Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756139AbYJHT0S (ORCPT ); Wed, 8 Oct 2008 15:26:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754639AbYJHT0A (ORCPT ); Wed, 8 Oct 2008 15:26:00 -0400 Received: from e28smtp04.in.ibm.com ([59.145.155.4]:52793 "EHLO e28esmtp04.in.ibm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754866AbYJHTZ7 (ORCPT ); Wed, 8 Oct 2008 15:25:59 -0400 Date: Thu, 9 Oct 2008 00:55:48 +0530 From: "K.Prasad" To: Linux Kernel Mailing List Cc: Alan Stern , Roland McGrath , akpm@linux-foundation.org, mingo@elte.hu, jason.wessel@windriver.com, avi@qumranet.com, richardj_moore@uk.ibm.com Subject: [RFC Patch 6/9] Use virtual debug registers in process/thread handling code Message-ID: <20081008192548.GF4989@in.ibm.com> Reply-To: prasad@linux.vnet.ibm.com References: <20081008192044.GA4510@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081008192044.GA4510@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: 6774 Lines: 226 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 | 45 +++++++++++++++++++++++++------------------ arch/x86/kernel/process_64.c | 42 +++++++++++++++++++++++----------------- 2 files changed, 52 insertions(+), 35 deletions(-) Index: linux-bkpt-lkml-27-rc9/arch/x86/kernel/process_32.c =================================================================== --- linux-bkpt-lkml-27-rc9.orig/arch/x86/kernel/process_32.c +++ linux-bkpt-lkml-27-rc9/arch/x86/kernel/process_32.c @@ -56,6 +56,8 @@ #include #include #include +#include +#include asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); @@ -257,6 +259,8 @@ 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; @@ -277,20 +281,17 @@ 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); } 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); + 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.. */ @@ -334,7 +335,15 @@ 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); @@ -354,10 +363,14 @@ int copy_thread(int nr, unsigned long cl 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); + return err; } @@ -460,16 +473,6 @@ __switch_to_xtra(struct task_struct *pre if (next->debugctlmsr != debugctl) 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 */ @@ -625,6 +628,12 @@ struct task_struct * __switch_to(struct 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-bkpt-lkml-27-rc9/arch/x86/kernel/process_64.c =================================================================== --- linux-bkpt-lkml-27-rc9.orig/arch/x86/kernel/process_64.c +++ linux-bkpt-lkml-27-rc9/arch/x86/kernel/process_64.c @@ -51,6 +51,8 @@ #include #include #include +#include +#include asmlinkage extern void ret_from_fork(void); @@ -240,6 +242,8 @@ void exit_thread(void) t->io_bitmap_max = 0; put_cpu(); } + if (unlikely(me->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(me); } void flush_thread(void) @@ -257,13 +261,9 @@ 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.. */ @@ -338,13 +338,21 @@ 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; @@ -375,6 +383,9 @@ out: kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + if (err) + flush_thread_hw_breakpoint(p); + return err; } @@ -484,16 +495,6 @@ static inline void __switch_to_xtra(stru if (next->debugctlmsr != debugctl) 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 */ @@ -524,6 +525,13 @@ static inline void __switch_to_xtra(stru if (test_tsk_thread_flag(next_p, TIF_BTS_TRACE_TS)) ptrace_bts_take_timestamp(next_p, BTS_TASK_ARRIVES); #endif + +/* + * 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/