Commit 9d5438f4 authored by Mark Salyzyn's avatar Mark Salyzyn Committed by Tony Luck
Browse files

pstore: Add pmsg - user-space accessible pstore object



A secured user-space accessible pstore object. Writes
to /dev/pmsg0 are appended to the buffer, on reboot
the persistent contents are available in
/sys/fs/pstore/pmsg-ramoops-[ID].

One possible use is syslogd, or other daemon, can
write messages, then on reboot provides a means to
triage user-space activities leading up to a panic
as a companion to the pstore dmesg or console logs.
Signed-off-by: default avatarMark Salyzyn <salyzyn@android.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent f44f9652
......@@ -21,6 +21,16 @@ config PSTORE_CONSOLE
When the option is enabled, pstore will log all kernel
messages, even if no oops or panic happened.
config PSTORE_PMSG
bool "Log user space messages"
depends on PSTORE
help
When the option is enabled, pstore will export a character
interface /dev/pmsg0 to log user space messages. On reboot
data can be retrieved from /sys/fs/pstore/pmsg-ramoops-[ID].
If unsure, say N.
config PSTORE_FTRACE
bool "Persistent function tracer"
depends on PSTORE
......
......@@ -7,5 +7,7 @@ obj-y += pstore.o
pstore-objs += inode.o platform.o
obj-$(CONFIG_PSTORE_FTRACE) += ftrace.o
obj-$(CONFIG_PSTORE_PMSG) += pmsg.o
ramoops-objs += ram.o ram_core.o
obj-$(CONFIG_PSTORE_RAM) += ramoops.o
......@@ -361,6 +361,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
psname, id);
break;
case PSTORE_TYPE_PMSG:
scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
break;
case PSTORE_TYPE_UNKNOWN:
scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
break;
......
......@@ -45,6 +45,12 @@ extern void pstore_register_ftrace(void);
static inline void pstore_register_ftrace(void) {}
#endif
#ifdef CONFIG_PSTORE_PMSG
extern void pstore_register_pmsg(void);
#else
static inline void pstore_register_pmsg(void) {}
#endif
extern struct pstore_info *psinfo;
extern void pstore_set_kmsg_bytes(int);
......
......@@ -447,6 +447,7 @@ int pstore_register(struct pstore_info *psi)
if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
pstore_register_console();
pstore_register_ftrace();
pstore_register_pmsg();
}
if (pstore_update_ms >= 0) {
......
/*
* Copyright 2014 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/cdev.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include "internal.h"
static DEFINE_MUTEX(pmsg_lock);
#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
static ssize_t write_pmsg(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
size_t i, buffer_size;
char *buffer;
if (!count)
return 0;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
buffer_size = count;
if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
buffer = vmalloc(buffer_size);
mutex_lock(&pmsg_lock);
for (i = 0; i < count; ) {
size_t c = min(count - i, buffer_size);
u64 id;
long ret;
ret = __copy_from_user(buffer, buf + i, c);
if (unlikely(ret != 0)) {
mutex_unlock(&pmsg_lock);
vfree(buffer);
return -EFAULT;
}
psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
psinfo);
i += c;
}
mutex_unlock(&pmsg_lock);
vfree(buffer);
return count;
}
static const struct file_operations pmsg_fops = {
.owner = THIS_MODULE,
.llseek = noop_llseek,
.write = write_pmsg,
};
static struct class *pmsg_class;
static int pmsg_major;
#define PMSG_NAME "pmsg"
#undef pr_fmt
#define pr_fmt(fmt) PMSG_NAME ": " fmt
static char *pmsg_devnode(struct device *dev, umode_t *mode)
{
if (mode)
*mode = 0220;
return NULL;
}
void pstore_register_pmsg(void)
{
struct device *pmsg_device;
pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
if (pmsg_major < 0) {
pr_err("register_chrdev failed\n");
goto err;
}
pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
if (IS_ERR(pmsg_class)) {
pr_err("device class file already in use\n");
goto err_class;
}
pmsg_class->devnode = pmsg_devnode;
pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
NULL, "%s%d", PMSG_NAME, 0);
if (IS_ERR(pmsg_device)) {
pr_err("failed to create device\n");
goto err_device;
}
return;
err_device:
class_destroy(pmsg_class);
err_class:
unregister_chrdev(pmsg_major, PMSG_NAME);
err:
return;
}
......@@ -51,6 +51,10 @@ static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
MODULE_PARM_DESC(pmsg_size, "size of user space message log");
static ulong mem_address;
module_param(mem_address, ulong, 0400);
MODULE_PARM_DESC(mem_address,
......@@ -82,12 +86,14 @@ struct ramoops_context {
struct persistent_ram_zone **przs;
struct persistent_ram_zone *cprz;
struct persistent_ram_zone *fprz;
struct persistent_ram_zone *mprz;
phys_addr_t phys_addr;
unsigned long size;
unsigned int memtype;
size_t record_size;
size_t console_size;
size_t ftrace_size;
size_t pmsg_size;
int dump_oops;
struct persistent_ram_ecc_info ecc_info;
unsigned int max_dump_cnt;
......@@ -96,6 +102,7 @@ struct ramoops_context {
unsigned int dump_read_cnt;
unsigned int console_read_cnt;
unsigned int ftrace_read_cnt;
unsigned int pmsg_read_cnt;
struct pstore_info pstore;
};
......@@ -109,6 +116,7 @@ static int ramoops_pstore_open(struct pstore_info *psi)
cxt->dump_read_cnt = 0;
cxt->console_read_cnt = 0;
cxt->ftrace_read_cnt = 0;
cxt->pmsg_read_cnt = 0;
return 0;
}
......@@ -190,6 +198,9 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
if (!prz_ok(prz))
prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
1, id, type, PSTORE_TYPE_FTRACE, 0);
if (!prz_ok(prz))
prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
1, id, type, PSTORE_TYPE_PMSG, 0);
if (!prz_ok(prz))
return 0;
......@@ -258,6 +269,11 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
return -ENOMEM;
persistent_ram_write(cxt->fprz, buf, size);
return 0;
} else if (type == PSTORE_TYPE_PMSG) {
if (!cxt->mprz)
return -ENOMEM;
persistent_ram_write(cxt->mprz, buf, size);
return 0;
}
if (type != PSTORE_TYPE_DMESG)
......@@ -315,6 +331,9 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
case PSTORE_TYPE_FTRACE:
prz = cxt->fprz;
break;
case PSTORE_TYPE_PMSG:
prz = cxt->mprz;
break;
default:
return -EINVAL;
}
......@@ -441,7 +460,7 @@ static int ramoops_probe(struct platform_device *pdev)
goto fail_out;
if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
!pdata->ftrace_size)) {
!pdata->ftrace_size && !pdata->pmsg_size)) {
pr_err("The memory size and the record/console size must be "
"non-zero\n");
goto fail_out;
......@@ -453,6 +472,8 @@ static int ramoops_probe(struct platform_device *pdev)
pdata->console_size = rounddown_pow_of_two(pdata->console_size);
if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
cxt->size = pdata->mem_size;
cxt->phys_addr = pdata->mem_address;
......@@ -460,12 +481,14 @@ static int ramoops_probe(struct platform_device *pdev)
cxt->record_size = pdata->record_size;
cxt->console_size = pdata->console_size;
cxt->ftrace_size = pdata->ftrace_size;
cxt->pmsg_size = pdata->pmsg_size;
cxt->dump_oops = pdata->dump_oops;
cxt->ecc_info = pdata->ecc_info;
paddr = cxt->phys_addr;
dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
- cxt->pmsg_size;
err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
if (err)
goto fail_out;
......@@ -480,6 +503,10 @@ static int ramoops_probe(struct platform_device *pdev)
if (err)
goto fail_init_fprz;
err = ramoops_init_prz(dev, cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
if (err)
goto fail_init_mprz;
cxt->pstore.data = cxt;
/*
* Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
......@@ -523,6 +550,8 @@ static int ramoops_probe(struct platform_device *pdev)
kfree(cxt->pstore.buf);
fail_clear:
cxt->pstore.bufsize = 0;
kfree(cxt->mprz);
fail_init_mprz:
kfree(cxt->fprz);
fail_init_fprz:
kfree(cxt->cprz);
......@@ -580,6 +609,7 @@ static void ramoops_register_dummy(void)
dummy_data->record_size = record_size;
dummy_data->console_size = ramoops_console_size;
dummy_data->ftrace_size = ramoops_ftrace_size;
dummy_data->pmsg_size = ramoops_pmsg_size;
dummy_data->dump_oops = dump_oops;
/*
* For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
......
......@@ -39,6 +39,7 @@ enum pstore_type_id {
PSTORE_TYPE_PPC_RTAS = 4,
PSTORE_TYPE_PPC_OF = 5,
PSTORE_TYPE_PPC_COMMON = 6,
PSTORE_TYPE_PMSG = 7,
PSTORE_TYPE_UNKNOWN = 255
};
......
......@@ -81,6 +81,7 @@ struct ramoops_platform_data {
unsigned long record_size;
unsigned long console_size;
unsigned long ftrace_size;
unsigned long pmsg_size;
int dump_oops;
struct persistent_ram_ecc_info ecc_info;
};
......
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