From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.windriver.com (mail1.windriver.com [147.11.146.13]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mail1.windriver.com", Issuer "Intel External Basic Issuing CA 3A" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 202432C00A5 for ; Wed, 17 Oct 2012 21:50:36 +1100 (EST) From: Tiejun Chen To: Subject: [PATCH 1/2] powerpc/kgdb: Fix a single stgep case of lazy IRQ Date: Wed, 17 Oct 2012 18:50:10 +0800 Message-ID: <1350471011-2478-1-git-send-email-tiejun.chen@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Cc: linuxppc-dev@lists.ozlabs.org, jason.wessel@windriver.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When we're in kgdb_singlestep(), we have to work around to get thread_info by copying from the kernel stack before calling kgdb_handle_exception(), then copying it back afterwards. But for PPC64, we have a lazy interrupt implementation. So after copying thread info frome kernle stack, if we need to replay an interrupt, we shouldn't restore that previous backup thread info to make sure we can replay an interrupt lately with a proper thread info. This patch use __check_irq_replay() to guarantee this process. Signed-off-by: Tiejun Chen --- arch/powerpc/kernel/irq.c | 12 +++++++++++- arch/powerpc/kernel/kgdb.c | 7 ++++--- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 71413f4..a773789 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -332,7 +332,17 @@ bool prep_irq_for_idle(void) return true; } -#endif /* CONFIG_PPC64 */ +notrace unsigned int check_irq_replay(void) +{ + return __check_irq_replay(); +} +#else /* CONFIG_PPC64 */ +notrace unsigned int check_irq_replay(void) +{ + return 0; +} +#endif /* !CONFIG_PPC64 */ +EXPORT_SYMBOL(check_irq_replay); int arch_show_interrupts(struct seq_file *p, int prec) { diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index c470a40..c4af341 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -151,6 +151,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) return 1; } +extern notrace unsigned int check_irq_replay(void); static int kgdb_singlestep(struct pt_regs *regs) { struct thread_info *thread_info, *exception_thread_info; @@ -181,9 +182,9 @@ static int kgdb_singlestep(struct pt_regs *regs) kgdb_handle_exception(0, SIGTRAP, 0, regs); - if (thread_info != exception_thread_info) - /* Restore current_thread_info lastly. */ - memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); + if ((thread_info != exception_thread_info) && (!check_irq_replay())) + /* Restore current_thread_info lastly only if we don't replay interrupt. */ + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); return 1; } -- 1.7.9.5