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linux/drivers/tty/hvc/hvsi_lib.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license 
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

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// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/console.h>
#include <asm/hvsi.h>
#include "hvc_console.h"
static int hvsi_send_packet(struct hvsi_priv *pv, struct hvsi_header *packet)
{
packet->seqno = cpu_to_be16(atomic_inc_return(&pv->seqno));
/* Assumes that always succeeds, works in practice */
return pv->put_chars(pv->termno, (char *)packet, packet->len);
}
static void hvsi_start_handshake(struct hvsi_priv *pv)
{
struct hvsi_query q;
/* Reset state */
pv->established = 0;
atomic_set(&pv->seqno, 0);
pr_devel("HVSI@%x: Handshaking started\n", pv->termno);
/* Send version query */
q.hdr.type = VS_QUERY_PACKET_HEADER;
q.hdr.len = sizeof(struct hvsi_query);
q.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
hvsi_send_packet(pv, &q.hdr);
}
static int hvsi_send_close(struct hvsi_priv *pv)
{
struct hvsi_control ctrl;
pv->established = 0;
ctrl.hdr.type = VS_CONTROL_PACKET_HEADER;
ctrl.hdr.len = sizeof(struct hvsi_control);
ctrl.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
return hvsi_send_packet(pv, &ctrl.hdr);
}
static void hvsi_cd_change(struct hvsi_priv *pv, int cd)
{
if (cd)
pv->mctrl |= TIOCM_CD;
else {
pv->mctrl &= ~TIOCM_CD;
/* We copy the existing hvsi driver semantics
* here which are to trigger a hangup when
* we get a carrier loss.
* Closing our connection to the server will
* do just that.
*/
if (!pv->is_console && pv->opened) {
pr_devel("HVSI@%x Carrier lost, hanging up !\n",
pv->termno);
hvsi_send_close(pv);
}
}
}
static void hvsi_got_control(struct hvsi_priv *pv)
{
struct hvsi_control *pkt = (struct hvsi_control *)pv->inbuf;
switch (be16_to_cpu(pkt->verb)) {
case VSV_CLOSE_PROTOCOL:
/* We restart the handshaking */
hvsi_start_handshake(pv);
break;
case VSV_MODEM_CTL_UPDATE:
/* Transition of carrier detect */
hvsi_cd_change(pv, be32_to_cpu(pkt->word) & HVSI_TSCD);
break;
}
}
static void hvsi_got_query(struct hvsi_priv *pv)
{
struct hvsi_query *pkt = (struct hvsi_query *)pv->inbuf;
struct hvsi_query_response r;
/* We only handle version queries */
if (be16_to_cpu(pkt->verb) != VSV_SEND_VERSION_NUMBER)
return;
pr_devel("HVSI@%x: Got version query, sending response...\n",
pv->termno);
/* Send version response */
r.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
r.hdr.len = sizeof(struct hvsi_query_response);
r.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
r.u.version = HVSI_VERSION;
r.query_seqno = pkt->hdr.seqno;
hvsi_send_packet(pv, &r.hdr);
/* Assume protocol is open now */
pv->established = 1;
}
static void hvsi_got_response(struct hvsi_priv *pv)
{
struct hvsi_query_response *r =
(struct hvsi_query_response *)pv->inbuf;
switch(r->verb) {
case VSV_SEND_MODEM_CTL_STATUS:
hvsi_cd_change(pv, be32_to_cpu(r->u.mctrl_word) & HVSI_TSCD);
pv->mctrl_update = 1;
break;
}
}
static int hvsi_check_packet(struct hvsi_priv *pv)
{
u8 len, type;
/* Check header validity. If it's invalid, we ditch
* the whole buffer and hope we eventually resync
*/
if (pv->inbuf[0] < 0xfc) {
pv->inbuf_len = pv->inbuf_pktlen = 0;
return 0;
}
type = pv->inbuf[0];
len = pv->inbuf[1];
/* Packet incomplete ? */
if (pv->inbuf_len < len)
return 0;
pr_devel("HVSI@%x: Got packet type %x len %d bytes:\n",
pv->termno, type, len);
/* We have a packet, yay ! Handle it */
switch(type) {
case VS_DATA_PACKET_HEADER:
pv->inbuf_pktlen = len - 4;
pv->inbuf_cur = 4;
return 1;
case VS_CONTROL_PACKET_HEADER:
hvsi_got_control(pv);
break;
case VS_QUERY_PACKET_HEADER:
hvsi_got_query(pv);
break;
case VS_QUERY_RESPONSE_PACKET_HEADER:
hvsi_got_response(pv);
break;
}
/* Swallow packet and retry */
pv->inbuf_len -= len;
memmove(pv->inbuf, &pv->inbuf[len], pv->inbuf_len);
return 1;
}
static int hvsi_get_packet(struct hvsi_priv *pv)
{
/* If we have room in the buffer, ask HV for more */
if (pv->inbuf_len < HVSI_INBUF_SIZE)
pv->inbuf_len += pv->get_chars(pv->termno,
&pv->inbuf[pv->inbuf_len],
HVSI_INBUF_SIZE - pv->inbuf_len);
/*
* If we have at least 4 bytes in the buffer, check for
* a full packet and retry
*/
if (pv->inbuf_len >= 4)
return hvsi_check_packet(pv);
return 0;
}
int hvsilib_get_chars(struct hvsi_priv *pv, char *buf, int count)
{
unsigned int tries, read = 0;
if (WARN_ON(!pv))
return -ENXIO;
/* If we aren't open, don't do anything in order to avoid races
* with connection establishment. The hvc core will call this
* before we have returned from notifier_add(), and we need to
* avoid multiple users playing with the receive buffer
*/
if (!pv->opened)
return 0;
/* We try twice, once with what data we have and once more
* after we try to fetch some more from the hypervisor
*/
for (tries = 1; count && tries < 2; tries++) {
/* Consume existing data packet */
if (pv->inbuf_pktlen) {
unsigned int l = min(count, (int)pv->inbuf_pktlen);
memcpy(&buf[read], &pv->inbuf[pv->inbuf_cur], l);
pv->inbuf_cur += l;
pv->inbuf_pktlen -= l;
count -= l;
read += l;
}
if (count == 0)
break;
/* Data packet fully consumed, move down remaning data */
if (pv->inbuf_cur) {
pv->inbuf_len -= pv->inbuf_cur;
memmove(pv->inbuf, &pv->inbuf[pv->inbuf_cur],
pv->inbuf_len);
pv->inbuf_cur = 0;
}
/* Try to get another packet */
if (hvsi_get_packet(pv))
tries--;
}
if (!pv->established) {
pr_devel("HVSI@%x: returning -EPIPE\n", pv->termno);
return -EPIPE;
}
return read;
}
int hvsilib_put_chars(struct hvsi_priv *pv, const char *buf, int count)
{
struct hvsi_data dp;
int rc, adjcount = min(count, HVSI_MAX_OUTGOING_DATA);
if (WARN_ON(!pv))
return -ENODEV;
dp.hdr.type = VS_DATA_PACKET_HEADER;
dp.hdr.len = adjcount + sizeof(struct hvsi_header);
memcpy(dp.data, buf, adjcount);
rc = hvsi_send_packet(pv, &dp.hdr);
if (rc <= 0)
return rc;
return adjcount;
}
static void maybe_msleep(unsigned long ms)
{
/* During early boot, IRQs are disabled, use mdelay */
if (irqs_disabled())
mdelay(ms);
else
msleep(ms);
}
int hvsilib_read_mctrl(struct hvsi_priv *pv)
{
struct hvsi_query q;
int rc, timeout;
pr_devel("HVSI@%x: Querying modem control status...\n",
pv->termno);
pv->mctrl_update = 0;
q.hdr.type = VS_QUERY_PACKET_HEADER;
q.hdr.len = sizeof(struct hvsi_query);
q.verb = cpu_to_be16(VSV_SEND_MODEM_CTL_STATUS);
rc = hvsi_send_packet(pv, &q.hdr);
if (rc <= 0) {
pr_devel("HVSI@%x: Error %d...\n", pv->termno, rc);
return rc;
}
/* Try for up to 200ms */
for (timeout = 0; timeout < 20; timeout++) {
if (!pv->established)
return -ENXIO;
if (pv->mctrl_update)
return 0;
if (!hvsi_get_packet(pv))
maybe_msleep(10);
}
return -EIO;
}
int hvsilib_write_mctrl(struct hvsi_priv *pv, int dtr)
{
struct hvsi_control ctrl;
unsigned short mctrl;
mctrl = pv->mctrl;
if (dtr)
mctrl |= TIOCM_DTR;
else
mctrl &= ~TIOCM_DTR;
if (mctrl == pv->mctrl)
return 0;
pv->mctrl = mctrl;
pr_devel("HVSI@%x: %s DTR...\n", pv->termno,
dtr ? "Setting" : "Clearing");
ctrl.hdr.type = VS_CONTROL_PACKET_HEADER,
ctrl.hdr.len = sizeof(struct hvsi_control);
ctrl.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
ctrl.mask = cpu_to_be32(HVSI_TSDTR);
ctrl.word = cpu_to_be32(dtr ? HVSI_TSDTR : 0);
return hvsi_send_packet(pv, &ctrl.hdr);
}
void hvsilib_establish(struct hvsi_priv *pv)
{
int timeout;
pr_devel("HVSI@%x: Establishing...\n", pv->termno);
/* Try for up to 200ms, there can be a packet to
* start the process waiting for us...
*/
for (timeout = 0; timeout < 20; timeout++) {
if (pv->established)
goto established;
if (!hvsi_get_packet(pv))
maybe_msleep(10);
}
/* Failed, send a close connection packet just
* in case
*/
pr_devel("HVSI@%x: ... sending close\n", pv->termno);
hvsi_send_close(pv);
/* Then restart handshake */
pr_devel("HVSI@%x: ... restarting handshake\n", pv->termno);
hvsi_start_handshake(pv);
pr_devel("HVSI@%x: ... waiting handshake\n", pv->termno);
/* Try for up to 400ms */
for (timeout = 0; timeout < 40; timeout++) {
if (pv->established)
goto established;
if (!hvsi_get_packet(pv))
maybe_msleep(10);
}
if (!pv->established) {
pr_devel("HVSI@%x: Timeout handshaking, giving up !\n",
pv->termno);
return;
}
established:
/* Query modem control lines */
pr_devel("HVSI@%x: ... established, reading mctrl\n", pv->termno);
hvsilib_read_mctrl(pv);
/* Set our own DTR */
pr_devel("HVSI@%x: ... setting mctrl\n", pv->termno);
hvsilib_write_mctrl(pv, 1);
/* Set the opened flag so reads are allowed */
wmb();
pv->opened = 1;
}
int hvsilib_open(struct hvsi_priv *pv, struct hvc_struct *hp)
{
pr_devel("HVSI@%x: open !\n", pv->termno);
/* Keep track of the tty data structure */
pv->tty = tty_port_tty_get(&hp->port);
hvsilib_establish(pv);
return 0;
}
void hvsilib_close(struct hvsi_priv *pv, struct hvc_struct *hp)
{
unsigned long flags;
pr_devel("HVSI@%x: close !\n", pv->termno);
if (!pv->is_console) {
pr_devel("HVSI@%x: Not a console, tearing down\n",
pv->termno);
/* Clear opened, synchronize with khvcd */
spin_lock_irqsave(&hp->lock, flags);
pv->opened = 0;
spin_unlock_irqrestore(&hp->lock, flags);
/* Clear our own DTR */
if (!pv->tty || (pv->tty->termios.c_cflag & HUPCL))
hvsilib_write_mctrl(pv, 0);
/* Tear down the connection */
hvsi_send_close(pv);
}
tty_kref_put(pv->tty);
pv->tty = NULL;
}
void hvsilib_init(struct hvsi_priv *pv,
int (*get_chars)(uint32_t termno, char *buf, int count),
int (*put_chars)(uint32_t termno, const char *buf,
int count),
int termno, int is_console)
{
memset(pv, 0, sizeof(*pv));
pv->get_chars = get_chars;
pv->put_chars = put_chars;
pv->termno = termno;
pv->is_console = is_console;
}
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