/* * 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/module.h> #include <linux/smp.h> #include <linux/timer.h> #include <linux/vmalloc.h> #include <linux/semaphore.h> #include <asm/sal.h> #include <asm/uaccess.h> MODULE_AUTHOR("Jesse Barnes <jbarnes@sgi.com>"); MODULE_DESCRIPTION("/proc interface to IA-64 SAL features"); MODULE_LICENSE("GPL"); static int salinfo_read(char *page, char **start, off_t off, int count, int *eof, void *data); 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 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 */ struct semaphore mutex; 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; int ret; }; /* Kick the mutex that tells user space that there is work to do. Instead of * trying to track the state of the mutex across multiple cpus, in user * context, interrupt context, non-maskable interrupt context and hotplug cpu, * it is far easier just to grab the mutex if it is free then release it. * * This routine must be called with data_saved_lock held, to make the down/up * operation atomic. */ static void salinfo_work_to_do(struct salinfo_data *data) { down_trylock(&data->mutex); up(&data->mutex); } static void salinfo_platform_oemdata_cpu(void *context) { struct salinfo_platform_oemdata_parms *parms = context; parms->ret = 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; } } cpu_set(smp_processor_id(), data->cpu_event); if (irqsafe) { salinfo_work_to_do(data); 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) { unsigned long flags; if (!data->open) return; if (!cpus_empty(data->cpu_event)) { spin_lock_irqsave(&data_saved_lock, flags); salinfo_work_to_do(data); spin_unlock_irqrestore(&data_saved_lock, flags); } } static void salinfo_timeout (unsigned long arg) { 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 inode *inode = file->f_path.dentry->d_inode; struct proc_dir_entry *entry = PDE(inode); struct salinfo_data *data = entry->data; char cmd[32]; size_t size; int i, n, cpu = -1; retry: if (cpus_empty(data->cpu_event) && down_trylock(&data->mutex)) { if (file->f_flags & O_NONBLOCK) return -EAGAIN; if (down_interruptible(&data->mutex)) return -EINTR; } n = data->cpu_check; for (i = 0; i < NR_CPUS; i++) { if (cpu_isset(n, data->cpu_event)) { if (!cpu_online(n)) { cpu_clear(n, data->cpu_event); continue; } cpu = n; break; } if (++n == NR_CPUS) 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_CPUS) 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 file_operations salinfo_event_fops = { .open = salinfo_event_open, .read = salinfo_event_read, }; static int salinfo_log_open(struct inode *inode, struct file *file) { struct proc_dir_entry *entry = PDE(inode); struct salinfo_data *data = entry->data; 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 proc_dir_entry *entry = PDE(inode); struct salinfo_data *data = entry->data; 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 void call_on_cpu(int cpu, void (*fn)(void *), void *arg) { cpumask_t save_cpus_allowed = current->cpus_allowed; cpumask_t new_cpus_allowed = cpumask_of_cpu(cpu); set_cpus_allowed(current, new_cpus_allowed); (*fn)(arg); set_cpus_allowed(current, save_cpus_allowed); } static void 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); } 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) call_on_cpu(cpu, salinfo_log_read_cpu, data); if (!data->log_size) { data->state = STATE_NO_DATA; cpu_clear(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 inode *inode = file->f_path.dentry->d_inode; struct proc_dir_entry *entry = PDE(inode); struct salinfo_data *data = entry->data; 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 void salinfo_log_clear_cpu(void *context) { struct salinfo_data *data = context; ia64_sal_clear_state_info(data->type); } 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 (!cpu_isset(cpu, data->cpu_event)) { spin_unlock_irqrestore(&data_saved_lock, flags); return 0; } cpu_clear(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) call_on_cpu(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); cpu_set(cpu, data->cpu_event); salinfo_work_to_do(data); 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 inode *inode = file->f_path.dentry->d_inode; struct proc_dir_entry *entry = PDE(inode); struct salinfo_data *data = entry->data; 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 }; call_on_cpu(cpu, salinfo_platform_oemdata_cpu, &parms); if (parms.ret) count = parms.ret; } else data->oemdata_size = 0; } else return -EINVAL; return count; } static const struct file_operations salinfo_data_fops = { .open = salinfo_log_open, .release = salinfo_log_release, .read = salinfo_log_read, .write = salinfo_log_write, }; static int __cpuinit salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu) { unsigned int i, cpu = (unsigned long)hcpu; unsigned long flags; struct salinfo_data *data; switch (action) { case CPU_ONLINE: case CPU_ONLINE_FROZEN: spin_lock_irqsave(&data_saved_lock, flags); for (i = 0, data = salinfo_data; i < ARRAY_SIZE(salinfo_data); ++i, ++data) { cpu_set(cpu, data->cpu_event); salinfo_work_to_do(data); } spin_unlock_irqrestore(&data_saved_lock, flags); break; case CPU_DEAD: case CPU_DEAD_FROZEN: spin_lock_irqsave(&data_saved_lock, flags); for (i = 0, data = salinfo_data; i < ARRAY_SIZE(salinfo_data); ++i, ++data) { struct salinfo_data_saved *data_saved; int j; for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j; j >= 0; --j, --data_saved) { if (data_saved->buffer && data_saved->cpu == cpu) { shift1_data_saved(data, j); } } cpu_clear(cpu, data->cpu_event); } spin_unlock_irqrestore(&data_saved_lock, flags); break; } return NOTIFY_OK; } static struct notifier_block salinfo_cpu_notifier __cpuinitdata = { .notifier_call = salinfo_cpu_callback, .priority = 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, j; 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++ = create_proc_read_entry (salinfo_entries[i].name, 0, salinfo_dir, salinfo_read, (void *)salinfo_entries[i].feature); } for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) { data = salinfo_data + i; data->type = i; init_MUTEX(&data->mutex); dir = proc_mkdir(salinfo_log_name[i], salinfo_dir); if (!dir) continue; entry = proc_create_data("event", S_IRUSR, dir, &salinfo_event_fops, data); if (!entry) continue; *sdir++ = entry; entry = proc_create_data("data", S_IRUSR | S_IWUSR, dir, &salinfo_data_fops, data); if (!entry) continue; *sdir++ = entry; /* we missed any events before now */ for_each_online_cpu(j) cpu_set(j, data->cpu_event); *sdir++ = dir; } *sdir++ = salinfo_dir; init_timer(&salinfo_timer); salinfo_timer.expires = jiffies + SALINFO_TIMER_DELAY; salinfo_timer.function = &salinfo_timeout; add_timer(&salinfo_timer); register_hotcpu_notifier(&salinfo_cpu_notifier); return 0; } /* * 'data' contains an integer that corresponds to the feature we're * testing */ static int salinfo_read(char *page, char **start, off_t off, int count, int *eof, void *data) { int len = 0; len = sprintf(page, (sal_platform_features & (unsigned long)data) ? "1\n" : "0\n"); if (len <= off+count) *eof = 1; *start = page + off; len -= off; if (len>count) len = count; if (len<0) len = 0; return len; } module_init(salinfo_init);