target/linux/generic/hack-4.9/930-crashlog.patch

   1 From 6b1ab74a9917012d0c559edc4ed299d9228ac89f Mon Sep 17 00:00:00 2001
   2 From: Felix Fietkau <nbd@nbd.name>
   3 Date: Sat, 8 Jul 2017 08:26:47 +0200
   4 Subject: kernel: add the new 'crashlog' feature
   5
   6 this tries to store kernel oops/panic logs in a fixed location in RAM to
   7 recover them available to user space using debugfs
   8
   9 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  10 ---
  11  include/linux/crashlog.h |  17 ++++
  12  init/Kconfig             |   4 +
  13  kernel/Makefile          |   1 +
  14  kernel/crashlog.c        | 213 +++++++++++++++++++++++++++++++++++++++++++++++
  15  kernel/module.c          |   3 +
  16  mm/bootmem.c             |   2 +
  17  mm/memblock.c            |   5 ++
  18  7 files changed, 245 insertions(+)
  19  create mode 100644 include/linux/crashlog.h
  20  create mode 100644 kernel/crashlog.c
  21
  22 diff --git a/include/linux/crashlog.h b/include/linux/crashlog.h
  23 new file mode 100644
  24 index 000000000000..7a9ee6138cc4
  25 --- /dev/null
  26 +++ b/include/linux/crashlog.h
  27 @@ -0,0 +1,17 @@
  28 +#ifndef __CRASHLOG_H
  29 +#define __CRASHLOG_H
  30 +
  31 +#ifdef CONFIG_CRASHLOG
  32 +void crashlog_init_bootmem(struct bootmem_data *bdata);
  33 +void crashlog_init_memblock(phys_addr_t addr, phys_addr_t size);
  34 +#else
  35 +static inline void crashlog_init_bootmem(struct bootmem_data *bdata)
  36 +{
  37 +}
  38 +
  39 +static inline void crashlog_init_memblock(phys_addr_t addr, phys_addr_t size)
  40 +{
  41 +}
  42 +#endif
  43 +
  44 +#endif
  45 diff --git a/init/Kconfig b/init/Kconfig
  46 index 9f2c0cabbc97..6d8f388fb9b3 100644
  47 --- a/init/Kconfig
  48 +++ b/init/Kconfig
  49 @@ -1298,6 +1298,10 @@ config RELAY
  50
  51           If unsure, say N.
  52
  53 +config CRASHLOG
  54 +       bool "Crash logging"
  55 +       depends on (!NO_BOOTMEM || HAVE_MEMBLOCK)
  56 +
  57  config BLK_DEV_INITRD
  58         bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
  59         depends on BROKEN || !FRV
  60 diff --git a/kernel/Makefile b/kernel/Makefile
  61 index 314e7d62f5f0..5fe0d8c3cb35 100644
  62 --- a/kernel/Makefile
  63 +++ b/kernel/Makefile
  64 @@ -113,6 +113,7 @@ obj-$(CONFIG_TORTURE_TEST) += torture.o
  65  obj-$(CONFIG_MEMBARRIER) += membarrier.o
  66
  67  obj-$(CONFIG_HAS_IOMEM) += memremap.o
  68 +obj-$(CONFIG_CRASHLOG) += crashlog.o
  69
  70  $(obj)/configs.o: $(obj)/config_data.h
  71
  72 diff --git a/kernel/crashlog.c b/kernel/crashlog.c
  73 new file mode 100644
  74 index 000000000000..11894b276e54
  75 --- /dev/null
  76 +++ b/kernel/crashlog.c
  77 @@ -0,0 +1,213 @@
  78 +/*
  79 + * Crash information logger
  80 + * Copyright (C) 2010 Felix Fietkau <nbd@nbd.name>
  81 + *
  82 + * Based on ramoops.c
  83 + *   Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
  84 + *
  85 + * This program is free software; you can redistribute it and/or
  86 + * modify it under the terms of the GNU General Public License
  87 + * version 2 as published by the Free Software Foundation.
  88 + *
  89 + * This program is distributed in the hope that it will be useful, but
  90 + * WITHOUT ANY WARRANTY; without even the implied warranty of
  91 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  92 + * General Public License for more details.
  93 + *
  94 + * You should have received a copy of the GNU General Public License
  95 + * along with this program; if not, write to the Free Software
  96 + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  97 + * 02110-1301 USA
  98 + *
  99 + */
 100 +
 101 +#include <linux/module.h>
 102 +#include <linux/bootmem.h>
 103 +#include <linux/memblock.h>
 104 +#include <linux/debugfs.h>
 105 +#include <linux/crashlog.h>
 106 +#include <linux/kmsg_dump.h>
 107 +#include <linux/module.h>
 108 +#include <linux/pfn.h>
 109 +#include <linux/vmalloc.h>
 110 +#include <asm/io.h>
 111 +
 112 +#define CRASHLOG_PAGES 4
 113 +#define CRASHLOG_SIZE  (CRASHLOG_PAGES * PAGE_SIZE)
 114 +#define CRASHLOG_MAGIC 0xa1eedead
 115 +
 116 +/*
 117 + * Start the log at 1M before the end of RAM, as some boot loaders like
 118 + * to use the end of the RAM for stack usage and other things
 119 + * If this fails, fall back to using the last part.
 120 + */
 121 +#define CRASHLOG_OFFSET        (1024 * 1024)
 122 +
 123 +struct crashlog_data {
 124 +       u32 magic;
 125 +       u32 len;
 126 +       u8 data[];
 127 +};
 128 +
 129 +static struct debugfs_blob_wrapper crashlog_blob;
 130 +static unsigned long crashlog_addr = 0;
 131 +static struct crashlog_data *crashlog_buf;
 132 +static struct kmsg_dumper dump;
 133 +static bool first = true;
 134 +
 135 +extern struct list_head *crashlog_modules;
 136 +
 137 +static bool crashlog_set_addr(phys_addr_t addr, phys_addr_t size)
 138 +{
 139 +       /* Limit to lower 64 MB to avoid highmem */
 140 +       phys_addr_t limit = 64 * 1024 * 1024;
 141 +
 142 +       if (crashlog_addr)
 143 +               return false;
 144 +
 145 +       if (addr > limit)
 146 +               return false;
 147 +
 148 +       if (addr + size > limit)
 149 +               size = limit - addr;
 150 +
 151 +       crashlog_addr = addr;
 152 +
 153 +       if (addr + size > CRASHLOG_OFFSET)
 154 +               crashlog_addr += size - CRASHLOG_OFFSET;
 155 +
 156 +       return true;
 157 +}
 158 +
 159 +#ifndef CONFIG_NO_BOOTMEM
 160 +void __init crashlog_init_bootmem(bootmem_data_t *bdata)
 161 +{
 162 +       phys_addr_t start, end;
 163 +
 164 +       start = PFN_PHYS(bdata->node_low_pfn);
 165 +       end = PFN_PHYS(bdata->node_min_pfn);
 166 +       if (!crashlog_set_addr(start, end - start))
 167 +               return;
 168 +
 169 +       if (reserve_bootmem(crashlog_addr, CRASHLOG_SIZE, BOOTMEM_EXCLUSIVE) < 0) {
 170 +               printk("Crashlog failed to allocate RAM at address 0x%lx\n",
 171 +                      crashlog_addr);
 172 +               crashlog_addr = 0;
 173 +       }
 174 +}
 175 +#endif
 176 +
 177 +#ifdef CONFIG_HAVE_MEMBLOCK
 178 +void __init_memblock crashlog_init_memblock(phys_addr_t addr, phys_addr_t size)
 179 +{
 180 +       if (!crashlog_set_addr(addr, size))
 181 +               return;
 182 +
 183 +       if (memblock_reserve(crashlog_addr, CRASHLOG_SIZE)) {
 184 +               printk("Crashlog failed to allocate RAM at address 0x%lx\n",
 185 +                      crashlog_addr);
 186 +               crashlog_addr = 0;
 187 +       }
 188 +}
 189 +#endif
 190 +
 191 +static void __init crashlog_copy(void)
 192 +{
 193 +       if (crashlog_buf->magic != CRASHLOG_MAGIC)
 194 +               return;
 195 +
 196 +       if (!crashlog_buf->len || crashlog_buf->len >
 197 +           CRASHLOG_SIZE - sizeof(*crashlog_buf))
 198 +               return;
 199 +
 200 +       crashlog_blob.size = crashlog_buf->len;
 201 +       crashlog_blob.data = kmemdup(crashlog_buf->data,
 202 +               crashlog_buf->len, GFP_KERNEL);
 203 +
 204 +       debugfs_create_blob("crashlog", 0700, NULL, &crashlog_blob);
 205 +}
 206 +
 207 +static int get_maxlen(void)
 208 +{
 209 +       return CRASHLOG_SIZE - sizeof(*crashlog_buf) - crashlog_buf->len;
 210 +}
 211 +
 212 +static void crashlog_printf(const char *fmt, ...)
 213 +{
 214 +       va_list args;
 215 +       int len = get_maxlen();
 216 +
 217 +       if (!len)
 218 +               return;
 219 +
 220 +       va_start(args, fmt);
 221 +       crashlog_buf->len += vscnprintf(
 222 +               &crashlog_buf->data[crashlog_buf->len],
 223 +               len, fmt, args);
 224 +       va_end(args);
 225 +}
 226 +
 227 +static void crashlog_do_dump(struct kmsg_dumper *dumper,
 228 +               enum kmsg_dump_reason reason)
 229 +{
 230 +       struct timeval tv;
 231 +       struct module *m;
 232 +       char *buf;
 233 +       size_t len;
 234 +
 235 +       if (!first)
 236 +               crashlog_printf("\n===================================\n");
 237 +
 238 +       do_gettimeofday(&tv);
 239 +       crashlog_printf("Time: %lu.%lu\n",
 240 +               (long)tv.tv_sec, (long)tv.tv_usec);
 241 +
 242 +       if (first) {
 243 +               crashlog_printf("Modules:");
 244 +               list_for_each_entry(m, crashlog_modules, list) {
 245 +                       crashlog_printf("\t%s@%p+%x", m->name,
 246 +                       m->core_layout.base, m->core_layout.size,
 247 +                       m->init_layout.base, m->init_layout.size);
 248 +               }
 249 +               crashlog_printf("\n");
 250 +               first = false;
 251 +       }
 252 +
 253 +       buf = (char *)&crashlog_buf->data[crashlog_buf->len];
 254 +
 255 +       kmsg_dump_get_buffer(dumper, true, buf, get_maxlen(), &len);
 256 +
 257 +       crashlog_buf->len += len;
 258 +}
 259 +
 260 +
 261 +int __init crashlog_init_fs(void)
 262 +{
 263 +       struct page *pages[CRASHLOG_PAGES];
 264 +       pgprot_t prot;
 265 +       int i;
 266 +
 267 +       if (!crashlog_addr) {
 268 +               printk("No memory allocated for crashlog\n");
 269 +               return -ENOMEM;
 270 +       }
 271 +
 272 +       printk("Crashlog allocated RAM at address 0x%lx\n", (unsigned long) crashlog_addr);
 273 +       for (i = 0; i < CRASHLOG_PAGES; i++)
 274 +               pages[i] = pfn_to_page((crashlog_addr >> PAGE_SHIFT) + i);
 275 +
 276 +       prot = pgprot_writecombine(PAGE_KERNEL);
 277 +       crashlog_buf = vmap(pages, CRASHLOG_PAGES, VM_MAP, prot);
 278 +
 279 +       crashlog_copy();
 280 +
 281 +       crashlog_buf->magic = CRASHLOG_MAGIC;
 282 +       crashlog_buf->len = 0;
 283 +
 284 +       dump.max_reason = KMSG_DUMP_OOPS;
 285 +       dump.dump = crashlog_do_dump;
 286 +       kmsg_dump_register(&dump);
 287 +
 288 +       return 0;
 289 +}
 290 +module_init(crashlog_init_fs);
 291 diff --git a/kernel/module.c b/kernel/module.c
 292 index 80b5ac4181c6..51d6e4e6f436 100644
 293 --- a/kernel/module.c
 294 +++ b/kernel/module.c
 295 @@ -253,6 +253,9 @@ static void mod_update_bounds(struct module *mod)
 296  #ifdef CONFIG_KGDB_KDB
 297  struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 298  #endif /* CONFIG_KGDB_KDB */
 299 +#ifdef CONFIG_CRASHLOG
 300 +struct list_head *crashlog_modules = &modules;
 301 +#endif
 302
 303  static void module_assert_mutex(void)
 304  {
 305 diff --git a/mm/bootmem.c b/mm/bootmem.c
 306 index e8a55a3c9feb..e0f3c0bf2709 100644
 307 --- a/mm/bootmem.c
 308 +++ b/mm/bootmem.c
 309 @@ -14,6 +14,7 @@
 310  #include <linux/export.h>
 311  #include <linux/kmemleak.h>
 312  #include <linux/range.h>
 313 +#include <linux/crashlog.h>
 314  #include <linux/bug.h>
 315  #include <linux/io.h>
 316  #include <linux/bootmem.h>
 317 @@ -174,6 +175,7 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 318         if (!bdata->node_bootmem_map)
 319                 return 0;
 320
 321 +       crashlog_init_bootmem(bdata);
 322         map = bdata->node_bootmem_map;
 323         start = bdata->node_min_pfn;
 324         end = bdata->node_low_pfn;
 325 diff --git a/mm/memblock.c b/mm/memblock.c
 326 index 68849d0ead09..aef9ca5e7f52 100644
 327 --- a/mm/memblock.c
 328 +++ b/mm/memblock.c
 329 @@ -19,6 +19,7 @@
 330  #include <linux/debugfs.h>
 331  #include <linux/seq_file.h>
 332  #include <linux/memblock.h>
 333 +#include <linux/crashlog.h>
 334
 335  #include <asm/sections.h>
 336  #include <linux/io.h>
 337 @@ -499,6 +500,8 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
 338         memblock_set_region_node(rgn, nid);
 339         type->cnt++;
 340         type->total_size += size;
 341 +       if (type == &memblock.memory)
 342 +               crashlog_init_memblock(base, size);
 343  }
 344
 345  /**
 346 @@ -538,6 +541,8 @@ int __init_memblock memblock_add_range(struct memblock_type *type,
 347                 type->regions[0].flags = flags;
 348                 memblock_set_region_node(&type->regions[0], nid);
 349                 type->total_size = size;
 350 +               if (type == &memblock.memory)
 351 +                       crashlog_init_memblock(base, size);
 352                 return 0;
 353         }
 354  repeat:
 355 --
 356 2.11.0
 357