From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id DE1AE1A2BD6 for ; Sat, 1 Aug 2015 01:54:46 +1000 (AEST) Received: from e28smtp01.in.ibm.com (e28smtp01.in.ibm.com [122.248.162.1]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3E97414031A for ; Sat, 1 Aug 2015 01:54:46 +1000 (AEST) Received: from /spool/local by e28smtp01.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 31 Jul 2015 21:24:44 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 8BA18E0058 for ; Fri, 31 Jul 2015 21:28:52 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay02.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t6VFsfsG40501472 for ; Fri, 31 Jul 2015 21:24:42 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t6VFseYT011210 for ; Fri, 31 Jul 2015 21:24:41 +0530 Subject: [PATCH] powernv: Invoke opal_cec_reboot2() on unrecoverable machine check errors. From: Mahesh J Salgaonkar To: linuxppc-dev , Michael Ellerman , Benjamin Herrenschmidt Cc: Jeremy Kerr , Vaidyanathan Srinivasan , Ananth Narayan Date: Fri, 31 Jul 2015 21:24:38 +0530 Message-ID: <20150731155312.30819.80637.stgit@mars> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Mahesh Salgaonkar On non-recoverable MCE errors in kernel space, Linux kernel panics and system reboots. On BMC based system opal-prd runs as a daemon in the host. Hence, kernel crash may prevent opal-prd to detect and analyze this MCE error. This may land us in a situation where the faulty memory never gets de-configured and Linux would keep hitting same MCE error again and again. If this happens in early stage of kernel initialization, then Linux will keep crashing and rebooting in a loop. This patch fixes this issue by invoking new opal_cec_reboot2() call with reboot type OPAL_REBOOT_PLATFORM_ERROR to inform BMC/OCC about this error, so that BMC can collect relevant data for error analysis and decide what component to de-configure before rebooting. This patch is dependent on OPAL patchset posted on skiboot mailing list at https://lists.ozlabs.org/pipermail/skiboot/2015-July/001771.html that introduces opal_cec_reboot2() opal call. Signed-off-by: Mahesh Salgaonkar --- arch/powerpc/include/asm/opal-api.h | 9 +++++- arch/powerpc/include/asm/opal.h | 1 + arch/powerpc/platforms/powernv/opal-wrappers.S | 1 + arch/powerpc/platforms/powernv/opal.c | 35 ++++++++++++++++++++++++ 4 files changed, 45 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h index 513d60e..4b620d99 100644 --- a/arch/powerpc/include/asm/opal-api.h +++ b/arch/powerpc/include/asm/opal-api.h @@ -154,7 +154,8 @@ #define OPAL_FLASH_WRITE 111 #define OPAL_FLASH_ERASE 112 #define OPAL_PRD_MSG 113 -#define OPAL_LAST 113 +#define OPAL_CEC_REBOOT2 116 +#define OPAL_LAST 116 /* Device tree flags */ @@ -817,6 +818,12 @@ struct opal_i2c_request { __be64 buffer_ra; /* Buffer real address */ }; +/* Argument to OPAL_CEC_REBOOT2() */ +enum { + OPAL_REBOOT_NORMAL = 0, + OPAL_REBOOT_PLATFORM_ERROR = 1, +}; + #endif /* __ASSEMBLY__ */ #endif /* __OPAL_API_H */ diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h index 958e941..fb8e4d7 100644 --- a/arch/powerpc/include/asm/opal.h +++ b/arch/powerpc/include/asm/opal.h @@ -44,6 +44,7 @@ int64_t opal_tpo_write(uint64_t token, uint32_t year_mon_day, uint32_t hour_min); int64_t opal_cec_power_down(uint64_t request); int64_t opal_cec_reboot(void); +int64_t opal_cec_reboot2(uint32_t reboot_type, char *diag); int64_t opal_read_nvram(uint64_t buffer, uint64_t size, uint64_t offset); int64_t opal_write_nvram(uint64_t buffer, uint64_t size, uint64_t offset); int64_t opal_handle_interrupt(uint64_t isn, __be64 *outstanding_event_mask); diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S index c56913d..4d5e967 100644 --- a/arch/powerpc/platforms/powernv/opal-wrappers.S +++ b/arch/powerpc/platforms/powernv/opal-wrappers.S @@ -200,6 +200,7 @@ OPAL_CALL(opal_rtc_read, OPAL_RTC_READ); OPAL_CALL(opal_rtc_write, OPAL_RTC_WRITE); OPAL_CALL(opal_cec_power_down, OPAL_CEC_POWER_DOWN); OPAL_CALL(opal_cec_reboot, OPAL_CEC_REBOOT); +OPAL_CALL(opal_cec_reboot2, OPAL_CEC_REBOOT2); OPAL_CALL(opal_read_nvram, OPAL_READ_NVRAM); OPAL_CALL(opal_write_nvram, OPAL_WRITE_NVRAM); OPAL_CALL(opal_handle_interrupt, OPAL_HANDLE_INTERRUPT); diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c index f084afa..a2b53f2 100644 --- a/arch/powerpc/platforms/powernv/opal.c +++ b/arch/powerpc/platforms/powernv/opal.c @@ -441,6 +441,7 @@ static int opal_recover_mce(struct pt_regs *regs, int opal_machine_check(struct pt_regs *regs) { struct machine_check_event evt; + int ret; if (!get_mce_event(&evt, MCE_EVENT_RELEASE)) return 0; @@ -455,6 +456,40 @@ int opal_machine_check(struct pt_regs *regs) if (opal_recover_mce(regs, &evt)) return 1; + + /* + * Unrecovered machine check, we are heading to panic path. + * + * We may have hit this MCE in very early stage of kernel + * initialization even before opal-prd has started running. If + * this is the case then this MCE error may go un-noticed or + * un-analyzed if we go down panic path. We need to inform + * BMC/OCC about this error so that they can collect relevant + * data for error analysis before rebooting. + * Use opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR) to do so. + * This function may not return on BMC based system. + */ + ret = opal_cec_reboot2(OPAL_REBOOT_PLATFORM_ERROR, + "Unrecoverable Machine Check exception"); + if (ret == OPAL_UNSUPPORTED) { + pr_emerg("Reboot type %d not supported\n", + OPAL_REBOOT_PLATFORM_ERROR); + } + + /* + * We reached here. There can be three possibilities: + * 1. We are running on a firmware level that do not support + * opal_cec_reboot2() + * 2. We are running on a firmware level that do not support + * OPAL_REBOOT_PLATFORM_ERROR reboot type. + * 3. We are running on FSP based system that does not need opal + * to trigger checkstop explicitly for error analysis. The FSP + * PRD component would have already got notified about this + * error through other channels. + * + * In any case, let us just fall through. We anyway heading + * down to panic path. + */ return 0; }