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 anton.vorontsov@linaro.org --- 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 tony.luck@intel.com * * 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 };

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 anton.vorontsov@linaro.org --- 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);

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 anton.vorontsov@linaro.org --- 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); }

Suggested-by: Shuah Khan shuahkhan@gmail.com Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org --- 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

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 anton.vorontsov@linaro.org --- 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);