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[PARISC] pdc_stable version 0.22

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pdc_stable v0.22, changes since v0.10:

  o renamed root subsystem from 'pdc' to 'stable'
  o split 'info' into several files, one per PDC field
  o implemented 'autoboot' and 'autosearch' write calls to toggle
    these flags
  o grant read permission to all users on "safe" files
  o more code cleanup (removed duplicate code)
  o avoid bad stable storage clobbering by write locking critical sections
  o print consistent data as well
  o SMP cleanups

Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Thibaut VARENE 2006-01-11 13:59:53 -07:00 committed by Kyle McMartin
parent 2c9aadabf4
commit c742842223
1 changed files with 262 additions and 94 deletions
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356
drivers/parisc/pdc_stable.c
View File

@ -1,7 +1,7 @@
/*
* Interfaces to retrieve and set PDC Stable options (firmware)
*
* Copyright (C) 2005 Thibaut VARENE <varenet@parisc-linux.org>
* Copyright (C) 2005-2006 Thibaut VARENE <varenet@parisc-linux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -26,11 +26,19 @@
*
* Since locations between 96 and 192 are the various paths, most (if not
* all) PA-RISC machines should have them. Anyway, for safety reasons, the
* following code can deal with only 96 bytes of Stable Storage, and all
* following code can deal with just 96 bytes of Stable Storage, and all
* sizes between 96 and 192 bytes (provided they are multiple of struct
* device_path size, eg: 128, 160 and 192) to provide full information.
* The code makes no use of data above 192 bytes. One last word: there's one
* path we can always count on: the primary path.
*
* The current policy wrt file permissions is:
* - write: root only
* - read: (reading triggers PDC calls) ? root only : everyone
* The rationale is that PDC calls could hog (DoS) the machine.
*
* TODO:
* - timer/fastsize write calls
*/
#undef PDCS_DEBUG
@ -50,13 +58,15 @@
#include <linux/kobject.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <asm/pdc.h>
#include <asm/page.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#define PDCS_VERSION "0.10"
#define PDCS_VERSION "0.22"
#define PDCS_PREFIX "PDC Stable Storage"
#define PDCS_ADDR_PPRI 0x00
#define PDCS_ADDR_OSID 0x40
@ -70,10 +80,12 @@ MODULE_DESCRIPTION("sysfs interface to HP PDC Stable Storage data");
MODULE_LICENSE("GPL");
MODULE_VERSION(PDCS_VERSION);
/* holds Stable Storage size. Initialized once and for all, no lock needed */
static unsigned long pdcs_size __read_mostly;
/* This struct defines what we need to deal with a parisc pdc path entry */
struct pdcspath_entry {
rwlock_t rw_lock; /* to protect path entry access */
short ready; /* entry record is valid if != 0 */
unsigned long addr; /* entry address in stable storage */
char *name; /* entry name */
@ -121,6 +133,8 @@ struct pdcspath_attribute paths_attr_##_name = { \
* content of the stable storage WRT various paths in these structs. We read
* these structs when reading the files, and we will write to these structs when
* writing to the files, and only then write them back to the Stable Storage.
*
* This function expects to be called with @entry->rw_lock write-hold.
*/
static int
pdcspath_fetch(struct pdcspath_entry *entry)
@ -160,14 +174,15 @@ pdcspath_fetch(struct pdcspath_entry *entry)
* pointer, from which it'll find out the corresponding hardware path.
* For now we do not handle the case where there's an error in writing to the
* Stable Storage area, so you'd better not mess up the data :P
*
* This function expects to be called with @entry->rw_lock write-hold.
*/
static int
static void
pdcspath_store(struct pdcspath_entry *entry)
{
struct device_path *devpath;
if (!entry)
return -EINVAL;
BUG_ON(!entry);
devpath = &entry->devpath;
@ -176,10 +191,8 @@ pdcspath_store(struct pdcspath_entry *entry)
First case, we don't have a preset hwpath... */
if (!entry->ready) {
/* ...but we have a device, map it */
if (entry->dev)
device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
else
return -EINVAL;
BUG_ON(!entry->dev);
device_to_hwpath(entry->dev, (struct hardware_path *)devpath);
}
/* else, we expect the provided hwpath to be valid. */
@ -191,15 +204,13 @@ pdcspath_store(struct pdcspath_entry *entry)
printk(KERN_ERR "%s: an error occured when writing to PDC.\n"
"It is likely that the Stable Storage data has been corrupted.\n"
"Please check it carefully upon next reboot.\n", __func__);
return -EIO;
WARN_ON(1);
}
/* kobject is already registered */
entry->ready = 2;
DPRINTK("%s: device: 0x%p\n", __func__, entry->dev);
return 0;
}
/**
@ -214,14 +225,17 @@ pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf)
{
char *out = buf;
struct device_path *devpath;
unsigned short i;
short i;
if (!entry || !buf)
return -EINVAL;
read_lock(&entry->rw_lock);
devpath = &entry->devpath;
i = entry->ready;
read_unlock(&entry->rw_lock);
if (!entry->ready)
if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; i < 6; i++) {
@ -242,7 +256,7 @@ pdcspath_hwpath_read(struct pdcspath_entry *entry, char *buf)
*
* We will call this function to change the current hardware path.
* Hardware paths are to be given '/'-delimited, without brackets.
* We take care to make sure that the provided path actually maps to an existing
* We make sure that the provided path actually maps to an existing
* device, BUT nothing would prevent some foolish user to set the path to some
* PCI bridge or even a CPU...
* A better work around would be to make sure we are at the end of a device tree
@ -298,17 +312,19 @@ pdcspath_hwpath_write(struct pdcspath_entry *entry, const char *buf, size_t coun
}
/* So far so good, let's get in deep */
write_lock(&entry->rw_lock);
entry->ready = 0;
entry->dev = dev;
/* Now, dive in. Write back to the hardware */
WARN_ON(pdcspath_store(entry)); /* this warn should *NEVER* happen */
pdcspath_store(entry);
/* Update the symlink to the real device */
sysfs_remove_link(&entry->kobj, "device");
sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
write_unlock(&entry->rw_lock);
printk(KERN_INFO "PDC Stable Storage: changed \"%s\" path to \"%s\"\n",
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" path to \"%s\"\n",
entry->name, buf);
return count;
@ -326,14 +342,17 @@ pdcspath_layer_read(struct pdcspath_entry *entry, char *buf)
{
char *out = buf;
struct device_path *devpath;
unsigned short i;
short i;
if (!entry || !buf)
return -EINVAL;
read_lock(&entry->rw_lock);
devpath = &entry->devpath;
i = entry->ready;
read_unlock(&entry->rw_lock);
if (!entry->ready)
if (!i) /* entry is not ready */
return -ENODATA;
for (i = 0; devpath->layers[i] && (likely(i < 6)); i++)
@ -388,15 +407,17 @@ pdcspath_layer_write(struct pdcspath_entry *entry, const char *buf, size_t count
}
/* So far so good, let's get in deep */
write_lock(&entry->rw_lock);
/* First, overwrite the current layers with the new ones, not touching
the hardware path. */
memcpy(&entry->devpath.layers, &layers, sizeof(layers));
/* Now, dive in. Write back to the hardware */
WARN_ON(pdcspath_store(entry)); /* this warn should *NEVER* happen */
pdcspath_store(entry);
write_unlock(&entry->rw_lock);
printk(KERN_INFO "PDC Stable Storage: changed \"%s\" layers to \"%s\"\n",
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" layers to \"%s\"\n",
entry->name, buf);
return count;
@ -415,9 +436,6 @@ pdcspath_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
struct pdcspath_attribute *pdcs_attr = to_pdcspath_attribute(attr);
ssize_t ret = 0;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (pdcs_attr->show)
ret = pdcs_attr->show(entry, buf);
@ -454,8 +472,8 @@ static struct sysfs_ops pdcspath_attr_ops = {
};
/* These are the two attributes of any PDC path. */
static PATHS_ATTR(hwpath, 0600, pdcspath_hwpath_read, pdcspath_hwpath_write);
static PATHS_ATTR(layer, 0600, pdcspath_layer_read, pdcspath_layer_write);
static PATHS_ATTR(hwpath, 0644, pdcspath_hwpath_read, pdcspath_hwpath_write);
static PATHS_ATTR(layer, 0644, pdcspath_layer_read, pdcspath_layer_write);
static struct attribute *paths_subsys_attrs[] = {
&paths_attr_hwpath.attr,
@ -484,36 +502,119 @@ static struct pdcspath_entry *pdcspath_entries[] = {
NULL,
};
/* For more insight of what's going on here, refer to PDC Procedures doc,
* Section PDC_STABLE */
/**
* pdcs_info_read - Pretty printing of the remaining useful data.
* pdcs_size_read - Stable Storage size output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*
* We will call this function to format the output of the 'info' attribute file.
* Please refer to PDC Procedures documentation, section PDC_STABLE to get a
* better insight of what we're doing here.
*/
static ssize_t
pdcs_info_read(struct subsystem *entry, char *buf)
pdcs_size_read(struct subsystem *entry, char *buf)
{
char *out = buf;
__u32 result;
struct device_path devpath;
char *tmpstr = NULL;
if (!entry || !buf)
return -EINVAL;
/* show the size of the stable storage */
out += sprintf(out, "Stable Storage size: %ld bytes\n", pdcs_size);
out += sprintf(out, "%ld\n", pdcs_size);
/* deal with flags */
if (pdc_stable_read(PDCS_ADDR_PPRI, &devpath, sizeof(devpath)) != PDC_OK)
return -EIO;
return out - buf;
}
/**
* pdcs_auto_read - Stable Storage autoboot/search flag output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
* @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
*/
static ssize_t
pdcs_auto_read(struct subsystem *entry, char *buf, int knob)
{
char *out = buf;
struct pdcspath_entry *pathentry;
out += sprintf(out, "Autoboot: %s\n", (devpath.flags & PF_AUTOBOOT) ? "On" : "Off");
out += sprintf(out, "Autosearch: %s\n", (devpath.flags & PF_AUTOSEARCH) ? "On" : "Off");
out += sprintf(out, "Timer: %u s\n", (devpath.flags & PF_TIMER) ? (1 << (devpath.flags & PF_TIMER)) : 0);
if (!entry || !buf)
return -EINVAL;
/* Current flags are stored in primary boot path entry */
pathentry = &pdcspath_entry_primary;
read_lock(&pathentry->rw_lock);
out += sprintf(out, "%s\n", (pathentry->devpath.flags & knob) ?
"On" : "Off");
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_autoboot_read - Stable Storage autoboot flag output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*/
static inline ssize_t
pdcs_autoboot_read(struct subsystem *entry, char *buf)
{
return pdcs_auto_read(entry, buf, PF_AUTOBOOT);
}
/**
* pdcs_autosearch_read - Stable Storage autoboot flag output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*/
static inline ssize_t
pdcs_autosearch_read(struct subsystem *entry, char *buf)
{
return pdcs_auto_read(entry, buf, PF_AUTOSEARCH);
}
/**
* pdcs_timer_read - Stable Storage timer count output (in seconds).
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*
* The value of the timer field correponds to a number of seconds in powers of 2.
*/
static ssize_t
pdcs_timer_read(struct subsystem *entry, char *buf)
{
char *out = buf;
struct pdcspath_entry *pathentry;
if (!entry || !buf)
return -EINVAL;
/* Current flags are stored in primary boot path entry */
pathentry = &pdcspath_entry_primary;
/* print the timer value in seconds */
read_lock(&pathentry->rw_lock);
out += sprintf(out, "%u\n", (pathentry->devpath.flags & PF_TIMER) ?
(1 << (pathentry->devpath.flags & PF_TIMER)) : 0);
read_unlock(&pathentry->rw_lock);
return out - buf;
}
/**
* pdcs_osid_read - Stable Storage OS ID register output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*/
static ssize_t
pdcs_osid_read(struct subsystem *entry, char *buf)
{
char *out = buf;
__u32 result;
char *tmpstr = NULL;
if (!entry || !buf)
return -EINVAL;
/* get OSID */
if (pdc_stable_read(PDCS_ADDR_OSID, &result, sizeof(result)) != PDC_OK)
@ -529,13 +630,31 @@ pdcs_info_read(struct subsystem *entry, char *buf)
case 0x0005: tmpstr = "Novell Netware dependent data"; break;
default: tmpstr = "Unknown"; break;
}
out += sprintf(out, "OS ID: %s (0x%.4x)\n", tmpstr, (result >> 16));
out += sprintf(out, "%s (0x%.4x)\n", tmpstr, (result >> 16));
return out - buf;
}
/**
* pdcs_fastsize_read - Stable Storage FastSize register output.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The output buffer to write to.
*
* This register holds the amount of system RAM to be tested during boot sequence.
*/
static ssize_t
pdcs_fastsize_read(struct subsystem *entry, char *buf)
{
char *out = buf;
__u32 result;
if (!entry || !buf)
return -EINVAL;
/* get fast-size */
if (pdc_stable_read(PDCS_ADDR_FSIZ, &result, sizeof(result)) != PDC_OK)
return -EIO;
out += sprintf(out, "Memory tested: ");
if ((result & 0x0F) < 0x0E)
out += sprintf(out, "%d kB", (1<<(result & 0x0F))*256);
else
@ -546,22 +665,18 @@ pdcs_info_read(struct subsystem *entry, char *buf)
}
/**
* pdcs_info_write - This function handles boot flag modifying.
* pdcs_auto_write - This function handles autoboot/search flag modifying.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
* @knob: The PF_AUTOBOOT or PF_AUTOSEARCH flag
*
* We will call this function to change the current boot flags.
* We will call this function to change the current autoboot flag.
* We expect a precise syntax:
* \"n n\" (n == 0 or 1) to toggle respectively AutoBoot and AutoSearch
*
* As of now there is no incentive on my side to provide more "knobs" to that
* interface, since modifying the rest of the data is pretty meaningless when
* the machine is running and for the expected use of that facility, such as
* PALO setting up the boot disk when installing a Linux distribution...
* \"n\" (n == 0 or 1) to toggle AutoBoot Off or On
*/
static ssize_t
pdcs_info_write(struct subsystem *entry, const char *buf, size_t count)
pdcs_auto_write(struct subsystem *entry, const char *buf, size_t count, int knob)
{
struct pdcspath_entry *pathentry;
unsigned char flags;
@ -582,7 +697,9 @@ pdcs_info_write(struct subsystem *entry, const char *buf, size_t count)
pathentry = &pdcspath_entry_primary;
/* Be nice to the existing flag record */
read_lock(&pathentry->rw_lock);
flags = pathentry->devpath.flags;
read_unlock(&pathentry->rw_lock);
DPRINTK("%s: flags before: 0x%X\n", __func__, flags);
@ -595,50 +712,85 @@ pdcs_info_write(struct subsystem *entry, const char *buf, size_t count)
if ((c != 0) && (c != 1))
goto parse_error;
if (c == 0)
flags &= ~PF_AUTOBOOT;
flags &= ~knob;
else
flags |= PF_AUTOBOOT;
if (*temp++ != ' ')
goto parse_error;
c = *temp++ - '0';
if ((c != 0) && (c != 1))
goto parse_error;
if (c == 0)
flags &= ~PF_AUTOSEARCH;
else
flags |= PF_AUTOSEARCH;
flags |= knob;
DPRINTK("%s: flags after: 0x%X\n", __func__, flags);
/* So far so good, let's get in deep */
write_lock(&pathentry->rw_lock);
/* Change the path entry flags first */
pathentry->devpath.flags = flags;
/* Now, dive in. Write back to the hardware */
WARN_ON(pdcspath_store(pathentry)); /* this warn should *NEVER* happen */
pdcspath_store(pathentry);
write_unlock(&pathentry->rw_lock);
printk(KERN_INFO "PDC Stable Storage: changed flags to \"%s\"\n", buf);
printk(KERN_INFO PDCS_PREFIX ": changed \"%s\" to \"%s\"\n",
(knob & PF_AUTOBOOT) ? "autoboot" : "autosearch",
(flags & knob) ? "On" : "Off");
return count;
parse_error:
printk(KERN_WARNING "%s: Parse error: expect \"n n\" (n == 0 or 1) for AB and AS\n", __func__);
printk(KERN_WARNING "%s: Parse error: expect \"n\" (n == 0 or 1)\n", __func__);
return -EINVAL;
}
/* The last attribute (the 'root' one actually) with all remaining data. */
static PDCS_ATTR(info, 0600, pdcs_info_read, pdcs_info_write);
/**
* pdcs_autoboot_write - This function handles autoboot flag modifying.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current boot flags.
* We expect a precise syntax:
* \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
*/
static inline ssize_t
pdcs_autoboot_write(struct subsystem *entry, const char *buf, size_t count)
{
return pdcs_auto_write(entry, buf, count, PF_AUTOBOOT);
}
/**
* pdcs_autosearch_write - This function handles autosearch flag modifying.
* @entry: An allocated and populated subsytem struct. We don't use it tho.
* @buf: The input buffer to read from.
* @count: The number of bytes to be read.
*
* We will call this function to change the current boot flags.
* We expect a precise syntax:
* \"n\" (n == 0 or 1) to toggle AutoSearch Off or On
*/
static inline ssize_t
pdcs_autosearch_write(struct subsystem *entry, const char *buf, size_t count)
{
return pdcs_auto_write(entry, buf, count, PF_AUTOSEARCH);
}
/* The remaining attributes. */
static PDCS_ATTR(size, 0444, pdcs_size_read, NULL);
static PDCS_ATTR(autoboot, 0644, pdcs_autoboot_read, pdcs_autoboot_write);
static PDCS_ATTR(autosearch, 0644, pdcs_autosearch_read, pdcs_autosearch_write);
static PDCS_ATTR(timer, 0444, pdcs_timer_read, NULL);
static PDCS_ATTR(osid, 0400, pdcs_osid_read, NULL);
static PDCS_ATTR(fastsize, 0400, pdcs_fastsize_read, NULL);
static struct subsys_attribute *pdcs_subsys_attrs[] = {
&pdcs_attr_info,
NULL, /* maybe more in the future? */
&pdcs_attr_size,
&pdcs_attr_autoboot,
&pdcs_attr_autosearch,
&pdcs_attr_timer,
&pdcs_attr_osid,
&pdcs_attr_fastsize,
NULL,
};
static decl_subsys(paths, &ktype_pdcspath, NULL);
static decl_subsys(pdc, NULL, NULL);
static decl_subsys(stable, NULL, NULL);
/**
* pdcs_register_pathentries - Prepares path entries kobjects for sysfs usage.
@ -656,8 +808,16 @@ pdcs_register_pathentries(void)
struct pdcspath_entry *entry;
int err;
/* Initialize the entries rw_lock before anything else */
for (i = 0; (entry = pdcspath_entries[i]); i++)
rwlock_init(&entry->rw_lock);
for (i = 0; (entry = pdcspath_entries[i]); i++) {
if (pdcspath_fetch(entry) < 0)
write_lock(&entry->rw_lock);
err = pdcspath_fetch(entry);
write_unlock(&entry->rw_lock);
if (err < 0)
continue;
if ((err = kobject_set_name(&entry->kobj, "%s", entry->name)))
@ -667,13 +827,14 @@ pdcs_register_pathentries(void)
return err;
/* kobject is now registered */
write_lock(&entry->rw_lock);
entry->ready = 2;
if (!entry->dev)
continue;
/* Add a nice symlink to the real device */
sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
if (entry->dev)
sysfs_create_link(&entry->kobj, &entry->dev->kobj, "device");
write_unlock(&entry->rw_lock);
}
return 0;
@ -688,14 +849,17 @@ pdcs_unregister_pathentries(void)
unsigned short i;
struct pdcspath_entry *entry;
for (i = 0; (entry = pdcspath_entries[i]); i++)
for (i = 0; (entry = pdcspath_entries[i]); i++) {
read_lock(&entry->rw_lock);
if (entry->ready >= 2)
kobject_unregister(&entry->kobj);
kobject_unregister(&entry->kobj);
read_unlock(&entry->rw_lock);
}
}
/*
* For now we register the pdc subsystem with the firmware subsystem
* and the paths subsystem with the pdc subsystem
* For now we register the stable subsystem with the firmware subsystem
* and the paths subsystem with the stable subsystem
*/
static int __init
pdc_stable_init(void)
@ -707,19 +871,23 @@ pdc_stable_init(void)
if (pdc_stable_get_size(&pdcs_size) != PDC_OK)
return -ENODEV;
printk(KERN_INFO "PDC Stable Storage facility v%s\n", PDCS_VERSION);
/* make sure we have enough data */
if (pdcs_size < 96)
return -ENODATA;
/* For now we'll register the pdc subsys within this driver */
if ((rc = firmware_register(&pdc_subsys)))
printk(KERN_INFO PDCS_PREFIX " facility v%s\n", PDCS_VERSION);
/* For now we'll register the stable subsys within this driver */
if ((rc = firmware_register(&stable_subsys)))
goto fail_firmreg;
/* Don't forget the info entry */
/* Don't forget the root entries */
for (i = 0; (attr = pdcs_subsys_attrs[i]) && !error; i++)
if (attr->show)
error = subsys_create_file(&pdc_subsys, attr);
error = subsys_create_file(&stable_subsys, attr);
/* register the paths subsys as a subsystem of pdc subsys */
kset_set_kset_s(&paths_subsys, pdc_subsys);
/* register the paths subsys as a subsystem of stable subsys */
kset_set_kset_s(&paths_subsys, stable_subsys);
if ((rc= subsystem_register(&paths_subsys)))
goto fail_subsysreg;
@ -734,10 +902,10 @@ fail_pdcsreg:
subsystem_unregister(&paths_subsys);
fail_subsysreg:
firmware_unregister(&pdc_subsys);
firmware_unregister(&stable_subsys);
fail_firmreg:
printk(KERN_INFO "PDC Stable Storage bailing out\n");
printk(KERN_INFO PDCS_PREFIX " bailing out\n");
return rc;
}
@ -747,7 +915,7 @@ pdc_stable_exit(void)
pdcs_unregister_pathentries();
subsystem_unregister(&paths_subsys);
firmware_unregister(&pdc_subsys);
firmware_unregister(&stable_subsys);
}