From d418b19f34ed0c751a69810080596f7e749595aa Mon Sep 17 00:00:00 2001 From: Sourabh Jain Date: Wed, 11 Dec 2019 21:39:07 +0530 Subject: [PATCH] powerpc/fadump: Reorganize /sys/kernel/fadump_* sysfs files As the number of FADump sysfs files increases it is hard to manage all of them inside /sys/kernel directory. It's better to have all the FADump related sysfs files in a dedicated directory /sys/kernel/fadump. But in order to maintain backward compatibility a symlink has been added for every sysfs that has moved to new location. As the FADump sysfs files are now part of a dedicated directory there is no need to prefix their name with fadump_, hence sysfs file names are also updated. For example fadump_enabled sysfs file is now referred as enabled. Also consolidate ABI documentation for all the FADump sysfs files in a single file Documentation/ABI/testing/sysfs-kernel-fadump. Signed-off-by: Sourabh Jain Tested-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191211160910.21656-4-sourabhjain@linux.ibm.com --- Documentation/ABI/testing/sysfs-kernel-fadump | 33 +++++++ arch/powerpc/kernel/fadump.c | 119 ++++++++++++++++++-------- 2 files changed, 118 insertions(+), 34 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump new file mode 100644 index 000000000000..5d988b919e81 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-fadump @@ -0,0 +1,33 @@ +What: /sys/kernel/fadump/* +Date: Dec 2019 +Contact: linuxppc-dev@lists.ozlabs.org +Description: + The /sys/kernel/fadump/* is a collection of FADump sysfs + file provide information about the configuration status + of Firmware Assisted Dump (FADump). + +What: /sys/kernel/fadump/enabled +Date: Dec 2019 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Primarily used to identify whether the FADump is enabled in + the kernel or not. +User: Kdump service + +What: /sys/kernel/fadump/registered +Date: Dec 2019 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read/write + Helps to control the dump collect feature from userspace. + Setting 1 to this file enables the system to collect the + dump and 0 to disable it. +User: Kdump service + +What: /sys/kernel/fadump/release_mem +Date: Dec 2019 +Contact: linuxppc-dev@lists.ozlabs.org +Description: write only + This is a special sysfs file and only available when + the system is booted to capture the vmcore using FADump. + It is used to release the memory reserved by FADump to + save the crash dump. diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index ff0114aeba9b..1182ae44ef14 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -36,6 +36,8 @@ static struct fw_dump fw_dump; static void __init fadump_reserve_crash_area(u64 base); +struct kobject *fadump_kobj; + #ifndef CONFIG_PRESERVE_FA_DUMP static DEFINE_MUTEX(fadump_mutex); struct fadump_mrange_info crash_mrange_info = { "crash", NULL, 0, 0, 0 }; @@ -1323,9 +1325,9 @@ static void fadump_invalidate_release_mem(void) fw_dump.ops->fadump_init_mem_struct(&fw_dump); } -static ssize_t fadump_release_memory_store(struct kobject *kobj, - struct kobj_attribute *attr, - const char *buf, size_t count) +static ssize_t release_mem_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) { int input = -1; @@ -1350,23 +1352,33 @@ static ssize_t fadump_release_memory_store(struct kobject *kobj, return count; } -static ssize_t fadump_enabled_show(struct kobject *kobj, - struct kobj_attribute *attr, - char *buf) +/* Release the reserved memory and disable the FADump */ +static void unregister_fadump(void) +{ + fadump_cleanup(); + fadump_release_memory(fw_dump.reserve_dump_area_start, + fw_dump.reserve_dump_area_size); + fw_dump.fadump_enabled = 0; + kobject_put(fadump_kobj); +} + +static ssize_t enabled_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) { return sprintf(buf, "%d\n", fw_dump.fadump_enabled); } -static ssize_t fadump_register_show(struct kobject *kobj, - struct kobj_attribute *attr, - char *buf) +static ssize_t registered_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) { return sprintf(buf, "%d\n", fw_dump.dump_registered); } -static ssize_t fadump_register_store(struct kobject *kobj, - struct kobj_attribute *attr, - const char *buf, size_t count) +static ssize_t registered_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) { int ret = 0; int input = -1; @@ -1418,15 +1430,17 @@ static int fadump_region_show(struct seq_file *m, void *private) return 0; } -static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem, - 0200, NULL, - fadump_release_memory_store); -static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled, - 0444, fadump_enabled_show, - NULL); -static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered, - 0644, fadump_register_show, - fadump_register_store); +static struct kobj_attribute release_attr = __ATTR_WO(release_mem); +static struct kobj_attribute enable_attr = __ATTR_RO(enabled); +static struct kobj_attribute register_attr = __ATTR_RW(registered); + +static struct attribute *fadump_attrs[] = { + &enable_attr.attr, + ®ister_attr.attr, + NULL, +}; + +ATTRIBUTE_GROUPS(fadump); DEFINE_SHOW_ATTRIBUTE(fadump_region); @@ -1435,16 +1449,11 @@ static void fadump_init_files(void) struct dentry *debugfs_file; int rc = 0; - rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr); - if (rc) - printk(KERN_ERR "fadump: unable to create sysfs file" - " fadump_enabled (%d)\n", rc); - - rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr); - if (rc) - printk(KERN_ERR "fadump: unable to create sysfs file" - " fadump_registered (%d)\n", rc); - + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj); + if (!fadump_kobj) { + pr_err("failed to create fadump kobject\n"); + return; + } debugfs_file = debugfs_create_file("fadump_region", 0444, powerpc_debugfs_root, NULL, &fadump_region_fops); @@ -1453,10 +1462,52 @@ static void fadump_init_files(void) " fadump_region\n"); if (fw_dump.dump_active) { - rc = sysfs_create_file(kernel_kobj, &fadump_release_attr.attr); + rc = sysfs_create_file(fadump_kobj, &release_attr.attr); + if (rc) + pr_err("unable to create release_mem sysfs file (%d)\n", + rc); + } + + rc = sysfs_create_groups(fadump_kobj, fadump_groups); + if (rc) { + pr_err("sysfs group creation failed (%d), unregistering FADump", + rc); + unregister_fadump(); + return; + } + + /* + * The FADump sysfs are moved from kernel_kobj to fadump_kobj need to + * create symlink at old location to maintain backward compatibility. + * + * - fadump_enabled -> fadump/enabled + * - fadump_registered -> fadump/registered + * - fadump_release_mem -> fadump/release_mem + */ + rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj, + "enabled", "fadump_enabled"); + if (rc) { + pr_err("unable to create fadump_enabled symlink (%d)", rc); + return; + } + + rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, fadump_kobj, + "registered", + "fadump_registered"); + if (rc) { + pr_err("unable to create fadump_registered symlink (%d)", rc); + sysfs_remove_link(kernel_kobj, "fadump_enabled"); + return; + } + + if (fw_dump.dump_active) { + rc = compat_only_sysfs_link_entry_to_kobj(kernel_kobj, + fadump_kobj, + "release_mem", + "fadump_release_mem"); if (rc) - printk(KERN_ERR "fadump: unable to create sysfs file" - " fadump_release_mem (%d)\n", rc); + pr_err("unable to create fadump_release_mem symlink (%d)", + rc); } return; } -- 2.11.0