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 <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 33 insertions, 23 deletions

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 51e240779a44..8f7bef8e9fff 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -9,23 +9,7 @@
  * 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
@@ -123,15 +107,13 @@ static void error(char *m);
 /*
  * 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
 #else
@@ -170,7 +152,21 @@ static void scroll(void)
                 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;
@@ -179,6 +175,14 @@ static void __putstr(int error, const char *s)
         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)
@@ -305,8 +309,10 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
 {
         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;
@@ -319,6 +325,10 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
         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;