1 files changed, 300 insertions, 232 deletions

diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 778f83ea2249..1850bacdb5b0 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -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)
 
 /*
@@ -177,12 +173,14 @@ vcs_poll_data_get(struct file *file)
 	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);
 
@@ -191,54 +189,177 @@ vcs_vc(struct inode *inode, int *viewed)
 	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)
@@ -246,11 +367,11 @@ 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;
-	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)
@@ -283,16 +404,14 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 	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;
 
 		/* 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;
@@ -313,104 +432,17 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 * 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;
-
-				/* clamp header values if they don't fit */
-				con_buf0[0] = min(vc->vc_rows, 0xFFu);
-				con_buf0[1] = min(vc->vc_cols, 0xFFu);
-				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
@@ -421,18 +453,18 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 */
 
 		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)
@@ -443,18 +475,129 @@ unlock_out:
 	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;
@@ -476,7 +619,11 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 	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;
@@ -484,9 +631,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 		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;
@@ -515,7 +660,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 		 * the user buffer, so recheck.
 		 * Return data written up to now on failure.
 		 */
-		size = vcs_size(inode);
+		size = vcs_size(vc, attr, false);
 		if (size < 0) {
 			if (written)
 				break;
@@ -531,95 +676,18 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 		 * 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;
-
-			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)
+		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;