From patchwork Thu Dec 17 19:46:06 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "H.J. Lu" X-Patchwork-Id: 10056 Received: (qmail 31633 invoked by alias); 17 Dec 2015 19:46:11 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 31619 invoked by uid 89); 17 Dec 2015 19:46:10 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.6 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 spammy=1, 38 X-HELO: mail-qg0-f43.google.com MIME-Version: 1.0 X-Received: by 10.140.142.206 with SMTP id 197mr64711185qho.77.1450381566633; Thu, 17 Dec 2015 11:46:06 -0800 (PST) In-Reply-To: References: <20151215032733.GA14426@gmail.com> <20151215052534.GA1512@altlinux.org> Date: Thu, 17 Dec 2015 11:46:06 -0800 Message-ID: Subject: Re: [PATCH] [BZ #19363] Use INTERNAL_SYSCALL_TIMES for Linux times From: "H.J. Lu" To: GNU C Library On Thu, Dec 17, 2015 at 5:31 AM, H.J. Lu wrote: > On Wed, Dec 16, 2015 at 5:49 AM, H.J. Lu wrote: >> On Tue, Dec 15, 2015 at 5:52 AM, H.J. Lu wrote: >>> On Mon, Dec 14, 2015 at 9:25 PM, Dmitry V. Levin wrote: >>>> On Mon, Dec 14, 2015 at 07:27:33PM -0800, H.J. Lu wrote: >>>>> The Linux times function, which returns clock_t, is implemented with >>>>> INTERNAL_SYSCALL. Since INTERNAL_SYSCALL returns 32-bit integer and >>>>> and clock_t is 64-bit on x32, there is mismatch on x32. times is the >>>>> only such function since there is lseek.S for x32. This patch replaces >>>>> INTERNAL_SYSCALL in Linux times.c with INTERNAL_SYSCALL_TIMES which is >>>>> default to INTERNAL_SYSCALL and provides x32 times.c with proper >>>>> INTERNAL_SYSCALL_TIMES. >>>>> >>>>> There is no code change on times for i686 nor x86-64. For x32, before >>>>> this patch, there are >>>>> >>>>> 0000000 <__times>: >>>>> 0: b8 64 00 00 40 mov $0x40000064,%eax >>>>> 5: 0f 05 syscall >>>>> 7: 48 63 d0 movslq %eax,%rdx >>>>> ^^^^^^^^^^ Incorrect signed extension >>>>> a: 48 83 fa f2 cmp $0xfffffffffffffff2,%rdx >>>>> e: 75 07 jne 17 <__times+0x17> >>>>> 10: 3d 00 f0 ff ff cmp $0xfffff000,%eax >>>>> 15: 77 11 ja 28 <__times+0x28> >>>>> 17: 48 83 fa ff cmp $0xffffffffffffffff,%rdx >>>>> 1b: b8 00 00 00 00 mov $0x0,%eax >>>>> 20: 48 0f 45 c2 cmovne %rdx,%rax >>>>> 24: c3 retq >>>>> >>>>> After this patch, there are >>>>> >>>>> 00000000 <__times>: >>>>> 0: b8 64 00 00 40 mov $0x40000064,%eax >>>>> 5: 0f 05 syscall >>>>> 7: 48 83 f8 f2 cmp $0xfffffffffffffff2,%rax >>>>> b: 75 07 jne 14 <__times+0x14> >>>>> d: 3d 00 f0 ff ff cmp $0xfffff000,%eax >>>> >>>> Looks like there is another truncation remaining here that comes >>>> from INTERNAL_SYSCALL_ERROR_P. >>>> >>> >>> You are right. Here is the updated patch with all INTERNAL_SYSCALL* >>> macros replaced by INTERNAL_SYSCALL_TIMES* macros. >>> >>> There is no code change on i686 nor x86-64. OK for master? >> >> Here is the updated patch using REGISTERS_CLOBBERED_BY_SYSCALL. >> OK for master? >> >> > > Any comments? If people don't want to change > sysdeps/unix/sysv/linux/times.c, I can make a > copy and update it for x32. It turns out that we only need to add x32 times.c I am checking in this patch now. From 78bce218b25a1fd5e52632a8ed9317ff20c54c5e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 14 Dec 2015 19:09:13 -0800 Subject: [PATCH] Provide x32 times Since times returns 64-bit clock_t on x32, we need to provide x32 times by redefining INTERNAL_SYSCALL_NCS and INTERNAL_SYSCALL_ERROR_P with 64-bit return type for syscall. All system calls returning 64-bit integer, which are lseek, time and times, must be handled specially for x32. lseek is handled by x32 lseek.S and time doesn't check syscall return. times is the only missed one. Before this patch, there are 0000000 <__times>: 0: b8 64 00 00 40 mov $0x40000064,%eax 5: 0f 05 syscall 7: 48 63 d0 movslq %eax,%rdx ^^^^^^^^^^ Incorrect signed extension a: 48 83 fa f2 cmp $0xfffffffffffffff2,%rdx e: 75 07 jne 17 <__times+0x17> 10: 3d 00 f0 ff ff cmp $0xfffff000,%eax ^^^^^^^^^^^^^^^^^^^^^ 32-bit compare 15: 77 11 ja 28 <__times+0x28> 17: 48 83 fa ff cmp $0xffffffffffffffff,%rdx 1b: b8 00 00 00 00 mov $0x0,%eax 20: 48 0f 45 c2 cmovne %rdx,%rax 24: c3 retq After this patch, there are 00000000 <__times>: 0: b8 64 00 00 40 mov $0x40000064,%eax 5: 0f 05 syscall 7: 48 83 f8 f2 cmp $0xfffffffffffffff2,%rax b: 75 08 jne 15 <__times+0x15> d: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax 13: 77 13 ja 28 <__times+0x28> 15: 48 83 f8 ff cmp $0xffffffffffffffff,%rax 19: ba 00 00 00 00 mov $0x0,%edx 1e: 48 0f 44 c2 cmove %rdx,%rax 22: c3 retq The incorrect signed extension and 32-bit compare are gone. [BZ #19363] * sysdeps/unix/sysv/linux/x86_64/x32/times.c: New file. --- sysdeps/unix/sysv/linux/x86_64/x32/times.c | 38 ++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/times.c diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/times.c b/sysdeps/unix/sysv/linux/x86_64/x32/times.c new file mode 100644 index 0000000..3002d92 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/x32/times.c @@ -0,0 +1,38 @@ +/* Linux times. X32 version. + Copyright (C) 2015 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +/* Linux times system call returns 64-bit integer. */ +#undef INTERNAL_SYSCALL_NCS +#define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ + ({ \ + unsigned long long int resultvar; \ + LOAD_ARGS_##nr (args) \ + LOAD_REGS_##nr \ + asm volatile ( \ + "syscall\n\t" \ + : "=a" (resultvar) \ + : "0" (name) ASM_ARGS_##nr : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \ + (long long int) resultvar; }) + +#undef INTERNAL_SYSCALL_ERROR_P +#define INTERNAL_SYSCALL_ERROR_P(val, err) \ + ((unsigned long long int) (val) >= -4095LL) + +#include -- 2.5.0