cf5..8af0fb5d2780 100644 > --- a/arch/x86/um/user-offsets.c > +++ b/arch/x86/um/user-offsets.c > @@ -50,7 +50,11 @@ void foo(void) > DEFINE(HOST_GS, GS); > DEFINE(HOST_ORIG_AX, ORIG_EAX); > #else > +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET) > DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long)); > +#else > + DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long)); > +#endif > DEFINE_LONGS(HOST_BX, RBX); > DEFINE_LONGS(HOST_CX, RCX); > DEFINE_LONGS(HOST_DI, RDI); >