[PATCH 31/33] x86_64 boot: Add serial output support to the decompressor

[Eric W. Biederman]

This patch does two very simple things.
It adds a serial output capability to the decompressor.
It adds a command line parser for the early_printk
option so we know which output method to use for the decompressor.

This makes debugging the decompressor a little easier, and
keeps us from assuming we always have a vga console on all
hardware.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
 arch/x86_64/boot/compressed/Makefile |    2 
 arch/x86_64/boot/compressed/misc.c   |  262 ++++++++++++++++++++++++++++++++--
 2 files changed, 248 insertions(+), 16 deletions(-)

diff --git a/arch/x86_64/boot/compressed/Makefile b/arch/x86_64/boot/compressed/Makefile
index f89d96f..8987c97 100644
--- a/arch/x86_64/boot/compressed/Makefile
+++ b/arch/x86_64/boot/compressed/Makefile
@@ -11,7 +11,7 @@ EXTRA_AFLAGS	:= -traditional -m32
 
 # cannot use EXTRA_CFLAGS because base CFLAGS contains -mkernel which conflicts with
 # -m32
-CFLAGS := -m32 -D__KERNEL__ -Iinclude -O2  -fno-strict-aliasing
+CFLAGS := -m32 -D__KERNEL__ -Iinclude -O2  -fno-strict-aliasing -fno-builtin
 LDFLAGS := -m elf_i386
 
 LDFLAGS_vmlinux := -Ttext $(IMAGE_OFFSET) -e startup_32 -m elf_i386
diff --git a/arch/x86_64/boot/compressed/misc.c b/arch/x86_64/boot/compressed/misc.c
index 259bb05..2cbd7cb 100644
--- a/arch/x86_64/boot/compressed/misc.c
+++ b/arch/x86_64/boot/compressed/misc.c
@@ -10,8 +10,10 @@
  */
 
 #include <linux/screen_info.h>
+#include <linux/serial_reg.h>
 #include <asm/io.h>
 #include <asm/page.h>
+#include <asm/setup.h>
 
 /*
  * gzip declarations
@@ -76,12 +78,17 @@ static void gzip_release(void **);
  * This is set up by the setup-routine at boot-time
  */
 static unsigned char *real_mode; /* Pointer to real-mode data */
+static char saved_command_line[COMMAND_LINE_SIZE];
 
 #define RM_EXT_MEM_K   (*(unsigned short *)(real_mode + 0x2))
 #ifndef STANDARD_MEMORY_BIOS_CALL
 #define RM_ALT_MEM_K   (*(unsigned long *)(real_mode + 0x1e0))
 #endif
 #define RM_SCREEN_INFO (*(struct screen_info *)(real_mode+0))
+#define RM_NEW_CL_POINTER ((char *)(unsigned long)(*(unsigned *)(real_mode+0x228)))
+#define RM_OLD_CL_MAGIC (*(unsigned short *)(real_mode + 0x20))
+#define RM_OLD_CL_OFFSET (*(unsigned short *)(real_mode + 0x22))
+#define OLD_CL_MAGIC 0xA33F
 
 extern unsigned char input_data[];
 extern int input_len;
@@ -95,8 +102,12 @@ static void free(void *where);
 
 static void *memset(void *s, int c, unsigned n);
 static void *memcpy(void *dest, const void *src, unsigned n);
+static int memcmp(const void *s1, const void *s2, unsigned n);
+static size_t strlen(const char *str);
+static char *strstr(const char *haystack, const char *needle);
 
 static void putstr(const char *);
+static unsigned simple_strtou(const char *cp, char **endp, unsigned base);
 
 extern int end;
 static long free_mem_ptr = (long)&end;
@@ -110,10 +121,21 @@ static unsigned int low_buffer_end, low_
 static int high_loaded =0;
 static uch *high_buffer_start /* = (uch *)(((ulg)&end) + HEAP_SIZE)*/;
 
-static char *vidmem = (char *)0xb8000;
+static char *vidmem;
 static int vidport;
 static int lines, cols;
 
+/* The early serial console */
+
+#define DEFAULT_BAUD 9600
+#define DEFAULT_BASE 0x3f8 /* ttyS0 */
+static unsigned serial_base = DEFAULT_BASE;
+
+#define CONSOLE_NOOP   0
+#define CONSOLE_VID    1
+#define CONSOLE_SERIAL 2
+static int console = CONSOLE_NOOP;
+
 #include "../../../../lib/inflate.c"
 
 static void *malloc(int size)
@@ -148,7 +170,8 @@ static void gzip_release(void **ptr)
 	free_mem_ptr = (long) *ptr;
 }
  
-static void scroll(void)
+/* The early video console */
+static void vid_scroll(void)
 {
 	int i;
 
@@ -157,7 +180,7 @@ static void scroll(void)
 		vidmem[i] = ' ';
 }
 
-static void putstr(const char *s)
+static void vid_putstr(const char *s)
 {
 	int x,y,pos;
 	char c;
@@ -169,7 +192,7 @@ static void putstr(const char *s)
 		if ( c == '\n' ) {
 			x = 0;
 			if ( ++y >= lines ) {
-				scroll();
+				vid_scroll();
 				y--;
 			}
 		} else {
@@ -177,7 +200,7 @@ static void putstr(const char *s)
 			if ( ++x >= cols ) {
 				x = 0;
 				if ( ++y >= lines ) {
-					scroll();
+					vid_scroll();
 					y--;
 				}
 			}
@@ -194,6 +217,178 @@ static void putstr(const char *s)
 	outb_p(0xff & (pos >> 1), vidport+1);
 }
 
+static void vid_console_init(void)
+{
+	if (RM_SCREEN_INFO.orig_video_mode == 7) {
+		vidmem = (char *) 0xb0000;
+		vidport = 0x3b4;
+	} else {
+		vidmem = (char *) 0xb8000;
+		vidport = 0x3d4;
+	}
+
+	lines = RM_SCREEN_INFO.orig_video_lines;
+	cols = RM_SCREEN_INFO.orig_video_cols;
+}
+
+/* The early serial console */
+static void serial_putc(int ch)
+{
+	if (ch == '\n') {
+		serial_putc('\r');
+	}
+	/* Wait until I can send a byte */
+	while ((inb(serial_base + UART_LSR) & UART_LSR_THRE) == 0)
+		;
+
+	/* Send the byte */
+	outb(ch, serial_base + UART_TX);
+
+	/* Wait until the byte is transmitted */
+	while (!(inb(serial_base + UART_LSR) & UART_LSR_TEMT))
+		;
+}
+
+static void serial_putstr(const char *str)
+{
+	int ch;
+	while((ch = *str++) != '\0') {
+		if (ch == '\n') {
+			serial_putc('\r');
+		}
+		serial_putc(ch);
+	}
+}
+
+static void serial_console_init(char *s)
+{
+	unsigned base = DEFAULT_BASE;
+	unsigned baud = DEFAULT_BAUD;
+	unsigned divisor;
+	char *e;
+
+	if (*s == ',')
+		++s;
+	if (*s && (*s != ' ')) {
+		if (memcmp(s, "0x", 2) == 0) {
+			base = simple_strtou(s, &e, 16);
+		} else {
+			static const unsigned bases[] = { 0x3f8, 0x2f8 };
+			unsigned port;
+
+			if (memcmp(s, "ttyS", 4) == 0)
+				s += 4;
+			port = simple_strtou(s, &e, 10);
+			if ((port > 1) || (s == e))
+				port = 0;
+			base = bases[port];
+		}
+		s = e;
+		if (*s == ',')
+			++s;
+	}
+	if (*s && (*s != ' ')) {
+		baud = simple_strtou(s, &e, 0);
+		if ((baud == 0) || (s == e))
+			baud = DEFAULT_BAUD;
+	}
+	divisor = 115200 / baud;
+	serial_base = base;
+
+	outb(0x00, serial_base + UART_IER); /* no interrupt */
+	outb(0x00, serial_base + UART_FCR); /* no fifo */
+	outb(0x03, serial_base + UART_MCR); /* DTR + RTS */
+
+	/* Set Baud Rate divisor  */
+	outb(0x83, serial_base + UART_LCR);
+	outb(divisor & 0xff, serial_base + UART_DLL);
+	outb(divisor >> 8, serial_base + UART_DLM);
+	outb(0x03, serial_base + UART_LCR); /* 8n1 */
+
+}
+
+static void putstr(const char *str)
+{
+	if (console == CONSOLE_VID) {
+		vid_putstr(str);
+	} else if (console == CONSOLE_SERIAL) {
+		serial_putstr(str);
+	}
+}
+
+static void console_init(char *cmdline)
+{
+	cmdline = strstr(cmdline, "earlyprintk=");
+	if (!cmdline)
+		return;
+	cmdline += 12;
+	if (memcmp(cmdline, "vga", 3) == 0) {
+		vid_console_init();
+		console = CONSOLE_VID;
+	} else if (memcmp(cmdline, "serial", 6) == 0) {
+		serial_console_init(cmdline + 6);
+		console = CONSOLE_SERIAL;
+	} else if (memcmp(cmdline, "ttyS", 4) == 0) {
+		serial_console_init(cmdline);
+		console = CONSOLE_SERIAL;
+	}
+}
+
+static inline int tolower(int ch)
+{
+	return ch | 0x20;
+}
+
+static inline int isdigit(int ch)
+{
+	return (ch >= '0') && (ch <= '9');
+}
+
+static inline int isxdigit(int ch)
+{
+	ch = tolower(ch);
+	return isdigit(ch) || ((ch >= 'a') && (ch <= 'f'));
+}
+
+
+static inline int digval(int ch)
+{
+	return isdigit(ch)? (ch - '0') : tolower(ch) - 'a' + 10;
+}
+
+/**
+ * simple_strtou - convert a string to an unsigned
+ * @cp: The start of the string
+ * @endp: A pointer to the end of the parsed string will be placed here
+ * @base: The number base to use
+ */
+static unsigned simple_strtou(const char *cp, char **endp, unsigned base)
+{
+	unsigned result = 0,value;
+
+	if (!base) {
+		base = 10;
+		if (*cp == '0') {
+			base = 8;
+			cp++;
+			if ((tolower(*cp) == 'x') && isxdigit(cp[1])) {
+				cp++;
+				base = 16;
+			}
+		}
+	} else if (base == 16) {
+		if (cp[0] == '0' && tolower(cp[1]) == 'x')
+			cp += 2;
+	}
+	while (isxdigit(*cp) && ((value = digval(*cp)) < base)) {
+		result = result*base + value;
+		cp++;
+	}
+	if (endp)
+		*endp = (char *)cp;
+	return result;
+}
+
 static void* memset(void* s, int c, unsigned n)
 {
 	int i;
@@ -212,6 +407,37 @@ static void* memcpy(void* dest, const vo
 	return dest;
 }
 
+static int memcmp(const void *s1, const void *s2, unsigned n)
+{
+	const unsigned char *str1 = s1, *str2 = s2;
+	size_t i;
+	int result = 0;
+	for(i = 0; (result == 0) && (i < n); i++) {
+		result = *str1++ - *str2++;
+		}
+	return result;
+}
+
+static size_t strlen(const char *str)
+{
+	size_t len = 0;
+	while (*str++)
+		len++;
+	return len;
+}
+
+static char *strstr(const char *haystack, const char *needle)
+{
+	size_t len;
+	len = strlen(needle);
+	while(*haystack) {
+		if (memcmp(haystack, needle, len) == 0)
+			return (char *)haystack;
+		haystack++;
+	}
+	return NULL;
+}
+
 /* ===========================================================================
  * Fill the input buffer. This is called only when the buffer is empty
  * and at least one byte is really needed.
@@ -331,20 +557,26 @@ static void close_output_buffer_if_we_ru
 	}
 }
 
+static void save_command_line(void)
+{
+	/* Find the command line */
+	char *cmdline;
+	cmdline = saved_command_line;
+	if (RM_NEW_CL_POINTER) {
+		cmdline = RM_NEW_CL_POINTER;
+	} else if (OLD_CL_MAGIC == RM_OLD_CL_MAGIC) {
+		cmdline = real_mode + RM_OLD_CL_OFFSET;
+	}
+	memcpy(saved_command_line, cmdline, COMMAND_LINE_SIZE);
+	saved_command_line[COMMAND_LINE_SIZE - 1] = '\0';
+}
+
 int decompress_kernel(struct moveparams *mv, void *rmode)
 {
 	real_mode = rmode;
 
-	if (RM_SCREEN_INFO.orig_video_mode == 7) {
-		vidmem = (char *) 0xb0000;
-		vidport = 0x3b4;
-	} else {
-		vidmem = (char *) 0xb8000;
-		vidport = 0x3d4;
-	}
-
-	lines = RM_SCREEN_INFO.orig_video_lines;
-	cols = RM_SCREEN_INFO.orig_video_cols;
+	save_command_line();
+	console_init(saved_command_line);
 
 	if (free_mem_ptr < 0x100000) setup_normal_output_buffer();
 	else setup_output_buffer_if_we_run_high(mv);
-- 
1.4.2.rc2.g5209e

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