From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Baydarov Subject: Re: [PATCH] kexec: reenable HPET before kexec Date: Tue, 21 Aug 2007 17:01:41 +0400 Message-ID: <20070821170141.70a95dac@windmill.dev.rtsoft.ru> References: <20070820205530.1ffd5876@windmill.dev.rtsoft.ru> <46CA035A.5050202@ru.mvista.com> <1187645464.7732.43.camel@imap.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: RT , linux-kernel To: Daniel Walker Return-path: Received: from rtsoft2.corbina.net ([85.21.88.2]:37624 "HELO mail.dev.rtsoft.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with SMTP id S1752690AbXHUMzc (ORCPT ); Tue, 21 Aug 2007 08:55:32 -0400 In-Reply-To: <1187645464.7732.43.camel@imap.mvista.com> Sender: linux-rt-users-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Mon, 20 Aug 2007 14:31:04 -0700 Daniel Walker wrote: > On Tue, 2007-08-21 at 01:10 +0400, Konstantin Baydarov wrote: > > It was in your original email .. Are you saying this it is not a > problem in plain 2.6.23-rc2? I thought I read that it was a problem on > i386 .. > > Daniel > I can reproduce bug with plain 2.6.23-rc3 i386 kernel, without RT patch, on pentiumd. So I fixed this issue the same way as I fixed RT kernel. The side effect of this fix is that when kernel 2 executes both Local APIC timer and HPET are enabled and produce timer interrupts: root@192.168.40.10:~# cat /proc/interrupts CPU0 CPU1 0: 5643 0 IO-APIC-edge timer 1: 8 0 IO-APIC-edge i8042 2: 0 0 XT-PIC-XT cascade 4: 303 181 IO-APIC-edge serial 6: 3 0 IO-APIC-edge floppy 12: 4 0 IO-APIC-edge i8042 14: 11 0 IO-APIC-edge ide0 17: 5701 16 IO-APIC-fasteoi uhci_hcd:usb3, eth0 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb4 19: 0 0 IO-APIC-fasteoi uhci_hcd:usb5 20: 38 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2 23: 3 0 IO-APIC-fasteoi libata NMI: 0 0 LOC: 5525 5489 ERR: 0 MIS: 0 root@192.168.40.10:~# IRQ0 and LOC values practically the same. Also I didn't see this bug on linux-rt-users@vger.kernel.org, maybe I should resend it? Patch against 2.6.23-rc3. Signed-off-by: Konstantin Baydarov arch/i386/kernel/hpet.c | 15 +++++++++++++++ arch/i386/kernel/machine_kexec.c | 5 +++++ include/asm-i386/hpet.h | 3 +++ 3 files changed, 23 insertions(+) Index: linux-2.6.23-rc3-i386/arch/i386/kernel/hpet.c =================================================================== --- linux-2.6.23-rc3-i386.orig/arch/i386/kernel/hpet.c +++ linux-2.6.23-rc3-i386/arch/i386/kernel/hpet.c @@ -340,6 +340,21 @@ out_nohpet: return 0; } +#ifdef CONFIG_KEXEC +/* + * reenable HPET timer + */ +int hpet_reenable(void) +{ + if (!is_hpet_capable()) + return -1; + + if (hpet_clockevent.mode != CLOCK_EVT_MODE_PERIODIC) + hpet_set_mode(CLOCK_EVT_MODE_PERIODIC, &hpet_clockevent); + + return 0; +} +#endif #ifdef CONFIG_HPET_EMULATE_RTC Index: linux-2.6.23-rc3-i386/arch/i386/kernel/machine_kexec.c =================================================================== --- linux-2.6.23-rc3-i386.orig/arch/i386/kernel/machine_kexec.c +++ linux-2.6.23-rc3-i386/arch/i386/kernel/machine_kexec.c @@ -19,6 +19,7 @@ #include #include #include +#include #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) static u32 kexec_pgd[1024] PAGE_ALIGNED; @@ -109,6 +110,10 @@ NORET_TYPE void machine_kexec(struct kim /* Interrupts aren't acceptable while we reboot */ local_irq_disable(); +#ifdef CONFIG_HPET_TIMER + hpet_reenable(); +#endif + control_page = page_address(image->control_code_page); memcpy(control_page, relocate_kernel, PAGE_SIZE); Index: linux-2.6.23-rc3-i386/include/asm-i386/hpet.h =================================================================== --- linux-2.6.23-rc3-i386.orig/include/asm-i386/hpet.h +++ linux-2.6.23-rc3-i386/include/asm-i386/hpet.h @@ -66,6 +66,9 @@ extern unsigned long hpet_address; extern int is_hpet_enabled(void); extern int hpet_enable(void); +#ifdef CONFIG_KEXEC +extern int hpet_reenable(void); +#endif #ifdef CONFIG_HPET_EMULATE_RTC