Hi all,
In v2:
- Updated documentation per Colin Cross' comments;
- Corrected return value in ramoops_pstore_write() (noticed by Kees Cook);
- Fixed large writes handling in pstore_console_write(), i.e. when
log_buf write is larger than pstore bufsize. Also Noticed by Kees Cook.
These patches depend on the the following series:
http://thread.gmane.org/gmane.linux.kernel/1298642
"[PATCH v3 0/3] Merge ramoops and persistent_ram, generic pstore RAM backend"
And a rationale for the series:
Currently pstore doesn't support logging kernel messages in run-time,
it only dumps dmesg when kernel oopses/panics. This makes pstore
useless for debugging hangs caused by HW issues or improper use of HW
(e.g. weird device inserted -> driver tried to write reserved bits ->
SoC hanged. In that case we don't get any messages in the pstore.
This series add a new message type for pstore, i.e. PSTORE_TYPE_CONSOLE,
plus make pstore/ram.c handle the new messages.
The old ram_console driver is removed. This might probably cause
some pain for out-of-tree code, as it would need to be adjusted...
but "no pain, no gain"? :-) Though, if there's some serious resistance,
we can probably postpone the last two patches.
Thanks!
--
Anton Vorontsov
Email: [email protected]
Pstore doesn't support logging kernel messages in run-time, it only
dumps dmesg when kernel oopses/panics. This makes pstore useless for
debugging hangs caused by HW issues or improper use of HW (e.g.
weird device inserted -> driver tried to write a reserved bits ->
SoC hanged. In that case we don't get any messages in the pstore.
Therefore, let's add a runtime logging support: PSTORE_TYPE_CONSOLE.
Signed-off-by: Anton Vorontsov <[email protected]>
---
fs/pstore/Kconfig | 7 +++++++
fs/pstore/inode.c | 3 +++
fs/pstore/platform.c | 33 +++++++++++++++++++++++++++++++++
include/linux/pstore.h | 1 +
4 files changed, 44 insertions(+)
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 23ade26..d044de6 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -12,6 +12,13 @@ config PSTORE
If you don't have a platform persistent store driver,
say N.
+config PSTORE_CONSOLE
+ bool "Log kernel console messages"
+ depends on PSTORE
+ help
+ When the option is enabled, pstore will log all kernel
+ messages, even if no oops or panic happened.
+
config PSTORE_RAM
tristate "Log panic/oops to a RAM buffer"
depends on PSTORE
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 1950788..97d35ee 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -212,6 +212,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
case PSTORE_TYPE_DMESG:
sprintf(name, "dmesg-%s-%lld", psname, id);
break;
+ case PSTORE_TYPE_CONSOLE:
+ sprintf(name, "console-%s", psname);
+ break;
case PSTORE_TYPE_MCE:
sprintf(name, "mce-%s-%lld", psname, id);
break;
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 82c585f..a3f6d96 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -1,6 +1,7 @@
/*
* Persistent Storage - platform driver interface parts.
*
+ * Copyright (C) 2007-2008 Google, Inc.
* Copyright (C) 2010 Intel Corporation <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
@@ -22,6 +23,7 @@
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmsg_dump.h>
+#include <linux/console.h>
#include <linux/module.h>
#include <linux/pstore.h>
#include <linux/string.h>
@@ -156,6 +158,36 @@ static struct kmsg_dumper pstore_dumper = {
.dump = pstore_dump,
};
+#ifdef CONFIG_PSTORE_CONSOLE
+static void pstore_console_write(struct console *con, const char *s, unsigned c)
+{
+ const char *e = s + c;
+
+ while (s < e) {
+ if (c > psinfo->bufsize)
+ c = psinfo->bufsize;
+ memcpy(psinfo->buf, s, c);
+ psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
+ s += c;
+ c = e - s;
+ }
+}
+
+static struct console pstore_console = {
+ .name = "pstore",
+ .write = pstore_console_write,
+ .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
+ .index = -1,
+};
+
+static void pstore_register_console(void)
+{
+ register_console(&pstore_console);
+}
+#else
+static void pstore_register_console(void) {}
+#endif
+
/*
* platform specific persistent storage driver registers with
* us here. If pstore is already mounted, call the platform
@@ -193,6 +225,7 @@ int pstore_register(struct pstore_info *psi)
pstore_get_records(0);
kmsg_dump_register(&pstore_dumper);
+ pstore_register_console();
pstore_timer.expires = jiffies + PSTORE_INTERVAL;
add_timer(&pstore_timer);
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e1461e1..1bd014b 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -29,6 +29,7 @@
enum pstore_type_id {
PSTORE_TYPE_DMESG = 0,
PSTORE_TYPE_MCE = 1,
+ PSTORE_TYPE_CONSOLE = 2,
PSTORE_TYPE_UNKNOWN = 255
};
--
1.7.9.2
Since we use multiple regions, the messages are somewhat annoying.
We do print total mapped memory already, so no need to print the
information for each region in the library routines.
Signed-off-by: Anton Vorontsov <[email protected]>
---
fs/pstore/ram_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 31f8d18..e0d8429 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -401,13 +401,13 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool
" size %zu, start %zu\n",
buffer_size(prz), buffer_start(prz));
else {
- pr_info("persistent_ram: found existing buffer,"
+ pr_debug("persistent_ram: found existing buffer,"
" size %zu, start %zu\n",
buffer_size(prz), buffer_start(prz));
persistent_ram_save_old(prz);
}
} else {
- pr_info("persistent_ram: no valid data in buffer"
+ pr_debug("persistent_ram: no valid data in buffer"
" (sig = 0x%08x)\n", prz->buffer->sig);
}
--
1.7.9.2
Suggested-by: Shuah Khan <[email protected]>
Signed-off-by: Anton Vorontsov <[email protected]>
---
Documentation/ramoops.txt | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 4ba7db2..59a74a8 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -40,6 +40,12 @@ corrupt, but usually it is restorable.
Setting the ramoops parameters can be done in 2 different manners:
1. Use the module parameters (which have the names of the variables described
as before).
+ For quick debugging, you can also reserve parts of memory during boot
+ and then use the reserved memory for ramoops. For example, assuming a machine
+ with > 128 MB of memory, the following kernel command line will tell the
+ kernel to use only the first 128 MB of memory, and place ECC-protected ramoops
+ region at 128 MB boundary:
+ "mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1"
2. Use a platform device and set the platform data. The parameters can then
be set through that platform data. An example of doing that is:
@@ -70,6 +76,14 @@ if (ret) {
return ret;
}
+You can specify either RAM memory or peripheral devices' memory. However, when
+specifying RAM, be sure to reserve the memory by issuing memblock_reserve()
+very early in the architecture code, e.g.:
+
+#include <linux/memblock.h>
+
+memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
+
3. Dump format
The data dump begins with a header, currently defined as "====" followed by a
--
1.7.9.2
All the functionality is now supported by pstore and pstore_ram drivers.
Signed-off-by: Anton Vorontsov <[email protected]>
---
drivers/staging/android/Kconfig | 5 -
drivers/staging/android/Makefile | 1 -
drivers/staging/android/ram_console.c | 179 ---------------------------------
3 files changed, 185 deletions(-)
delete mode 100644 drivers/staging/android/ram_console.c
diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 63f9822..df42c6b 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -25,11 +25,6 @@ config ANDROID_LOGGER
tristate "Android log driver"
default n
-config ANDROID_RAM_CONSOLE
- bool "Android RAM buffer console"
- depends on !S390 && !UML && HAVE_MEMBLOCK && PSTORE_RAM=y
- default n
-
config ANDROID_TIMED_OUTPUT
bool "Timed output class driver"
default y
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 4677e7b..5f3ef2e 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -1,7 +1,6 @@
obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o
obj-$(CONFIG_ASHMEM) += ashmem.o
obj-$(CONFIG_ANDROID_LOGGER) += logger.o
-obj-$(CONFIG_ANDROID_RAM_CONSOLE) += ram_console.o
obj-$(CONFIG_ANDROID_TIMED_OUTPUT) += timed_output.o
obj-$(CONFIG_ANDROID_TIMED_GPIO) += timed_gpio.o
obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER) += lowmemorykiller.o
diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c
deleted file mode 100644
index 82323bb..0000000
--- a/drivers/staging/android/ram_console.c
+++ /dev/null
@@ -1,179 +0,0 @@
-/* drivers/android/ram_console.c
- *
- * Copyright (C) 2007-2008 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
- *
- */
-
-#include <linux/console.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/proc_fs.h>
-#include <linux/string.h>
-#include <linux/uaccess.h>
-#include <linux/io.h>
-#include <linux/pstore_ram.h>
-#include "ram_console.h"
-
-static struct persistent_ram_zone *ram_console_zone;
-static const char *bootinfo;
-static size_t bootinfo_size;
-
-static void
-ram_console_write(struct console *console, const char *s, unsigned int count)
-{
- struct persistent_ram_zone *prz = console->data;
- persistent_ram_write(prz, s, count);
-}
-
-static struct console ram_console = {
- .name = "ram",
- .write = ram_console_write,
- .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
- .index = -1,
-};
-
-void ram_console_enable_console(int enabled)
-{
- if (enabled)
- ram_console.flags |= CON_ENABLED;
- else
- ram_console.flags &= ~CON_ENABLED;
-}
-
-static int __init ram_console_probe(struct platform_device *pdev)
-{
- struct ram_console_platform_data *pdata = pdev->dev.platform_data;
- struct persistent_ram_zone *prz;
-
- prz = persistent_ram_init_ringbuffer(&pdev->dev, true);
- if (IS_ERR(prz))
- return PTR_ERR(prz);
-
-
- if (pdata) {
- bootinfo = kstrdup(pdata->bootinfo, GFP_KERNEL);
- if (bootinfo)
- bootinfo_size = strlen(bootinfo);
- }
-
- ram_console_zone = prz;
- ram_console.data = prz;
-
- register_console(&ram_console);
-
- return 0;
-}
-
-static struct platform_driver ram_console_driver = {
- .driver = {
- .name = "ram_console",
- },
-};
-
-static int __init ram_console_module_init(void)
-{
- return platform_driver_probe(&ram_console_driver, ram_console_probe);
-}
-
-#ifndef CONFIG_PRINTK
-#define dmesg_restrict 0
-#endif
-
-static ssize_t ram_console_read_old(struct file *file, char __user *buf,
- size_t len, loff_t *offset)
-{
- loff_t pos = *offset;
- ssize_t count;
- struct persistent_ram_zone *prz = ram_console_zone;
- size_t old_log_size = persistent_ram_old_size(prz);
- const char *old_log = persistent_ram_old(prz);
- char *str;
- int ret;
-
- if (dmesg_restrict && !capable(CAP_SYSLOG))
- return -EPERM;
-
- /* Main last_kmsg log */
- if (pos < old_log_size) {
- count = min(len, (size_t)(old_log_size - pos));
- if (copy_to_user(buf, old_log + pos, count))
- return -EFAULT;
- goto out;
- }
-
- /* ECC correction notice */
- pos -= old_log_size;
- count = persistent_ram_ecc_string(prz, NULL, 0);
- if (pos < count) {
- str = kmalloc(count, GFP_KERNEL);
- if (!str)
- return -ENOMEM;
- persistent_ram_ecc_string(prz, str, count + 1);
- count = min(len, (size_t)(count - pos));
- ret = copy_to_user(buf, str + pos, count);
- kfree(str);
- if (ret)
- return -EFAULT;
- goto out;
- }
-
- /* Boot info passed through pdata */
- pos -= count;
- if (pos < bootinfo_size) {
- count = min(len, (size_t)(bootinfo_size - pos));
- if (copy_to_user(buf, bootinfo + pos, count))
- return -EFAULT;
- goto out;
- }
-
- /* EOF */
- return 0;
-
-out:
- *offset += count;
- return count;
-}
-
-static const struct file_operations ram_console_file_ops = {
- .owner = THIS_MODULE,
- .read = ram_console_read_old,
-};
-
-static int __init ram_console_late_init(void)
-{
- struct proc_dir_entry *entry;
- struct persistent_ram_zone *prz = ram_console_zone;
-
- if (!prz)
- return 0;
-
- if (persistent_ram_old_size(prz) == 0)
- return 0;
-
- entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
- if (!entry) {
- printk(KERN_ERR "ram_console: failed to create proc entry\n");
- persistent_ram_free_old(prz);
- return 0;
- }
-
- entry->proc_fops = &ram_console_file_ops;
- entry->size = persistent_ram_old_size(prz) +
- persistent_ram_ecc_string(prz, NULL, 0) +
- bootinfo_size;
-
- return 0;
-}
-
-late_initcall(ram_console_late_init);
-postcore_initcall(ram_console_module_init);
--
1.7.9.2
The code tried to maintain the global list of persistent ram zones,
which isn't a great idea overall, plus since Android's ram_console
is no longer there, we can remove some unused functions.
Signed-off-by: Anton Vorontsov <[email protected]>
---
fs/pstore/ram_core.c | 77 --------------------------------------------
include/linux/pstore_ram.h | 19 -----------
2 files changed, 96 deletions(-)
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index e0d8429..b216381 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -35,8 +35,6 @@ struct persistent_ram_buffer {
#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
-static __initdata LIST_HEAD(persistent_ram_list);
-
static inline size_t buffer_size(struct persistent_ram_zone *prz)
{
return atomic_read(&prz->buffer->size);
@@ -455,78 +453,3 @@ err:
kfree(prz);
return ERR_PTR(ret);
}
-
-#ifndef MODULE
-static int __init persistent_ram_buffer_init(const char *name,
- struct persistent_ram_zone *prz)
-{
- int i;
- struct persistent_ram *ram;
- struct persistent_ram_descriptor *desc;
- phys_addr_t start;
-
- list_for_each_entry(ram, &persistent_ram_list, node) {
- start = ram->start;
- for (i = 0; i < ram->num_descs; i++) {
- desc = &ram->descs[i];
- if (!strcmp(desc->name, name))
- return persistent_ram_buffer_map(start,
- desc->size, prz);
- start += desc->size;
- }
- }
-
- return -EINVAL;
-}
-
-static __init
-struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
-{
- struct persistent_ram_zone *prz;
- int ret = -ENOMEM;
-
- prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
- if (!prz) {
- pr_err("persistent_ram: failed to allocate persistent ram zone\n");
- goto err;
- }
-
- ret = persistent_ram_buffer_init(dev_name(dev), prz);
- if (ret) {
- pr_err("persistent_ram: failed to initialize buffer\n");
- goto err;
- }
-
- persistent_ram_post_init(prz, ecc);
-
- return prz;
-err:
- kfree(prz);
- return ERR_PTR(ret);
-}
-
-struct persistent_ram_zone * __init
-persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
-{
- return __persistent_ram_init(dev, ecc);
-}
-
-int __init persistent_ram_early_init(struct persistent_ram *ram)
-{
- int ret;
-
- ret = memblock_reserve(ram->start, ram->size);
- if (ret) {
- pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
- (long)ram->start, (long)(ram->start + ram->size - 1));
- return ret;
- }
-
- list_add_tail(&ram->node, &persistent_ram_list);
-
- pr_info("Initialized persistent memory from %08lx-%08lx\n",
- (long)ram->start, (long)(ram->start + ram->size - 1));
-
- return 0;
-}
-#endif
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 7ed7fd4..d1d7d51 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -25,21 +25,6 @@
struct persistent_ram_buffer;
-struct persistent_ram_descriptor {
- const char *name;
- phys_addr_t size;
-};
-
-struct persistent_ram {
- phys_addr_t start;
- phys_addr_t size;
-
- int num_descs;
- struct persistent_ram_descriptor *descs;
-
- struct list_head node;
-};
-
struct persistent_ram_zone {
phys_addr_t paddr;
size_t size;
@@ -63,14 +48,10 @@ struct persistent_ram_zone {
size_t old_log_size;
};
-int persistent_ram_early_init(struct persistent_ram *ram);
-
struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
size_t size,
bool ecc);
void persistent_ram_free(struct persistent_ram_zone *prz);
-struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
- bool ecc);
int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
unsigned int count);
--
1.7.9.2
This is all straightforward: we just use the last region for
console logging. If there's just one region, we fall-back to
the old behaviour: just a oops/dumps logging.
Signed-off-by: Anton Vorontsov <[email protected]>
---
fs/pstore/ram.c | 40 +++++++++++++++++++++++++++++++---------
1 file changed, 31 insertions(+), 9 deletions(-)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 9123cce..5d6d53e 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -63,6 +63,7 @@ MODULE_PARM_DESC(ramoops_ecc,
struct ramoops_context {
struct persistent_ram_zone **przs;
+ struct persistent_ram_zone *cprz;
phys_addr_t phys_addr;
unsigned long size;
size_t record_size;
@@ -70,6 +71,7 @@ struct ramoops_context {
bool ecc;
unsigned int count;
unsigned int max_count;
+ unsigned int max_dump_count;
unsigned int read_count;
struct pstore_info pstore;
};
@@ -92,16 +94,20 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
{
ssize_t size;
struct ramoops_context *cxt = psi->data;
- struct persistent_ram_zone *prz;
-
- if (cxt->read_count >= cxt->max_count)
- return -EINVAL;
+ struct persistent_ram_zone *prz = cxt->przs[cxt->read_count];
*id = cxt->read_count++;
- prz = cxt->przs[*id];
- /* Only supports dmesg output so far. */
- *type = PSTORE_TYPE_DMESG;
+ if (*id < cxt->max_dump_count && persistent_ram_old_size(prz)) {
+ *type = PSTORE_TYPE_DMESG;
+ } else if (*id < cxt->max_count) {
+ *type = PSTORE_TYPE_CONSOLE;
+ prz = cxt->cprz;
+ cxt->read_count = cxt->max_count;
+ } else {
+ return 0;
+ }
+
/* TODO(kees): Bogus time for the moment. */
time->tv_sec = 0;
time->tv_nsec = 0;
@@ -142,7 +148,13 @@ static int ramoops_pstore_write(enum pstore_type_id type,
struct persistent_ram_zone *prz = cxt->przs[cxt->count];
size_t hlen;
- /* Currently ramoops is designed to only store dmesg dumps. */
+ if (type == PSTORE_TYPE_CONSOLE) {
+ if (!cxt->cprz)
+ return -ENOMEM;
+ persistent_ram_write(cxt->cprz, cxt->pstore.buf, size);
+ return 0;
+ }
+
if (type != PSTORE_TYPE_DMESG)
return -EINVAL;
@@ -170,7 +182,7 @@ static int ramoops_pstore_write(enum pstore_type_id type,
size = prz->buffer_size - hlen;
persistent_ram_write(prz, cxt->pstore.buf, size);
- cxt->count = (cxt->count + 1) % cxt->max_count;
+ cxt->count = (cxt->count + 1) % cxt->max_dump_count;
return 0;
}
@@ -264,6 +276,16 @@ static int __init ramoops_probe(struct platform_device *pdev)
}
}
+ /*
+ * The last zone is for TYPE_CONSOLE, unless we have only
+ * one, in which case we use it for oops/panic logging.
+ */
+ cxt->max_dump_count = cxt->max_count;
+ if (cxt->max_count > 1) {
+ cxt->max_dump_count--;
+ cxt->cprz = cxt->przs[cxt->max_count - 1];
+ }
+
cxt->pstore.data = cxt;
cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
--
1.7.9.2
On Thu, May 17, 2012 at 1:40 AM, Anton Vorontsov
<[email protected]> wrote:
> Pstore doesn't support logging kernel messages in run-time, it only
> dumps dmesg when kernel oopses/panics. This makes pstore useless for
> debugging hangs caused by HW issues or improper use of HW (e.g.
> weird device inserted -> driver tried to write a reserved bits ->
> SoC hanged. In that case we don't get any messages in the pstore.
>
> Therefore, let's add a runtime logging support: PSTORE_TYPE_CONSOLE.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Kees Cook <[email protected]>
--
Kees Cook
Chrome OS Security
On Thu, May 17, 2012 at 1:40 AM, Anton Vorontsov
<[email protected]> wrote:
> This is all straightforward: we just use the last region for
> console logging. If there's just one region, we fall-back to
> the old behaviour: just a oops/dumps logging.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Kees Cook <[email protected]>
-Kees
--
Kees Cook
Chrome OS Security
On Thu, May 17, 2012 at 1:40 AM, Anton Vorontsov
<[email protected]> wrote:
> Since we use multiple regions, the messages are somewhat annoying.
> We do print total mapped memory already, so no need to print the
> information for each region in the library routines.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Kees Cook <[email protected]>
-Kees
--
Kees Cook
Chrome OS Security
On Thu, May 17, 2012 at 1:41 AM, Anton Vorontsov
<[email protected]> wrote:
> The code tried to maintain the global list of persistent ram zones,
> which isn't a great idea overall, plus since Android's ram_console
> is no longer there, we can remove some unused functions.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Kees Cook <[email protected]>
-Kees
--
Kees Cook
Chrome OS Security
On Thu, May 17, 2012 at 1:40 AM, Anton Vorontsov
<[email protected]> wrote:
> This is all straightforward: we just use the last region for
> console logging. If there's just one region, we fall-back to
> the old behaviour: just a oops/dumps logging.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
I don't think using the last region is the right way to handle this.
We often use very large regions for ramconsole, up to 2MB. Using a
single region would require a 2MB region for console and a 2MB region
for oops, which is far too large.
On Thu, May 17, 2012 at 1:37 AM, Anton Vorontsov
<[email protected]> wrote:
> Hi all,
>
> In v2:
>
> - Updated documentation per Colin Cross' comments;
> - Corrected return value in ramoops_pstore_write() (noticed by Kees Cook);
> - Fixed large writes handling in pstore_console_write(), i.e. when
> ?log_buf write is larger than pstore bufsize. Also Noticed by Kees Cook.
>
> These patches depend on the the following series:
> http://thread.gmane.org/gmane.linux.kernel/1298642
> "[PATCH v3 0/3] Merge ramoops and persistent_ram, generic pstore RAM backend"
>
> And a rationale for the series:
>
> Currently pstore doesn't support logging kernel messages in run-time,
> it only dumps dmesg when kernel oopses/panics. This makes pstore
> useless for debugging hangs caused by HW issues or improper use of HW
> (e.g. weird device inserted -> driver tried to write reserved bits ->
> SoC hanged. In that case we don't get any messages in the pstore.
>
> This series add a new message type for pstore, i.e. PSTORE_TYPE_CONSOLE,
> plus make pstore/ram.c handle the new messages.
>
> The old ram_console driver is removed. This might probably cause
> some pain for out-of-tree code, as it would need to be adjusted...
> but "no pain, no gain"? :-) Though, if there's some serious resistance,
> we can probably postpone the last two patches.
>
> Thanks!
>
> --
> Anton Vorontsov
> Email: [email protected]
Other than my comment on logging console into a single record,
Acked-by: Colin Cross <[email protected]>
There is one feature that ram_console had but lost when I added
persistent_ram, which would be nice to get back: registering the
platform driver before module_init, to allow it to log oopses that
happen during device probing. This requires changing module_init to
postcore_initcall, and switching from platform_driver_probe to
platform_driver_register because the platform device is not registered
when the platform driver is registered. Depending on what functions
are __init, it may cause a cascading change from __init to __devinit
as well.
On Thu, May 17, 2012 at 11:42:29AM -0700, Colin Cross wrote:
[...]
> Other than my comment on logging console into a single record,
> Acked-by: Colin Cross <[email protected]>
Thanks!
> There is one feature that ram_console had but lost when I added
> persistent_ram, which would be nice to get back: registering the
> platform driver before module_init, to allow it to log oopses that
> happen during device probing. This requires changing module_init to
> postcore_initcall, and switching from platform_driver_probe to
> platform_driver_register because the platform device is not registered
> when the platform driver is registered. Depending on what functions
> are __init, it may cause a cascading change from __init to __devinit
> as well.
Yep, I'll look into it.
Thanks,
--
Anton Vorontsov
Email: [email protected]
On Thu, May 17, 2012 at 11:28:22AM -0700, Colin Cross wrote:
> On Thu, May 17, 2012 at 1:40 AM, Anton Vorontsov
> <[email protected]> wrote:
> > This is all straightforward: we just use the last region for
> > console logging. If there's just one region, we fall-back to
> > the old behaviour: just a oops/dumps logging.
> >
> > Signed-off-by: Anton Vorontsov <[email protected]>
>
> I don't think using the last region is the right way to handle this.
> We often use very large regions for ramconsole, up to 2MB. Using a
> single region would require a 2MB region for console and a 2MB region
> for oops, which is far too large.
Yeah, I agree. I planned to take care of it later, as this would
involve touching more code. But OK, let's do this right away.
Thanks!
--
Anton Vorontsov
Email: [email protected]