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>

1 files changed, 56 insertions, 0 deletions

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;
 }