// SPDX-License-Identifier: GPL-2.0-only
/*
* salinfo.c
*
* Creates entries in /proc/sal for various system features.
*
* Copyright (c) 2003, 2006 Silicon Graphics, Inc. All rights reserved.
* Copyright (c) 2003 Hewlett-Packard Co
* Bjorn Helgaas <bjorn.helgaas@hp.com>
*
* 10/30/2001 jbarnes@sgi.com copied much of Stephane's palinfo
* code to create this file
* Oct 23 2003 kaos@sgi.com
* Replace IPI with set_cpus_allowed() to read a record from the required cpu.
* Redesign salinfo log processing to separate interrupt and user space
* contexts.
* Cache the record across multi-block reads from user space.
* Support > 64 cpus.
* Delete module_exit and MOD_INC/DEC_COUNT, salinfo cannot be a module.
*
* Jan 28 2004 kaos@sgi.com
* Periodically check for outstanding MCA or INIT records.
*
* Dec 5 2004 kaos@sgi.com
* Standardize which records are cleared automatically.
*
* Aug 18 2005 kaos@sgi.com
* mca.c may not pass a buffer, a NULL buffer just indicates that a new
* record is available in SAL.
* Replace some NR_CPUS by cpus_online, for hotplug cpu.
*
* Jan 5 2006 kaos@sgi.com
* Handle hotplug cpus coming online.
* Handle hotplug cpus going offline while they still have outstanding records.
* Use the cpu_* macros consistently.
* Replace the counting semaphore with a mutex and a test if the cpumask is non-empty.
* Modify the locking to make the test for "work to do" an atomic operation.
*/
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/smp.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/semaphore.h>
#include <asm/sal.h>
#include <linux/uaccess.h>
MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>");
MODULE_DESCRIPTION("/proc interface to IA-64 SAL features");
MODULE_LICENSE("GPL");
typedef struct {
const char *name; /* name of the proc entry */
unsigned long feature; /* feature bit */
struct proc_dir_entry *entry; /* registered entry (removal) */
} salinfo_entry_t;
/*
* List {name,feature} pairs for every entry in /proc/sal/<feature>
* that this module exports
*/
static const salinfo_entry_t salinfo_entries[]={
{ "bus_lock", IA64_SAL_PLATFORM_FEATURE_BUS_LOCK, },
{ "irq_redirection", IA64_SAL_PLATFORM_FEATURE_IRQ_REDIR_HINT, },
{ "ipi_redirection", IA64_SAL_PLATFORM_FEATURE_IPI_REDIR_HINT, },
{ "itc_drift", IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT, },
};
#define NR_SALINFO_ENTRIES ARRAY_SIZE(salinfo_entries)
static char *salinfo_log_name[] = {
"mca",
"init",
"cmc",
"cpe",
};
static struct proc_dir_entry *salinfo_proc_entries[
ARRAY_SIZE(salinfo_entries) + /* /proc/sal/bus_lock */
ARRAY_SIZE(salinfo_log_name) + /* /proc/sal/{mca,...} */
(2 * ARRAY_SIZE(salinfo_log_name)) + /* /proc/sal/mca/{event,data} */
1]; /* /proc/sal */
/* Some records we get ourselves, some are accessed as saved data in buffers
* that are owned by mca.c.
*/
struct salinfo_data_saved {
u8* buffer;
u64 size;
u64 id;
int cpu;
};
/* State transitions. Actions are :-
* Write "read <cpunum>" to the data file.
* Write "clear <cpunum>" to the data file.
* Write "oemdata <cpunum> <offset> to the data file.
* Read from the data file.
* Close the data file.
*
* Start state is NO_DATA.
*
* NO_DATA
* write "read <cpunum>" -> NO_DATA or LOG_RECORD.
* write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
* write "oemdata <cpunum> <offset> -> return -EINVAL.
* read data -> return EOF.
* close -> unchanged. Free record areas.
*
* LOG_RECORD
* write "read <cpunum>" -> NO_DATA or LOG_RECORD.
* write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
* write "oemdata <cpunum> <offset> -> format the oem data, goto OEMDATA.
* read data -> return the INIT/MCA/CMC/CPE record.
* close -> unchanged. Keep record areas.
*
* OEMDATA
* write "read <cpunum>" -> NO_DATA or LOG_RECORD.
* write "clear <cpunum>" -> NO_DATA or LOG_RECORD.
* write "oemdata <cpunum> <offset> -> format the oem data, goto OEMDATA.
* read data -> return the formatted oemdata.
* close -> unchanged. Keep record areas.
*
* Closing the data file does not change the state. This allows shell scripts
* to manipulate salinfo data, each shell redirection opens the file, does one
* action then closes it again. The record areas are only freed at close when
* the state is NO_DATA.
*/
enum salinfo_state {
STATE_NO_DATA,
STATE_LOG_RECORD,
STATE_OEMDATA,
};
struct salinfo_data {
cpumask_t cpu_event; /* which cpus have outstanding events */
wait_queue_head_t read_wait;
u8 *log_buffer;
u64 log_size;
u8 *oemdata; /* decoded oem data */
u64 oemdata_size;
int open; /* single-open to prevent races */
u8 type;
u8 saved_num; /* using a saved record? */
enum salinfo_state state :8; /* processing state */
u8 padding;
int cpu_check; /* next CPU to check */
struct salinfo_data_saved data_saved[5];/* save last 5 records from mca.c, must be < 255 */
};
static struct salinfo_data salinfo_data[ARRAY_SIZE(salinfo_log_name)];
static DEFINE_SPINLOCK(data_lock);
static DEFINE_SPINLOCK(data_saved_lock);
/** salinfo_platform_oemdata - optional callback to decode oemdata from an error
* record.
* @sect_header: pointer to the start of the section to decode.
* @oemdata: returns vmalloc area containing the decoded output.
* @oemdata_size: returns length of decoded output (strlen).
*
* Description: If user space asks for oem data to be decoded by the kernel
* and/or prom and the platform has set salinfo_platform_oemdata to the address
* of a platform specific routine then call that routine. salinfo_platform_oemdata
* vmalloc's and formats its output area, returning the address of the text
* and its strlen. Returns 0 for success, -ve for error. The callback is
* invoked on the cpu that generated the error record.
*/
int (*salinfo_platform_oemdata)(const u8 *sect_header, u8 **oemdata, u64 *oemdata_size);
struct salinfo_platform_oemdata_parms {
const u8 *efi_guid;
u8 **oemdata;
u64 *oemdata_size;
};
static long
salinfo_platform_oemdata_cpu(void *context)
{
struct salinfo_platform_oemdata_parms *parms = context;
return salinfo_platform_oemdata(parms->efi_guid, parms->oemdata, parms->oemdata_size);
}
static void
shift1_data_saved (struct salinfo_data *data, int shift)
{
memcpy(data->data_saved+shift, data->data_saved+shift+1,
(ARRAY_SIZE(data->data_saved) - (shift+1)) * sizeof(data->data_saved[0]));
memset(data->data_saved + ARRAY_SIZE(data->data_saved) - 1, 0,
sizeof(data->data_saved[0]));
}
/* This routine is invoked in interrupt context. Note: mca.c enables
* interrupts before calling this code for CMC/CPE. MCA and INIT events are
* not irq safe, do not call any routines that use spinlocks, they may deadlock.
* MCA and INIT records are recorded, a timer event will look for any
* outstanding events and wake up the user space code.
*
* The buffer passed from mca.c points to the output from ia64_log_get. This is
* a persistent buffer but its contents can change between the interrupt and
* when user space processes the record. Save the record id to identify
* changes. If the buffer is NULL then just update the bitmap.
*/
void
salinfo_log_wakeup(int type, u8 *buffer, u64 size, int irqsafe)
{
struct salinfo_data *data = salinfo_data + type;
struct salinfo_data_saved *data_saved;
unsigned long flags = 0;
int i;
int saved_size = ARRAY_SIZE(data->data_saved);
BUG_ON(type >= ARRAY_SIZE(salinfo_log_name));
if (irqsafe)
spin_lock_irqsave(&data_saved_lock, flags);
if (buffer) {
for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
if (!data_saved->buffer)
break;
}
if (i == saved_size) {
if (!data->saved_num) {
shift1_data_saved(data, 0);
data_saved = data->data_saved + saved_size - 1;
} else
data_saved = NULL;
}
if (data_saved) {
data_saved->cpu = smp_processor_id();
data_saved->id = ((sal_log_record_header_t *)buffer)->id;
data_saved->size = size;
data_saved->buffer = buffer;
}
}
cpumask_set_cpu(smp_processor_id(), &data->cpu_event);
if (irqsafe) {
wake_up_interruptible(&data->read_wait);
spin_unlock_irqrestore(&data_saved_lock, flags);
}
}
/* Check for outstanding MCA/INIT records every minute (arbitrary) */
#define SALINFO_TIMER_DELAY (60*HZ)
static struct timer_list salinfo_timer;
extern void ia64_mlogbuf_dump(void);
static void
salinfo_timeout_check(struct salinfo_data *data)
{
if (!data->open)
return;
if (!cpumask_empty(&data->cpu_event))
wake_up_interruptible(&data->read_wait);
}
static void
salinfo_timeout(struct timer_list *unused)
{
ia64_mlogbuf_dump();
salinfo_timeout_check(salinfo_data + SAL_INFO_TYPE_MCA);
salinfo_timeout_check(salinfo_data + SAL_INFO_TYPE_INIT);
salinfo_timer.expires = jiffies + SALINFO_TIMER_DELAY;
add_timer(&salinfo_timer);
}
static int
salinfo_event_open(struct inode *inode, struct file *file)
{
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return 0;
}
static ssize_t
salinfo_event_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct salinfo_data *data = pde_data(file_inode(file));
char cmd[32];
size_t size;
int i, n, cpu = -1;
retry:
if (cpumask_empty(&data->cpu_event)) {
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
if (wait_event_interruptible(data->read_wait,
!cpumask_empty(&data->cpu_event)))
return -EINTR;
}
n = data->cpu_check;
for (i = 0; i < nr_cpu_ids; i++) {
if (cpumask_test_cpu(n, &data->cpu_event)) {
if (!cpu_online(n)) {
cpumask_clear_cpu(n, &data->cpu_event);
continue;
}
cpu = n;
break;
}
if (++n == nr_cpu_ids)
n = 0;
}
if (cpu == -1)
goto retry;
ia64_mlogbuf_dump();
/* for next read, start checking at next CPU */
data->cpu_check = cpu;
if (++data->cpu_check == nr_cpu_ids)
data->cpu_check = 0;
snprintf(cmd, sizeof(cmd), "read %d\n", cpu);
size = strlen(cmd);
if (size > count)
size = count;
if (copy_to_user(buffer, cmd, size))
return -EFAULT;
return size;
}
static const struct proc_ops salinfo_event_proc_ops = {
.proc_open = salinfo_event_open,
.proc_read = salinfo_event_read,
.proc_lseek = noop_llseek,
};
static int
salinfo_log_open(struct inode *inode, struct file *file)
{
struct salinfo_data *data = pde_data(inode);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
spin_lock(&data_lock);
if (data->open) {
spin_unlock(&data_lock);
return -EBUSY;
}
data->open = 1;
spin_unlock(&data_lock);
if (data->state == STATE_NO_DATA &&
!(data->log_buffer = vmalloc(ia64_sal_get_state_info_size(data->type)))) {
data->open = 0;
return -ENOMEM;
}
return 0;
}
static int
salinfo_log_release(struct inode *inode, struct file *file)
{
struct salinfo_data *data = pde_data(inode);
if (data->state == STATE_NO_DATA) {
vfree(data->log_buffer);
vfree(data->oemdata);
data->log_buffer = NULL;
data->oemdata = NULL;
}
spin_lock(&data_lock);
data->open = 0;
spin_unlock(&data_lock);
return 0;
}
static long
salinfo_log_read_cpu(void *context)
{
struct salinfo_data *data = context;
sal_log_record_header_t *rh;
data->log_size = ia64_sal_get_state_info(data->type, (u64 *) data->log_buffer);
rh = (sal_log_record_header_t *)(data->log_buffer);
/* Clear corrected errors as they are read from SAL */
if (rh->severity == sal_log_severity_corrected)
ia64_sal_clear_state_info(data->type);
return 0;
}
static void
salinfo_log_new_read(int cpu, struct salinfo_data *data)
{
struct salinfo_data_saved *data_saved;
unsigned long flags;
int i;
int saved_size = ARRAY_SIZE(data->data_saved);
data->saved_num = 0;
spin_lock_irqsave(&data_saved_lock, flags);
retry:
for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
if (data_saved->buffer && data_saved->cpu == cpu) {
sal_log_record_header_t *rh = (sal_log_record_header_t *)(data_saved->buffer);
data->log_size = data_saved->size;
memcpy(data->log_buffer, rh, data->log_size);
barrier(); /* id check must not be moved */
if (rh->id == data_saved->id) {
data->saved_num = i+1;
break;
}
/* saved record changed by mca.c since interrupt, discard it */
shift1_data_saved(data, i);
goto retry;
}
}
spin_unlock_irqrestore(&data_saved_lock, flags);
if (!data->saved_num)
work_on_cpu_safe(cpu, salinfo_log_read_cpu, data);
if (!data->log_size) {
data->state = STATE_NO_DATA;
cpumask_clear_cpu(cpu, &data->cpu_event);
} else {
data->state = STATE_LOG_RECORD;
}
}
static ssize_t
salinfo_log_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct salinfo_data *data = pde_data(file_inode(file));
u8 *buf;
u64 bufsize;
if (data->state == STATE_LOG_RECORD) {
buf = data->log_buffer;
bufsize = data->log_size;
} else if (data->state == STATE_OEMDATA) {
buf = data->oemdata;
bufsize = data->oemdata_size;
} else {
buf = NULL;
bufsize = 0;
}
return simple_read_from_buffer(buffer, count, ppos, buf, bufsize);
}
static long
salinfo_log_clear_cpu(void *context)
{
struct salinfo_data *data = context;
ia64_sal_clear_state_info(data->type);
return 0;
}
static int
salinfo_log_clear(struct salinfo_data *data, int cpu)
{
sal_log_record_header_t *rh;
unsigned long flags;
spin_lock_irqsave(&data_saved_lock, flags);
data->state = STATE_NO_DATA;
if (!cpumask_test_cpu(cpu, &data->cpu_event)) {
spin_unlock_irqrestore(&data_saved_lock, flags);
return 0;
}
cpumask_clear_cpu(cpu, &data->cpu_event);
if (data->saved_num) {
shift1_data_saved(data, data->saved_num - 1);
data->saved_num = 0;
}
spin_unlock_irqrestore(&data_saved_lock, flags);
rh = (sal_log_record_header_t *)(data->log_buffer);
/* Corrected errors have already been cleared from SAL */
if (rh->severity != sal_log_severity_corrected)
work_on_cpu_safe(cpu, salinfo_log_clear_cpu, data);
/* clearing a record may make a new record visible */
salinfo_log_new_read(cpu, data);
if (data->state == STATE_LOG_RECORD) {
spin_lock_irqsave(&data_saved_lock, flags);
cpumask_set_cpu(cpu, &data->cpu_event);
wake_up_interruptible(&data->read_wait);
spin_unlock_irqrestore(&data_saved_lock, flags);
}
return 0;
}
static ssize_t
salinfo_log_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct salinfo_data *data = pde_data(file_inode(file));
char cmd[32];
size_t size;
u32 offset;
int cpu;
size = sizeof(cmd);
if (count < size)
size = count;
if (copy_from_user(cmd, buffer, size))
return -EFAULT;
if (sscanf(cmd, "read %d", &cpu) == 1) {
salinfo_log_new_read(cpu, data);
} else if (sscanf(cmd, "clear %d", &cpu) == 1) {
int ret;
if ((ret = salinfo_log_clear(data, cpu)))
count = ret;
} else if (sscanf(cmd, "oemdata %d %d", &cpu, &offset) == 2) {
if (data->state != STATE_LOG_RECORD && data->state != STATE_OEMDATA)
return -EINVAL;
if (offset > data->log_size - sizeof(efi_guid_t))
return -EINVAL;
data->state = STATE_OEMDATA;
if (salinfo_platform_oemdata) {
struct salinfo_platform_oemdata_parms parms = {
.efi_guid = data->log_buffer + offset,
.oemdata = &data->oemdata,
.oemdata_size = &data->oemdata_size
};
count = work_on_cpu_safe(cpu, salinfo_platform_oemdata_cpu,
&parms);
} else
data->oemdata_size = 0;
} else
return -EINVAL;
return count;
}
static const struct proc_ops salinfo_data_proc_ops = {
.proc_open = salinfo_log_open,
.proc_release = salinfo_log_release,
.proc_read = salinfo_log_read,
.proc_write = salinfo_log_write,
.proc_lseek = default_llseek,
};
static int salinfo_cpu_online(unsigned int cpu)
{
unsigned int i, end = ARRAY_SIZE(salinfo_data);
struct salinfo_data *data;
spin_lock_irq(&data_saved_lock);
for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
cpumask_set_cpu(cpu, &data->cpu_event);
wake_up_interruptible(&data->read_wait);
}
spin_unlock_irq(&data_saved_lock);
return 0;
}
static int salinfo_cpu_pre_down(unsigned int cpu)
{
unsigned int i, end = ARRAY_SIZE(salinfo_data);
struct salinfo_data *data;
spin_lock_irq(&data_saved_lock);
for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
struct salinfo_data_saved *data_saved;
int j = ARRAY_SIZE(data->data_saved) - 1;
for (data_saved = data->data_saved + j; j >= 0;
--j, --data_saved) {
if (data_saved->buffer && data_saved->cpu == cpu)
shift1_data_saved(data, j);
}
cpumask_clear_cpu(cpu, &data->cpu_event);
}
spin_unlock_irq(&data_saved_lock);
return 0;
}
/*
* 'data' contains an integer that corresponds to the feature we're
* testing
*/
static int __maybe_unused proc_salinfo_show(struct seq_file *m, void *v)
{
unsigned long data = (unsigned long)v;
seq_puts(m, (sal_platform_features & data) ? "1\n" : "0\n");
return 0;
}
static int __init
salinfo_init(void)
{
struct proc_dir_entry *salinfo_dir; /* /proc/sal dir entry */
struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
struct proc_dir_entry *dir, *entry;
struct salinfo_data *data;
int i;
salinfo_dir = proc_mkdir("sal", NULL);
if (!salinfo_dir)
return 0;
for (i=0; i < NR_SALINFO_ENTRIES; i++) {
/* pass the feature bit in question as misc data */
*sdir++ = proc_create_single_data(salinfo_entries[i].name, 0,
salinfo_dir, proc_salinfo_show,
(void *)salinfo_entries[i].feature);
}
for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
data = salinfo_data + i;
data->type = i;
init_waitqueue_head(&data->read_wait);
dir = proc_mkdir(salinfo_log_name[i], salinfo_dir);
if (!dir)
continue;
entry = proc_create_data("event", S_IRUSR, dir,
&salinfo_event_proc_ops, data);
if (!entry)
continue;
*sdir++ = entry;
entry = proc_create_data("data", S_IRUSR | S_IWUSR, dir,
&salinfo_data_proc_ops, data);
if (!entry)
continue;
*sdir++ = entry;
*sdir++ = dir;
}
*sdir++ = salinfo_dir;
timer_setup(&salinfo_timer, salinfo_timeout, 0);
salinfo_timer.expires = jiffies + SALINFO_TIMER_DELAY;
add_timer(&salinfo_timer);
i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/salinfo:online",
salinfo_cpu_online, salinfo_cpu_pre_down);
WARN_ON(i < 0);
return 0;
}
module_init(salinfo_init);