x86: use ELF format in compressed images.

Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: virtualization@lists.linux-foundation.org
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 95 insertions, 1 deletions

diff --git a/Documentation/i386/boot.txt b/Documentation/i386/boot.txt
index fc49b79bc1ab..b5f5ba1ea668 100644
--- a/Documentation/i386/boot.txt
+++ b/Documentation/i386/boot.txt
@@ -170,6 +170,8 @@ Offset	Proto	Name		Meaning
 0238/4  2.06+   cmdline_size    Maximum size of the kernel command line
 023C/4  2.07+   hardware_subarch Hardware subarchitecture
 0240/8  2.07+   hardware_subarch_data Subarchitecture-specific data
+0248/4  2.08+   compressed_payload_offset
+024C/4  2.08+   compressed_payload_length
 
 (1) For backwards compatibility, if the setup_sects field contains 0, the
     real value is 4.
@@ -512,6 +514,22 @@ Protocol:	2.07+
 
   A pointer to data that is specific to hardware subarch
 
+Field name:     compressed_payload_offset
+Type:           read
+Offset/size:    0x248/4
+Protocol:       2.08+
+
+  If non-zero then this field contains the offset from the end of the
+  real-mode code to the compressed payload. The compression format
+  should be determined using the standard magic number, currently only
+  gzip is used.
+  
+Field name:     compressed_payload_length
+Type:           read
+Offset/size:    0x24c/4
+Protocol:       2.08+
+
+  The length of the compressed payload.
 
 **** THE KERNEL COMMAND LINE
 
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index f88458e83ef0..9695affeb584 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -94,6 +94,20 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
 
 SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
 
+sed-offsets := -e 's/^00*/0/' \
+        -e 's/^\([0-9a-fA-F]*\) . \(input_data\|input_data_end\)$$/\#define \2 0x\1/p'
+
+quiet_cmd_offsets = OFFSETS $@
+      cmd_offsets = $(NM) $< | sed -n $(sed-offsets) > $@
+
+$(obj)/offsets.h: $(obj)/compressed/vmlinux FORCE
+        $(call if_changed,offsets)
+
+targets += offsets.h
+
+AFLAGS_header.o += -I$(obj)
+$(obj)/header.o: $(obj)/offsets.h
+
 LDFLAGS_setup.elf       := -T
 $(obj)/setup.elf: $(src)/setup.ld $(SETUP_OBJS) FORCE
         $(call if_changed,ld)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index d2b9f3bb87c0..92fdd35bd93e 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -22,7 +22,7 @@ $(obj)/vmlinux: $(src)/vmlinux_$(BITS).lds $(obj)/head_$(BITS).o $(obj)/misc.o $
         $(call if_changed,ld)
         @:
 
-OBJCOPYFLAGS_vmlinux.bin := -O binary -R .note -R .comment -S
+OBJCOPYFLAGS_vmlinux.bin :=  -R .comment -S
 $(obj)/vmlinux.bin: vmlinux FORCE
         $(call if_changed,objcopy)
 
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 8182e32c1b42..69aec2f4155d 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -15,6 +15,10 @@
  * we just keep it from happening
  */
 #undef CONFIG_PARAVIRT
+#ifdef CONFIG_X86_32
+#define _ASM_DESC_H_ 1
+#endif
+
 #ifdef CONFIG_X86_64
 #define _LINUX_STRING_H_ 1
 #define __LINUX_BITMAP_H 1
@@ -22,6 +26,7 @@
 
 #include <linux/linkage.h>
 #include <linux/screen_info.h>
+#include <linux/elf.h>
 #include <asm/io.h>
 #include <asm/page.h>
 #include <asm/boot.h>
@@ -365,6 +370,56 @@ static void error(char *x)
                 asm("hlt");
 }
 
+static void parse_elf(void *output)
+{
+#ifdef CONFIG_X86_64
+        Elf64_Ehdr ehdr;
+        Elf64_Phdr *phdrs, *phdr;
+#else
+        Elf32_Ehdr ehdr;
+        Elf32_Phdr *phdrs, *phdr;
+#endif
+        void *dest;
+        int i;
+
+        memcpy(&ehdr, output, sizeof(ehdr));
+        if(ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
+           ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
+           ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
+           ehdr.e_ident[EI_MAG3] != ELFMAG3)
+        {
+                error("Kernel is not a valid ELF file");
+                return;
+        }
+
+        putstr("Parsing ELF... ");
+
+        phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
+        if (!phdrs)
+                error("Failed to allocate space for phdrs");
+
+        memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
+
+        for (i=0; i<ehdr.e_phnum; i++) {
+                phdr = &phdrs[i];
+
+                switch (phdr->p_type) {
+                case PT_LOAD:
+#ifdef CONFIG_RELOCATABLE
+                        dest = output;
+                        dest += (phdr->p_paddr - LOAD_PHYSICAL_ADDR);
+#else
+                        dest = (void*)(phdr->p_paddr);
+#endif
+                        memcpy(dest,
+                               output + phdr->p_offset,
+                               phdr->p_filesz);
+                        break;
+                default: /* Ignore other PT_* */ break;
+                }
+        }
+}
+
 asmlinkage void decompress_kernel(void *rmode, memptr heap,
                                   uch *input_data, unsigned long input_len,
                                   uch *output)
@@ -408,6 +463,7 @@ asmlinkage void decompress_kernel(void *rmode, memptr heap,
         makecrc();
         putstr("\nDecompressing Linux... ");
         gunzip();
+        parse_elf(output);
         putstr("done.\nBooting the kernel.\n");
         return;
 }
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 64ad9016585a..8471658d5534 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -22,6 +22,7 @@
 #include <asm/page.h>
 #include <asm/setup.h>
 #include "boot.h"
+#include "offsets.h"
 
 SETUPSECTS      = 4                     /* default nr of setup-sectors */
 BOOTSEG         = 0x07C0                /* original address of boot-sector */
@@ -223,6 +224,11 @@ hardware_subarch:	.long 0			# subarchitecture, added with 2.07
 
 hardware_subarch_data:  .quad 0
 
+compressed_payload_offset:
+                        .long input_data
+compressed_payload_length:
+                        .long input_data_end-input_data
+
 # End of setup header #####################################################
 
         .section ".inittext", "ax"