x86, setup: enable early console output from the decompressor

This enables the decompressor output to be seen on the serial console.
Most of the code is shared with the regular boot code.

We could add printf to the decompressor if needed, but currently there
is no sufficiently compelling user.

-v2: define BOOT_BOOT_H to avoid include boot.h
-v3: early_serial_base need to be static in misc.c ?
-v4: create seperate string.c printf.c cmdline.c early_serial_console.c
after hpa's patch that allow global variables in compressed/misc stage
-v5: remove printf.c related

Signed-off-by: Yinghai Lu <[e-mail]>
Signed-off-by: H. Peter Anvin <[e-mail]>

arch/x86/boot/compressed/Makefile

···
 # create a compressed vmlinux image from the original vmlinux
 #
 
-targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma vmlinux.bin.lzo head_$(BITS).o misc.o piggy.o
+targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma vmlinux.bin.lzo head_$(BITS).o misc.o string.o cmdline.o early_serial_console.o piggy.o
 
 KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
 KBUILD_CFLAGS += -fno-strict-aliasing -fPIC
···
 
 hostprogs-y	:= mkpiggy
 
-$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o $(obj)/piggy.o FORCE
+$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o $(obj)/string.o $(obj)/cmdline.o $(obj)/early_serial_console.o $(obj)/piggy.o FORCE
 	$(call if_changed,ld)
 	@:
 

arch/x86/boot/compressed/cmdline.c

···
+#include "misc.h"
+
+static unsigned long fs;
+static inline void set_fs(unsigned long seg)
+{
+	fs = seg << 4;  /* shift it back */
+}
+typedef unsigned long addr_t;
+static inline char rdfs8(addr_t addr)
+{
+	return *((char *)(fs + addr));
+}
+#include "../cmdline.c"
+int cmdline_find_option(const char *option, char *buffer, int bufsize)
+{
+	return __cmdline_find_option(real_mode->hdr.cmd_line_ptr, option, buffer, bufsize);
+}
+int cmdline_find_option_bool(const char *option)
+{
+	return __cmdline_find_option_bool(real_mode->hdr.cmd_line_ptr, option);
+}

arch/x86/boot/compressed/early_serial_console.c

···
+#include "misc.h"
+
+int early_serial_base;
+
+#include "../early_serial_console.c"

arch/x86/boot/compressed/misc.c

···
  * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
  */
 
-/*
- * we have to be careful, because no indirections are allowed here, and
- * paravirt_ops is a kind of one. As it will only run in baremetal anyway,
- * we just keep it from happening
- */
-#undef CONFIG_PARAVIRT
-#ifdef CONFIG_X86_32
-#define _ASM_X86_DESC_H 1
-#endif
-
-#include <linux/linkage.h>
-#include <linux/screen_info.h>
-#include <linux/elf.h>
-#include <linux/io.h>
-#include <asm/page.h>
-#include <asm/boot.h>
-#include <asm/bootparam.h>
+#include "misc.h"
 
 /* WARNING!!
  * This code is compiled with -fPIC and it is relocated dynamically
···
 /*
  * This is set up by the setup-routine at boot-time
  */
-static struct boot_params *real_mode;		/* Pointer to real-mode data */
+struct boot_params *real_mode;		/* Pointer to real-mode data */
 static int quiet;
+static int debug;
 
 void *memset(void *s, int c, size_t n);
 void *memcpy(void *dest, const void *src, size_t n);
-
-static void __putstr(int, const char *);
-#define putstr(__x)  __putstr(0, __x)
 
 #ifdef CONFIG_X86_64
 #define memptr long
···
 		vidmem[i] = ' ';
 }
 
-static void __putstr(int error, const char *s)
+#define XMTRDY          0x20
+
+#define TXR             0       /*  Transmit register (WRITE) */
+#define LSR             5       /*  Line Status               */
+static void serial_putchar(int ch)
+{
+	unsigned timeout = 0xffff;
+
+	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
+		cpu_relax();
+
+	outb(ch, early_serial_base + TXR);
+}
+
+void __putstr(int error, const char *s)
 {
 	int x, y, pos;
 	char c;
···
 	if (!error)
 		return;
 #endif
+	if (early_serial_base) {
+		const char *str = s;
+		while (*str) {
+			if (*str == '\n')
+				serial_putchar('\r');
+			serial_putchar(*str++);
+		}
+	}
 
 	if (real_mode->screen_info.orig_video_mode == 0 &&
 	    lines == 0 && cols == 0)
···
 {
 	real_mode = rmode;
 
-	if (real_mode->hdr.loadflags & QUIET_FLAG)
+	if (cmdline_find_option_bool("quiet"))
 		quiet = 1;
+	if (cmdline_find_option_bool("debug"))
+		debug = 1;
 
 	if (real_mode->screen_info.orig_video_mode == 7) {
 		vidmem = (char *) 0xb0000;
···
 
 	lines = real_mode->screen_info.orig_video_lines;
 	cols = real_mode->screen_info.orig_video_cols;
+
+	console_init();
+	if (debug)
+		putstr("early console in decompress_kernel\n");
 
 	free_mem_ptr     = heap;	/* Heap */
 	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;

arch/x86/boot/compressed/misc.h

···
+#ifndef BOOT_COMPRESSED_MISC_H
+#define BOOT_COMPRESSED_MISC_H
+
+/*
+ * we have to be careful, because no indirections are allowed here, and
+ * paravirt_ops is a kind of one. As it will only run in baremetal anyway,
+ * we just keep it from happening
+ */
+#undef CONFIG_PARAVIRT
+#ifdef CONFIG_X86_32
+#define _ASM_X86_DESC_H 1
+#endif
+
+#include <linux/linkage.h>
+#include <linux/screen_info.h>
+#include <linux/elf.h>
+#include <linux/io.h>
+#include <asm/page.h>
+#include <asm/boot.h>
+#include <asm/bootparam.h>
+
+#define BOOT_BOOT_H
+
+/* misc.c */
+extern struct boot_params *real_mode;		/* Pointer to real-mode data */
+void __putstr(int error, const char *s);
+#define putstr(__x)  __putstr(0, __x)
+#define puts(__x)  __putstr(0, __x)
+
+/* cmdline.c */
+int cmdline_find_option(const char *option, char *buffer, int bufsize);
+int cmdline_find_option_bool(const char *option);
+
+/* early_serial_console.c */
+extern int early_serial_base;
+void console_init(void);
+
+#endif

arch/x86/boot/compressed/string.c

···
+#include "misc.h"
+
+#include "../isdigit.h"
+#include "../string.c"

arch/x86/boot/main.c

···
 
 	/* Initialize the early-boot console */
 	console_init();
+	if (cmdline_find_option_bool("debug"))
+		puts("early console in setup code\n");
 
 	/* End of heap check */
 	init_heap();
···
 
 	/* Set the video mode */
 	set_video();
-
-	/* Parse command line for 'quiet' and pass it to decompressor. */
-	if (cmdline_find_option_bool("quiet"))
-		boot_params.hdr.loadflags |= QUIET_FLAG;
 
 	/* Do the last things and invoke protected mode */
 	go_to_protected_mode();