linux-stable/drivers/misc/cxl/sysfs.c
Vaibhav Jain 70b565bbdb cxl: Prevent adapter reset if an active context exists
This patch prevents resetting the cxl adapter via sysfs in presence of
one or more active cxl_context on it. This protects against an
unrecoverable error caused by PSL owning a dirty cache line even after
reset and host tries to touch the same cache line. In case a force reset
of the card is required irrespective of any active contexts, the int
value -1 can be stored in the 'reset' sysfs attribute of the card.

The patch introduces a new atomic_t member named contexts_num inside
struct cxl that holds the number of active context attached to the card
, which is checked against '0' before proceeding with the reset. To
prevent against a race condition where a context is activated just after
reset check is performed, the contexts_num is atomically set to '-1'
after reset-check to indicate that no more contexts can be activated on
the card anymore.

Before activating a context we atomically test if contexts_num is
non-negative and if so, increment its value by one. In case the value of
contexts_num is negative then it indicates that the card is about to be
reset and context activation is error-ed out at that point.

Fixes: 62fa19d4b4 ("cxl: Add ability to reset the card")
Cc: stable@vger.kernel.org # v4.0+
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-10-19 20:35:39 +11:00

744 lines
18 KiB
C

/*
* Copyright 2014 IBM Corp.
*
* 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 the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/pci_regs.h>
#include "cxl.h"
#define to_afu_chardev_m(d) dev_get_drvdata(d)
/********* Adapter attributes **********************************************/
static ssize_t caia_version_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
return scnprintf(buf, PAGE_SIZE, "%i.%i\n", adapter->caia_major,
adapter->caia_minor);
}
static ssize_t psl_revision_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->psl_rev);
}
static ssize_t base_image_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->base_image);
}
static ssize_t image_loaded_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
if (adapter->user_image_loaded)
return scnprintf(buf, PAGE_SIZE, "user\n");
return scnprintf(buf, PAGE_SIZE, "factory\n");
}
static ssize_t psl_timebase_synced_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->psl_timebase_synced);
}
static ssize_t reset_adapter_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl *adapter = to_cxl_adapter(device);
int rc;
int val;
rc = sscanf(buf, "%i", &val);
if ((rc != 1) || (val != 1 && val != -1))
return -EINVAL;
/*
* See if we can lock the context mapping that's only allowed
* when there are no contexts attached to the adapter. Once
* taken this will also prevent any context from getting activated.
*/
if (val == 1) {
rc = cxl_adapter_context_lock(adapter);
if (rc)
goto out;
rc = cxl_ops->adapter_reset(adapter);
/* In case reset failed release context lock */
if (rc)
cxl_adapter_context_unlock(adapter);
} else if (val == -1) {
/* Perform a forced adapter reset */
rc = cxl_ops->adapter_reset(adapter);
}
out:
return rc ? rc : count;
}
static ssize_t load_image_on_perst_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
if (!adapter->perst_loads_image)
return scnprintf(buf, PAGE_SIZE, "none\n");
if (adapter->perst_select_user)
return scnprintf(buf, PAGE_SIZE, "user\n");
return scnprintf(buf, PAGE_SIZE, "factory\n");
}
static ssize_t load_image_on_perst_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl *adapter = to_cxl_adapter(device);
int rc;
if (!strncmp(buf, "none", 4))
adapter->perst_loads_image = false;
else if (!strncmp(buf, "user", 4)) {
adapter->perst_select_user = true;
adapter->perst_loads_image = true;
} else if (!strncmp(buf, "factory", 7)) {
adapter->perst_select_user = false;
adapter->perst_loads_image = true;
} else
return -EINVAL;
if ((rc = cxl_update_image_control(adapter)))
return rc;
return count;
}
static ssize_t perst_reloads_same_image_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->perst_same_image);
}
static ssize_t perst_reloads_same_image_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl *adapter = to_cxl_adapter(device);
int rc;
int val;
rc = sscanf(buf, "%i", &val);
if ((rc != 1) || !(val == 1 || val == 0))
return -EINVAL;
adapter->perst_same_image = (val == 1 ? true : false);
return count;
}
static struct device_attribute adapter_attrs[] = {
__ATTR_RO(caia_version),
__ATTR_RO(psl_revision),
__ATTR_RO(base_image),
__ATTR_RO(image_loaded),
__ATTR_RO(psl_timebase_synced),
__ATTR_RW(load_image_on_perst),
__ATTR_RW(perst_reloads_same_image),
__ATTR(reset, S_IWUSR, NULL, reset_adapter_store),
};
/********* AFU master specific attributes **********************************/
static ssize_t mmio_size_show_master(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_afu_chardev_m(device);
return scnprintf(buf, PAGE_SIZE, "%llu\n", afu->adapter->ps_size);
}
static ssize_t pp_mmio_off_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_afu_chardev_m(device);
return scnprintf(buf, PAGE_SIZE, "%llu\n", afu->native->pp_offset);
}
static ssize_t pp_mmio_len_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_afu_chardev_m(device);
return scnprintf(buf, PAGE_SIZE, "%llu\n", afu->pp_size);
}
static struct device_attribute afu_master_attrs[] = {
__ATTR(mmio_size, S_IRUGO, mmio_size_show_master, NULL),
__ATTR_RO(pp_mmio_off),
__ATTR_RO(pp_mmio_len),
};
/********* AFU attributes **************************************************/
static ssize_t mmio_size_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
if (afu->pp_size)
return scnprintf(buf, PAGE_SIZE, "%llu\n", afu->pp_size);
return scnprintf(buf, PAGE_SIZE, "%llu\n", afu->adapter->ps_size);
}
static ssize_t reset_store_afu(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl_afu *afu = to_cxl_afu(device);
int rc;
/* Not safe to reset if it is currently in use */
mutex_lock(&afu->contexts_lock);
if (!idr_is_empty(&afu->contexts_idr)) {
rc = -EBUSY;
goto err;
}
if ((rc = cxl_ops->afu_reset(afu)))
goto err;
rc = count;
err:
mutex_unlock(&afu->contexts_lock);
return rc;
}
static ssize_t irqs_min_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", afu->pp_irqs);
}
static ssize_t irqs_max_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
return scnprintf(buf, PAGE_SIZE, "%i\n", afu->irqs_max);
}
static ssize_t irqs_max_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl_afu *afu = to_cxl_afu(device);
ssize_t ret;
int irqs_max;
ret = sscanf(buf, "%i", &irqs_max);
if (ret != 1)
return -EINVAL;
if (irqs_max < afu->pp_irqs)
return -EINVAL;
if (cpu_has_feature(CPU_FTR_HVMODE)) {
if (irqs_max > afu->adapter->user_irqs)
return -EINVAL;
} else {
/* pHyp sets a per-AFU limit */
if (irqs_max > afu->guest->max_ints)
return -EINVAL;
}
afu->irqs_max = irqs_max;
return count;
}
static ssize_t modes_supported_show(struct device *device,
struct device_attribute *attr, char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
char *p = buf, *end = buf + PAGE_SIZE;
if (afu->modes_supported & CXL_MODE_DEDICATED)
p += scnprintf(p, end - p, "dedicated_process\n");
if (afu->modes_supported & CXL_MODE_DIRECTED)
p += scnprintf(p, end - p, "afu_directed\n");
return (p - buf);
}
static ssize_t prefault_mode_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
switch (afu->prefault_mode) {
case CXL_PREFAULT_WED:
return scnprintf(buf, PAGE_SIZE, "work_element_descriptor\n");
case CXL_PREFAULT_ALL:
return scnprintf(buf, PAGE_SIZE, "all\n");
default:
return scnprintf(buf, PAGE_SIZE, "none\n");
}
}
static ssize_t prefault_mode_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl_afu *afu = to_cxl_afu(device);
enum prefault_modes mode = -1;
if (!strncmp(buf, "work_element_descriptor", 23))
mode = CXL_PREFAULT_WED;
if (!strncmp(buf, "all", 3))
mode = CXL_PREFAULT_ALL;
if (!strncmp(buf, "none", 4))
mode = CXL_PREFAULT_NONE;
if (mode == -1)
return -EINVAL;
afu->prefault_mode = mode;
return count;
}
static ssize_t mode_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
struct cxl_afu *afu = to_cxl_afu(device);
if (afu->current_mode == CXL_MODE_DEDICATED)
return scnprintf(buf, PAGE_SIZE, "dedicated_process\n");
if (afu->current_mode == CXL_MODE_DIRECTED)
return scnprintf(buf, PAGE_SIZE, "afu_directed\n");
return scnprintf(buf, PAGE_SIZE, "none\n");
}
static ssize_t mode_store(struct device *device, struct device_attribute *attr,
const char *buf, size_t count)
{
struct cxl_afu *afu = to_cxl_afu(device);
int old_mode, mode = -1;
int rc = -EBUSY;
/* can't change this if we have a user */
mutex_lock(&afu->contexts_lock);
if (!idr_is_empty(&afu->contexts_idr))
goto err;
if (!strncmp(buf, "dedicated_process", 17))
mode = CXL_MODE_DEDICATED;
if (!strncmp(buf, "afu_directed", 12))
mode = CXL_MODE_DIRECTED;
if (!strncmp(buf, "none", 4))
mode = 0;
if (mode == -1) {
rc = -EINVAL;
goto err;
}
/*
* afu_deactivate_mode needs to be done outside the lock, prevent
* other contexts coming in before we are ready:
*/
old_mode = afu->current_mode;
afu->current_mode = 0;
afu->num_procs = 0;
mutex_unlock(&afu->contexts_lock);
if ((rc = cxl_ops->afu_deactivate_mode(afu, old_mode)))
return rc;
if ((rc = cxl_ops->afu_activate_mode(afu, mode)))
return rc;
return count;
err:
mutex_unlock(&afu->contexts_lock);
return rc;
}
static ssize_t api_version_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
return scnprintf(buf, PAGE_SIZE, "%i\n", CXL_API_VERSION);
}
static ssize_t api_version_compatible_show(struct device *device,
struct device_attribute *attr,
char *buf)
{
return scnprintf(buf, PAGE_SIZE, "%i\n", CXL_API_VERSION_COMPATIBLE);
}
static ssize_t afu_eb_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct cxl_afu *afu = to_cxl_afu(kobj_to_dev(kobj));
return cxl_ops->afu_read_err_buffer(afu, buf, off, count);
}
static struct device_attribute afu_attrs[] = {
__ATTR_RO(mmio_size),
__ATTR_RO(irqs_min),
__ATTR_RW(irqs_max),
__ATTR_RO(modes_supported),
__ATTR_RW(mode),
__ATTR_RW(prefault_mode),
__ATTR_RO(api_version),
__ATTR_RO(api_version_compatible),
__ATTR(reset, S_IWUSR, NULL, reset_store_afu),
};
int cxl_sysfs_adapter_add(struct cxl *adapter)
{
struct device_attribute *dev_attr;
int i, rc;
for (i = 0; i < ARRAY_SIZE(adapter_attrs); i++) {
dev_attr = &adapter_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_ADAPTER_ATTRS)) {
if ((rc = device_create_file(&adapter->dev, dev_attr)))
goto err;
}
}
return 0;
err:
for (i--; i >= 0; i--) {
dev_attr = &adapter_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_ADAPTER_ATTRS))
device_remove_file(&adapter->dev, dev_attr);
}
return rc;
}
void cxl_sysfs_adapter_remove(struct cxl *adapter)
{
struct device_attribute *dev_attr;
int i;
for (i = 0; i < ARRAY_SIZE(adapter_attrs); i++) {
dev_attr = &adapter_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_ADAPTER_ATTRS))
device_remove_file(&adapter->dev, dev_attr);
}
}
struct afu_config_record {
struct kobject kobj;
struct bin_attribute config_attr;
struct list_head list;
int cr;
u16 device;
u16 vendor;
u32 class;
};
#define to_cr(obj) container_of(obj, struct afu_config_record, kobj)
static ssize_t vendor_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct afu_config_record *cr = to_cr(kobj);
return scnprintf(buf, PAGE_SIZE, "0x%.4x\n", cr->vendor);
}
static ssize_t device_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct afu_config_record *cr = to_cr(kobj);
return scnprintf(buf, PAGE_SIZE, "0x%.4x\n", cr->device);
}
static ssize_t class_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct afu_config_record *cr = to_cr(kobj);
return scnprintf(buf, PAGE_SIZE, "0x%.6x\n", cr->class);
}
static ssize_t afu_read_config(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct afu_config_record *cr = to_cr(kobj);
struct cxl_afu *afu = to_cxl_afu(kobj_to_dev(kobj->parent));
u64 i, j, val, rc;
for (i = 0; i < count;) {
rc = cxl_ops->afu_cr_read64(afu, cr->cr, off & ~0x7, &val);
if (rc)
val = ~0ULL;
for (j = off & 0x7; j < 8 && i < count; i++, j++, off++)
buf[i] = (val >> (j * 8)) & 0xff;
}
return count;
}
static struct kobj_attribute vendor_attribute =
__ATTR_RO(vendor);
static struct kobj_attribute device_attribute =
__ATTR_RO(device);
static struct kobj_attribute class_attribute =
__ATTR_RO(class);
static struct attribute *afu_cr_attrs[] = {
&vendor_attribute.attr,
&device_attribute.attr,
&class_attribute.attr,
NULL,
};
static void release_afu_config_record(struct kobject *kobj)
{
struct afu_config_record *cr = to_cr(kobj);
kfree(cr);
}
static struct kobj_type afu_config_record_type = {
.sysfs_ops = &kobj_sysfs_ops,
.release = release_afu_config_record,
.default_attrs = afu_cr_attrs,
};
static struct afu_config_record *cxl_sysfs_afu_new_cr(struct cxl_afu *afu, int cr_idx)
{
struct afu_config_record *cr;
int rc;
cr = kzalloc(sizeof(struct afu_config_record), GFP_KERNEL);
if (!cr)
return ERR_PTR(-ENOMEM);
cr->cr = cr_idx;
rc = cxl_ops->afu_cr_read16(afu, cr_idx, PCI_DEVICE_ID, &cr->device);
if (rc)
goto err;
rc = cxl_ops->afu_cr_read16(afu, cr_idx, PCI_VENDOR_ID, &cr->vendor);
if (rc)
goto err;
rc = cxl_ops->afu_cr_read32(afu, cr_idx, PCI_CLASS_REVISION, &cr->class);
if (rc)
goto err;
cr->class >>= 8;
/*
* Export raw AFU PCIe like config record. For now this is read only by
* root - we can expand that later to be readable by non-root and maybe
* even writable provided we have a good use-case. Once we support
* exposing AFUs through a virtual PHB they will get that for free from
* Linux' PCI infrastructure, but until then it's not clear that we
* need it for anything since the main use case is just identifying
* AFUs, which can be done via the vendor, device and class attributes.
*/
sysfs_bin_attr_init(&cr->config_attr);
cr->config_attr.attr.name = "config";
cr->config_attr.attr.mode = S_IRUSR;
cr->config_attr.size = afu->crs_len;
cr->config_attr.read = afu_read_config;
rc = kobject_init_and_add(&cr->kobj, &afu_config_record_type,
&afu->dev.kobj, "cr%i", cr->cr);
if (rc)
goto err;
rc = sysfs_create_bin_file(&cr->kobj, &cr->config_attr);
if (rc)
goto err1;
rc = kobject_uevent(&cr->kobj, KOBJ_ADD);
if (rc)
goto err2;
return cr;
err2:
sysfs_remove_bin_file(&cr->kobj, &cr->config_attr);
err1:
kobject_put(&cr->kobj);
return ERR_PTR(rc);
err:
kfree(cr);
return ERR_PTR(rc);
}
void cxl_sysfs_afu_remove(struct cxl_afu *afu)
{
struct device_attribute *dev_attr;
struct afu_config_record *cr, *tmp;
int i;
/* remove the err buffer bin attribute */
if (afu->eb_len)
device_remove_bin_file(&afu->dev, &afu->attr_eb);
for (i = 0; i < ARRAY_SIZE(afu_attrs); i++) {
dev_attr = &afu_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_ATTRS))
device_remove_file(&afu->dev, &afu_attrs[i]);
}
list_for_each_entry_safe(cr, tmp, &afu->crs, list) {
sysfs_remove_bin_file(&cr->kobj, &cr->config_attr);
kobject_put(&cr->kobj);
}
}
int cxl_sysfs_afu_add(struct cxl_afu *afu)
{
struct device_attribute *dev_attr;
struct afu_config_record *cr;
int i, rc;
INIT_LIST_HEAD(&afu->crs);
for (i = 0; i < ARRAY_SIZE(afu_attrs); i++) {
dev_attr = &afu_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_ATTRS)) {
if ((rc = device_create_file(&afu->dev, &afu_attrs[i])))
goto err;
}
}
/* conditionally create the add the binary file for error info buffer */
if (afu->eb_len) {
sysfs_attr_init(&afu->attr_eb.attr);
afu->attr_eb.attr.name = "afu_err_buff";
afu->attr_eb.attr.mode = S_IRUGO;
afu->attr_eb.size = afu->eb_len;
afu->attr_eb.read = afu_eb_read;
rc = device_create_bin_file(&afu->dev, &afu->attr_eb);
if (rc) {
dev_err(&afu->dev,
"Unable to create eb attr for the afu. Err(%d)\n",
rc);
goto err;
}
}
for (i = 0; i < afu->crs_num; i++) {
cr = cxl_sysfs_afu_new_cr(afu, i);
if (IS_ERR(cr)) {
rc = PTR_ERR(cr);
goto err1;
}
list_add(&cr->list, &afu->crs);
}
return 0;
err1:
cxl_sysfs_afu_remove(afu);
return rc;
err:
/* reset the eb_len as we havent created the bin attr */
afu->eb_len = 0;
for (i--; i >= 0; i--) {
dev_attr = &afu_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_ATTRS))
device_remove_file(&afu->dev, &afu_attrs[i]);
}
return rc;
}
int cxl_sysfs_afu_m_add(struct cxl_afu *afu)
{
struct device_attribute *dev_attr;
int i, rc;
for (i = 0; i < ARRAY_SIZE(afu_master_attrs); i++) {
dev_attr = &afu_master_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_MASTER_ATTRS)) {
if ((rc = device_create_file(afu->chardev_m, &afu_master_attrs[i])))
goto err;
}
}
return 0;
err:
for (i--; i >= 0; i--) {
dev_attr = &afu_master_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_MASTER_ATTRS))
device_remove_file(afu->chardev_m, &afu_master_attrs[i]);
}
return rc;
}
void cxl_sysfs_afu_m_remove(struct cxl_afu *afu)
{
struct device_attribute *dev_attr;
int i;
for (i = 0; i < ARRAY_SIZE(afu_master_attrs); i++) {
dev_attr = &afu_master_attrs[i];
if (cxl_ops->support_attributes(dev_attr->attr.name,
CXL_AFU_MASTER_ATTRS))
device_remove_file(afu->chardev_m, &afu_master_attrs[i]);
}
}