Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 816 insertions, 0 deletions

diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
new file mode 100644
index 000000000..f566eb183
--- /dev/null
+++ b/drivers/tty/vt/vc_screen.c
@@ -0,0 +1,816 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Provide access to virtual console memory.
+ * /dev/vcs: the screen as it is being viewed right now (possibly scrolled)
+ * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
+ *            [minor: N]
+ *
+ * /dev/vcsaN: idem, but including attributes, and prefixed with
+ *	the 4 bytes lines,columns,x,y (as screendump used to give).
+ *	Attribute/character pair is in native endianity.
+ *            [minor: N+128]
+ *
+ * /dev/vcsuN: similar to /dev/vcsaN but using 4-byte unicode values
+ *	instead of 1-byte screen glyph values.
+ *            [minor: N+64]
+ *
+ * /dev/vcsuaN: same idea as /dev/vcsaN for unicode (not yet implemented).
+ *
+ * This replaces screendump and part of selection, so that the system
+ * administrator can control access using file system permissions.
+ *
+ * aeb@cwi.nl - efter Friedas begravelse - 950211
+ *
+ * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
+ *	 - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
+ *	 - making it shorter - scr_readw are macros which expand in PRETTY long code
+ */
+
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/tty.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/vt_kern.h>
+#include <linux/selection.h>
+#include <linux/kbd_kern.h>
+#include <linux/console.h>
+#include <linux/device.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/notifier.h>
+
+#include <linux/uaccess.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+#define HEADER_SIZE	4u
+#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
+
+/*
+ * Our minor space:
+ *
+ *   0 ... 63	glyph mode without attributes
+ *  64 ... 127	unicode mode without attributes
+ * 128 ... 191	glyph mode with attributes
+ * 192 ... 255	unused (reserved for unicode with attributes)
+ *
+ * This relies on MAX_NR_CONSOLES being  <= 63, meaning 63 actual consoles
+ * with minors 0, 64, 128 and 192 being proxies for the foreground console.
+ */
+#if MAX_NR_CONSOLES > 63
+#warning "/dev/vcs* devices may not accommodate more than 63 consoles"
+#endif
+
+#define console(inode)		(iminor(inode) & 63)
+#define use_unicode(inode)	(iminor(inode) & 64)
+#define use_attributes(inode)	(iminor(inode) & 128)
+
+
+struct vcs_poll_data {
+	struct notifier_block notifier;
+	unsigned int cons_num;
+	int event;
+	wait_queue_head_t waitq;
+	struct fasync_struct *fasync;
+};
+
+static int
+vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
+{
+	struct vt_notifier_param *param = _param;
+	struct vc_data *vc = param->vc;
+	struct vcs_poll_data *poll =
+		container_of(nb, struct vcs_poll_data, notifier);
+	int currcons = poll->cons_num;
+	int fa_band;
+
+	switch (code) {
+	case VT_UPDATE:
+		fa_band = POLL_PRI;
+		break;
+	case VT_DEALLOCATE:
+		fa_band = POLL_HUP;
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	if (currcons == 0)
+		currcons = fg_console;
+	else
+		currcons--;
+	if (currcons != vc->vc_num)
+		return NOTIFY_DONE;
+
+	poll->event = code;
+	wake_up_interruptible(&poll->waitq);
+	kill_fasync(&poll->fasync, SIGIO, fa_band);
+	return NOTIFY_OK;
+}
+
+static void
+vcs_poll_data_free(struct vcs_poll_data *poll)
+{
+	unregister_vt_notifier(&poll->notifier);
+	kfree(poll);
+}
+
+static struct vcs_poll_data *
+vcs_poll_data_get(struct file *file)
+{
+	struct vcs_poll_data *poll = file->private_data, *kill = NULL;
+
+	if (poll)
+		return poll;
+
+	poll = kzalloc(sizeof(*poll), GFP_KERNEL);
+	if (!poll)
+		return NULL;
+	poll->cons_num = console(file_inode(file));
+	init_waitqueue_head(&poll->waitq);
+	poll->notifier.notifier_call = vcs_notifier;
+	/*
+	 * In order not to lose any update event, we must pretend one might
+	 * have occurred before we have a chance to register our notifier.
+	 * This is also how user space has come to detect which kernels
+	 * support POLLPRI on /dev/vcs* devices i.e. using poll() with
+	 * POLLPRI and a zero timeout.
+	 */
+	poll->event = VT_UPDATE;
+
+	if (register_vt_notifier(&poll->notifier) != 0) {
+		kfree(poll);
+		return NULL;
+	}
+
+	/*
+	 * This code may be called either through ->poll() or ->fasync().
+	 * If we have two threads using the same file descriptor, they could
+	 * both enter this function, both notice that the structure hasn't
+	 * been allocated yet and go ahead allocating it in parallel, but
+	 * only one of them must survive and be shared otherwise we'd leak
+	 * memory with a dangling notifier callback.
+	 */
+	spin_lock(&file->f_lock);
+	if (!file->private_data) {
+		file->private_data = poll;
+	} else {
+		/* someone else raced ahead of us */
+		kill = poll;
+		poll = file->private_data;
+	}
+	spin_unlock(&file->f_lock);
+	if (kill)
+		vcs_poll_data_free(kill);
+
+	return poll;
+}
+
+/**
+ * vcs_vc -- return VC for @inode
+ * @inode: inode for which to return a VC
+ * @viewed: returns whether this console is currently foreground (viewed)
+ *
+ * Must be called with console_lock.
+ */
+static struct vc_data *vcs_vc(struct inode *inode, bool *viewed)
+{
+	unsigned int currcons = console(inode);
+
+	WARN_CONSOLE_UNLOCKED();
+
+	if (currcons == 0) {
+		currcons = fg_console;
+		if (viewed)
+			*viewed = true;
+	} else {
+		currcons--;
+		if (viewed)
+			*viewed = false;
+	}
+	return vc_cons[currcons].d;
+}
+
+/**
+ * vcs_size -- return size for a VC in @vc
+ * @vc: which VC
+ * @attr: does it use attributes?
+ * @unicode: is it unicode?
+ *
+ * Must be called with console_lock.
+ */
+static int vcs_size(const struct vc_data *vc, bool attr, bool unicode)
+{
+	int size;
+
+	WARN_CONSOLE_UNLOCKED();
+
+	size = vc->vc_rows * vc->vc_cols;
+
+	if (attr) {
+		if (unicode)
+			return -EOPNOTSUPP;
+
+		size = 2 * size + HEADER_SIZE;
+	} else if (unicode)
+		size *= 4;
+
+	return size;
+}
+
+static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
+{
+	struct inode *inode = file_inode(file);
+	struct vc_data *vc;
+	int size;
+
+	console_lock();
+	vc = vcs_vc(inode, NULL);
+	if (!vc) {
+		console_unlock();
+		return -ENXIO;
+	}
+
+	size = vcs_size(vc, use_attributes(inode), use_unicode(inode));
+	console_unlock();
+	if (size < 0)
+		return size;
+	return fixed_size_llseek(file, offset, orig, size);
+}
+
+static int vcs_read_buf_uni(struct vc_data *vc, char *con_buf,
+		unsigned int pos, unsigned int count, bool viewed)
+{
+	unsigned int nr, row, col, maxcol = vc->vc_cols;
+	int ret;
+
+	ret = vc_uniscr_check(vc);
+	if (ret)
+		return ret;
+
+	pos /= 4;
+	row = pos / maxcol;
+	col = pos % maxcol;
+	nr = maxcol - col;
+	do {
+		if (nr > count / 4)
+			nr = count / 4;
+		vc_uniscr_copy_line(vc, con_buf, viewed, row, col, nr);
+		con_buf += nr * 4;
+		count -= nr * 4;
+		row++;
+		col = 0;
+		nr = maxcol;
+	} while (count);
+
+	return 0;
+}
+
+static void vcs_read_buf_noattr(const struct vc_data *vc, char *con_buf,
+		unsigned int pos, unsigned int count, bool viewed)
+{
+	u16 *org;
+	unsigned int col, maxcol = vc->vc_cols;
+
+	org = screen_pos(vc, pos, viewed);
+	col = pos % maxcol;
+	pos += maxcol - col;
+
+	while (count-- > 0) {
+		*con_buf++ = (vcs_scr_readw(vc, org++) & 0xff);
+		if (++col == maxcol) {
+			org = screen_pos(vc, pos, viewed);
+			col = 0;
+			pos += maxcol;
+		}
+	}
+}
+
+static unsigned int vcs_read_buf(const struct vc_data *vc, char *con_buf,
+		unsigned int pos, unsigned int count, bool viewed,
+		unsigned int *skip)
+{
+	u16 *org, *con_buf16;
+	unsigned int col, maxcol = vc->vc_cols;
+	unsigned int filled = count;
+
+	if (pos < HEADER_SIZE) {
+		/* clamp header values if they don't fit */
+		con_buf[0] = min(vc->vc_rows, 0xFFu);
+		con_buf[1] = min(vc->vc_cols, 0xFFu);
+		getconsxy(vc, con_buf + 2);
+
+		*skip += pos;
+		count += pos;
+		if (count > CON_BUF_SIZE) {
+			count = CON_BUF_SIZE;
+			filled = count - pos;
+		}
+
+		/* Advance state pointers and move on. */
+		count -= min(HEADER_SIZE, count);
+		pos = HEADER_SIZE;
+		con_buf += HEADER_SIZE;
+		/* If count >= 0, then pos is even... */
+	} else if (pos & 1) {
+		/*
+		 * Skip first byte for output if start address is odd. Update
+		 * region sizes up/down depending on free space in buffer.
+		 */
+		(*skip)++;
+		if (count < CON_BUF_SIZE)
+			count++;
+		else
+			filled--;
+	}
+
+	if (!count)
+		return filled;
+
+	pos -= HEADER_SIZE;
+	pos /= 2;
+	col = pos % maxcol;
+
+	org = screen_pos(vc, pos, viewed);
+	pos += maxcol - col;
+
+	/*
+	 * Buffer has even length, so we can always copy character + attribute.
+	 * We do not copy last byte to userspace if count is odd.
+	 */
+	count = (count + 1) / 2;
+	con_buf16 = (u16 *)con_buf;
+
+	while (count) {
+		*con_buf16++ = vcs_scr_readw(vc, org++);
+		count--;
+		if (++col == maxcol) {
+			org = screen_pos(vc, pos, viewed);
+			col = 0;
+			pos += maxcol;
+		}
+	}
+
+	return filled;
+}
+
+static ssize_t
+vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct inode *inode = file_inode(file);
+	struct vc_data *vc;
+	struct vcs_poll_data *poll;
+	unsigned int read;
+	ssize_t ret;
+	char *con_buf;
+	loff_t pos;
+	bool viewed, attr, uni_mode;
+
+	con_buf = (char *) __get_free_page(GFP_KERNEL);
+	if (!con_buf)
+		return -ENOMEM;
+
+	pos = *ppos;
+
+	/* Select the proper current console and verify
+	 * sanity of the situation under the console lock.
+	 */
+	console_lock();
+
+	uni_mode = use_unicode(inode);
+	attr = use_attributes(inode);
+
+	ret = -EINVAL;
+	if (pos < 0)
+		goto unlock_out;
+	/* we enforce 32-bit alignment for pos and count in unicode mode */
+	if (uni_mode && (pos | count) & 3)
+		goto unlock_out;
+
+	poll = file->private_data;
+	if (count && poll)
+		poll->event = 0;
+	read = 0;
+	ret = 0;
+	while (count) {
+		unsigned int this_round, skip = 0;
+		int size;
+
+		ret = -ENXIO;
+		vc = vcs_vc(inode, &viewed);
+		if (!vc)
+			goto unlock_out;
+
+		/* Check whether we are above size each round,
+		 * as copy_to_user at the end of this loop
+		 * could sleep.
+		 */
+		size = vcs_size(vc, attr, uni_mode);
+		if (size < 0) {
+			if (read)
+				break;
+			ret = size;
+			goto unlock_out;
+		}
+		if (pos >= size)
+			break;
+		if (count > size - pos)
+			count = size - pos;
+
+		this_round = count;
+		if (this_round > CON_BUF_SIZE)
+			this_round = CON_BUF_SIZE;
+
+		/* Perform the whole read into the local con_buf.
+		 * Then we can drop the console spinlock and safely
+		 * attempt to move it to userspace.
+		 */
+
+		if (uni_mode) {
+			ret = vcs_read_buf_uni(vc, con_buf, pos, this_round,
+					viewed);
+			if (ret)
+				break;
+		} else if (!attr) {
+			vcs_read_buf_noattr(vc, con_buf, pos, this_round,
+					viewed);
+		} else {
+			this_round = vcs_read_buf(vc, con_buf, pos, this_round,
+					viewed, &skip);
+		}
+
+		/* Finally, release the console semaphore while we push
+		 * all the data to userspace from our temporary buffer.
+		 *
+		 * AKPM: Even though it's a semaphore, we should drop it because
+		 * the pagefault handling code may want to call printk().
+		 */
+
+		console_unlock();
+		ret = copy_to_user(buf, con_buf + skip, this_round);
+		console_lock();
+
+		if (ret) {
+			read += this_round - ret;
+			ret = -EFAULT;
+			break;
+		}
+		buf += this_round;
+		pos += this_round;
+		read += this_round;
+		count -= this_round;
+	}
+	*ppos += read;
+	if (read)
+		ret = read;
+unlock_out:
+	console_unlock();
+	free_page((unsigned long) con_buf);
+	return ret;
+}
+
+static u16 *vcs_write_buf_noattr(struct vc_data *vc, const char *con_buf,
+		unsigned int pos, unsigned int count, bool viewed, u16 **org0)
+{
+	u16 *org;
+	unsigned int col, maxcol = vc->vc_cols;
+
+	*org0 = org = screen_pos(vc, pos, viewed);
+	col = pos % maxcol;
+	pos += maxcol - col;
+
+	while (count > 0) {
+		unsigned char c = *con_buf++;
+
+		count--;
+		vcs_scr_writew(vc,
+			       (vcs_scr_readw(vc, org) & 0xff00) | c, org);
+		org++;
+		if (++col == maxcol) {
+			org = screen_pos(vc, pos, viewed);
+			col = 0;
+			pos += maxcol;
+		}
+	}
+
+	return org;
+}
+
+/*
+ * Compilers (gcc 10) are unable to optimize the swap in cpu_to_le16. So do it
+ * the poor man way.
+ */
+static inline u16 vc_compile_le16(u8 hi, u8 lo)
+{
+#ifdef __BIG_ENDIAN
+	return (lo << 8u) | hi;
+#else
+	return (hi << 8u) | lo;
+#endif
+}
+
+static u16 *vcs_write_buf(struct vc_data *vc, const char *con_buf,
+		unsigned int pos, unsigned int count, bool viewed, u16 **org0)
+{
+	u16 *org;
+	unsigned int col, maxcol = vc->vc_cols;
+	unsigned char c;
+
+	/* header */
+	if (pos < HEADER_SIZE) {
+		char header[HEADER_SIZE];
+
+		getconsxy(vc, header + 2);
+		while (pos < HEADER_SIZE && count > 0) {
+			count--;
+			header[pos++] = *con_buf++;
+		}
+		if (!viewed)
+			putconsxy(vc, header + 2);
+	}
+
+	if (!count)
+		return NULL;
+
+	pos -= HEADER_SIZE;
+	col = (pos/2) % maxcol;
+
+	*org0 = org = screen_pos(vc, pos/2, viewed);
+
+	/* odd pos -- the first single character */
+	if (pos & 1) {
+		count--;
+		c = *con_buf++;
+		vcs_scr_writew(vc, vc_compile_le16(c, vcs_scr_readw(vc, org)),
+				org);
+		org++;
+		pos++;
+		if (++col == maxcol) {
+			org = screen_pos(vc, pos/2, viewed);
+			col = 0;
+		}
+	}
+
+	pos /= 2;
+	pos += maxcol - col;
+
+	/* even pos -- handle attr+character pairs */
+	while (count > 1) {
+		unsigned short w;
+
+		w = get_unaligned(((unsigned short *)con_buf));
+		vcs_scr_writew(vc, w, org++);
+		con_buf += 2;
+		count -= 2;
+		if (++col == maxcol) {
+			org = screen_pos(vc, pos, viewed);
+			col = 0;
+			pos += maxcol;
+		}
+	}
+
+	if (!count)
+		return org;
+
+	/* odd pos -- the remaining character */
+	c = *con_buf++;
+	vcs_scr_writew(vc, vc_compile_le16(vcs_scr_readw(vc, org) >> 8, c),
+				org);
+
+	return org;
+}
+
+static ssize_t
+vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct inode *inode = file_inode(file);
+	struct vc_data *vc;
+	char *con_buf;
+	u16 *org0, *org;
+	unsigned int written;
+	int size;
+	ssize_t ret;
+	loff_t pos;
+	bool viewed, attr;
+
+	if (use_unicode(inode))
+		return -EOPNOTSUPP;
+
+	con_buf = (char *) __get_free_page(GFP_KERNEL);
+	if (!con_buf)
+		return -ENOMEM;
+
+	pos = *ppos;
+
+	/* Select the proper current console and verify
+	 * sanity of the situation under the console lock.
+	 */
+	console_lock();
+
+	attr = use_attributes(inode);
+	ret = -ENXIO;
+	vc = vcs_vc(inode, &viewed);
+	if (!vc)
+		goto unlock_out;
+
+	size = vcs_size(vc, attr, false);
+	if (size < 0) {
+		ret = size;
+		goto unlock_out;
+	}
+	ret = -EINVAL;
+	if (pos < 0 || pos > size)
+		goto unlock_out;
+	if (count > size - pos)
+		count = size - pos;
+	written = 0;
+	while (count) {
+		unsigned int this_round = count;
+
+		if (this_round > CON_BUF_SIZE)
+			this_round = CON_BUF_SIZE;
+
+		/* Temporarily drop the console lock so that we can read
+		 * in the write data from userspace safely.
+		 */
+		console_unlock();
+		ret = copy_from_user(con_buf, buf, this_round);
+		console_lock();
+
+		if (ret) {
+			this_round -= ret;
+			if (!this_round) {
+				/* Abort loop if no data were copied. Otherwise
+				 * fail with -EFAULT.
+				 */
+				if (written)
+					break;
+				ret = -EFAULT;
+				goto unlock_out;
+			}
+		}
+
+		/* The vcs_size might have changed while we slept to grab
+		 * the user buffer, so recheck.
+		 * Return data written up to now on failure.
+		 */
+		size = vcs_size(vc, attr, false);
+		if (size < 0) {
+			if (written)
+				break;
+			ret = size;
+			goto unlock_out;
+		}
+		if (pos >= size)
+			break;
+		if (this_round > size - pos)
+			this_round = size - pos;
+
+		/* OK, now actually push the write to the console
+		 * under the lock using the local kernel buffer.
+		 */
+
+		if (attr)
+			org = vcs_write_buf(vc, con_buf, pos, this_round,
+					viewed, &org0);
+		else
+			org = vcs_write_buf_noattr(vc, con_buf, pos, this_round,
+					viewed, &org0);
+
+		count -= this_round;
+		written += this_round;
+		buf += this_round;
+		pos += this_round;
+		if (org)
+			update_region(vc, (unsigned long)(org0), org - org0);
+	}
+	*ppos += written;
+	ret = written;
+	if (written)
+		vcs_scr_updated(vc);
+
+unlock_out:
+	console_unlock();
+	free_page((unsigned long) con_buf);
+	return ret;
+}
+
+static __poll_t
+vcs_poll(struct file *file, poll_table *wait)
+{
+	struct vcs_poll_data *poll = vcs_poll_data_get(file);
+	__poll_t ret = DEFAULT_POLLMASK|EPOLLERR;
+
+	if (poll) {
+		poll_wait(file, &poll->waitq, wait);
+		switch (poll->event) {
+		case VT_UPDATE:
+			ret = DEFAULT_POLLMASK|EPOLLPRI;
+			break;
+		case VT_DEALLOCATE:
+			ret = DEFAULT_POLLMASK|EPOLLHUP|EPOLLERR;
+			break;
+		case 0:
+			ret = DEFAULT_POLLMASK;
+			break;
+		}
+	}
+	return ret;
+}
+
+static int
+vcs_fasync(int fd, struct file *file, int on)
+{
+	struct vcs_poll_data *poll = file->private_data;
+
+	if (!poll) {
+		/* don't allocate anything if all we want is disable fasync */
+		if (!on)
+			return 0;
+		poll = vcs_poll_data_get(file);
+		if (!poll)
+			return -ENOMEM;
+	}
+
+	return fasync_helper(fd, file, on, &poll->fasync);
+}
+
+static int
+vcs_open(struct inode *inode, struct file *filp)
+{
+	unsigned int currcons = console(inode);
+	bool attr = use_attributes(inode);
+	bool uni_mode = use_unicode(inode);
+	int ret = 0;
+
+	/* we currently don't support attributes in unicode mode */
+	if (attr && uni_mode)
+		return -EOPNOTSUPP;
+
+	console_lock();
+	if(currcons && !vc_cons_allocated(currcons-1))
+		ret = -ENXIO;
+	console_unlock();
+	return ret;
+}
+
+static int vcs_release(struct inode *inode, struct file *file)
+{
+	struct vcs_poll_data *poll = file->private_data;
+
+	if (poll)
+		vcs_poll_data_free(poll);
+	return 0;
+}
+
+static const struct file_operations vcs_fops = {
+	.llseek		= vcs_lseek,
+	.read		= vcs_read,
+	.write		= vcs_write,
+	.poll		= vcs_poll,
+	.fasync		= vcs_fasync,
+	.open		= vcs_open,
+	.release	= vcs_release,
+};
+
+static struct class *vc_class;
+
+void vcs_make_sysfs(int index)
+{
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
+		      "vcs%u", index + 1);
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 65), NULL,
+		      "vcsu%u", index + 1);
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
+		      "vcsa%u", index + 1);
+}
+
+void vcs_remove_sysfs(int index)
+{
+	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
+	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 65));
+	device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
+}
+
+int __init vcs_init(void)
+{
+	unsigned int i;
+
+	if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
+		panic("unable to get major %d for vcs device", VCS_MAJOR);
+	vc_class = class_create(THIS_MODULE, "vc");
+
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 64), NULL, "vcsu");
+	device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
+	for (i = 0; i < MIN_NR_CONSOLES; i++)
+		vcs_make_sysfs(i);
+	return 0;
+}