diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/platforms/pseries/Kconfig | 10 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/Makefile | 1 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/dtl.c | 274 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/plpar_wrappers.h | 10 |
4 files changed, 295 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index c0e6ec240f4..f0e6f28427b 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -68,3 +68,13 @@ config CMM makes sense for a system running in an LPAR where the unused pages will be reused for other LPARs. The interface allows firmware to balance memory across many LPARs. + +config DTL + bool "Dispatch Trace Log" + depends on PPC_SPLPAR && DEBUG_FS + help + SPLPAR machines can log hypervisor preempt & dispatch events to a + kernel buffer. Saying Y here will enable logging these events, + which are accessible through a debugfs file. + + Say N if you are unsure. diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile index 0ce691df595..790c0b872d4 100644 --- a/arch/powerpc/platforms/pseries/Makefile +++ b/arch/powerpc/platforms/pseries/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_HVCS) += hvcserver.o obj-$(CONFIG_HCALL_STATS) += hvCall_inst.o obj-$(CONFIG_PHYP_DUMP) += phyp_dump.o obj-$(CONFIG_CMM) += cmm.o +obj-$(CONFIG_DTL) += dtl.o diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c new file mode 100644 index 00000000000..dc9b0f81e60 --- /dev/null +++ b/arch/powerpc/platforms/pseries/dtl.c @@ -0,0 +1,274 @@ +/* + * Virtual Processor Dispatch Trace Log + * + * (C) Copyright IBM Corporation 2009 + * + * Author: Jeremy Kerr <jk@ozlabs.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/init.h> +#include <linux/debugfs.h> +#include <asm/smp.h> +#include <asm/system.h> +#include <asm/uaccess.h> + +#include "plpar_wrappers.h" + +/* + * Layout of entries in the hypervisor's DTL buffer. Although we don't + * actually access the internals of an entry (we only need to know the size), + * we might as well define it here for reference. + */ +struct dtl_entry { + u8 dispatch_reason; + u8 preempt_reason; + u16 processor_id; + u32 enqueue_to_dispatch_time; + u32 ready_to_enqueue_time; + u32 waiting_to_ready_time; + u64 timebase; + u64 fault_addr; + u64 srr0; + u64 srr1; +}; + +struct dtl { + struct dtl_entry *buf; + struct dentry *file; + int cpu; + int buf_entries; + u64 last_idx; +}; +static DEFINE_PER_CPU(struct dtl, dtl); + +/* + * Dispatch trace log event mask: + * 0x7: 0x1: voluntary virtual processor waits + * 0x2: time-slice preempts + * 0x4: virtual partition memory page faults + */ +static u8 dtl_event_mask = 0x7; + + +/* + * Size of per-cpu log buffers. Default is just under 16 pages worth. + */ +static int dtl_buf_entries = (16 * 85); + + +static int dtl_enable(struct dtl *dtl) +{ + unsigned long addr; + int ret, hwcpu; + + /* only allow one reader */ + if (dtl->buf) + return -EBUSY; + + /* we need to store the original allocation size for use during read */ + dtl->buf_entries = dtl_buf_entries; + + dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry), + GFP_KERNEL, cpu_to_node(dtl->cpu)); + if (!dtl->buf) { + printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", + __func__, dtl->cpu); + return -ENOMEM; + } + + /* Register our dtl buffer with the hypervisor. The HV expects the + * buffer size to be passed in the second word of the buffer */ + ((u32 *)dtl->buf)[1] = dtl->buf_entries * sizeof(struct dtl_entry); + + hwcpu = get_hard_smp_processor_id(dtl->cpu); + addr = __pa(dtl->buf); + ret = register_dtl(hwcpu, addr); + if (ret) { + printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) " + "failed with %d\n", __func__, dtl->cpu, hwcpu, ret); + kfree(dtl->buf); + return -EIO; + } + + /* set our initial buffer indices */ + dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0; + + /* enable event logging */ + lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask; + + return 0; +} + +static void dtl_disable(struct dtl *dtl) +{ + int hwcpu = get_hard_smp_processor_id(dtl->cpu); + + lppaca[dtl->cpu].dtl_enable_mask = 0x0; + + unregister_dtl(hwcpu, __pa(dtl->buf)); + + kfree(dtl->buf); + dtl->buf = NULL; + dtl->buf_entries = 0; +} + +/* file interface */ + +static int dtl_file_open(struct inode *inode, struct file *filp) +{ + struct dtl *dtl = inode->i_private; + int rc; + + rc = dtl_enable(dtl); + if (rc) + return rc; + + filp->private_data = dtl; + return 0; +} + +static int dtl_file_release(struct inode *inode, struct file *filp) +{ + struct dtl *dtl = inode->i_private; + dtl_disable(dtl); + return 0; +} + +static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len, + loff_t *pos) +{ + int rc, cur_idx, last_idx, n_read, n_req, read_size; + struct dtl *dtl; + + if ((len % sizeof(struct dtl_entry)) != 0) + return -EINVAL; + + dtl = filp->private_data; + + /* requested number of entries to read */ + n_req = len / sizeof(struct dtl_entry); + + /* actual number of entries read */ + n_read = 0; + + cur_idx = lppaca[dtl->cpu].dtl_idx; + last_idx = dtl->last_idx; + + if (cur_idx - last_idx > dtl->buf_entries) { + pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n", + __func__, dtl->cpu); + } + + cur_idx %= dtl->buf_entries; + last_idx %= dtl->buf_entries; + + /* read the tail of the buffer if we've wrapped */ + if (last_idx > cur_idx) { + read_size = min(n_req, dtl->buf_entries - last_idx); + + rc = copy_to_user(buf, &dtl->buf[last_idx], + read_size * sizeof(struct dtl_entry)); + if (rc) + return -EFAULT; + + last_idx = 0; + n_req -= read_size; + n_read += read_size; + buf += read_size * sizeof(struct dtl_entry); + } + + /* .. and now the head */ + read_size = min(n_req, cur_idx - last_idx); + rc = copy_to_user(buf, &dtl->buf[last_idx], + read_size * sizeof(struct dtl_entry)); + if (rc) + return -EFAULT; + + n_read += read_size; + dtl->last_idx += n_read; + + return n_read * sizeof(struct dtl_entry); +} + +static struct file_operations dtl_fops = { + .open = dtl_file_open, + .release = dtl_file_release, + .read = dtl_file_read, + .llseek = no_llseek, +}; + +static struct dentry *dtl_dir; + +static int dtl_setup_file(struct dtl *dtl) +{ + char name[10]; + + sprintf(name, "cpu-%d", dtl->cpu); + + dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops); + if (!dtl->file) + return -ENOMEM; + + return 0; +} + +static int dtl_init(void) +{ + struct dentry *event_mask_file, *buf_entries_file; + int rc, i; + + if (!firmware_has_feature(FW_FEATURE_SPLPAR)) + return -ENODEV; + + /* set up common debugfs structure */ + + rc = -ENOMEM; + dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root); + if (!dtl_dir) { + printk(KERN_WARNING "%s: can't create dtl root dir\n", + __func__); + goto err; + } + + event_mask_file = debugfs_create_x8("dtl_event_mask", 0600, + dtl_dir, &dtl_event_mask); + buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0600, + dtl_dir, &dtl_buf_entries); + + if (!event_mask_file || !buf_entries_file) { + printk(KERN_WARNING "%s: can't create dtl files\n", __func__); + goto err_remove_dir; + } + + /* set up the per-cpu log structures */ + for_each_possible_cpu(i) { + struct dtl *dtl = &per_cpu(dtl, i); + dtl->cpu = i; + + rc = dtl_setup_file(dtl); + if (rc) + goto err_remove_dir; + } + + return 0; + +err_remove_dir: + debugfs_remove_recursive(dtl_dir); +err: + return rc; +} +arch_initcall(dtl_init); diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h index d967c1893ab..a24a6b2333b 100644 --- a/arch/powerpc/platforms/pseries/plpar_wrappers.h +++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h @@ -43,6 +43,16 @@ static inline long register_slb_shadow(unsigned long cpu, unsigned long vpa) return vpa_call(0x3, cpu, vpa); } +static inline long unregister_dtl(unsigned long cpu, unsigned long vpa) +{ + return vpa_call(0x6, cpu, vpa); +} + +static inline long register_dtl(unsigned long cpu, unsigned long vpa) +{ + return vpa_call(0x2, cpu, vpa); +} + static inline long plpar_page_set_loaned(unsigned long vpa) { unsigned long cmo_page_sz = cmo_get_page_size(); |