Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757956AbZAVOHh (ORCPT ); Thu, 22 Jan 2009 09:07:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753195AbZAVOH3 (ORCPT ); Thu, 22 Jan 2009 09:07:29 -0500 Received: from [202.81.31.148] ([202.81.31.148]:32861 "EHLO e23smtp06.au.ibm.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752488AbZAVOH2 (ORCPT ); Thu, 22 Jan 2009 09:07:28 -0500 X-Greylist: delayed 636 seconds by postgrey-1.27 at vger.kernel.org; Thu, 22 Jan 2009 09:07:27 EST Date: Thu, 22 Jan 2009 19:37:18 +0530 From: "K.Prasad" To: Linux Kernel Mailing List Cc: Alan Stern , Roland McGrath , akpm@linux-foundation.org, mingo@elte.hu, richardj_moore@uk.ibm.com Subject: [RFC Patch 6/10] Use virtual debug registers in process/thread handling code Message-ID: <20090122140718.GE19592@in.ibm.com> Reply-To: prasad@linux.vnet.ibm.com References: <20090122135640.GA11161@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090122135640.GA11161@in.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6828 Lines: 225 This patch enables the use of abstract/virtual debug registers in process-handling routines. Signed-off-by: K.Prasad Signed-off-by: Alan Stern --- arch/x86/kernel/process_32.c | 43 +++++++++++++++++++++++++------------------ arch/x86/kernel/process_64.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 49 insertions(+), 35 deletions(-) Index: linux-hbkpt-lkml-29-rc2/arch/x86/kernel/process_32.c =================================================================== --- linux-hbkpt-lkml-29-rc2.orig/arch/x86/kernel/process_32.c +++ linux-hbkpt-lkml-29-rc2/arch/x86/kernel/process_32.c @@ -60,6 +60,8 @@ #include #include #include +#include +#include asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); @@ -231,6 +233,8 @@ EXPORT_SYMBOL(kernel_thread); */ void exit_thread(void) { + struct task_struct *tsk = current; + /* The process may have allocated an io port bitmap... nuke it. */ if (unlikely(test_thread_flag(TIF_IO_BITMAP))) { struct task_struct *tsk = current; @@ -251,6 +255,8 @@ void exit_thread(void) tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET; put_cpu(); } + if (unlikely(tsk->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(tsk); ds_exit_thread(current); } @@ -259,14 +265,9 @@ void flush_thread(void) { struct task_struct *tsk = current; - tsk->thread.debugreg0 = 0; - tsk->thread.debugreg1 = 0; - tsk->thread.debugreg2 = 0; - tsk->thread.debugreg3 = 0; - tsk->thread.debugreg6 = 0; - tsk->thread.debugreg7 = 0; memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); - clear_tsk_thread_flag(tsk, TIF_DEBUG); + if (unlikely(tsk->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(tsk); /* * Forget coprocessor state.. */ @@ -310,7 +311,15 @@ int copy_thread(int nr, unsigned long cl savesegment(gs, p->thread.gs); + p->thread.hw_breakpoint_info = NULL; + p->thread.io_bitmap_ptr = NULL; + tsk = current; + err = -ENOMEM; + if (unlikely(tsk->thread.hw_breakpoint_info)) { + if (copy_thread_hw_breakpoint(tsk, p, clone_flags)) + goto out; + } if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, IO_BITMAP_BYTES, GFP_KERNEL); @@ -329,11 +338,13 @@ int copy_thread(int nr, unsigned long cl if (clone_flags & CLONE_SETTLS) err = do_set_thread_area(p, -1, (struct user_desc __user *)childregs->si, 0); - + out: if (err && p->thread.io_bitmap_ptr) { kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + if (err) + flush_thread_hw_breakpoint(p); ds_copy_thread(p, current); @@ -435,16 +446,6 @@ __switch_to_xtra(struct task_struct *pre else if (next->debugctlmsr != prev->debugctlmsr) update_debugctlmsr(next->debugctlmsr); - if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { - set_debugreg(next->debugreg0, 0); - set_debugreg(next->debugreg1, 1); - set_debugreg(next->debugreg2, 2); - set_debugreg(next->debugreg3, 3); - /* no 4 and 5 */ - set_debugreg(next->debugreg6, 6); - set_debugreg(next->debugreg7, 7); - } - if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ test_tsk_thread_flag(next_p, TIF_NOTSC)) { /* prev and next are different */ @@ -592,6 +593,12 @@ __switch_to(struct task_struct *prev_p, loadsegment(gs, next->gs); x86_write_percpu(current_task, next_p); + /* + * Handle debug registers. This must be done _after_ current + * is updated. + */ + if (unlikely(test_tsk_thread_flag(next_p, TIF_DEBUG))) + switch_to_thread_hw_breakpoint(next_p); return prev_p; } Index: linux-hbkpt-lkml-29-rc2/arch/x86/kernel/process_64.c =================================================================== --- linux-hbkpt-lkml-29-rc2.orig/arch/x86/kernel/process_64.c +++ linux-hbkpt-lkml-29-rc2/arch/x86/kernel/process_64.c @@ -52,6 +52,8 @@ #include #include #include +#include +#include #include #include @@ -256,13 +258,9 @@ void flush_thread(void) } clear_tsk_thread_flag(tsk, TIF_DEBUG); - tsk->thread.debugreg0 = 0; - tsk->thread.debugreg1 = 0; - tsk->thread.debugreg2 = 0; - tsk->thread.debugreg3 = 0; - tsk->thread.debugreg6 = 0; - tsk->thread.debugreg7 = 0; memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); + if (unlikely(tsk->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(tsk); /* * Forget coprocessor state.. */ @@ -282,6 +280,8 @@ void release_thread(struct task_struct * BUG(); } } + if (unlikely(me->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(me); } static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr) @@ -337,13 +337,21 @@ int copy_thread(int nr, unsigned long cl p->thread.fs = me->thread.fs; p->thread.gs = me->thread.gs; + p->thread.hw_breakpoint_info = NULL; + p->thread.io_bitmap_ptr = NULL; savesegment(gs, p->thread.gsindex); savesegment(fs, p->thread.fsindex); savesegment(es, p->thread.es); savesegment(ds, p->thread.ds); - if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { + err = -ENOMEM; + if (unlikely(me->thread.hw_breakpoint_info)) { + if (copy_thread_hw_breakpoint(me, p, clone_flags)) + goto out; + } + +if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); if (!p->thread.io_bitmap_ptr) { p->thread.io_bitmap_max = 0; @@ -380,6 +388,9 @@ out: kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + if (err) + flush_thread_hw_breakpoint(p); + return err; } @@ -482,16 +493,6 @@ static inline void __switch_to_xtra(stru else if (next->debugctlmsr != prev->debugctlmsr) update_debugctlmsr(next->debugctlmsr); - if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { - loaddebug(next, 0); - loaddebug(next, 1); - loaddebug(next, 2); - loaddebug(next, 3); - /* no 4 and 5 */ - loaddebug(next, 6); - loaddebug(next, 7); - } - if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ test_tsk_thread_flag(next_p, TIF_NOTSC)) { /* prev and next are different */ @@ -514,6 +515,12 @@ static inline void __switch_to_xtra(stru */ memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); } + /* + * Handle debug registers. This must be done _after_ current + * is updated. + */ + if (unlikely(test_tsk_thread_flag(next_p, TIF_DEBUG))) + switch_to_thread_hw_breakpoint(next_p); } /* -- 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/