Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Virtual Processor Dispatch Trace Log |
| 3 | * |
| 4 | * (C) Copyright IBM Corporation 2009 |
| 5 | * |
| 6 | * Author: Jeremy Kerr <jk@ozlabs.org> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; either version 2, or (at your option) |
| 11 | * any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program; if not, write to the Free Software |
| 20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 21 | */ |
| 22 | |
| 23 | #include <linux/init.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 24 | #include <linux/slab.h> |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 25 | #include <linux/debugfs.h> |
| 26 | #include <asm/smp.h> |
| 27 | #include <asm/system.h> |
| 28 | #include <asm/uaccess.h> |
Sachin Sant | b71a0c2 | 2009-04-14 14:35:55 +0000 | [diff] [blame] | 29 | #include <asm/firmware.h> |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 30 | |
| 31 | #include "plpar_wrappers.h" |
| 32 | |
| 33 | /* |
| 34 | * Layout of entries in the hypervisor's DTL buffer. Although we don't |
| 35 | * actually access the internals of an entry (we only need to know the size), |
| 36 | * we might as well define it here for reference. |
| 37 | */ |
| 38 | struct dtl_entry { |
| 39 | u8 dispatch_reason; |
| 40 | u8 preempt_reason; |
| 41 | u16 processor_id; |
| 42 | u32 enqueue_to_dispatch_time; |
| 43 | u32 ready_to_enqueue_time; |
| 44 | u32 waiting_to_ready_time; |
| 45 | u64 timebase; |
| 46 | u64 fault_addr; |
| 47 | u64 srr0; |
| 48 | u64 srr1; |
| 49 | }; |
| 50 | |
| 51 | struct dtl { |
| 52 | struct dtl_entry *buf; |
| 53 | struct dentry *file; |
| 54 | int cpu; |
| 55 | int buf_entries; |
| 56 | u64 last_idx; |
| 57 | }; |
Tejun Heo | 6b7487f | 2009-10-29 22:34:14 +0900 | [diff] [blame] | 58 | static DEFINE_PER_CPU(struct dtl, cpu_dtl); |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 59 | |
| 60 | /* |
| 61 | * Dispatch trace log event mask: |
| 62 | * 0x7: 0x1: voluntary virtual processor waits |
| 63 | * 0x2: time-slice preempts |
| 64 | * 0x4: virtual partition memory page faults |
| 65 | */ |
| 66 | static u8 dtl_event_mask = 0x7; |
| 67 | |
| 68 | |
| 69 | /* |
| 70 | * Size of per-cpu log buffers. Default is just under 16 pages worth. |
| 71 | */ |
| 72 | static int dtl_buf_entries = (16 * 85); |
| 73 | |
| 74 | |
| 75 | static int dtl_enable(struct dtl *dtl) |
| 76 | { |
| 77 | unsigned long addr; |
| 78 | int ret, hwcpu; |
| 79 | |
| 80 | /* only allow one reader */ |
| 81 | if (dtl->buf) |
| 82 | return -EBUSY; |
| 83 | |
| 84 | /* we need to store the original allocation size for use during read */ |
| 85 | dtl->buf_entries = dtl_buf_entries; |
| 86 | |
| 87 | dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry), |
| 88 | GFP_KERNEL, cpu_to_node(dtl->cpu)); |
| 89 | if (!dtl->buf) { |
| 90 | printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", |
| 91 | __func__, dtl->cpu); |
| 92 | return -ENOMEM; |
| 93 | } |
| 94 | |
| 95 | /* Register our dtl buffer with the hypervisor. The HV expects the |
| 96 | * buffer size to be passed in the second word of the buffer */ |
| 97 | ((u32 *)dtl->buf)[1] = dtl->buf_entries * sizeof(struct dtl_entry); |
| 98 | |
| 99 | hwcpu = get_hard_smp_processor_id(dtl->cpu); |
| 100 | addr = __pa(dtl->buf); |
| 101 | ret = register_dtl(hwcpu, addr); |
| 102 | if (ret) { |
| 103 | printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) " |
| 104 | "failed with %d\n", __func__, dtl->cpu, hwcpu, ret); |
| 105 | kfree(dtl->buf); |
| 106 | return -EIO; |
| 107 | } |
| 108 | |
| 109 | /* set our initial buffer indices */ |
| 110 | dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0; |
| 111 | |
Jeremy Kerr | 82631f5 | 2009-03-23 16:55:08 +0000 | [diff] [blame] | 112 | /* ensure that our updates to the lppaca fields have occurred before |
| 113 | * we actually enable the logging */ |
| 114 | smp_wmb(); |
| 115 | |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 116 | /* enable event logging */ |
| 117 | lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask; |
| 118 | |
| 119 | return 0; |
| 120 | } |
| 121 | |
| 122 | static void dtl_disable(struct dtl *dtl) |
| 123 | { |
| 124 | int hwcpu = get_hard_smp_processor_id(dtl->cpu); |
| 125 | |
| 126 | lppaca[dtl->cpu].dtl_enable_mask = 0x0; |
| 127 | |
| 128 | unregister_dtl(hwcpu, __pa(dtl->buf)); |
| 129 | |
| 130 | kfree(dtl->buf); |
| 131 | dtl->buf = NULL; |
| 132 | dtl->buf_entries = 0; |
| 133 | } |
| 134 | |
| 135 | /* file interface */ |
| 136 | |
| 137 | static int dtl_file_open(struct inode *inode, struct file *filp) |
| 138 | { |
| 139 | struct dtl *dtl = inode->i_private; |
| 140 | int rc; |
| 141 | |
| 142 | rc = dtl_enable(dtl); |
| 143 | if (rc) |
| 144 | return rc; |
| 145 | |
| 146 | filp->private_data = dtl; |
| 147 | return 0; |
| 148 | } |
| 149 | |
| 150 | static int dtl_file_release(struct inode *inode, struct file *filp) |
| 151 | { |
| 152 | struct dtl *dtl = inode->i_private; |
| 153 | dtl_disable(dtl); |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len, |
| 158 | loff_t *pos) |
| 159 | { |
| 160 | int rc, cur_idx, last_idx, n_read, n_req, read_size; |
| 161 | struct dtl *dtl; |
| 162 | |
| 163 | if ((len % sizeof(struct dtl_entry)) != 0) |
| 164 | return -EINVAL; |
| 165 | |
| 166 | dtl = filp->private_data; |
| 167 | |
| 168 | /* requested number of entries to read */ |
| 169 | n_req = len / sizeof(struct dtl_entry); |
| 170 | |
| 171 | /* actual number of entries read */ |
| 172 | n_read = 0; |
| 173 | |
| 174 | cur_idx = lppaca[dtl->cpu].dtl_idx; |
| 175 | last_idx = dtl->last_idx; |
| 176 | |
| 177 | if (cur_idx - last_idx > dtl->buf_entries) { |
| 178 | pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n", |
| 179 | __func__, dtl->cpu); |
| 180 | } |
| 181 | |
| 182 | cur_idx %= dtl->buf_entries; |
| 183 | last_idx %= dtl->buf_entries; |
| 184 | |
| 185 | /* read the tail of the buffer if we've wrapped */ |
| 186 | if (last_idx > cur_idx) { |
| 187 | read_size = min(n_req, dtl->buf_entries - last_idx); |
| 188 | |
| 189 | rc = copy_to_user(buf, &dtl->buf[last_idx], |
| 190 | read_size * sizeof(struct dtl_entry)); |
| 191 | if (rc) |
| 192 | return -EFAULT; |
| 193 | |
| 194 | last_idx = 0; |
| 195 | n_req -= read_size; |
| 196 | n_read += read_size; |
| 197 | buf += read_size * sizeof(struct dtl_entry); |
| 198 | } |
| 199 | |
| 200 | /* .. and now the head */ |
| 201 | read_size = min(n_req, cur_idx - last_idx); |
| 202 | rc = copy_to_user(buf, &dtl->buf[last_idx], |
| 203 | read_size * sizeof(struct dtl_entry)); |
| 204 | if (rc) |
| 205 | return -EFAULT; |
| 206 | |
| 207 | n_read += read_size; |
| 208 | dtl->last_idx += n_read; |
| 209 | |
| 210 | return n_read * sizeof(struct dtl_entry); |
| 211 | } |
| 212 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 213 | static const struct file_operations dtl_fops = { |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 214 | .open = dtl_file_open, |
| 215 | .release = dtl_file_release, |
| 216 | .read = dtl_file_read, |
| 217 | .llseek = no_llseek, |
| 218 | }; |
| 219 | |
| 220 | static struct dentry *dtl_dir; |
| 221 | |
| 222 | static int dtl_setup_file(struct dtl *dtl) |
| 223 | { |
| 224 | char name[10]; |
| 225 | |
| 226 | sprintf(name, "cpu-%d", dtl->cpu); |
| 227 | |
| 228 | dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops); |
| 229 | if (!dtl->file) |
| 230 | return -ENOMEM; |
| 231 | |
| 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | static int dtl_init(void) |
| 236 | { |
| 237 | struct dentry *event_mask_file, *buf_entries_file; |
| 238 | int rc, i; |
| 239 | |
| 240 | if (!firmware_has_feature(FW_FEATURE_SPLPAR)) |
| 241 | return -ENODEV; |
| 242 | |
| 243 | /* set up common debugfs structure */ |
| 244 | |
| 245 | rc = -ENOMEM; |
| 246 | dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root); |
| 247 | if (!dtl_dir) { |
| 248 | printk(KERN_WARNING "%s: can't create dtl root dir\n", |
| 249 | __func__); |
| 250 | goto err; |
| 251 | } |
| 252 | |
| 253 | event_mask_file = debugfs_create_x8("dtl_event_mask", 0600, |
| 254 | dtl_dir, &dtl_event_mask); |
| 255 | buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0600, |
| 256 | dtl_dir, &dtl_buf_entries); |
| 257 | |
| 258 | if (!event_mask_file || !buf_entries_file) { |
| 259 | printk(KERN_WARNING "%s: can't create dtl files\n", __func__); |
| 260 | goto err_remove_dir; |
| 261 | } |
| 262 | |
| 263 | /* set up the per-cpu log structures */ |
| 264 | for_each_possible_cpu(i) { |
Tejun Heo | 6b7487f | 2009-10-29 22:34:14 +0900 | [diff] [blame] | 265 | struct dtl *dtl = &per_cpu(cpu_dtl, i); |
Jeremy Kerr | fc59a3f | 2009-03-11 17:55:52 +0000 | [diff] [blame] | 266 | dtl->cpu = i; |
| 267 | |
| 268 | rc = dtl_setup_file(dtl); |
| 269 | if (rc) |
| 270 | goto err_remove_dir; |
| 271 | } |
| 272 | |
| 273 | return 0; |
| 274 | |
| 275 | err_remove_dir: |
| 276 | debugfs_remove_recursive(dtl_dir); |
| 277 | err: |
| 278 | return rc; |
| 279 | } |
| 280 | arch_initcall(dtl_init); |