x86: Honor 'quiet' command line option in real mode boot decompressor.

This patch lets the early real mode code look for the 'quiet' option
on the kernel command line and pass a loadflag to the decompressor.
When this flag is set, we suppress the "Decompressing Linux... Parsing
ELF... done." messages.
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/boot/compressed/misc.c

@@ -189,6 +189,7 @@ static void gzip_release(void **);
  * This is set up by the setup-routine at boot-time
  */
 static struct boot_params *real_mode;		/* Pointer to real-mode data */
+static int quiet;
 
 extern unsigned char input_data[];
 extern int input_len;
@@ -391,6 +392,7 @@ static void parse_elf(void *output)
 		return;
 	}
 
+	if (!quiet)
 		putstr("Parsing ELF... ");
 
 	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
@@ -426,6 +428,9 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
 {
 	real_mode = rmode;
 
+	if (real_mode->hdr.loadflags & QUIET_FLAG)
+		quiet = 1;
+
 	if (real_mode->screen_info.orig_video_mode == 7) {
 		vidmem = (char *) 0xb0000;
 		vidport = 0x3b4;
@@ -461,9 +466,11 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
 #endif
 
 	makecrc();
+	if (!quiet)
 		putstr("\nDecompressing Linux... ");
 	gunzip();
 	parse_elf(output);
+	if (!quiet)
 		putstr("done.\nBooting the kernel.\n");
 	return;
 }

arch/x86/boot/main.c

@@ -165,6 +165,10 @@ void main(void)
 	/* 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();
 }

include/asm-x86/bootparam.h

@@ -40,6 +40,7 @@ struct setup_header {
 	__u8	type_of_loader;
 	__u8	loadflags;
 #define LOADED_HIGH	(1<<0)
+#define QUIET_FLAG	(1<<5)
 #define KEEP_SEGMENTS	(1<<6)
 #define CAN_USE_HEAP	(1<<7)
 	__u16	setup_move_size;