From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e4.ny.us.ibm.com (e4.ny.us.ibm.com [32.97.182.144]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e4.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id F171CDDE3F for ; Fri, 29 Feb 2008 11:28:00 +1100 (EST) Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e4.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m1T0RuLe030504 for ; Thu, 28 Feb 2008 19:27:56 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m1T0RunY241904 for ; Thu, 28 Feb 2008 19:27:56 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m1T0RtD3025682 for ; Thu, 28 Feb 2008 19:27:56 -0500 Message-ID: <47C75189.4070801@austin.ibm.com> Date: Thu, 28 Feb 2008 18:27:53 -0600 From: Manish Ahuja MIME-Version: 1.0 To: linuxppc-dev@ozlabs.org, paulus@samba.org, michael@ellerman.id.au Subject: [PATCH 3/8] pseries: phyp dump: use sysfs to release reserved mem References: <47B90F55.2080606@austin.ibm.com> <1203641584.15378.2.camel@concordia.ozlabs.ibm.com> <47C74A66.1060105@austin.ibm.com> In-Reply-To: <47C74A66.1060105@austin.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Cc: mahuja@us.ibm.com, linasvepstas@gmail.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Check to see if there actually is data from a previously crashed kernel waiting. If so, Allow user-sapce tools to grab the data (by reading /proc/kcore). When user-space finishes dumping a section, it must release that memory by writing to sysfs. For example, echo "0x40000000 0x10000000" > /sys/kernel/release_region will release 256MB starting at the 1GB. The released memory becomes free for general use. Signed-off-by: Linas Vepstas Signed-off-by: Manish Ahuja ------ arch/powerpc/platforms/pseries/phyp_dump.c | 82 +++++++++++++++++++++++++++-- 1 file changed, 77 insertions(+), 5 deletions(-) Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c =================================================================== --- 2.6.25-rc1.orig/arch/powerpc/platforms/pseries/phyp_dump.c 2008-02-28 21:57:52.000000000 -0600 +++ 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c 2008-02-28 23:36:01.000000000 -0600 @@ -12,19 +12,25 @@ */ #include +#include #include +#include #include #include +#include #include #include #include #include +#include + /* Global, used to communicate data between early boot and late boot */ static struct phyp_dump phyp_dump_global; struct phyp_dump *phyp_dump_info = &phyp_dump_global; +/* ------------------------------------------------- */ /** * release_memory_range -- release memory previously lmb_reserved * @start_pfn: starting physical frame number @@ -54,18 +60,84 @@ release_memory_range(unsigned long start } } -static int __init phyp_dump_setup(void) +/* ------------------------------------------------- */ +/** + * sysfs_release_region -- sysfs interface to release memory range. + * + * Usage: + * "echo > /sys/kernel/release_region" + * + * Example: + * "echo 0x40000000 0x10000000 > /sys/kernel/release_region" + * + * will release 256MB starting at 1GB. + */ +static ssize_t store_release_region(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) { + unsigned long start_addr, length, end_addr; unsigned long start_pfn, nr_pages; + ssize_t ret; + + ret = sscanf(buf, "%lx %lx", &start_addr, &length); + if (ret != 2) + return -EINVAL; + + /* Range-check - don't free any reserved memory that + * wasn't reserved for phyp-dump */ + if (start_addr < phyp_dump_info->init_reserve_start) + start_addr = phyp_dump_info->init_reserve_start; + + end_addr = phyp_dump_info->init_reserve_start + + phyp_dump_info->init_reserve_size; + if (start_addr+length > end_addr) + length = end_addr - start_addr; + + /* Release the region of memory assed in by user */ + start_pfn = PFN_DOWN(start_addr); + nr_pages = PFN_DOWN(length); + release_memory_range(start_pfn, nr_pages); + + return count; +} + +static struct kobj_attribute rr = __ATTR(release_region, 0600, + NULL, store_release_region); + +static int __init phyp_dump_setup(void) +{ + struct device_node *rtas; + const int *dump_header = NULL; + int header_len = 0; + int rc; /* If no memory was reserved in early boot, there is nothing to do */ if (phyp_dump_info->init_reserve_size == 0) return 0; - /* Release memory that was reserved in early boot */ - start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start); - nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size); - release_memory_range(start_pfn, nr_pages); + /* Return if phyp dump not supported */ + if (!phyp_dump_info->phyp_dump_configured) + return -ENOSYS; + + /* Is there dump data waiting for us? */ + rtas = of_find_node_by_path("/rtas"); + if (rtas) { + dump_header = of_get_property(rtas, "ibm,kernel-dump", + &header_len); + of_node_put(rtas); + } + + if (dump_header == NULL) + return 0; + + /* Should we create a dump_subsys, analogous to s390/ipl.c ? */ + rc = sysfs_create_file(kernel_kobj, &rr.attr); + if (rc) { + printk(KERN_ERR "phyp-dump: unable to create sysfs file (%d)\n", + rc); + return 0; + } return 0; }