Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752379AbbB0KNJ (ORCPT ); Fri, 27 Feb 2015 05:13:09 -0500 Received: from mail.skyhub.de ([78.46.96.112]:60910 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750777AbbB0KNG (ORCPT ); Fri, 27 Feb 2015 05:13:06 -0500 Date: Fri, 27 Feb 2015 11:11:59 +0100 From: Borislav Petkov To: Wang Nan Cc: luto@amacapital.net, lizefan@huawei.com, mingo@kernel.org, masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, linux-tip-commits@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com, dave.hansen@linux.intel.com, oleg@redhat.com Subject: Re: [PATCH] x86, traps: early_trap_init() cleanup. Message-ID: <20150227101159.GA3511@pd.tnic> References: <1425007730-55260-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1425007730-55260-1-git-send-email-wangnan0@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2645 Lines: 72 On Fri, Feb 27, 2015 at 11:28:50AM +0800, Wang Nan wrote: > As early_trap_init() doesn't use IST, replace set_intr_gate_ist(..., 0) > and set_system_intr_gate_ist(..., 0) with their standard counterparts. > > set_intr_gate() requires a trace_debug symbol which we don't have and > won't use. Use a small macro trick as a workaround. > > Signed-off-by: Wang Nan > --- > > Hi Andy Lutomirski, > > This patch is a bit tricky, but I think we don't need to define another > helper for such a small problem. What's your opinion? > > Thank you! > > --- > arch/x86/kernel/traps.c | 23 ++++++++++++++--------- > 1 file changed, 14 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index 4281988..c24434a 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -925,17 +925,22 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) > /* Set of traps needed for early debugging. */ > void __init early_trap_init(void) > { > + > /* > - * Don't set ist to DEBUG_STACK as it doesn't work until TSS is > - * ready in cpu_init() <-- trap_init(). Before trap_init(), CPU > - * runs at ring 0 so it is impossible to hit an invalid stack. > - * Using the original stack works well enough at this early > - * stage. DEBUG_STACK will be equipped after cpu_init() in > - * trap_init(). > + * Don't use IST to set DEBUG_STACK as it doesn't work until TSS is > + * ready in cpu_init() <-- trap_init(). Before trap_init(), CPU runs at > + * ring 0 so it is impossible to hit an invalid stack. Using the > + * original stack works well enough at this early stage. DEBUG_STACK > + * will be equipped after cpu_init() in trap_init(). > + * > + * Since set_intr_gate() needs a trace_debug but we don't have it, > + * use the following #define as a workaround. > */ > - set_intr_gate_ist(X86_TRAP_DB, &debug, 0); > +#define trace_debug debug This goes to arch/x86/include/asm/traps.h like the rest of the trace_* defines. > + set_intr_gate(X86_TRAP_DB, debug); > +#undef trace_debug > /* int3 can be called from all */ > - set_system_intr_gate_ist(X86_TRAP_BP, &int3, 0); > + set_system_intr_gate(X86_TRAP_BP, &int3); > #ifdef CONFIG_X86_32 > set_intr_gate(X86_TRAP_PF, page_fault); > #endif -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- 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/