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: Mark Salyzyn <salyzyn@android.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
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9d5438f462
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@ -21,6 +21,16 @@ config PSTORE_CONSOLE
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When the option is enabled, pstore will log all kernel
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messages, even if no oops or panic happened.
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config PSTORE_PMSG
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bool "Log user space messages"
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depends on PSTORE
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help
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When the option is enabled, pstore will export a character
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interface /dev/pmsg0 to log user space messages. On reboot
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data can be retrieved from /sys/fs/pstore/pmsg-ramoops-[ID].
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If unsure, say N.
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config PSTORE_FTRACE
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bool "Persistent function tracer"
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depends on PSTORE
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@ -7,5 +7,7 @@ obj-y += pstore.o
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pstore-objs += inode.o platform.o
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obj-$(CONFIG_PSTORE_FTRACE) += ftrace.o
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obj-$(CONFIG_PSTORE_PMSG) += pmsg.o
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ramoops-objs += ram.o ram_core.o
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obj-$(CONFIG_PSTORE_RAM) += ramoops.o
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@ -361,6 +361,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
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scnprintf(name, sizeof(name), "powerpc-common-%s-%lld",
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psname, id);
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break;
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case PSTORE_TYPE_PMSG:
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scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id);
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break;
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case PSTORE_TYPE_UNKNOWN:
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scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id);
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break;
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@ -45,6 +45,12 @@ extern void pstore_register_ftrace(void);
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static inline void pstore_register_ftrace(void) {}
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#endif
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#ifdef CONFIG_PSTORE_PMSG
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extern void pstore_register_pmsg(void);
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#else
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static inline void pstore_register_pmsg(void) {}
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#endif
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extern struct pstore_info *psinfo;
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extern void pstore_set_kmsg_bytes(int);
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@ -447,6 +447,7 @@ int pstore_register(struct pstore_info *psi)
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if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
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pstore_register_console();
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pstore_register_ftrace();
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pstore_register_pmsg();
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}
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if (pstore_update_ms >= 0) {
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@ -0,0 +1,114 @@
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/*
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* Copyright 2014 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/uaccess.h>
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#include <linux/vmalloc.h>
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#include "internal.h"
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static DEFINE_MUTEX(pmsg_lock);
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#define PMSG_MAX_BOUNCE_BUFFER_SIZE (2*PAGE_SIZE)
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static ssize_t write_pmsg(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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size_t i, buffer_size;
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char *buffer;
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if (!count)
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return 0;
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if (!access_ok(VERIFY_READ, buf, count))
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return -EFAULT;
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buffer_size = count;
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if (buffer_size > PMSG_MAX_BOUNCE_BUFFER_SIZE)
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buffer_size = PMSG_MAX_BOUNCE_BUFFER_SIZE;
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buffer = vmalloc(buffer_size);
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mutex_lock(&pmsg_lock);
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for (i = 0; i < count; ) {
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size_t c = min(count - i, buffer_size);
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u64 id;
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long ret;
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ret = __copy_from_user(buffer, buf + i, c);
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if (unlikely(ret != 0)) {
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mutex_unlock(&pmsg_lock);
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vfree(buffer);
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return -EFAULT;
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}
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psinfo->write_buf(PSTORE_TYPE_PMSG, 0, &id, 0, buffer, 0, c,
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psinfo);
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i += c;
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}
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mutex_unlock(&pmsg_lock);
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vfree(buffer);
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return count;
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}
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static const struct file_operations pmsg_fops = {
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.owner = THIS_MODULE,
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.llseek = noop_llseek,
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.write = write_pmsg,
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};
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static struct class *pmsg_class;
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static int pmsg_major;
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#define PMSG_NAME "pmsg"
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#undef pr_fmt
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#define pr_fmt(fmt) PMSG_NAME ": " fmt
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static char *pmsg_devnode(struct device *dev, umode_t *mode)
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{
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if (mode)
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*mode = 0220;
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return NULL;
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}
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void pstore_register_pmsg(void)
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{
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struct device *pmsg_device;
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pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops);
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if (pmsg_major < 0) {
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pr_err("register_chrdev failed\n");
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goto err;
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}
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pmsg_class = class_create(THIS_MODULE, PMSG_NAME);
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if (IS_ERR(pmsg_class)) {
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pr_err("device class file already in use\n");
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goto err_class;
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}
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pmsg_class->devnode = pmsg_devnode;
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pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0),
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NULL, "%s%d", PMSG_NAME, 0);
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if (IS_ERR(pmsg_device)) {
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pr_err("failed to create device\n");
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goto err_device;
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}
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return;
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err_device:
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class_destroy(pmsg_class);
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err_class:
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unregister_chrdev(pmsg_major, PMSG_NAME);
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err:
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return;
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}
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@ -51,6 +51,10 @@ static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
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module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
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MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
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static ulong ramoops_pmsg_size = MIN_MEM_SIZE;
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module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
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MODULE_PARM_DESC(pmsg_size, "size of user space message log");
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static ulong mem_address;
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module_param(mem_address, ulong, 0400);
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MODULE_PARM_DESC(mem_address,
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@ -82,12 +86,14 @@ struct ramoops_context {
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struct persistent_ram_zone **przs;
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struct persistent_ram_zone *cprz;
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struct persistent_ram_zone *fprz;
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struct persistent_ram_zone *mprz;
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phys_addr_t phys_addr;
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unsigned long size;
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unsigned int memtype;
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size_t record_size;
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size_t console_size;
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size_t ftrace_size;
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size_t pmsg_size;
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int dump_oops;
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struct persistent_ram_ecc_info ecc_info;
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unsigned int max_dump_cnt;
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@ -96,6 +102,7 @@ struct ramoops_context {
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unsigned int dump_read_cnt;
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unsigned int console_read_cnt;
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unsigned int ftrace_read_cnt;
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unsigned int pmsg_read_cnt;
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struct pstore_info pstore;
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};
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@ -109,6 +116,7 @@ static int ramoops_pstore_open(struct pstore_info *psi)
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cxt->dump_read_cnt = 0;
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cxt->console_read_cnt = 0;
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cxt->ftrace_read_cnt = 0;
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cxt->pmsg_read_cnt = 0;
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return 0;
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}
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@ -190,6 +198,9 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
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if (!prz_ok(prz))
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prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
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1, id, type, PSTORE_TYPE_FTRACE, 0);
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if (!prz_ok(prz))
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prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
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1, id, type, PSTORE_TYPE_PMSG, 0);
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if (!prz_ok(prz))
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return 0;
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@ -258,6 +269,11 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
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return -ENOMEM;
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persistent_ram_write(cxt->fprz, buf, size);
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return 0;
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} else if (type == PSTORE_TYPE_PMSG) {
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if (!cxt->mprz)
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return -ENOMEM;
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persistent_ram_write(cxt->mprz, buf, size);
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return 0;
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}
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if (type != PSTORE_TYPE_DMESG)
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@ -315,6 +331,9 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
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case PSTORE_TYPE_FTRACE:
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prz = cxt->fprz;
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break;
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case PSTORE_TYPE_PMSG:
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prz = cxt->mprz;
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break;
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default:
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return -EINVAL;
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}
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@ -441,7 +460,7 @@ static int ramoops_probe(struct platform_device *pdev)
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goto fail_out;
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if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
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!pdata->ftrace_size)) {
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!pdata->ftrace_size && !pdata->pmsg_size)) {
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pr_err("The memory size and the record/console size must be "
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"non-zero\n");
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goto fail_out;
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pdata->console_size = rounddown_pow_of_two(pdata->console_size);
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if (pdata->ftrace_size && !is_power_of_2(pdata->ftrace_size))
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pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
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if (pdata->pmsg_size && !is_power_of_2(pdata->pmsg_size))
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pdata->pmsg_size = rounddown_pow_of_two(pdata->pmsg_size);
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cxt->size = pdata->mem_size;
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cxt->phys_addr = pdata->mem_address;
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@ -460,12 +481,14 @@ static int ramoops_probe(struct platform_device *pdev)
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cxt->record_size = pdata->record_size;
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cxt->console_size = pdata->console_size;
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cxt->ftrace_size = pdata->ftrace_size;
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cxt->pmsg_size = pdata->pmsg_size;
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cxt->dump_oops = pdata->dump_oops;
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cxt->ecc_info = pdata->ecc_info;
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paddr = cxt->phys_addr;
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dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
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dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size
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- cxt->pmsg_size;
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err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
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if (err)
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goto fail_out;
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@ -480,6 +503,10 @@ static int ramoops_probe(struct platform_device *pdev)
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if (err)
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goto fail_init_fprz;
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err = ramoops_init_prz(dev, cxt, &cxt->mprz, &paddr, cxt->pmsg_size, 0);
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if (err)
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goto fail_init_mprz;
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cxt->pstore.data = cxt;
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/*
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* Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
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@ -523,6 +550,8 @@ fail_buf:
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kfree(cxt->pstore.buf);
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fail_clear:
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cxt->pstore.bufsize = 0;
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kfree(cxt->mprz);
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fail_init_mprz:
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kfree(cxt->fprz);
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fail_init_fprz:
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kfree(cxt->cprz);
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@ -580,6 +609,7 @@ static void ramoops_register_dummy(void)
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dummy_data->record_size = record_size;
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dummy_data->console_size = ramoops_console_size;
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dummy_data->ftrace_size = ramoops_ftrace_size;
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dummy_data->pmsg_size = ramoops_pmsg_size;
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dummy_data->dump_oops = dump_oops;
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/*
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* For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
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@ -39,6 +39,7 @@ enum pstore_type_id {
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PSTORE_TYPE_PPC_RTAS = 4,
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PSTORE_TYPE_PPC_OF = 5,
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PSTORE_TYPE_PPC_COMMON = 6,
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PSTORE_TYPE_PMSG = 7,
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PSTORE_TYPE_UNKNOWN = 255
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};
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@ -81,6 +81,7 @@ struct ramoops_platform_data {
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unsigned long record_size;
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unsigned long console_size;
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unsigned long ftrace_size;
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unsigned long pmsg_size;
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int dump_oops;
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struct persistent_ram_ecc_info ecc_info;
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};
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