From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1FOO7z-0004PD-7w for user-mode-linux-devel@lists.sourceforge.net; Tue, 28 Mar 2006 16:01:35 -0800 Received: from [151.97.230.9] (helo=ssc.unict.it) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1FOO7y-0003GB-MJ for user-mode-linux-devel@lists.sourceforge.net; Tue, 28 Mar 2006 16:01:35 -0800 From: "Paolo 'Blaisorblade' Giarrusso" Message-Id: <20060328235702.13838.48788.stgit@zion.home.lan> In-Reply-To: <20060328235442.13838.26861.stgit@zion.home.lan> References: <20060328235442.13838.26861.stgit@zion.home.lan> Subject: [uml-devel] [PATCH 6/7] uml: add arch_switch_to for newly forked thread Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Wed, 29 Mar 2006 01:57:03 +0200 To: Andrew Morton Cc: Jeff Dike , linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net From: Paolo 'Blaisorblade' Giarrusso Newly forked threads have no arch_switch_to_skas() called before their first run, because when schedule() switches to them they're resumed in the body of thread_wait() inside fork_handler() rather than in switch_threads() in switch_to_skas(). Compensate this missing call. Signed-off-by: Paolo 'Blaisorblade' Giarrusso --- arch/um/kernel/skas/process_kern.c | 7 +++++++ arch/um/sys-i386/ptrace.c | 9 ++++++++- arch/um/sys-i386/tls.c | 13 ++++++++++--- 3 files changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c index 38b1853..2135eaf 100644 --- a/arch/um/kernel/skas/process_kern.c +++ b/arch/um/kernel/skas/process_kern.c @@ -91,10 +91,17 @@ void fork_handler(int sig) panic("blech"); schedule_tail(current->thread.prev_sched); + + /* XXX: if interrupt_end() calls schedule, this call to + * arch_switch_to_skas isn't needed. We could want to apply this to + * improve performance. -bb */ + arch_switch_to_skas(current->thread.prev_sched, current); + current->thread.prev_sched = NULL; /* Handle any immediate reschedules or signals */ interrupt_end(); + userspace(¤t->thread.regs.regs); } diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c index b587b4b..ce71923 100644 --- a/arch/um/sys-i386/ptrace.c +++ b/arch/um/sys-i386/ptrace.c @@ -23,7 +23,14 @@ void arch_switch_to_tt(struct task_struc void arch_switch_to_skas(struct task_struct *from, struct task_struct *to) { - arch_switch_tls_skas(from, to); + int err = arch_switch_tls_skas(from, to); + if (!err) + return; + + if (err != -EINVAL) + printk(KERN_WARNING "arch_switch_tls_skas failed, errno %d, not EINVAL\n", -err); + else + printk(KERN_WARNING "arch_switch_tls_skas failed, errno = EINVAL\n"); } int is_syscall(unsigned long addr) diff --git a/arch/um/sys-i386/tls.c b/arch/um/sys-i386/tls.c index e3c5bc5..2251654 100644 --- a/arch/um/sys-i386/tls.c +++ b/arch/um/sys-i386/tls.c @@ -70,8 +70,6 @@ static int get_free_idx(struct task_stru return -ESRCH; } -#define O_FORCE 1 - static inline void clear_user_desc(struct user_desc* info) { /* Postcondition: LDT_empty(info) returns true. */ @@ -84,6 +82,8 @@ static inline void clear_user_desc(struc info->seg_not_present = 1; } +#define O_FORCE 1 + static int load_TLS(int flags, struct task_struct *to) { int ret = 0; @@ -162,7 +162,13 @@ void clear_flushed_tls(struct task_struc * SKAS patch. */ int arch_switch_tls_skas(struct task_struct *from, struct task_struct *to) { - return load_TLS(O_FORCE, to); + /* We have no need whatsoever to switch TLS for kernel threads; beyond + * that, that would also result in us calling os_set_thread_area with + * userspace_pid[cpu] == 0, which gives an error. */ + if (likely(to->mm)) + return load_TLS(O_FORCE, to); + + return 0; } int arch_switch_tls_tt(struct task_struct *from, struct task_struct *to) @@ -324,3 +330,4 @@ int ptrace_get_thread_area(struct task_s out: return ret; } + ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel