libpayload: The initial chunk of code writen by AMD

This is the initial chunk of code written by me and copyrighted
by AMD.  Includes everything but a few files that we pulled from
outside sources.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3170 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

7 files changed, 542 insertions, 0 deletions

diff --git a/payloads/libpayload/i386/Makefile.inc b/payloads/libpayload/i386/Makefile.inc
new file mode 100644
index 0000000000..75b0749973
--- /dev/null
+++ b/payloads/libpayload/i386/Makefile.inc
@@ -0,0 +1,31 @@
+#
+# This file is part of the libpayload project.
+#
+# Copyright (C) 2008 Advanced Micro Devices, Inc.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+
+TARGETS-y += i386/head.o i386/main.o i386/sysinfo.o
+TARGETS-y += i386/timer.o i386/coreboot.o i386/util.o
diff --git a/payloads/libpayload/i386/coreboot.c b/payloads/libpayload/i386/coreboot.c
new file mode 100644
index 0000000000..6d310d0325
--- /dev/null
+++ b/payloads/libpayload/i386/coreboot.c
@@ -0,0 +1,147 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <libpayload.h>
+#include <sysinfo.h>
+#include <ipchecksum.h>
+#include <coreboot_tables.h>
+
+/* Some of this is x86 specific, and the rest of it
+   is generic.  Right now, since we only support x86,
+   we'll avoid trying to make lots of infrastructure
+   we don't need.  If in the future, we want to use
+   coreboot on some other architecture, then take out
+   the generic parsing code and move it elsewhere
+*/
+
+/* === Parsing code === */
+/* This is the generic parsing code */
+
+static void cb_parse_memory(unsigned char *ptr, struct sysinfo_t *info)
+{
+	struct cb_memory *mem = (struct cb_memory *) ptr;
+	int count = MEM_RANGE_COUNT(mem);
+	int i;
+
+	if (count > SYSINFO_MAX_MEM_RANGES)
+		count = SYSINFO_MAX_MEM_RANGES;
+
+	info->n_memranges = 0;
+
+	for(i = 0; i < count; i++) {
+		struct cb_memory_range *range = 
+			(struct cb_memory_range *) MEM_RANGE_PTR(mem, i);
+		
+		if (range->type != CB_MEM_RAM)
+			continue;
+
+		info->memrange[info->n_memranges].base =
+			UNPACK_CB64(range->start);
+
+		info->memrange[info->n_memranges].size =
+			UNPACK_CB64(range->size);
+
+		info->n_memranges++;
+	}
+}
+
+static void cb_parse_serial(unsigned char *ptr, struct sysinfo_t *info)
+{
+	struct cb_serial *ser = (struct cb_serial *) ptr;
+	info->ser_ioport = ser->ioport;
+}
+
+static int cb_parse_header(void *addr, int len, struct sysinfo_t *info)
+{
+	struct cb_header *header;
+	unsigned char *ptr = (unsigned char *) addr;
+	int i;
+
+	for (i = 0; i < len; i += 16, ptr += 16) {
+		header = (struct cb_header *) ptr;
+
+		if (!strncmp(header->signature, "LBIO", 4))
+			break;
+	}
+	
+	/* We walked the entire space and didn't find anything */
+
+	if (i >= len)
+		return -1;
+
+	if (!header->table_bytes)
+		return 0;
+
+	/* Make sure the checksums match */
+
+	if (ipchksum((uint16_t *) header, sizeof(*header)) != 0)
+		return -1;
+
+	if (ipchksum((uint16_t *) (ptr + sizeof(*header)),
+		header->table_bytes) != header->table_checksum)
+		return -1;
+
+	/* Now, walk the tables */
+	ptr += header->header_bytes;
+    
+	for(i = 0; i < header->table_entries; i++) {
+		struct cb_record *rec = (struct cb_record *) ptr;
+
+		/* We only care about a few tags here - maybe
+		   more will be interesting later 
+		*/
+
+ 		switch(rec->tag) {
+		case CB_TAG_MEMORY:
+			cb_parse_memory(ptr, info);
+			break;
+			
+		case CB_TAG_SERIAL:
+			cb_parse_serial(ptr, info);
+			break;
+		}
+
+		ptr += rec->size;
+	}
+	
+	return 1;
+}
+
+/* == Architecture specific ==*/
+/* This is the x86 specific stuff */
+
+int get_coreboot_info(struct sysinfo_t *info)
+{
+	int ret = cb_parse_header((void *) 0x0, 0x1000, info);
+
+	if (ret != 1)
+		ret = cb_parse_header((void *) 0xf0000, 0x1000, info);
+
+	return (ret == 1) ? 0 : -1;
+}
diff --git a/payloads/libpayload/i386/head.S b/payloads/libpayload/i386/head.S
new file mode 100644
index 0000000000..1278bdf4ed
--- /dev/null
+++ b/payloads/libpayload/i386/head.S
@@ -0,0 +1,85 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+	
+	.global _entry, _leave
+	.text
+	.align 4
+
+/* Our entry point - assume that the CPU is in
+ *  32 bit protected mode and all segments are in a
+ *  flat model.  Thats our operating mode, so we won't
+ *  change anything
+ */
+	
+_entry:
+	call _init
+
+	/* We're back - go back to the bootloader */
+	ret
+
+/* This function saves off the previous stack and
+   switches us to our own execution enviornment
+*/	
+
+_init:
+	/* No interrupts, please */
+	cli
+
+	/* Get the current stack pointer */
+	movl %esp, %esi
+
+	movl _istack, %ebx
+
+	/* lret needs %cs in the stack, so copy it over */
+	movw %cs, 4(%ebx)
+
+	/* Exchange the current stack pointer for the one in
+	   the initial stack (which happens to be the new
+	   stack pointer) */
+
+	xchgl %esi, 16(%ebx)
+
+	/* Set the new stack pointer */
+	movl %esi, %esp
+
+	/* Return into the main entry function
+	   and go
+	 */
+
+	lret
+
+_leave:
+	movl _istack, %ebx
+
+	/* Restore the stack pointer from the storage area */
+	movl 16(%ebx), %esp
+
+	/* Return to the original context */
+	lret
+
diff --git a/payloads/libpayload/i386/main.c b/payloads/libpayload/i386/main.c
new file mode 100644
index 0000000000..846d46a426
--- /dev/null
+++ b/payloads/libpayload/i386/main.c
@@ -0,0 +1,79 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <arch/types.h>
+
+/* This structure seeds the stack.  We provide
+   the return address of our main function, and
+   further down, the address of the function 
+   that we call when we leave and try to restore
+   the original stack.  At the very bottom of the
+   stack we store the orignal stack pointer
+   from the calling application
+*/
+
+static void start_main(void);
+extern void _leave(void);
+
+static struct {
+	uint32_t eip[2];
+	uint32_t raddr[2];
+	uint32_t esp;
+} initial_stack __attribute__((section (".istack"))) = {
+	{ (uint32_t) start_main, 0 },
+	{ (uint32_t) _leave, 0 },
+	(uint32_t) &initial_stack,
+};
+
+void * _istack = &initial_stack;
+
+/* This is our C entry function - set up the system
+   and jump into the payload entry point */
+
+static void start_main(void)
+{
+	extern int main(void);
+
+	/* Set up the consoles */
+	console_init();
+
+	/* Gather system information */
+	lib_get_sysinfo();
+
+	/* Any other system init that has to happen before the
+	   user gets control goes here. */
+
+	/* Go to the entry point */
+
+	/* in the future we may care about the return value */
+	(void) main();
+
+	/* Returning here will go to the _leave function to return
+	   us to the original context */
+}
diff --git a/payloads/libpayload/i386/sysinfo.c b/payloads/libpayload/i386/sysinfo.c
new file mode 100644
index 0000000000..1fdf3fc419
--- /dev/null
+++ b/payloads/libpayload/i386/sysinfo.c
@@ -0,0 +1,70 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <libpayload.h>
+#include <sysinfo.h>
+
+/* This is a global structure that is used through the
+   library - we set it up initially with some dummy
+   values - hopefully they will be overridden 
+*/
+
+struct sysinfo_t lib_sysinfo = {
+	. cpu_khz = 200,
+	. ser_ioport = CONFIG_SERIAL_IOBASE,
+};
+       
+void lib_get_sysinfo(void)
+{
+	/* Get the CPU speed (for delays) */
+	lib_sysinfo.cpu_khz = get_cpu_speed();
+	
+	/* Get the memory information */
+
+	get_coreboot_info(&lib_sysinfo);
+
+	if (!lib_sysinfo.n_memranges) {
+		
+		/* If we couldn't get a good memory range,
+		   then use a hard coded default */
+	
+		lib_sysinfo.n_memranges = 2;
+
+		lib_sysinfo.memrange[0].base = 0;
+		lib_sysinfo.memrange[0].size = 640 * 1024;
+		lib_sysinfo.memrange[1].base = 1024 * 1024;
+		lib_sysinfo.memrange[1].size = 31 * 1024 * 1024;
+	}
+}
+
+	
+
+
+
+	
diff --git a/payloads/libpayload/i386/timer.c b/payloads/libpayload/i386/timer.c
new file mode 100644
index 0000000000..72a3ee8f48
--- /dev/null
+++ b/payloads/libpayload/i386/timer.c
@@ -0,0 +1,92 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <libpayload.h>
+#include <arch/rdtsc.h>
+
+static unsigned int cpu_khz;
+
+/* Calculate the speed of the processor for use in delays */
+
+void get_cpu_speed(void)
+{
+	unsigned long long start, end;
+
+	/* Set up the PPC port - disable the speaker, 
+	 * enable the T2 gate */
+	
+	outb((inb(0x61) & ~0x02) | 0x01, 0x61);
+
+	/* Set the PIT to Mode 0, counter 2, word access */
+	outb(0xB0, 0x43);
+
+	/* Load the counter with 0xFFFF */
+	
+	outb(0xFF, 0x42);
+	outb(0xFF, 0x42);
+
+	/* Read the number of ticks during the period */
+
+	start = rdtsc();
+	while(!(inb(0x61) & 0x20));
+	end = rdtsc();
+
+	/* The clock rate is 1193180 Hz
+	* the number of miliseconds for a period
+	* of 0xFFFF is 1193180 / (0xFFFF * 1000)
+	* or .0182.  Multiply that by the number of 
+	* measured clocks to get the khz value 
+	*/
+
+	cpu_khz =
+		(unsigned int ) ((end - start) * 1193180U / (1000 * 0xFFFF));
+}
+
+/* Global delay functions */
+
+static inline void _delay(unsigned int delta)
+{
+	unsigned long long timeout = rdtsc() + delta;
+	while (rdtsc() < timeout);
+}
+
+void ndelay(unsigned int n)
+{
+ 	_delay(n * cpu_khz / 1000000);
+}
+
+void mdelay(unsigned int m)
+{
+	_delay(m * cpu_khz);
+}
+
+void delay(unsigned int s)
+{
+	_delay(s * cpu_khz * 1000);
+}
diff --git a/payloads/libpayload/i386/util.S b/payloads/libpayload/i386/util.S
new file mode 100644
index 0000000000..a0b1b0980d
--- /dev/null
+++ b/payloads/libpayload/i386/util.S
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+	.global halt	
+	.text
+	.align 4
+	
+/* This function puts the system into a halt.  */		
+
+halt:
+	cli
+	hlt
+	jmp halt