9 files changed, 558 insertions, 3 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index fd7620f025fa..f6f3b990d837 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -22,6 +22,7 @@ choice
 
 config MACH_ALCHEMY
         bool "Alchemy processor based machines"
+        select SYS_SUPPORTS_ZBOOT
 
 config AR7
         bool "Texas Instruments AR7"
@@ -36,6 +37,7 @@ config AR7
         select SYS_HAS_EARLY_PRINTK
         select SYS_SUPPORTS_32BIT_KERNEL
         select SYS_SUPPORTS_LITTLE_ENDIAN
+        select SYS_SUPPORTS_ZBOOT_UART16550
         select GENERIC_GPIO
         select GCD
         select VLYNQ
@@ -192,6 +194,7 @@ config LASAT
 
 config MACH_LOONGSON
         bool "Loongson family of machines"
+        select SYS_SUPPORTS_ZBOOT_UART16550
         help
           This enables the support of Loongson family of machines.
 
@@ -233,6 +236,7 @@ config MIPS_MALTA
         select SYS_SUPPORTS_MIPS_CMP
         select SYS_SUPPORTS_MULTITHREADING
         select SYS_SUPPORTS_SMARTMIPS
+        select SYS_SUPPORTS_ZBOOT
         help
           This enables support for the MIPS Technologies Malta evaluation
           board.
@@ -1294,6 +1298,16 @@ config CPU_CAVIUM_OCTEON
 
 endchoice
 
+config SYS_SUPPORTS_ZBOOT
+        bool
+        select HAVE_KERNEL_GZIP
+        select HAVE_KERNEL_BZIP2
+        select HAVE_KERNEL_LZMA
+
+config SYS_SUPPORTS_ZBOOT_UART16550
+        bool
+        select SYS_SUPPORTS_ZBOOT
+
 config CPU_LOONGSON2
         bool
         select CPU_SUPPORTS_32BIT_KERNEL
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 77f5021218d3..ba04782c4b91 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -69,6 +69,7 @@ endif
 
 all-$(CONFIG_BOOT_ELF32)        := $(vmlinux-32)
 all-$(CONFIG_BOOT_ELF64)        := $(vmlinux-64)
+all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlinuz
 
 #
 # GCC uses -G 0 -mabicalls -fpic as default.  We don't want PIC in the kernel
@@ -331,7 +332,7 @@ load-$(CONFIG_LEMOTE_FULOONG2E) +=0xffffffff80100000
 core-$(CONFIG_MIPS_MALTA)       += arch/mips/mti-malta/
 cflags-$(CONFIG_MIPS_MALTA)     += -I$(srctree)/arch/mips/include/asm/mach-malta
 load-$(CONFIG_MIPS_MALTA)       += 0xffffffff80100000
-all-$(CONFIG_MIPS_MALTA)        := vmlinux.bin
+all-$(CONFIG_MIPS_MALTA)        := vmlinuz.bin
 
 #
 # MIPS SIM
@@ -581,7 +582,7 @@ load-$(CONFIG_SNI_RM)		+= 0xffffffff80600000
 else
 load-$(CONFIG_SNI_RM)           += 0xffffffff80030000
 endif
-all-$(CONFIG_SNI_RM)            := vmlinux.ecoff
+all-$(CONFIG_SNI_RM)            := vmlinuz.ecoff
 
 #
 # Common TXx9
@@ -699,9 +700,23 @@ vmlinux.64: vmlinux
         $(OBJCOPY) -O $(64bit-bfd) $(OBJCOPYFLAGS) $< $@
 
 makeboot =$(Q)$(MAKE) $(build)=arch/mips/boot VMLINUX=$(vmlinux-32) $(1)
+makezboot =$(Q)$(MAKE) $(build)=arch/mips/boot/compressed \
+           VMLINUX_LOAD_ADDRESS=$(load-y) 32bit-bfd=$(32bit-bfd) $(1)
 
 all:    $(all-y)
 
+vmlinuz: vmlinux FORCE
+        +@$(call makezboot,$@)
+
+vmlinuz.bin: vmlinux
+        +@$(call makezboot,$@)
+
+vmlinuz.ecoff: vmlinux
+        +@$(call makezboot,$@)
+
+vmlinuz.srec: vmlinux
+        +@$(call makezboot,$@)
+
 vmlinux.bin: $(vmlinux-32)
         +@$(call makeboot,$@)
 
@@ -726,11 +741,13 @@ endif
 
 install:
         $(Q)install -D -m 755 vmlinux $(INSTALL_PATH)/vmlinux-$(KERNELRELEASE)
+        $(Q)install -D -m 755 vmlinuz $(INSTALL_PATH)/vmlinuz-$(KERNELRELEASE)
         $(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
         $(Q)install -D -m 644 System.map $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
 
 archclean:
         @$(MAKE) $(clean)=arch/mips/boot
+        @$(MAKE) $(clean)=arch/mips/boot/compressed
         @$(MAKE) $(clean)=arch/mips/lasat
 
 define archhelp
@@ -738,10 +755,18 @@ define archhelp
         echo '  vmlinux.ecoff        - ECOFF boot image'
         echo '  vmlinux.bin          - Raw binary boot image'
         echo '  vmlinux.srec         - SREC boot image'
+        echo '  vmlinuz              - Compressed boot(zboot) image'
+        echo '  vmlinuz.ecoff        - ECOFF zboot image'
+        echo '  vmlinuz.bin          - Raw binary zboot image'
+        echo '  vmlinuz.srec         - SREC zboot image'
         echo
         echo '  These will be default as apropriate for a configured platform.'
 endef
 
 CLEAN_FILES += vmlinux.32 \
                vmlinux.64 \
-               vmlinux.ecoff
+               vmlinux.ecoff \
+               vmlinuz \
+               vmlinuz.ecoff \
+               vmlinuz.bin \
+               vmlinuz.srec
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
new file mode 100644
index 000000000000..e27f40bbd4e5
--- /dev/null
+++ b/arch/mips/boot/compressed/Makefile
@@ -0,0 +1,100 @@
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.
+#
+# Adapted for MIPS Pete Popov, Dan Malek
+#
+# Copyright (C) 1994 by Linus Torvalds
+# Adapted for PowerPC by Gary Thomas
+# modified by Cort (cort@cs.nmt.edu)
+#
+# Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University
+# Author: Wu Zhangjin <wuzj@lemote.com>
+#
+
+# compressed kernel load addr: VMLINUZ_LOAD_ADDRESS > VMLINUX_LOAD_ADDRESS + VMLINUX_SIZE
+VMLINUX_SIZE := $(shell wc -c $(objtree)/$(KBUILD_IMAGE) 2>/dev/null | cut -d' ' -f1)
+VMLINUX_SIZE := $(shell [ -n "$(VMLINUX_SIZE)" ] && echo $$(($(VMLINUX_SIZE) + (65536 - $(VMLINUX_SIZE) % 65536))))
+VMLINUZ_LOAD_ADDRESS := 0x$(shell [ -n "$(VMLINUX_SIZE)" ] && printf %x $$(($(VMLINUX_LOAD_ADDRESS) + $(VMLINUX_SIZE))))
+
+# set the default size of the mallocing area for decompressing
+BOOT_HEAP_SIZE := 0x400000
+
+# Disable Function Tracer
+KBUILD_CFLAGS := $(shell echo $(KBUILD_CFLAGS) | sed -e "s/-pg//")
+
+KBUILD_CFLAGS := $(LINUXINCLUDE) $(KBUILD_CFLAGS) -D__KERNEL__ \
+        -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) -D"VMLINUX_LOAD_ADDRESS_ULL=$(VMLINUX_LOAD_ADDRESS)ull" \
+
+KBUILD_AFLAGS := $(LINUXINCLUDE) $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
+        -DKERNEL_ENTRY=0x$(shell $(NM) $(objtree)/$(KBUILD_IMAGE) 2>/dev/null | grep " kernel_entry" | cut -f1 -d \ ) \
+        -DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE)
+
+obj-y := $(obj)/head.o $(obj)/decompress.o $(obj)/dbg.o
+
+obj-$(CONFIG_SYS_SUPPORTS_ZBOOT_UART16550) += $(obj)/uart-16550.o
+
+OBJCOPYFLAGS_vmlinux.bin := $(OBJCOPYFLAGS) -O binary -R .comment -S
+$(obj)/vmlinux.bin: $(KBUILD_IMAGE)
+        $(call if_changed,objcopy)
+
+suffix_$(CONFIG_KERNEL_GZIP)  = gz
+suffix_$(CONFIG_KERNEL_BZIP2) = bz2
+suffix_$(CONFIG_KERNEL_LZMA)  = lzma
+tool_$(CONFIG_KERNEL_GZIP)    = gzip
+tool_$(CONFIG_KERNEL_BZIP2)   = bzip2
+tool_$(CONFIG_KERNEL_LZMA)    = lzma
+$(obj)/vmlinux.$(suffix_y): $(obj)/vmlinux.bin
+        $(call if_changed,$(tool_y))
+
+$(obj)/piggy.o: $(obj)/vmlinux.$(suffix_y) $(obj)/dummy.o
+        $(Q)$(OBJCOPY) $(OBJCOPYFLAGS) \
+                --add-section=.image=$< \
+                --set-section-flags=.image=contents,alloc,load,readonly,data \
+                $(obj)/dummy.o $@
+
+LDFLAGS_vmlinuz := $(LDFLAGS) -Ttext $(VMLINUZ_LOAD_ADDRESS) -T
+vmlinuz: $(src)/ld.script $(obj-y) $(obj)/piggy.o
+        $(call if_changed,ld)
+        $(Q)$(OBJCOPY) $(OBJCOPYFLAGS) -R .comment -R .stab -R .stabstr -R .initrd -R .sysmap $@
+
+#
+# Some DECstations need all possible sections of an ECOFF executable
+#
+ifdef CONFIG_MACH_DECSTATION
+  E2EFLAGS = -a
+else
+  E2EFLAGS =
+endif
+
+# elf2ecoff can only handle 32bit image
+
+ifdef CONFIG_32BIT
+        VMLINUZ = vmlinuz
+else
+        VMLINUZ = vmlinuz.32
+endif
+
+vmlinuz.32: vmlinuz
+        $(Q)$(OBJCOPY) -O $(32bit-bfd) $(OBJCOPYFLAGS) $< $@
+
+vmlinuz.ecoff: $(obj)/../elf2ecoff $(VMLINUZ)
+        $(Q)$(obj)/../elf2ecoff $(VMLINUZ) vmlinuz.ecoff $(E2EFLAGS)
+
+$(obj)/../elf2ecoff: $(src)/../elf2ecoff.c
+        $(Q)$(HOSTCC) -o $@ $^
+
+drop-sections   = .reginfo .mdebug .comment .note .pdr .options .MIPS.options
+strip-flags     = $(addprefix --remove-section=,$(drop-sections))
+
+OBJCOPYFLAGS_vmlinuz.bin := $(OBJCOPYFLAGS) -O binary $(strip-flags)
+vmlinuz.bin: vmlinuz
+        $(call if_changed,objcopy)
+
+OBJCOPYFLAGS_vmlinuz.srec := $(OBJCOPYFLAGS) -S -O srec $(strip-flags)
+vmlinuz.srec: vmlinuz
+        $(call if_changed,objcopy)
+
+clean:
+clean-files += *.o \
+               vmlinu*
diff --git a/arch/mips/boot/compressed/dbg.c b/arch/mips/boot/compressed/dbg.c
new file mode 100644
index 000000000000..ff4dc7a33a9f
--- /dev/null
+++ b/arch/mips/boot/compressed/dbg.c
@@ -0,0 +1,37 @@
+/*
+ * MIPS-specific debug support for pre-boot environment
+ *
+ * NOTE: putc() is board specific, if your board have a 16550 compatible uart,
+ * please select SYS_SUPPORTS_ZBOOT_UART16550 for your machine. othewise, you
+ * need to implement your own putc().
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+
+void __attribute__ ((weak)) putc(char c)
+{
+}
+
+void puts(const char *s)
+{
+        char c;
+        while ((c = *s++) != '\0') {
+                putc(c);
+                if (c == '\n')
+                        putc('\r');
+        }
+}
+
+void puthex(unsigned long long val)
+{
+
+        unsigned char buf[10];
+        int i;
+        for (i = 7; i >= 0; i--) {
+                buf[i] = "0123456789ABCDEF"[val & 0x0F];
+                val >>= 4;
+        }
+        buf[8] = '\0';
+        puts(buf);
+}
diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
new file mode 100644
index 000000000000..67330c2f7318
--- /dev/null
+++ b/arch/mips/boot/compressed/decompress.c
@@ -0,0 +1,126 @@
+/*
+ * Misc. bootloader code for many machines.
+ *
+ * Copyright 2001 MontaVista Software Inc.
+ * Author: Matt Porter <mporter@mvista.com> Derived from
+ * arch/ppc/boot/prep/misc.c
+ *
+ * Copyright (C) 2009 Lemote, Inc. & Institute of Computing Technology
+ * Author: Wu Zhangjin <wuzj@lemote.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+
+#include <asm/addrspace.h>
+
+/* These two variables specify the free mem region
+ * that can be used for temporary malloc area
+ */
+unsigned long free_mem_ptr;
+unsigned long free_mem_end_ptr;
+char *zimage_start;
+
+/* The linker tells us where the image is. */
+extern unsigned char __image_begin, __image_end;
+extern unsigned char __ramdisk_begin, __ramdisk_end;
+unsigned long initrd_size;
+
+/* debug interfaces  */
+extern void puts(const char *s);
+extern void puthex(unsigned long long val);
+
+void error(char *x)
+{
+        puts("\n\n");
+        puts(x);
+        puts("\n\n -- System halted");
+
+        while (1)
+                ;       /* Halt */
+}
+
+/* activate the code for pre-boot environment */
+#define STATIC static
+
+#ifdef CONFIG_KERNEL_GZIP
+void *memcpy(void *dest, const void *src, size_t n)
+{
+        int i;
+        const char *s = src;
+        char *d = dest;
+
+        for (i = 0; i < n; i++)
+                d[i] = s[i];
+        return dest;
+}
+#include "../../../../lib/decompress_inflate.c"
+#endif
+
+#ifdef CONFIG_KERNEL_BZIP2
+void *memset(void *s, int c, size_t n)
+{
+        int i;
+        char *ss = s;
+
+        for (i = 0; i < n; i++)
+                ss[i] = c;
+        return s;
+}
+#include "../../../../lib/decompress_bunzip2.c"
+#endif
+
+#ifdef CONFIG_KERNEL_LZMA
+#include "../../../../lib/decompress_unlzma.c"
+#endif
+
+void decompress_kernel(unsigned long boot_heap_start)
+{
+        int zimage_size;
+
+        /*
+         * We link ourself to an arbitrary low address.  When we run, we
+         * relocate outself to that address.  __image_beign points to
+         * the part of the image where the zImage is. -- Tom
+         */
+        zimage_start = (char *)(unsigned long)(&__image_begin);
+        zimage_size = (unsigned long)(&__image_end) -
+            (unsigned long)(&__image_begin);
+
+        /*
+         * The zImage and initrd will be between start and _end, so they've
+         * already been moved once.  We're good to go now. -- Tom
+         */
+        puts("zimage at:     ");
+        puthex((unsigned long)zimage_start);
+        puts(" ");
+        puthex((unsigned long)(zimage_size + zimage_start));
+        puts("\n");
+
+        if (initrd_size) {
+                puts("initrd at:     ");
+                puthex((unsigned long)(&__ramdisk_begin));
+                puts(" ");
+                puthex((unsigned long)(&__ramdisk_end));
+                puts("\n");
+        }
+
+        /* this area are prepared for mallocing when decompressing */
+        free_mem_ptr = boot_heap_start;
+        free_mem_end_ptr = boot_heap_start + BOOT_HEAP_SIZE;
+
+        /* Display standard Linux/MIPS boot prompt for kernel args */
+        puts("Uncompressing Linux at load address ");
+        puthex(VMLINUX_LOAD_ADDRESS_ULL);
+        puts("\n");
+        /* Decompress the kernel with according algorithm */
+        decompress(zimage_start, zimage_size, 0, 0,
+                   (void *)VMLINUX_LOAD_ADDRESS_ULL, 0, error);
+        /* FIXME: is there a need to flush cache here? */
+        puts("Now, booting the kernel...\n");
+}
diff --git a/arch/mips/boot/compressed/dummy.c b/arch/mips/boot/compressed/dummy.c
new file mode 100644
index 000000000000..31dbf45bf99c
--- /dev/null
+++ b/arch/mips/boot/compressed/dummy.c
@@ -0,0 +1,4 @@
+int main(void)
+{
+        return 0;
+}
diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S
new file mode 100644
index 000000000000..4e65a8420bee
--- /dev/null
+++ b/arch/mips/boot/compressed/head.S
@@ -0,0 +1,56 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994, 1995 Waldorf Electronics
+ * Written by Ralf Baechle and Andreas Busse
+ * Copyright (C) 1995 - 1999 Ralf Baechle
+ * Copyright (C) 1996 Paul M. Antoine
+ * Modified for DECStation and hence R3000 support by Paul M. Antoine
+ * Further modifications by David S. Miller and Harald Koerfgen
+ * Copyright (C) 1999 Silicon Graphics, Inc.
+ */
+
+#include <asm/asm.h>
+#include <asm/regdef.h>
+
+        .set noreorder
+        .cprestore
+        LEAF(start)
+start:
+        /* Save boot rom start args */
+        move    s0, a0
+        move    s1, a1
+        move    s2, a2
+        move    s3, a3
+
+        /* Clear BSS */
+        PTR_LA  a0, _edata
+        PTR_LA  a2, _end
+1:      sw      zero, 0(a0)
+        bne     a2, a0, 1b
+         addiu  a0, a0, 4
+
+        PTR_LA  a0, (.heap)          /* heap address */
+        PTR_LA  sp, (.stack + 8192)  /* stack address */
+
+        PTR_LA  ra, 2f
+        PTR_LA  k0, decompress_kernel
+        jr      k0
+         nop
+2:
+        move    a0, s0
+        move    a1, s1
+        move    a2, s2
+        move    a3, s3
+        PTR_LI  k0, KERNEL_ENTRY
+        jr      k0
+         nop
+3:
+        b       3b
+         nop
+        END(start)
+
+        .comm .heap,BOOT_HEAP_SIZE,4
+        .comm .stack,4096*2,4
diff --git a/arch/mips/boot/compressed/ld.script b/arch/mips/boot/compressed/ld.script
new file mode 100644
index 000000000000..29e9f4c0d5d8
--- /dev/null
+++ b/arch/mips/boot/compressed/ld.script
@@ -0,0 +1,150 @@
+OUTPUT_ARCH(mips)
+ENTRY(start)
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  .init          : { *(.init)           } =0
+  .text      :
+  {
+    _ftext = . ;
+    *(.text)
+    *(.rodata)
+    *(.rodata1)
+    /* .gnu.warning sections are handled specially by elf32.em.  */
+    *(.gnu.warning)
+  } =0
+  .kstrtab : { *(.kstrtab) }
+
+  . = ALIGN(16);                /* Exception table */
+  __start___ex_table = .;
+  __ex_table : { *(__ex_table) }
+  __stop___ex_table = .;
+
+  __start___dbe_table = .;      /* Exception table for data bus errors */
+  __dbe_table : { *(__dbe_table) }
+  __stop___dbe_table = .;
+
+  __start___ksymtab = .;        /* Kernel symbol table */
+  __ksymtab : { *(__ksymtab) }
+  __stop___ksymtab = .;
+
+  _etext = .;
+
+  . = ALIGN(8192);
+  .data.init_task : { *(.data.init_task) }
+
+  /* Startup code */
+  . = ALIGN(4096);
+  __init_begin = .;
+  .text.init : { *(.text.init) }
+  .data.init : { *(.data.init) }
+  . = ALIGN(16);
+  __setup_start = .;
+  .setup.init : { *(.setup.init) }
+  __setup_end = .;
+  __initcall_start = .;
+  .initcall.init : { *(.initcall.init) }
+  __initcall_end = .;
+  . = ALIGN(4096);      /* Align double page for init_task_union */
+  __init_end = .;
+
+  . = ALIGN(4096);
+  .data.page_aligned : { *(.data.idt) }
+
+  . = ALIGN(32);
+  .data.cacheline_aligned : { *(.data.cacheline_aligned) }
+
+  .fini      : { *(.fini)    } =0
+  .reginfo : { *(.reginfo) }
+  /* Adjust the address for the data segment.  We want to adjust up to
+     the same address within the page on the next page up.  It would
+     be more correct to do this:
+       . = .;
+     The current expression does not correctly handle the case of a
+     text segment ending precisely at the end of a page; it causes the
+     data segment to skip a page.  The above expression does not have
+     this problem, but it will currently (2/95) cause BFD to allocate
+     a single segment, combining both text and data, for this case.
+     This will prevent the text segment from being shared among
+     multiple executions of the program; I think that is more
+     important than losing a page of the virtual address space (note
+     that no actual memory is lost; the page which is skipped can not
+     be referenced).  */
+  . = .;
+  .data    :
+  {
+    _fdata = . ;
+    *(.data)
+
+   /* Put the compressed image here, so bss is on the end. */
+   __image_begin = .;
+   *(.image)
+   __image_end = .;
+   /* Align the initial ramdisk image (INITRD) on page boundaries. */
+   . = ALIGN(4096);
+   __ramdisk_begin = .;
+   *(.initrd)
+   __ramdisk_end = .;
+   . = ALIGN(4096);
+
+    CONSTRUCTORS
+  }
+  .data1   : { *(.data1) }
+  _gp = . + 0x8000;
+  .lit8 : { *(.lit8) }
+  .lit4 : { *(.lit4) }
+  .ctors         : { *(.ctors)   }
+  .dtors         : { *(.dtors)   }
+  .got           : { *(.got.plt) *(.got) }
+  .dynamic       : { *(.dynamic) }
+  /* We want the small data sections together, so single-instruction offsets
+     can access them all, and initialized data all before uninitialized, so
+     we can shorten the on-disk segment size.  */
+  .sdata     : { *(.sdata) }
+  . = ALIGN(4);
+  _edata  =  .;
+  PROVIDE (edata = .);
+
+  __bss_start = .;
+  _fbss = .;
+  .sbss      : { *(.sbss) *(.scommon) }
+  .bss       :
+  {
+   *(.dynbss)
+   *(.bss)
+   *(COMMON)
+   .  = ALIGN(4);
+  _end = . ;
+  PROVIDE (end = .);
+  }
+
+  /* Sections to be discarded */
+  /DISCARD/ :
+  {
+        *(.text.exit)
+        *(.data.exit)
+        *(.exitcall.exit)
+  }
+
+  /* This is the MIPS specific mdebug section.  */
+  .mdebug : { *(.mdebug) }
+  /* These are needed for ELF backends which have not yet been
+     converted to the new style linker.  */
+  .stab 0 : { *(.stab) }
+  .stabstr 0 : { *(.stabstr) }
+  /* DWARF debug sections.
+     Symbols in the .debug DWARF section are relative to the beginning of the
+     section so we begin .debug at 0.  It's not clear yet what needs to happen
+     for the others.   */
+  .debug          0 : { *(.debug) }
+  .debug_srcinfo  0 : { *(.debug_srcinfo) }
+  .debug_aranges  0 : { *(.debug_aranges) }
+  .debug_pubnames 0 : { *(.debug_pubnames) }
+  .debug_sfnames  0 : { *(.debug_sfnames) }
+  .line           0 : { *(.line) }
+  /* These must appear regardless of  .  */
+  .gptab.sdata : { *(.gptab.data) *(.gptab.sdata) }
+  .gptab.sbss : { *(.gptab.bss) *(.gptab.sbss) }
+  .comment : { *(.comment) }
+  .note : { *(.note) }
+}
diff --git a/arch/mips/boot/compressed/uart-16550.c b/arch/mips/boot/compressed/uart-16550.c
new file mode 100644
index 000000000000..c9caaf4fbf60
--- /dev/null
+++ b/arch/mips/boot/compressed/uart-16550.c
@@ -0,0 +1,43 @@
+/*
+ * 16550 compatible uart based serial debug support for zboot
+ */
+
+#include <linux/types.h>
+#include <linux/serial_reg.h>
+#include <linux/init.h>
+
+#include <asm/addrspace.h>
+
+#if defined(CONFIG_MACH_LOONGSON) || defined(CONFIG_MIPS_MALTA)
+#define UART_BASE 0x1fd003f8
+#define PORT(offset) (CKSEG1ADDR(UART_BASE) + (offset))
+#endif
+
+#ifdef CONFIG_AR7
+#include <ar7.h>
+#define PORT(offset) (CKSEG1ADDR(AR7_REGS_UART0) + (4 * offset))
+#endif
+
+#ifndef PORT
+#error please define the serial port address for your own machine
+#endif
+
+static inline unsigned int serial_in(int offset)
+{
+        return *((char *)PORT(offset));
+}
+
+static inline void serial_out(int offset, int value)
+{
+        *((char *)PORT(offset)) = value;
+}
+
+void putc(char c)
+{
+        int timeout = 1024;
+
+        while (((serial_in(UART_LSR) & UART_LSR_THRE) == 0) && (timeout-- > 0))
+                ;
+
+        serial_out(UART_TX, c);
+}