swh:1:snp:32555a3fd8878f019c2ebd6c964bc1edcaeff337
Tip revision: 2c523b344dfa65a3738e7039832044aa133c75fb authored by Linus Torvalds on 09 March 2020, 00:44:44 UTC
Linux 5.6-rc5
Linux 5.6-rc5
Tip revision: 2c523b3
visorchannel.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 - 2015 UNISYS CORPORATION
* All rights reserved.
*/
/*
* This provides s-Par channel communication primitives, which are
* independent of the mechanism used to access the channel data.
*/
#include <linux/uuid.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/visorbus.h>
#include "visorbus_private.h"
#include "controlvmchannel.h"
#define VISOR_DRV_NAME "visorchannel"
#define VISOR_CONSOLEVIDEO_CHANNEL_GUID \
GUID_INIT(0x3cd6e705, 0xd6a2, 0x4aa5, \
0xad, 0x5c, 0x7b, 0x8, 0x88, 0x9d, 0xff, 0xe2)
static const guid_t visor_video_guid = VISOR_CONSOLEVIDEO_CHANNEL_GUID;
struct visorchannel {
u64 physaddr;
ulong nbytes;
void *mapped;
bool requested;
struct channel_header chan_hdr;
guid_t guid;
/*
* channel creator knows if more than one thread will be inserting or
* removing
*/
bool needs_lock;
/* protect head writes in chan_hdr */
spinlock_t insert_lock;
/* protect tail writes in chan_hdr */
spinlock_t remove_lock;
guid_t type;
guid_t inst;
};
void visorchannel_destroy(struct visorchannel *channel)
{
if (!channel)
return;
if (channel->mapped) {
memunmap(channel->mapped);
if (channel->requested)
release_mem_region(channel->physaddr, channel->nbytes);
}
kfree(channel);
}
u64 visorchannel_get_physaddr(struct visorchannel *channel)
{
return channel->physaddr;
}
ulong visorchannel_get_nbytes(struct visorchannel *channel)
{
return channel->nbytes;
}
char *visorchannel_guid_id(const guid_t *guid, char *s)
{
sprintf(s, "%pUL", guid);
return s;
}
char *visorchannel_id(struct visorchannel *channel, char *s)
{
return visorchannel_guid_id(&channel->guid, s);
}
char *visorchannel_zoneid(struct visorchannel *channel, char *s)
{
return visorchannel_guid_id(&channel->chan_hdr.zone_guid, s);
}
u64 visorchannel_get_clientpartition(struct visorchannel *channel)
{
return channel->chan_hdr.partition_handle;
}
int visorchannel_set_clientpartition(struct visorchannel *channel,
u64 partition_handle)
{
channel->chan_hdr.partition_handle = partition_handle;
return 0;
}
/**
* visorchannel_get_guid() - queries the GUID of the designated channel
* @channel: the channel to query
*
* Return: the GUID of the provided channel
*/
const guid_t *visorchannel_get_guid(struct visorchannel *channel)
{
return &channel->guid;
}
EXPORT_SYMBOL_GPL(visorchannel_get_guid);
int visorchannel_read(struct visorchannel *channel, ulong offset, void *dest,
ulong nbytes)
{
if (offset + nbytes > channel->nbytes)
return -EIO;
memcpy(dest, channel->mapped + offset, nbytes);
return 0;
}
int visorchannel_write(struct visorchannel *channel, ulong offset, void *dest,
ulong nbytes)
{
size_t chdr_size = sizeof(struct channel_header);
size_t copy_size;
if (offset + nbytes > channel->nbytes)
return -EIO;
if (offset < chdr_size) {
copy_size = min(chdr_size - offset, nbytes);
memcpy(((char *)(&channel->chan_hdr)) + offset,
dest, copy_size);
}
memcpy(channel->mapped + offset, dest, nbytes);
return 0;
}
void *visorchannel_get_header(struct visorchannel *channel)
{
return &channel->chan_hdr;
}
/*
* Return offset of a specific SIGNAL_QUEUE_HEADER from the beginning of a
* channel header
*/
static int sig_queue_offset(struct channel_header *chan_hdr, int q)
{
return ((chan_hdr)->ch_space_offset +
((q) * sizeof(struct signal_queue_header)));
}
/*
* Return offset of a specific queue entry (data) from the beginning of a
* channel header
*/
static int sig_data_offset(struct channel_header *chan_hdr, int q,
struct signal_queue_header *sig_hdr, int slot)
{
return (sig_queue_offset(chan_hdr, q) + sig_hdr->sig_base_offset +
(slot * sig_hdr->signal_size));
}
/*
* Write the contents of a specific field within a SIGNAL_QUEUE_HEADER back into
* host memory
*/
#define SIG_WRITE_FIELD(channel, queue, sig_hdr, FIELD) \
visorchannel_write(channel, \
sig_queue_offset(&channel->chan_hdr, queue) + \
offsetof(struct signal_queue_header, FIELD), \
&((sig_hdr)->FIELD), \
sizeof((sig_hdr)->FIELD))
static int sig_read_header(struct visorchannel *channel, u32 queue,
struct signal_queue_header *sig_hdr)
{
if (channel->chan_hdr.ch_space_offset < sizeof(struct channel_header))
return -EINVAL;
/* Read the appropriate SIGNAL_QUEUE_HEADER into local memory. */
return visorchannel_read(channel,
sig_queue_offset(&channel->chan_hdr, queue),
sig_hdr, sizeof(struct signal_queue_header));
}
static int sig_read_data(struct visorchannel *channel, u32 queue,
struct signal_queue_header *sig_hdr, u32 slot,
void *data)
{
int signal_data_offset = sig_data_offset(&channel->chan_hdr, queue,
sig_hdr, slot);
return visorchannel_read(channel, signal_data_offset,
data, sig_hdr->signal_size);
}
static int sig_write_data(struct visorchannel *channel, u32 queue,
struct signal_queue_header *sig_hdr, u32 slot,
void *data)
{
int signal_data_offset = sig_data_offset(&channel->chan_hdr, queue,
sig_hdr, slot);
return visorchannel_write(channel, signal_data_offset,
data, sig_hdr->signal_size);
}
static int signalremove_inner(struct visorchannel *channel, u32 queue,
void *msg)
{
struct signal_queue_header sig_hdr;
int error;
error = sig_read_header(channel, queue, &sig_hdr);
if (error)
return error;
/* No signals to remove; have caller try again. */
if (sig_hdr.head == sig_hdr.tail)
return -EAGAIN;
sig_hdr.tail = (sig_hdr.tail + 1) % sig_hdr.max_slots;
error = sig_read_data(channel, queue, &sig_hdr, sig_hdr.tail, msg);
if (error)
return error;
sig_hdr.num_received++;
/*
* For each data field in SIGNAL_QUEUE_HEADER that was modified, update
* host memory. Required for channel sync.
*/
mb();
error = SIG_WRITE_FIELD(channel, queue, &sig_hdr, tail);
if (error)
return error;
error = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_received);
if (error)
return error;
return 0;
}
/**
* visorchannel_signalremove() - removes a message from the designated
* channel/queue
* @channel: the channel the message will be removed from
* @queue: the queue the message will be removed from
* @msg: the message to remove
*
* Return: integer error code indicating the status of the removal
*/
int visorchannel_signalremove(struct visorchannel *channel, u32 queue,
void *msg)
{
int rc;
unsigned long flags;
if (channel->needs_lock) {
spin_lock_irqsave(&channel->remove_lock, flags);
rc = signalremove_inner(channel, queue, msg);
spin_unlock_irqrestore(&channel->remove_lock, flags);
} else {
rc = signalremove_inner(channel, queue, msg);
}
return rc;
}
EXPORT_SYMBOL_GPL(visorchannel_signalremove);
static bool queue_empty(struct visorchannel *channel, u32 queue)
{
struct signal_queue_header sig_hdr;
if (sig_read_header(channel, queue, &sig_hdr))
return true;
return (sig_hdr.head == sig_hdr.tail);
}
/**
* visorchannel_signalempty() - checks if the designated channel/queue contains
* any messages
* @channel: the channel to query
* @queue: the queue in the channel to query
*
* Return: boolean indicating whether any messages in the designated
* channel/queue are present
*/
bool visorchannel_signalempty(struct visorchannel *channel, u32 queue)
{
bool rc;
unsigned long flags;
if (!channel->needs_lock)
return queue_empty(channel, queue);
spin_lock_irqsave(&channel->remove_lock, flags);
rc = queue_empty(channel, queue);
spin_unlock_irqrestore(&channel->remove_lock, flags);
return rc;
}
EXPORT_SYMBOL_GPL(visorchannel_signalempty);
static int signalinsert_inner(struct visorchannel *channel, u32 queue,
void *msg)
{
struct signal_queue_header sig_hdr;
int err;
err = sig_read_header(channel, queue, &sig_hdr);
if (err)
return err;
sig_hdr.head = (sig_hdr.head + 1) % sig_hdr.max_slots;
if (sig_hdr.head == sig_hdr.tail) {
sig_hdr.num_overflows++;
err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_overflows);
if (err)
return err;
return -EIO;
}
err = sig_write_data(channel, queue, &sig_hdr, sig_hdr.head, msg);
if (err)
return err;
sig_hdr.num_sent++;
/*
* For each data field in SIGNAL_QUEUE_HEADER that was modified, update
* host memory. Required for channel sync.
*/
mb();
err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, head);
if (err)
return err;
err = SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_sent);
if (err)
return err;
return 0;
}
/*
* visorchannel_create() - creates the struct visorchannel abstraction for a
* data area in memory, but does NOT modify this data
* area
* @physaddr: physical address of start of channel
* @gfp: gfp_t to use when allocating memory for the data struct
* @guid: GUID that identifies channel type;
* @needs_lock: must specify true if you have multiple threads of execution
* that will be calling visorchannel methods of this
* visorchannel at the same time
*
* Return: pointer to visorchannel that was created if successful,
* otherwise NULL
*/
struct visorchannel *visorchannel_create(u64 physaddr, gfp_t gfp,
const guid_t *guid, bool needs_lock)
{
struct visorchannel *channel;
int err;
size_t size = sizeof(struct channel_header);
if (physaddr == 0)
return NULL;
channel = kzalloc(sizeof(*channel), gfp);
if (!channel)
return NULL;
channel->needs_lock = needs_lock;
spin_lock_init(&channel->insert_lock);
spin_lock_init(&channel->remove_lock);
/*
* Video driver constains the efi framebuffer so it will get a conflict
* resource when requesting its full mem region. Since we are only
* using the efi framebuffer for video we can ignore this. Remember that
* we haven't requested it so we don't try to release later on.
*/
channel->requested = request_mem_region(physaddr, size, VISOR_DRV_NAME);
if (!channel->requested && !guid_equal(guid, &visor_video_guid))
/* we only care about errors if this is not the video channel */
goto err_destroy_channel;
channel->mapped = memremap(physaddr, size, MEMREMAP_WB);
if (!channel->mapped) {
release_mem_region(physaddr, size);
goto err_destroy_channel;
}
channel->physaddr = physaddr;
channel->nbytes = size;
err = visorchannel_read(channel, 0, &channel->chan_hdr, size);
if (err)
goto err_destroy_channel;
size = (ulong)channel->chan_hdr.size;
memunmap(channel->mapped);
if (channel->requested)
release_mem_region(channel->physaddr, channel->nbytes);
channel->mapped = NULL;
channel->requested = request_mem_region(channel->physaddr, size,
VISOR_DRV_NAME);
if (!channel->requested && !guid_equal(guid, &visor_video_guid))
/* we only care about errors if this is not the video channel */
goto err_destroy_channel;
channel->mapped = memremap(channel->physaddr, size, MEMREMAP_WB);
if (!channel->mapped) {
release_mem_region(channel->physaddr, size);
goto err_destroy_channel;
}
channel->nbytes = size;
guid_copy(&channel->guid, guid);
return channel;
err_destroy_channel:
visorchannel_destroy(channel);
return NULL;
}
/**
* visorchannel_signalinsert() - inserts a message into the designated
* channel/queue
* @channel: the channel the message will be added to
* @queue: the queue the message will be added to
* @msg: the message to insert
*
* Return: integer error code indicating the status of the insertion
*/
int visorchannel_signalinsert(struct visorchannel *channel, u32 queue,
void *msg)
{
int rc;
unsigned long flags;
if (channel->needs_lock) {
spin_lock_irqsave(&channel->insert_lock, flags);
rc = signalinsert_inner(channel, queue, msg);
spin_unlock_irqrestore(&channel->insert_lock, flags);
} else {
rc = signalinsert_inner(channel, queue, msg);
}
return rc;
}
EXPORT_SYMBOL_GPL(visorchannel_signalinsert);