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Date: Tue, 29 Nov 2011 12:50:05 +0800
From: Chen Gong <gong.chen@...ux.intel.com>
To: Kees Cook <keescook@...omium.org>
CC: linux-kernel@...r.kernel.org,
Marco Stornelli <marco.stornelli@...il.com>,
Tony Luck <tony.luck@...il.com>,
Randy Dunlap <rdunlap@...otime.net>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <greg@...ah.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2] ramoops: use pstore interface
δΊ 2011/11/29 4:09, Kees Cook ει:
> Instead of using /dev/mem directly, use the common pstore infrastructure
> to handle Oops gathering and extraction.
>
> Signed-off-by: Kees Cook<keescook@...omium.org>
> ---
> This depends on the pstore changes waiting for -next in:
> http://git.kernel.org/?p=linux/kernel/git/aegl/linux.git;a=shortlog;h=refs/heads/next
> ---
> Documentation/ramoops.txt | 8 +-
> drivers/char/Kconfig | 1 +
> drivers/char/ramoops.c | 206 ++++++++++++++++++++++++++++++++++-----------
> 3 files changed, 160 insertions(+), 55 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@...omium.org>
>
> -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.
I think the definition of "mem_address" in the doc is not very clear. It is not
a normal memory instead of a persistent RAM. I suggest adding more descriptions.
It's better if there is a real example.
> 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 7c7f42a..c544213 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@...il.com>
> + * Copyright (C) 2011 Kees Cook<keescook@...omium.org>
> *
> * 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 +57,154 @@ 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)
As Andrew mentioned here (http://lkml.org/lkml/2011/11/28/495),
who should take this responsibility to fix this issue when conflicting
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