MIPS: Add support for GZIP / BZIP2 / LZMA compressed kernel images

This patch helps to generate smaller kernel images for linux-MIPS,

Here is the effect when using lzma:

$ ls -sh vmlinux
7.1M vmlinux
$ ls -sh vmlinuz
1.5M vmlinuz

Have tested the 32bit kernel on Qemu/Malta and 64bit kernel on FuLoong
Mini PC. both of them work well. and also, tested by Alexander Clouter
on an AR7 based Linksys WAG54Gv2, and by Manuel Lauss on an Alchemy
board.

This -v2 version incorporate the feedback from Ralf, and add the
following changes:

1. add .ecoff, .bin, .erec format support
2. only enable it and the debug source code for the machines we tested
3. a dozen of fixups and cleanups

and if you want to enable it for your board, please try to select
SYS_SUPPORTS_ZBOOT for it, and if the board have an 16550 compatible
uart, you can select SYS_SUPPORTS_ZBOOT_UART16550 directly. and then
sending the relative patches to Ralf.

Tested-by: Manuel Lauss <manuel.lauss@googlemail.com>
Tested-by: Alexander Clouter <alex@digriz.org.uk>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/arch/mips/boot/compressed/ld.script b/arch/mips/boot/compressed/ld.script
new file mode 100644
index 00000000000..29e9f4c0d5d
--- /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) }
+}