aboutsummaryrefslogtreecommitdiff
path: root/kernel/debug/kdb/kdb_keyboard.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/debug/kdb/kdb_keyboard.c')
-rw-r--r--kernel/debug/kdb/kdb_keyboard.c95
1 files changed, 73 insertions, 22 deletions
diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
index 4bca634975c..118527aa60e 100644
--- a/kernel/debug/kdb/kdb_keyboard.c
+++ b/kernel/debug/kdb/kdb_keyboard.c
@@ -25,6 +25,7 @@
#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.
@@ -90,8 +91,11 @@ int kdb_get_kbd_char(void)
return -1;
}
- if ((scancode & 0x80) != 0)
+ if ((scancode & 0x80) != 0) {
+ if (scancode == 0x9c)
+ kbd_last_ret = 0;
return -1;
+ }
scancode &= 0x7f;
@@ -178,35 +182,82 @@ int kdb_get_kbd_char(void)
return -1; /* ignore unprintables */
}
- if ((scancode & 0x7f) == 0x1c) {
- /*
- * enter key. All done. Absorb the release scancode.
- */
+ 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
+ * Fetch the scancode.
*/
scancode = inb(KBD_DATA_REG);
scanstatus = inb(KBD_STATUS_REG);
- while (scanstatus & KBD_STAT_MOUSE_OBF) {
- scancode = inb(KBD_DATA_REG);
- scanstatus = inb(KBD_STATUS_REG);
- }
+ /*
+ * Skip mouse input.
+ */
+ if (scanstatus & KBD_STAT_MOUSE_OBF)
+ continue;
- if (scancode != 0x9c) {
- /*
- * Wasn't an enter-release, why not?
- */
- kdb_printf("kdb: expected enter got 0x%x status 0x%x\n",
- scancode, scanstatus);
- }
+ /*
+ * 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 13;
+ return;
}
-
- return keychar & 0xff;
}
-EXPORT_SYMBOL_GPL(kdb_get_kbd_char);