From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB
---
kernel/drivers/tty/vt/vc_screen.c | 597 +++++++++++++++++++++++++++++++++++------------------------
1 files changed, 350 insertions(+), 247 deletions(-)
diff --git a/kernel/drivers/tty/vt/vc_screen.c b/kernel/drivers/tty/vt/vc_screen.c
index 2fb509d..01c9653 100644
--- a/kernel/drivers/tty/vt/vc_screen.c
+++ b/kernel/drivers/tty/vt/vc_screen.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Provide access to virtual console memory.
- * /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
+ * /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]
*
@@ -50,11 +50,7 @@
#include <asm/byteorder.h>
#include <asm/unaligned.h>
-#undef attr
-#undef org
-#undef addr
-#define HEADER_SIZE 4
-
+#define HEADER_SIZE 4u
#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
/*
@@ -80,7 +76,7 @@
struct vcs_poll_data {
struct notifier_block notifier;
unsigned int cons_num;
- bool seen_last_update;
+ int event;
wait_queue_head_t waitq;
struct fasync_struct *fasync;
};
@@ -93,9 +89,18 @@
struct vcs_poll_data *poll =
container_of(nb, struct vcs_poll_data, notifier);
int currcons = poll->cons_num;
+ int fa_band;
- if (code != VT_UPDATE)
+ 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;
@@ -104,9 +109,9 @@
if (currcons != vc->vc_num)
return NOTIFY_DONE;
- poll->seen_last_update = false;
+ poll->event = code;
wake_up_interruptible(&poll->waitq);
- kill_fasync(&poll->fasync, SIGIO, POLL_IN);
+ kill_fasync(&poll->fasync, SIGIO, fa_band);
return NOTIFY_OK;
}
@@ -131,6 +136,15 @@
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;
@@ -159,12 +173,14 @@
return poll;
}
-/*
- * Returns VC for inode.
+/**
+ * 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, int *viewed)
+static struct vc_data *vcs_vc(struct inode *inode, bool *viewed)
{
unsigned int currcons = console(inode);
@@ -173,54 +189,177 @@
if (currcons == 0) {
currcons = fg_console;
if (viewed)
- *viewed = 1;
+ *viewed = true;
} else {
currcons--;
if (viewed)
- *viewed = 0;
+ *viewed = false;
}
return vc_cons[currcons].d;
}
-/*
- * Returns size for VC carried by inode.
+/**
+ * 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(struct inode *inode)
+static int vcs_size(const struct vc_data *vc, bool attr, bool unicode)
{
int size;
- struct vc_data *vc;
WARN_CONSOLE_UNLOCKED();
- vc = vcs_vc(inode, NULL);
- if (!vc)
- return -ENXIO;
-
size = vc->vc_rows * vc->vc_cols;
- if (use_attributes(inode)) {
- if (use_unicode(inode))
+ if (attr) {
+ if (unicode)
return -EOPNOTSUPP;
- size = 2*size + HEADER_SIZE;
- } else if (use_unicode(inode))
+
+ 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();
- size = vcs_size(file_inode(file));
+ 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)
@@ -228,11 +367,11 @@
struct inode *inode = file_inode(file);
struct vc_data *vc;
struct vcs_poll_data *poll;
- long pos, read;
- int attr, uni_mode, row, col, maxcol, viewed;
- unsigned short *org = NULL;
+ 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)
@@ -247,10 +386,6 @@
uni_mode = use_unicode(inode);
attr = use_attributes(inode);
- ret = -ENXIO;
- vc = vcs_vc(inode, &viewed);
- if (!vc)
- goto unlock_out;
ret = -EINVAL;
if (pos < 0)
@@ -261,25 +396,27 @@
poll = file->private_data;
if (count && poll)
- poll->seen_last_update = true;
+ poll->event = 0;
read = 0;
ret = 0;
while (count) {
- char *con_buf0, *con_buf_start;
- long this_round, size;
- ssize_t orig_count;
- long p = pos;
+ unsigned int this_round, skip = 0;
+ int size;
+
+ vc = vcs_vc(inode, &viewed);
+ if (!vc) {
+ ret = -ENXIO;
+ break;
+ }
/* Check whether we are above size each round,
* as copy_to_user at the end of this loop
* could sleep.
*/
- size = vcs_size(inode);
+ size = vcs_size(vc, attr, uni_mode);
if (size < 0) {
- if (read)
- break;
ret = size;
- goto unlock_out;
+ break;
}
if (pos >= size)
break;
@@ -295,103 +432,17 @@
* attempt to move it to userspace.
*/
- con_buf_start = con_buf0 = con_buf;
- orig_count = this_round;
- maxcol = vc->vc_cols;
if (uni_mode) {
- unsigned int nr;
-
- ret = vc_uniscr_check(vc);
+ ret = vcs_read_buf_uni(vc, con_buf, pos, this_round,
+ viewed);
if (ret)
break;
- p /= 4;
- row = p / vc->vc_cols;
- col = p % maxcol;
- nr = maxcol - col;
- do {
- if (nr > this_round/4)
- nr = this_round/4;
- vc_uniscr_copy_line(vc, con_buf0, viewed,
- row, col, nr);
- con_buf0 += nr * 4;
- this_round -= nr * 4;
- row++;
- col = 0;
- nr = maxcol;
- } while (this_round);
} else if (!attr) {
- org = screen_pos(vc, p, viewed);
- col = p % maxcol;
- p += maxcol - col;
- while (this_round-- > 0) {
- *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
- if (++col == maxcol) {
- org = screen_pos(vc, p, viewed);
- col = 0;
- p += maxcol;
- }
- }
+ vcs_read_buf_noattr(vc, con_buf, pos, this_round,
+ viewed);
} else {
- if (p < HEADER_SIZE) {
- size_t tmp_count;
-
- con_buf0[0] = (char)vc->vc_rows;
- con_buf0[1] = (char)vc->vc_cols;
- getconsxy(vc, con_buf0 + 2);
-
- con_buf_start += p;
- this_round += p;
- if (this_round > CON_BUF_SIZE) {
- this_round = CON_BUF_SIZE;
- orig_count = this_round - p;
- }
-
- tmp_count = HEADER_SIZE;
- if (tmp_count > this_round)
- tmp_count = this_round;
-
- /* Advance state pointers and move on. */
- this_round -= tmp_count;
- p = HEADER_SIZE;
- con_buf0 = con_buf + HEADER_SIZE;
- /* If this_round >= 0, then p is even... */
- } else if (p & 1) {
- /* Skip first byte for output if start address is odd
- * Update region sizes up/down depending on free
- * space in buffer.
- */
- con_buf_start++;
- if (this_round < CON_BUF_SIZE)
- this_round++;
- else
- orig_count--;
- }
- if (this_round > 0) {
- unsigned short *tmp_buf = (unsigned short *)con_buf0;
-
- p -= HEADER_SIZE;
- p /= 2;
- col = p % maxcol;
-
- org = screen_pos(vc, p, viewed);
- p += maxcol - col;
-
- /* Buffer has even length, so we can always copy
- * character + attribute. We do not copy last byte
- * to userspace if this_round is odd.
- */
- this_round = (this_round + 1) >> 1;
-
- while (this_round) {
- *tmp_buf++ = vcs_scr_readw(vc, org++);
- this_round --;
- if (++col == maxcol) {
- org = screen_pos(vc, p, viewed);
- col = 0;
- p += maxcol;
- }
- }
- }
+ this_round = vcs_read_buf(vc, con_buf, pos, this_round,
+ viewed, &skip);
}
/* Finally, release the console semaphore while we push
@@ -402,18 +453,18 @@
*/
console_unlock();
- ret = copy_to_user(buf, con_buf_start, orig_count);
+ ret = copy_to_user(buf, con_buf + skip, this_round);
console_lock();
if (ret) {
- read += (orig_count - ret);
+ read += this_round - ret;
ret = -EFAULT;
break;
}
- buf += orig_count;
- pos += orig_count;
- read += orig_count;
- count -= orig_count;
+ buf += this_round;
+ pos += this_round;
+ read += this_round;
+ count -= this_round;
}
*ppos += read;
if (read)
@@ -424,18 +475,129 @@
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;
- long pos;
- long attr, size, written;
- char *con_buf0;
- int col, maxcol, viewed;
- u16 *org0 = NULL, *org = NULL;
- size_t ret;
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;
@@ -457,7 +619,11 @@
if (!vc)
goto unlock_out;
- size = vcs_size(inode);
+ size = vcs_size(vc, attr, false);
+ if (size < 0) {
+ ret = size;
+ goto unlock_out;
+ }
ret = -EINVAL;
if (pos < 0 || pos > size)
goto unlock_out;
@@ -465,9 +631,7 @@
count = size - pos;
written = 0;
while (count) {
- long this_round = count;
- size_t orig_count;
- long p;
+ unsigned int this_round = count;
if (this_round > CON_BUF_SIZE)
this_round = CON_BUF_SIZE;
@@ -492,11 +656,18 @@
}
}
- /* The vcs_size might have changed while we slept to grab
- * the user buffer, so recheck.
+ /* The vc might have been freed or 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(inode);
+ vc = vcs_vc(inode, &viewed);
+ if (!vc) {
+ if (written)
+ break;
+ ret = -ENXIO;
+ goto unlock_out;
+ }
+ size = vcs_size(vc, attr, false);
if (size < 0) {
if (written)
break;
@@ -512,95 +683,18 @@
* under the lock using the local kernel buffer.
*/
- con_buf0 = con_buf;
- orig_count = this_round;
- maxcol = vc->vc_cols;
- p = pos;
- if (!attr) {
- org0 = org = screen_pos(vc, p, viewed);
- col = p % maxcol;
- p += maxcol - col;
+ 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);
- while (this_round > 0) {
- unsigned char c = *con_buf0++;
-
- this_round--;
- vcs_scr_writew(vc,
- (vcs_scr_readw(vc, org) & 0xff00) | c, org);
- org++;
- if (++col == maxcol) {
- org = screen_pos(vc, p, viewed);
- col = 0;
- p += maxcol;
- }
- }
- } else {
- if (p < HEADER_SIZE) {
- char header[HEADER_SIZE];
-
- getconsxy(vc, header + 2);
- while (p < HEADER_SIZE && this_round > 0) {
- this_round--;
- header[p++] = *con_buf0++;
- }
- if (!viewed)
- putconsxy(vc, header + 2);
- }
- p -= HEADER_SIZE;
- col = (p/2) % maxcol;
- if (this_round > 0) {
- org0 = org = screen_pos(vc, p/2, viewed);
- if ((p & 1) && this_round > 0) {
- char c;
-
- this_round--;
- c = *con_buf0++;
-#ifdef __BIG_ENDIAN
- vcs_scr_writew(vc, c |
- (vcs_scr_readw(vc, org) & 0xff00), org);
-#else
- vcs_scr_writew(vc, (c << 8) |
- (vcs_scr_readw(vc, org) & 0xff), org);
-#endif
- org++;
- p++;
- if (++col == maxcol) {
- org = screen_pos(vc, p/2, viewed);
- col = 0;
- }
- }
- p /= 2;
- p += maxcol - col;
- }
- while (this_round > 1) {
- unsigned short w;
-
- w = get_unaligned(((unsigned short *)con_buf0));
- vcs_scr_writew(vc, w, org++);
- con_buf0 += 2;
- this_round -= 2;
- if (++col == maxcol) {
- org = screen_pos(vc, p, viewed);
- col = 0;
- p += maxcol;
- }
- }
- if (this_round > 0) {
- unsigned char c;
-
- c = *con_buf0++;
-#ifdef __BIG_ENDIAN
- vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
-#else
- vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
-#endif
- }
- }
- count -= orig_count;
- written += orig_count;
- buf += orig_count;
- pos += orig_count;
- if (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;
@@ -618,12 +712,21 @@
vcs_poll(struct file *file, poll_table *wait)
{
struct vcs_poll_data *poll = vcs_poll_data_get(file);
- __poll_t ret = DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
+ __poll_t ret = DEFAULT_POLLMASK|EPOLLERR;
if (poll) {
poll_wait(file, &poll->waitq, wait);
- if (poll->seen_last_update)
+ 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;
}
--
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