From 0a99f8650b9ae9a0113664a42dd25bd3b9a16c91 Mon Sep 17 00:00:00 2001 From: Tyrel Datwyler Date: Wed, 4 Mar 2015 18:25:38 -0800 Subject: [PATCH 2/3] powerpc/pseries: Introduce api_version to migration sysfs interface The /sys/kernel/mobility/migration interface was added all the way back in 2.6.37. However, the drmgr userspace tool was never augmented to use this interface to perfrom migrations. Instead it has continued using a faux rtas call coupled with performing the device tree update processing in userspace and communicating it back to the kernel via the ugly /proc/ppc64/ofdt interface. Up until 3.12 the device tree update code in the kernel was badly broken and bit rotting. This code was fixed in 3.12 and is now utilized by the kernel suspend code as of 3.15. The kernel is now better suited to handle the post-mobility fixup of the device tree and drmgr should be transitioned to using the sysfs migration interface. This patch introduces the api_version sysfs file to /sys/kernel/mobility as a means for drmgr to query the current implementation level of the kernel migration code. This initial versioning indicates it is capable of perfroming all current PAPR requirements for migration including the post-mobility firmware activation and device tree update. Signed-off-by: Tyrel Datwyler Cc: Nathan Fontenot Cc: Cyril Bur Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/pseries/mobility.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index 8f35d52..a9a54e2 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -341,7 +341,16 @@ static ssize_t migrate_store(struct class *class, struct class_attribute *attr, return count; } +/* + * Used by drmgr to determine the kernel behavior of the migration interface. + * + * Version 1: Performs all PAPR requirements for migration including + * firmware activation and device tree update. + */ +#define MIGRATION_API_VERSION 1 + static CLASS_ATTR(migration, S_IWUSR, NULL, migrate_store); +static CLASS_ATTR_STRING(api_version, S_IRUGO, __stringify(MIGRATION_API_VERSION)); static int __init mobility_sysfs_init(void) { @@ -352,7 +361,13 @@ static int __init mobility_sysfs_init(void) return -ENOMEM; rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr); + if (rc) + pr_err("mobility: unable to create migration sysfs file (%d)\n", rc); - return rc; + rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr); + if (rc) + pr_err("mobility: unable to create api_version sysfs file (%d)\n", rc); + + return 0; } machine_device_initcall(pseries, mobility_sysfs_init); -- 2.1.4