Instead of using /dev/mem directly, use the common pstore infrastructure to handle Oops gathering and extraction. Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- v4: - rebased to Linus's tree. Still time to get into merge window? v3: - Added more documentation about which memory regions it would be used with. v2: - general reworking. --- Documentation/ramoops.txt | 8 +- drivers/char/Kconfig | 1 + drivers/char/ramoops.c | 218 +++++++++++++++++++++++++++++++++----------- 3 files changed, 168 insertions(+), 59 deletions(-) diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt index 8fb1ba7..a0b9d8e 100644 --- a/Documentation/ramoops.txt +++ b/Documentation/ramoops.txt @@ -3,7 +3,7 @@ Ramoops oops/panic logger Sergiu Iordache <sergiu@xxxxxxxxxxxx> -Updated: 8 August 2011 +Updated: 17 November 2011 0. Introduction @@ -71,6 +71,6 @@ timestamp and a new line. The dump then continues with the actual data. 4. Reading the data -The dump data can be read from memory (through /dev/mem or other means). -Getting the module parameters, which are needed in order to parse the data, can -be done through /sys/module/ramoops/parameters/* . +The dump data can be read from the pstore filesystem. The format for these +files is "dmesg-ramoops-N", where N is the record number in memory. To delete +a stored record from RAM, simply unlink the respective pstore file. diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 4364303..f166499 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -603,6 +603,7 @@ source "drivers/s390/char/Kconfig" config RAMOOPS tristate "Log panic/oops to a RAM buffer" depends on HAS_IOMEM + depends on PSTORE default n help This enables panic and oops messages to be logged to a circular diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c index 7c7f42a1f8..51f4dcc 100644 --- a/drivers/char/ramoops.c +++ b/drivers/char/ramoops.c @@ -2,6 +2,7 @@ * RAM Oops/Panic logger * * Copyright (C) 2010 Marco Stornelli <marco.stornelli@xxxxxxxxx> + * Copyright (C) 2011 Kees Cook <keescook@xxxxxxxxxxxx> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -24,7 +25,7 @@ #include <linux/kernel.h> #include <linux/err.h> #include <linux/module.h> -#include <linux/kmsg_dump.h> +#include <linux/pstore.h> #include <linux/time.h> #include <linux/err.h> #include <linux/io.h> @@ -56,74 +57,153 @@ module_param(dump_oops, int, 0600); MODULE_PARM_DESC(dump_oops, "set to 1 to dump oopses, 0 to only dump panics (default 1)"); -static struct ramoops_context { - struct kmsg_dumper dump; +struct ramoops_context { void *virt_addr; phys_addr_t phys_addr; unsigned long size; - unsigned long record_size; + size_t record_size; int dump_oops; - int count; - int max_count; -} oops_cxt; + unsigned int count; + unsigned int max_count; + unsigned int read_count; + struct pstore_info pstore; +}; static struct platform_device *dummy; static struct ramoops_platform_data *dummy_data; -static void ramoops_do_dump(struct kmsg_dumper *dumper, - enum kmsg_dump_reason reason, const char *s1, unsigned long l1, - const char *s2, unsigned long l2) +static int ramoops_pstore_open(struct pstore_info *psi) +{ + struct ramoops_context *cxt = (struct ramoops_context *)psi->data; + + cxt->read_count = 0; + return 0; +} + +static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, + struct timespec *time, + char **buf, + struct pstore_info *psi) +{ + ssize_t size; + char *rambuf; + struct ramoops_context *cxt = (struct ramoops_context *)psi->data; + + if (cxt->read_count >= cxt->max_count) + return -EINVAL; + *id = cxt->read_count++; + /* Only supports dmesg output so far. */ + *type = PSTORE_TYPE_DMESG; + /* TODO(kees): Bogus time for the moment. */ + time->tv_sec = 0; + time->tv_nsec = 0; + + rambuf = cxt->virt_addr + (*id * cxt->record_size); + size = strnlen(rambuf, cxt->record_size); + *buf = kmalloc(size, GFP_KERNEL); + if (*buf == NULL) + return -ENOMEM; + memcpy(*buf, rambuf, size); + + return size; +} + +static int ramoops_pstore_write(enum pstore_type_id type, + enum kmsg_dump_reason reason, + u64 *id, + unsigned int part, + size_t size, struct pstore_info *psi) { - struct ramoops_context *cxt = container_of(dumper, - struct ramoops_context, dump); - unsigned long s1_start, s2_start; - unsigned long l1_cpy, l2_cpy; - int res, hdr_size; - char *buf, *buf_orig; + char *buf; + size_t res; struct timeval timestamp; + struct ramoops_context *cxt = (struct ramoops_context *)psi->data; + size_t available = cxt->record_size; + /* Only store dmesg dumps. */ + if (type != PSTORE_TYPE_DMESG) + return -EINVAL; + + /* Only store crash dumps. */ if (reason != KMSG_DUMP_OOPS && - reason != KMSG_DUMP_PANIC && - reason != KMSG_DUMP_KEXEC) - return; + reason != KMSG_DUMP_PANIC) + return -EINVAL; /* Only dump oopses if dump_oops is set */ if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops) - return; + return -EINVAL; + + /* Explicitly only take the first part of any new crash. + * If our buffer is larger than kmsg_bytes, this can never happen, + * and if our buffer is smaller than kmsg_bytes, we don't want the + * report split across multiple records. */ + if (part != 1) + return -ENOSPC; buf = cxt->virt_addr + (cxt->count * cxt->record_size); - buf_orig = buf; - memset(buf, '\0', cxt->record_size); res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR); buf += res; + available -= res; + do_gettimeofday(×tamp); res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec); buf += res; + available -= res; - hdr_size = buf - buf_orig; - l2_cpy = min(l2, cxt->record_size - hdr_size); - l1_cpy = min(l1, cxt->record_size - hdr_size - l2_cpy); - - s2_start = l2 - l2_cpy; - s1_start = l1 - l1_cpy; + if (size > available) + size = available; - memcpy(buf, s1 + s1_start, l1_cpy); - memcpy(buf + l1_cpy, s2 + s2_start, l2_cpy); + memcpy(buf, cxt->pstore.buf, size); + memset(buf + size, '\0', available - size); cxt->count = (cxt->count + 1) % cxt->max_count; + + return 0; +} + +static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, + struct pstore_info *psi) +{ + char *buf; + struct ramoops_context *cxt = (struct ramoops_context *)psi->data; + + if (id >= cxt->max_count) + return -EINVAL; + + buf = cxt->virt_addr + (id * cxt->record_size); + memset(buf, '\0', cxt->record_size); + + return 0; } +static struct ramoops_context oops_cxt = { + .pstore = { + .owner = THIS_MODULE, + .name = "ramoops", + .open = ramoops_pstore_open, + .read = ramoops_pstore_read, + .write = ramoops_pstore_write, + .erase = ramoops_pstore_erase, + }, +}; + static int __init ramoops_probe(struct platform_device *pdev) { struct ramoops_platform_data *pdata = pdev->dev.platform_data; struct ramoops_context *cxt = &oops_cxt; int err = -EINVAL; + /* Only a single ramoops area allowed at a time, so fail extra + * probes. + */ + if (cxt->max_count) + goto fail_out; + if (!pdata->mem_size || !pdata->record_size) { pr_err("The memory size and the record size must be " "non-zero\n"); - goto fail3; + goto fail_out; } rounddown_pow_of_two(pdata->mem_size); @@ -132,14 +212,15 @@ static int __init ramoops_probe(struct platform_device *pdev) /* Check for the minimum memory size */ if (pdata->mem_size < MIN_MEM_SIZE && pdata->record_size < MIN_MEM_SIZE) { - pr_err("memory size too small, minium is %lu\n", MIN_MEM_SIZE); - goto fail3; + pr_err("memory size too small, minimum is %lu\n", + MIN_MEM_SIZE); + goto fail_out; } if (pdata->mem_size < pdata->record_size) { pr_err("The memory size must be larger than the " "records size\n"); - goto fail3; + goto fail_out; } cxt->max_count = pdata->mem_size / pdata->record_size; @@ -148,54 +229,81 @@ static int __init ramoops_probe(struct platform_device *pdev) cxt->phys_addr = pdata->mem_address; cxt->record_size = pdata->record_size; cxt->dump_oops = pdata->dump_oops; - /* - * Update the module parameter variables as well so they are visible - * through /sys/module/ramoops/parameters/ - */ - mem_size = pdata->mem_size; - mem_address = pdata->mem_address; - record_size = pdata->record_size; - dump_oops = pdata->dump_oops; + + cxt->pstore.data = cxt; + cxt->pstore.bufsize = cxt->record_size; + cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL); + spin_lock_init(&cxt->pstore.buf_lock); + if (!cxt->pstore.buf) { + pr_err("cannot allocate pstore buffer\n"); + goto fail_clear; + } if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) { - pr_err("request mem region failed\n"); + pr_err("request mem region (0x%lx@0x%llx) failed\n", + cxt->size, cxt->phys_addr); err = -EINVAL; - goto fail3; + goto fail_buf; } cxt->virt_addr = ioremap(cxt->phys_addr, cxt->size); if (!cxt->virt_addr) { pr_err("ioremap failed\n"); - goto fail2; + goto fail_mem_region; } - cxt->dump.dump = ramoops_do_dump; - err = kmsg_dump_register(&cxt->dump); + err = pstore_register(&cxt->pstore); if (err) { - pr_err("registering kmsg dumper failed\n"); - goto fail1; + pr_err("registering with pstore failed\n"); + goto fail_iounmap; } + /* + * Update the module parameter variables as well so they are visible + * through /sys/module/ramoops/parameters/ + */ + mem_size = pdata->mem_size; + mem_address = pdata->mem_address; + record_size = pdata->record_size; + dump_oops = pdata->dump_oops; + + pr_info("attached 0x%lx@0x%llx (%ux0x%zx)\n", + cxt->size, cxt->phys_addr, cxt->max_count, cxt->record_size); + return 0; -fail1: +fail_iounmap: iounmap(cxt->virt_addr); -fail2: +fail_mem_region: release_mem_region(cxt->phys_addr, cxt->size); -fail3: +fail_buf: + kfree(cxt->pstore.buf); +fail_clear: + cxt->pstore.bufsize = 0; + cxt->max_count = 0; +fail_out: return err; } static int __exit ramoops_remove(struct platform_device *pdev) { +/* TODO(kees): We cannot unload ramoops since pstore doesn't support + * unregistering yet. + */ +#if 0 struct ramoops_context *cxt = &oops_cxt; - if (kmsg_dump_unregister(&cxt->dump) < 0) - pr_warn("could not unregister kmsg_dumper\n"); - iounmap(cxt->virt_addr); release_mem_region(cxt->phys_addr, cxt->size); + cxt->max_count = 0; + + /* TODO(kees): When pstore supports unregistering, call it here. */ + kfree(cxt->pstore.buf); + cxt->pstore.bufsize = 0; + return 0; +#endif + return -EBUSY; } static struct platform_driver ramoops_driver = { -- 1.7.4.1 -- Kees Cook ChromeOS Security -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html