Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753987Ab0HYNr0 (ORCPT ); Wed, 25 Aug 2010 09:47:26 -0400 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:53842 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753902Ab0HYNrV (ORCPT ); Wed, 25 Aug 2010 09:47:21 -0400 From: Srikar Dronamraju To: Peter Zijlstra , Ingo Molnar Cc: Steven Rostedt , Srikar Dronamraju , Randy Dunlap , Arnaldo Carvalho de Melo , Linus Torvalds , Christoph Hellwig , Masami Hiramatsu , Oleg Nesterov , Mark Wielaard , Mathieu Desnoyers , LKML , Naren A Devaiah , Jim Keniston , Frederic Weisbecker , "Frank Ch. Eigler" , Ananth N Mavinakayanahalli , Andrew Morton , "Paul E. McKenney" Date: Wed, 25 Aug 2010 19:12:34 +0530 Message-Id: <20100825134234.5447.80101.sendpatchset@localhost6.localdomain6> In-Reply-To: <20100825134117.5447.55209.sendpatchset@localhost6.localdomain6> References: <20100825134117.5447.55209.sendpatchset@localhost6.localdomain6> Subject: [PATCHv11 2.6.36-rc2-tip 6/15] 6: uprobes: X86 support for Uprobes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3227 Lines: 113 Provides x86 specific details for uprobes. This includes interrupt notifier for uprobes, enabling/disabling singlestep. Signed-off-by: Srikar Dronamraju Signed-off-by: Ananth N Mavinakayanahalli --- Changelog from V5: Using local_irq_enable() instead of native_irq_enable and no more disabling irqs as suggested by Oleg Nesterov. arch/x86/kernel/signal.c | 13 +++++++++++ arch/x86/kernel/uprobes.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 4fd173c..3657563 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -848,6 +848,19 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); + if (thread_info_flags & _TIF_UPROBE) { + clear_thread_flag(TIF_UPROBE); +#ifdef CONFIG_X86_32 + /* + * On x86_32, do_notify_resume() gets called with + * interrupts disabled. Hence enable interrupts if they + * are still disabled. + */ + local_irq_enable(); +#endif + uprobe_notify_resume(regs); + } + if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index ceaedc9..6985b4c 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -26,6 +26,7 @@ #include #include +#include #include #ifdef CONFIG_X86_32 @@ -559,3 +560,54 @@ struct user_bkpt_arch_info user_bkpt_arch_info = { .ip_advancement_by_bkpt_insn = 1, .max_insn_bytes = MAX_UINSN_BYTES, }; + +/* + * Wrapper routine for handling exceptions. + */ +int uprobes_exception_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + struct pt_regs *regs = args->regs; + int ret = NOTIFY_DONE; + + /* We are only interested in userspace traps */ + if (regs && !user_mode_vm(regs)) + return NOTIFY_DONE; + + switch (val) { + case DIE_INT3: + /* Run your handler here */ + if (uprobe_bkpt_notifier(regs)) + ret = NOTIFY_STOP; + break; + case DIE_DEBUG: + if (uprobe_post_notifier(regs)) + ret = NOTIFY_STOP; + default: + break; + } + return ret; +} + +void arch_uprobe_enable_sstep(struct pt_regs *regs) +{ + /* + * Enable single-stepping by + * - Set TF on stack + * - Set TIF_SINGLESTEP: Guarantees that TF is set when + * returning to user mode. + * - Indicate that TF is set by us. + */ + regs->flags |= X86_EFLAGS_TF; + set_thread_flag(TIF_SINGLESTEP); + set_thread_flag(TIF_FORCED_TF); +} + +void arch_uprobe_disable_sstep(struct pt_regs *regs) +{ + /* Disable single-stepping by clearing what we set */ + clear_thread_flag(TIF_SINGLESTEP); + clear_thread_flag(TIF_FORCED_TF); + regs->flags &= ~X86_EFLAGS_TF; +} -- 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/