blob: 87b9f2bfa623b1c6a2752519fffcdb5957646874 [file] [log] [blame]
/*
* AMD Cryptographic Coprocessor (CCP) driver
*
* Copyright (C) 2013,2016 Advanced Micro Devices, Inc.
*
* Author: Tom Lendacky <thomas.lendacky@amd.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/spinlock_types.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/hw_random.h>
#include <linux/cpu.h>
#ifdef CONFIG_X86
#include <asm/cpu_device_id.h>
#endif
#include <linux/ccp.h>
#include "ccp-dev.h"
MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0.0");
MODULE_DESCRIPTION("AMD Cryptographic Coprocessor driver");
struct ccp_tasklet_data {
struct completion completion;
struct ccp_cmd *cmd;
};
/* List of CCPs, CCP count, read-write access lock, and access functions
*
* Lock structure: get ccp_unit_lock for reading whenever we need to
* examine the CCP list. While holding it for reading we can acquire
* the RR lock to update the round-robin next-CCP pointer. The unit lock
* must be acquired before the RR lock.
*
* If the unit-lock is acquired for writing, we have total control over
* the list, so there's no value in getting the RR lock.
*/
static DEFINE_RWLOCK(ccp_unit_lock);
static LIST_HEAD(ccp_units);
/* Round-robin counter */
static DEFINE_SPINLOCK(ccp_rr_lock);
static struct ccp_device *ccp_rr;
/* Ever-increasing value to produce unique unit numbers */
static atomic_t ccp_unit_ordinal;
unsigned int ccp_increment_unit_ordinal(void)
{
return atomic_inc_return(&ccp_unit_ordinal);
}
/**
* ccp_add_device - add a CCP device to the list
*
* @ccp: ccp_device struct pointer
*
* Put this CCP on the unit list, which makes it available
* for use.
*
* Returns zero if a CCP device is present, -ENODEV otherwise.
*/
void ccp_add_device(struct ccp_device *ccp)
{
unsigned long flags;
write_lock_irqsave(&ccp_unit_lock, flags);
list_add_tail(&ccp->entry, &ccp_units);
if (!ccp_rr)
/* We already have the list lock (we're first) so this
* pointer can't change on us. Set its initial value.
*/
ccp_rr = ccp;
write_unlock_irqrestore(&ccp_unit_lock, flags);
}
/**
* ccp_del_device - remove a CCP device from the list
*
* @ccp: ccp_device struct pointer
*
* Remove this unit from the list of devices. If the next device
* up for use is this one, adjust the pointer. If this is the last
* device, NULL the pointer.
*/
void ccp_del_device(struct ccp_device *ccp)
{
unsigned long flags;
write_lock_irqsave(&ccp_unit_lock, flags);
if (ccp_rr == ccp) {
/* ccp_unit_lock is read/write; any read access
* will be suspended while we make changes to the
* list and RR pointer.
*/
if (list_is_last(&ccp_rr->entry, &ccp_units))
ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
entry);
else
ccp_rr = list_next_entry(ccp_rr, entry);
}
list_del(&ccp->entry);
if (list_empty(&ccp_units))
ccp_rr = NULL;
write_unlock_irqrestore(&ccp_unit_lock, flags);
}
static struct ccp_device *ccp_get_device(void)
{
unsigned long flags;
struct ccp_device *dp = NULL;
/* We round-robin through the unit list.
* The (ccp_rr) pointer refers to the next unit to use.
*/
read_lock_irqsave(&ccp_unit_lock, flags);
if (!list_empty(&ccp_units)) {
spin_lock(&ccp_rr_lock);
dp = ccp_rr;
if (list_is_last(&ccp_rr->entry, &ccp_units))
ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
entry);
else
ccp_rr = list_next_entry(ccp_rr, entry);
spin_unlock(&ccp_rr_lock);
}
read_unlock_irqrestore(&ccp_unit_lock, flags);
return dp;
}
/**
* ccp_present - check if a CCP device is present
*
* Returns zero if a CCP device is present, -ENODEV otherwise.
*/
int ccp_present(void)
{
unsigned long flags;
int ret;
read_lock_irqsave(&ccp_unit_lock, flags);
ret = list_empty(&ccp_units);
read_unlock_irqrestore(&ccp_unit_lock, flags);
return ret ? -ENODEV : 0;
}
EXPORT_SYMBOL_GPL(ccp_present);
/**
* ccp_version - get the version of the CCP device
*
* Returns the version from the first unit on the list;
* otherwise a zero if no CCP device is present
*/
unsigned int ccp_version(void)
{
struct ccp_device *dp;
unsigned long flags;
int ret = 0;
read_lock_irqsave(&ccp_unit_lock, flags);
if (!list_empty(&ccp_units)) {
dp = list_first_entry(&ccp_units, struct ccp_device, entry);
ret = dp->vdata->version;
}
read_unlock_irqrestore(&ccp_unit_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(ccp_version);
/**
* ccp_enqueue_cmd - queue an operation for processing by the CCP
*
* @cmd: ccp_cmd struct to be processed
*
* Queue a cmd to be processed by the CCP. If queueing the cmd
* would exceed the defined length of the cmd queue the cmd will
* only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
* result in a return code of -EBUSY.
*
* The callback routine specified in the ccp_cmd struct will be
* called to notify the caller of completion (if the cmd was not
* backlogged) or advancement out of the backlog. If the cmd has
* advanced out of the backlog the "err" value of the callback
* will be -EINPROGRESS. Any other "err" value during callback is
* the result of the operation.
*
* The cmd has been successfully queued if:
* the return code is -EINPROGRESS or
* the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
*/
int ccp_enqueue_cmd(struct ccp_cmd *cmd)
{
struct ccp_device *ccp = ccp_get_device();
unsigned long flags;
unsigned int i;
int ret;
if (!ccp)
return -ENODEV;
/* Caller must supply a callback routine */
if (!cmd->callback)
return -EINVAL;
cmd->ccp = ccp;
spin_lock_irqsave(&ccp->cmd_lock, flags);
i = ccp->cmd_q_count;
if (ccp->cmd_count >= MAX_CMD_QLEN) {
ret = -EBUSY;
if (cmd->flags & CCP_CMD_MAY_BACKLOG)
list_add_tail(&cmd->entry, &ccp->backlog);
} else {
ret = -EINPROGRESS;
ccp->cmd_count++;
list_add_tail(&cmd->entry, &ccp->cmd);
/* Find an idle queue */
if (!ccp->suspending) {
for (i = 0; i < ccp->cmd_q_count; i++) {
if (ccp->cmd_q[i].active)
continue;
break;
}
}
}
spin_unlock_irqrestore(&ccp->cmd_lock, flags);
/* If we found an idle queue, wake it up */
if (i < ccp->cmd_q_count)
wake_up_process(ccp->cmd_q[i].kthread);
return ret;
}
EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);
static void ccp_do_cmd_backlog(struct work_struct *work)
{
struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
struct ccp_device *ccp = cmd->ccp;
unsigned long flags;
unsigned int i;
cmd->callback(cmd->data, -EINPROGRESS);
spin_lock_irqsave(&ccp->cmd_lock, flags);
ccp->cmd_count++;
list_add_tail(&cmd->entry, &ccp->cmd);
/* Find an idle queue */
for (i = 0; i < ccp->cmd_q_count; i++) {
if (ccp->cmd_q[i].active)
continue;
break;
}
spin_unlock_irqrestore(&ccp->cmd_lock, flags);
/* If we found an idle queue, wake it up */
if (i < ccp->cmd_q_count)
wake_up_process(ccp->cmd_q[i].kthread);
}
static struct ccp_cmd *ccp_dequeue_cmd(struct ccp_cmd_queue *cmd_q)
{
struct ccp_device *ccp = cmd_q->ccp;
struct ccp_cmd *cmd = NULL;
struct ccp_cmd *backlog = NULL;
unsigned long flags;
spin_lock_irqsave(&ccp->cmd_lock, flags);
cmd_q->active = 0;
if (ccp->suspending) {
cmd_q->suspended = 1;
spin_unlock_irqrestore(&ccp->cmd_lock, flags);
wake_up_interruptible(&ccp->suspend_queue);
return NULL;
}
if (ccp->cmd_count) {
cmd_q->active = 1;
cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
list_del(&cmd->entry);
ccp->cmd_count--;
}
if (!list_empty(&ccp->backlog)) {
backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
entry);
list_del(&backlog->entry);
}
spin_unlock_irqrestore(&ccp->cmd_lock, flags);
if (backlog) {
INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
schedule_work(&backlog->work);
}
return cmd;
}
static void ccp_do_cmd_complete(unsigned long data)
{
struct ccp_tasklet_data *tdata = (struct ccp_tasklet_data *)data;
struct ccp_cmd *cmd = tdata->cmd;
cmd->callback(cmd->data, cmd->ret);
complete(&tdata->completion);
}
/**
* ccp_cmd_queue_thread - create a kernel thread to manage a CCP queue
*
* @data: thread-specific data
*/
int ccp_cmd_queue_thread(void *data)
{
struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
struct ccp_cmd *cmd;
struct ccp_tasklet_data tdata;
struct tasklet_struct tasklet;
tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
schedule();
set_current_state(TASK_INTERRUPTIBLE);
cmd = ccp_dequeue_cmd(cmd_q);
if (!cmd)
continue;
__set_current_state(TASK_RUNNING);
/* Execute the command */
cmd->ret = ccp_run_cmd(cmd_q, cmd);
/* Schedule the completion callback */
tdata.cmd = cmd;
init_completion(&tdata.completion);
tasklet_schedule(&tasklet);
wait_for_completion(&tdata.completion);
}
__set_current_state(TASK_RUNNING);
return 0;
}
/**
* ccp_alloc_struct - allocate and initialize the ccp_device struct
*
* @dev: device struct of the CCP
*/
struct ccp_device *ccp_alloc_struct(struct device *dev)
{
struct ccp_device *ccp;
ccp = devm_kzalloc(dev, sizeof(*ccp), GFP_KERNEL);
if (!ccp)
return NULL;
ccp->dev = dev;
INIT_LIST_HEAD(&ccp->cmd);
INIT_LIST_HEAD(&ccp->backlog);
spin_lock_init(&ccp->cmd_lock);
mutex_init(&ccp->req_mutex);
mutex_init(&ccp->ksb_mutex);
ccp->ksb_count = KSB_COUNT;
ccp->ksb_start = 0;
ccp->ord = ccp_increment_unit_ordinal();
snprintf(ccp->name, MAX_CCP_NAME_LEN, "ccp-%u", ccp->ord);
snprintf(ccp->rngname, MAX_CCP_NAME_LEN, "ccp-%u-rng", ccp->ord);
return ccp;
}
#ifdef CONFIG_PM
bool ccp_queues_suspended(struct ccp_device *ccp)
{
unsigned int suspended = 0;
unsigned long flags;
unsigned int i;
spin_lock_irqsave(&ccp->cmd_lock, flags);
for (i = 0; i < ccp->cmd_q_count; i++)
if (ccp->cmd_q[i].suspended)
suspended++;
spin_unlock_irqrestore(&ccp->cmd_lock, flags);
return ccp->cmd_q_count == suspended;
}
#endif
static int __init ccp_mod_init(void)
{
#ifdef CONFIG_X86
int ret;
ret = ccp_pci_init();
if (ret)
return ret;
/* Don't leave the driver loaded if init failed */
if (ccp_present() != 0) {
ccp_pci_exit();
return -ENODEV;
}
return 0;
#endif
#ifdef CONFIG_ARM64
int ret;
ret = ccp_platform_init();
if (ret)
return ret;
/* Don't leave the driver loaded if init failed */
if (ccp_present() != 0) {
ccp_platform_exit();
return -ENODEV;
}
return 0;
#endif
return -ENODEV;
}
static void __exit ccp_mod_exit(void)
{
#ifdef CONFIG_X86
ccp_pci_exit();
#endif
#ifdef CONFIG_ARM64
ccp_platform_exit();
#endif
}
module_init(ccp_mod_init);
module_exit(ccp_mod_exit);