Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759915AbYGPXF3 (ORCPT ); Wed, 16 Jul 2008 19:05:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759323AbYGPXFL (ORCPT ); Wed, 16 Jul 2008 19:05:11 -0400 Received: from mx1.redhat.com ([66.187.233.31]:34199 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759305AbYGPXFK (ORCPT ); Wed, 16 Jul 2008 19:05:10 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Ingo Molnar , Thomas Gleixner X-Fcc: ~/Mail/linus Cc: linux-kernel@vger.kernel.org X-Fcc: ~/Mail/linus Subject: [PATCH 2/4] x86 ptrace: unify TIF_SINGLESTEP In-Reply-To: Roland McGrath's message of Wednesday, 16 July 2008 16:02:17 -0700 <20080716230217.3C25715410D@magilla.localdomain> References: <20080716230217.3C25715410D@magilla.localdomain> X-Zippy-Says: Alright, you!! Imitate a WOUNDED SEAL pleading for a PARKING SPACE!! Message-Id: <20080716230437.499BC15410D@magilla.localdomain> Date: Wed, 16 Jul 2008 16:04:37 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3861 Lines: 99 This unifies the treatment of TIF_SINGLESTEP on i386 and x86_64. The bit is now excluded from _TIF_WORK_MASK on i386 as it has been on x86_64. This means the do_notify_resume() path using it is never used, so TIF_SINGLESTEP is not cleared on returning to user mode. Both now leave TIF_SINGLESTEP set when returning to user, so that it's already set on an int $0x80 system call entry. This removes the need for testing TF on the system_call path. Doing it this way fixes the regression for PTRACE_SINGLESTEP into a sigreturn syscall, introduced by commit 1e2e99f0e4aa6363e8515ed17011c210c8f1b52a. The clear_TF_reenable case that sets TIF_SINGLESTEP can only happen on a non-exception kernel entry, i.e. sysenter/syscall instruction. That will always get to the syscall exit tracing path. Signed-off-by: Roland McGrath --- arch/x86/kernel/entry_32.S | 4 ---- arch/x86/kernel/signal_32.c | 6 ------ arch/x86/kernel/signal_64.c | 6 ------ include/asm-x86/thread_info.h | 4 ++-- 4 files changed, 2 insertions(+), 18 deletions(-) diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 6bc07f0..0ad987d 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -383,10 +383,6 @@ syscall_exit: # setting need_resched or sigpending # between sampling and the iret TRACE_IRQS_OFF - testl $X86_EFLAGS_TF,PT_EFLAGS(%esp) # If tracing set singlestep flag on exit - jz no_singlestep - orl $_TIF_SINGLESTEP,TI_flags(%ebp) -no_singlestep: movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx # current->work jne syscall_exit_work diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c index d923736..295b5f5 100644 --- a/arch/x86/kernel/signal_32.c +++ b/arch/x86/kernel/signal_32.c @@ -657,12 +657,6 @@ static void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) { - /* Pending single-step? */ - if (thread_info_flags & _TIF_SINGLESTEP) { - regs->flags |= X86_EFLAGS_TF; - clear_thread_flag(TIF_SINGLESTEP); - } - /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index e53b267..bf87684 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -487,12 +487,6 @@ static void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) { - /* Pending single-step? */ - if (thread_info_flags & _TIF_SINGLESTEP) { - regs->flags |= X86_EFLAGS_TF; - clear_thread_flag(TIF_SINGLESTEP); - } - #ifdef CONFIG_X86_MCE /* notify userspace of pending MCEs */ if (thread_info_flags & _TIF_MCE_NOTIFY) diff --git a/include/asm-x86/thread_info.h b/include/asm-x86/thread_info.h index 895339d..fb8d3cd 100644 --- a/include/asm-x86/thread_info.h +++ b/include/asm-x86/thread_info.h @@ -124,7 +124,7 @@ struct thread_info { /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ (0x0000FFFF & \ - ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP| \ + ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \ _TIF_SECCOMP|_TIF_SYSCALL_EMU)) /* work to do on any return to user space */ @@ -132,7 +132,7 @@ struct thread_info { /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ - (_TIF_SIGPENDING|_TIF_SINGLESTEP|_TIF_MCE_NOTIFY|_TIF_HRTICK_RESCHED) + (_TIF_SIGPENDING|_TIF_MCE_NOTIFY|_TIF_HRTICK_RESCHED) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/