v4.19.13 snapshot.
diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
new file mode 100644
index 0000000..118527a
--- /dev/null
+++ b/kernel/debug/kdb/kdb_keyboard.c
@@ -0,0 +1,263 @@
+/*
+ * Kernel Debugger Architecture Dependent Console I/O handler
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.
+ *
+ * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
+ */
+
+#include <linux/kdb.h>
+#include <linux/keyboard.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/io.h>
+
+/* Keyboard Controller Registers on normal PCs. */
+
+#define KBD_STATUS_REG 0x64 /* Status register (R) */
+#define KBD_DATA_REG 0x60 /* Keyboard data register (R/W) */
+
+/* Status Register Bits */
+
+#define KBD_STAT_OBF 0x01 /* Keyboard output buffer full */
+#define KBD_STAT_MOUSE_OBF 0x20 /* Mouse output buffer full */
+
+static int kbd_exists;
+static int kbd_last_ret;
+
+/*
+ * Check if the keyboard controller has a keypress for us.
+ * Some parts (Enter Release, LED change) are still blocking polled here,
+ * but hopefully they are all short.
+ */
+int kdb_get_kbd_char(void)
+{
+ int scancode, scanstatus;
+ static int shift_lock; /* CAPS LOCK state (0-off, 1-on) */
+ static int shift_key; /* Shift next keypress */
+ static int ctrl_key;
+ u_short keychar;
+
+ if (KDB_FLAG(NO_I8042) || KDB_FLAG(NO_VT_CONSOLE) ||
+ (inb(KBD_STATUS_REG) == 0xff && inb(KBD_DATA_REG) == 0xff)) {
+ kbd_exists = 0;
+ return -1;
+ }
+ kbd_exists = 1;
+
+ if ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+ return -1;
+
+ /*
+ * Fetch the scancode
+ */
+ scancode = inb(KBD_DATA_REG);
+ scanstatus = inb(KBD_STATUS_REG);
+
+ /*
+ * Ignore mouse events.
+ */
+ if (scanstatus & KBD_STAT_MOUSE_OBF)
+ return -1;
+
+ /*
+ * Ignore release, trigger on make
+ * (except for shift keys, where we want to
+ * keep the shift state so long as the key is
+ * held down).
+ */
+
+ if (((scancode&0x7f) == 0x2a) || ((scancode&0x7f) == 0x36)) {
+ /*
+ * Next key may use shift table
+ */
+ if ((scancode & 0x80) == 0)
+ shift_key = 1;
+ else
+ shift_key = 0;
+ return -1;
+ }
+
+ if ((scancode&0x7f) == 0x1d) {
+ /*
+ * Left ctrl key
+ */
+ if ((scancode & 0x80) == 0)
+ ctrl_key = 1;
+ else
+ ctrl_key = 0;
+ return -1;
+ }
+
+ if ((scancode & 0x80) != 0) {
+ if (scancode == 0x9c)
+ kbd_last_ret = 0;
+ return -1;
+ }
+
+ scancode &= 0x7f;
+
+ /*
+ * Translate scancode
+ */
+
+ if (scancode == 0x3a) {
+ /*
+ * Toggle caps lock
+ */
+ shift_lock ^= 1;
+
+#ifdef KDB_BLINK_LED
+ kdb_toggleled(0x4);
+#endif
+ return -1;
+ }
+
+ if (scancode == 0x0e) {
+ /*
+ * Backspace
+ */
+ return 8;
+ }
+
+ /* Special Key */
+ switch (scancode) {
+ case 0xF: /* Tab */
+ return 9;
+ case 0x53: /* Del */
+ return 4;
+ case 0x47: /* Home */
+ return 1;
+ case 0x4F: /* End */
+ return 5;
+ case 0x4B: /* Left */
+ return 2;
+ case 0x48: /* Up */
+ return 16;
+ case 0x50: /* Down */
+ return 14;
+ case 0x4D: /* Right */
+ return 6;
+ }
+
+ if (scancode == 0xe0)
+ return -1;
+
+ /*
+ * For Japanese 86/106 keyboards
+ * See comment in drivers/char/pc_keyb.c.
+ * - Masahiro Adegawa
+ */
+ if (scancode == 0x73)
+ scancode = 0x59;
+ else if (scancode == 0x7d)
+ scancode = 0x7c;
+
+ if (!shift_lock && !shift_key && !ctrl_key) {
+ keychar = plain_map[scancode];
+ } else if ((shift_lock || shift_key) && key_maps[1]) {
+ keychar = key_maps[1][scancode];
+ } else if (ctrl_key && key_maps[4]) {
+ keychar = key_maps[4][scancode];
+ } else {
+ keychar = 0x0020;
+ kdb_printf("Unknown state/scancode (%d)\n", scancode);
+ }
+ keychar &= 0x0fff;
+ if (keychar == '\t')
+ keychar = ' ';
+ switch (KTYP(keychar)) {
+ case KT_LETTER:
+ case KT_LATIN:
+ if (isprint(keychar))
+ break; /* printable characters */
+ /* drop through */
+ case KT_SPEC:
+ if (keychar == K_ENTER)
+ break;
+ /* drop through */
+ default:
+ return -1; /* ignore unprintables */
+ }
+
+ if (scancode == 0x1c) {
+ kbd_last_ret = 1;
+ return 13;
+ }
+
+ return keychar & 0xff;
+}
+EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
+
+/*
+ * Best effort cleanup of ENTER break codes on leaving KDB. Called on
+ * exiting KDB, when we know we processed an ENTER or KP ENTER scan
+ * code.
+ */
+void kdb_kbd_cleanup_state(void)
+{
+ int scancode, scanstatus;
+
+ /*
+ * Nothing to clean up, since either
+ * ENTER was never pressed, or has already
+ * gotten cleaned up.
+ */
+ if (!kbd_last_ret)
+ return;
+
+ kbd_last_ret = 0;
+ /*
+ * Enter key. Need to absorb the break code here, lest it gets
+ * leaked out if we exit KDB as the result of processing 'g'.
+ *
+ * This has several interesting implications:
+ * + Need to handle KP ENTER, which has break code 0xe0 0x9c.
+ * + Need to handle repeat ENTER and repeat KP ENTER. Repeats
+ * only get a break code at the end of the repeated
+ * sequence. This means we can't propagate the repeated key
+ * press, and must swallow it away.
+ * + Need to handle possible PS/2 mouse input.
+ * + Need to handle mashed keys.
+ */
+
+ while (1) {
+ while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
+ cpu_relax();
+
+ /*
+ * Fetch the scancode.
+ */
+ scancode = inb(KBD_DATA_REG);
+ scanstatus = inb(KBD_STATUS_REG);
+
+ /*
+ * Skip mouse input.
+ */
+ if (scanstatus & KBD_STAT_MOUSE_OBF)
+ continue;
+
+ /*
+ * If we see 0xe0, this is either a break code for KP
+ * ENTER, or a repeat make for KP ENTER. Either way,
+ * since the second byte is equivalent to an ENTER,
+ * skip the 0xe0 and try again.
+ *
+ * If we see 0x1c, this must be a repeat ENTER or KP
+ * ENTER (and we swallowed 0xe0 before). Try again.
+ *
+ * We can also see make and break codes for other keys
+ * mashed before or after pressing ENTER. Thus, if we
+ * see anything other than 0x9c, we have to try again.
+ *
+ * Note, if you held some key as ENTER was depressed,
+ * that break code would get leaked out.
+ */
+ if (scancode != 0x9c)
+ continue;
+
+ return;
+ }
+}