i386: improve the immediate console

Improve the immediate console to the point that it can be enabled and
display e.g. assertion failures from very early on (i.e. from
`c_boot_entry').

* device/cons.h (romgetc, romputc): New declarations.
* i386/configfrag.ac: Add configuration variable.
* i386/i386at/conf.c (dev_name_list): Add entry.
* i386/i386at/cons_conf.c (constab): Add entry.
* i386/i386at/immc.c: Add missing includes.
(immc_cnprobe, immc_cninit, immc_cngetc, immc_romputc): New functions.
(immc_cnputc): Fix signature, use virtual addresses.
* i386/i386at/immc.h: New file.
* i386/i386at/kd.c: Use `#if ENABLE_IMMEDIATE_CONSOLE'.
* i386/i386at/kd.h (kd_setpos): Add missing declaration.
* i386/i386at/model_dep.c (c_boot_entry): Install immediate console as
early boot console.

9 files changed, 130 insertions, 14 deletions

diff --git a/device/cons.h b/device/cons.h
index 8ac796cd..34f3bc56 100644
--- a/device/cons.h
+++ b/device/cons.h
@@ -54,4 +54,15 @@ extern int cngetc(void);
 extern int cnmaygetc(void);
 
 extern void cnputc(char);
+
+/*
+ * ROM getc/putc primitives.
+ * On some architectures, the boot ROM provides basic character input/output
+ * routines that can be used before devices are configured or virtual memory
+ * is enabled.  This can be useful to debug (or catch panics from) code early
+ * in the bootstrap procedure.
+ */
+extern int	(*romgetc)(char c);
+extern void	(*romputc)(char c);
+
 #endif /* _DEVICE_CONS_H */
diff --git a/i386/configfrag.ac b/i386/configfrag.ac
index 1eaabcad..48744b12 100644
--- a/i386/configfrag.ac
+++ b/i386/configfrag.ac
@@ -73,6 +73,10 @@ AC_DEFINE_UNQUOTED([NLPR], [$nlpr], [NLPR])
 # Options.
 #
 
+# The immediate console, useful for debugging early system
+# initialization.  Disabled by default.
+AC_DEFINE([ENABLE_IMMEDIATE_CONSOLE], [0], [ENABLE_IMMEDIATE_CONSOLE])
+
 AC_ARG_ENABLE([lpr],
   AS_HELP_STRING([--enable-lpr], [lpr device; on ix86-at enabled by default]))
 [case $host_platform:$host_cpu in
diff --git a/i386/i386at/conf.c b/i386/i386at/conf.c
index ab4f6807..fe7c7c09 100644
--- a/i386/i386at/conf.c
+++ b/i386/i386at/conf.c
@@ -87,6 +87,12 @@ struct dev_ops	dev_name_list[] =
 	  nodev },
 
 #ifndef	MACH_HYP
+#if	ENABLE_IMMEDIATE_CONSOLE
+	{ "immc",	nulldev_open,	nulldev_close,	nulldev_read,
+	  nulldev_write,	nulldev_getstat,	nulldev_setstat,
+	  nomap,	nodev,	nulldev,	nulldev_portdeath,	0,
+	  nodev },
+#endif	/* ENABLE_IMMEDIATE_CONSOLE */
 	{ kdname,	kdopen,		kdclose,	kdread,
 	  kdwrite,	kdgetstat,	kdsetstat,	kdmmap,
 	  nodev,	nulldev,	kdportdeath,	0,
diff --git a/i386/i386at/cons_conf.c b/i386/i386at/cons_conf.c
index cf42bb63..1d7dd387 100644
--- a/i386/i386at/cons_conf.c
+++ b/i386/i386at/cons_conf.c
@@ -39,6 +39,10 @@
 #endif
 #endif	/* MACH_HYP */
 
+#if	ENABLE_IMMEDIATE_CONSOLE
+#include "immc.h"
+#endif	/* ENABLE_IMMEDIATE_CONSOLE */
+
 /*
  * The rest of the consdev fields are filled in by the respective
  * cnprobe routine.
@@ -47,6 +51,9 @@ struct	consdev constab[] = {
 #ifdef	MACH_HYP
 	{"hyp",	hypcnprobe,	hypcninit,	hypcngetc,	hypcnputc},
 #else	/* MACH_HYP */
+#if	ENABLE_IMMEDIATE_CONSOLE
+	{"immc", immc_cnprobe,	immc_cninit,	immc_cngetc,	immc_cnputc},
+#endif	/* ENABLE_IMMEDIATE_CONSOLE */
 	{"kd",	kdcnprobe,	kdcninit,	kdcngetc,	kdcnputc},
 #if NCOM > 0
 	{"com",	comcnprobe,	comcninit,	comcngetc,	comcnputc},
diff --git a/i386/i386at/immc.c b/i386/i386at/immc.c
index e0837f2c..ea951690 100644
--- a/i386/i386at/immc.c
+++ b/i386/i386at/immc.c
@@ -21,8 +21,11 @@
  *      Author: Bryan Ford, University of Utah CSL
  */
 
-#ifdef ENABLE_IMMEDIATE_CONSOLE
+#if	ENABLE_IMMEDIATE_CONSOLE
 
+#include <device/cons.h>
+#include <mach/boolean.h>
+#include <i386/vm_param.h>
 #include <string.h>
 
 /* This is a special "feature" (read: kludge)
@@ -35,22 +38,65 @@
 
 boolean_t immediate_console_enable = TRUE;
 
-void
-immc_cnputc(unsigned char c)
+/*
+ * XXX we assume that pcs *always* have a console
+ */
+int
+immc_cnprobe(struct consdev *cp)
+{
+	int maj, unit, pri;
+
+	maj = 0;
+	unit = 0;
+	pri = CN_INTERNAL;
+
+	cp->cn_dev = makedev(maj, unit);
+	cp->cn_pri = pri;
+	return 0;
+}
+
+int
+immc_cninit(struct consdev *cp)
+{
+	return 0;
+}
+
+int immc_cnmaygetc(void)
+{
+	return -1;
+}
+
+int
+immc_cngetc(dev_t dev, int wait)
+{
+	if (wait) {
+		int c;
+		while ((c = immc_cnmaygetc()) < 0)
+			continue;
+		return c;
+	}
+	else
+		return immc_cnmaygetc();
+}
+
+int
+immc_cnputc(dev_t dev, int c)
 {
 	static int ofs = -1;
 
 	if (!immediate_console_enable)
-		return;
+		return -1;
 	if (ofs < 0)
 	{
 		ofs = 0;
-		immc_cnputc('\n');
+		immc_cnputc(dev, '\n');
 	}
-	else if (c == '\n')
+
+	if (c == '\n')
 	{
-		memmove((void *)0xb8000, (void *)0xb8000+80*2, 80*2*24);
-		memset((void *)(0xb8000+80*2*24), 0, 80*2);
+		memmove((void *) phystokv(0xb8000),
+			(void *) phystokv(0xb8000+80*2), 80*2*24);
+		memset((void *) phystokv((0xb8000+80*2*24)), 0, 80*2);
 		ofs = 0;
 	}
 	else
@@ -59,20 +105,22 @@ immc_cnputc(unsigned char c)
 
 		if (ofs >= 80)
 		{
-			immc_cnputc('\r');
-			immc_cnputc('\n');
+			immc_cnputc(dev, '\r');
+			immc_cnputc(dev, '\n');
 		}
 
-		p = (void*)0xb8000 + 80*2*24 + ofs*2;
+		p = (void *) phystokv(0xb8000 + 80*2*24 + ofs*2);
 		p[0] = c;
 		p[1] = 0x0f;
 		ofs++;
 	}
+	return 0;
 }
 
-int immc_cnmaygetc(void)
+void
+immc_romputc(char c)
 {
-	return -1;
+	immc_cnputc (0, c);
 }
 
 #endif /* ENABLE_IMMEDIATE_CONSOLE */
diff --git a/i386/i386at/immc.h b/i386/i386at/immc.h
new file mode 100644
index 00000000..dc802c84
--- /dev/null
+++ b/i386/i386at/immc.h
@@ -0,0 +1,31 @@
+/* Declarations for the immediate console.
+
+   Copyright (C) 2015 Free Software Foundation, Inc.
+
+   This file is part of the GNU Mach.
+
+   The GNU Mach is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Mach is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the GNU Mach.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef	_IMMC_H_
+#define	_IMMC_H_
+
+#include <sys/types.h>
+
+int immc_cnprobe(struct consdev *cp);
+int immc_cninit(struct consdev *cp);
+int immc_cngetc(dev_t dev, int wait);
+int immc_cnputc(dev_t dev, int c);
+void immc_romputc(char c);
+
+#endif	/* _IMMC_H_ */
diff --git a/i386/i386at/kd.c b/i386/i386at/kd.c
index bbb00239..5656e830 100644
--- a/i386/i386at/kd.c
+++ b/i386/i386at/kd.c
@@ -1162,7 +1162,7 @@ kdinit(void)
 	kd_senddata(k_comm);
 	kd_initialized = TRUE;
 
-#ifdef ENABLE_IMMEDIATE_CONSOLE
+#if	ENABLE_IMMEDIATE_CONSOLE
 	/* Now that we're set up, we no longer need or want the
            immediate console.  */
 	{
diff --git a/i386/i386at/kd.h b/i386/i386at/kd.h
index 4ac93c7b..0cfed695 100644
--- a/i386/i386at/kd.h
+++ b/i386/i386at/kd.h
@@ -740,6 +740,7 @@ extern int kdcninit(struct consdev *cp);
 extern int kdcngetc(dev_t dev, int wait);
 extern int kdcnmaygetc (void);
 extern int kdcnputc(dev_t dev, int c);
+extern void kd_setpos(csrpos_t newpos);
 
 extern void kd_slmwd (void *start, int count, int value);
 extern void kd_slmscu (void *from, void *to, int count);
diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
index 03a9f15d..fdf983b9 100644
--- a/i386/i386at/model_dep.c
+++ b/i386/i386at/model_dep.c
@@ -77,6 +77,10 @@
 #include <xen/xen.h>
 #endif	/* MACH_XEN */
 
+#if	ENABLE_IMMEDIATE_CONSOLE
+#include "immc.h"
+#endif	/* ENABLE_IMMEDIATE_CONSOLE */
+
 /* Location of the kernel's symbol table.
    Both of these are 0 if none is available.  */
 #if MACH_KDB
@@ -541,6 +545,10 @@ i386at_init(void)
  */
 void c_boot_entry(vm_offset_t bi)
 {
+#if	ENABLE_IMMEDIATE_CONSOLE
+	romputc = immc_romputc;
+#endif	/* ENABLE_IMMEDIATE_CONSOLE */
+
 	/* Stash the boot_image_info pointer.  */
 	boot_info = *(typeof(boot_info)*)phystokv(bi);
 	int cpu_type;