x86: allow Dom0 image to be compressed ELF

Rather than being able to decompress only the payloads of bzImage
containers, extend the logic to also decompress simple compressed ELF
images. At once, allow uncompressed bzImage payloads.

This is a prerequisite for native EFI booting support (where, in the
absence of a capable secondary boot loader, the image will always be
in compressed form).

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/xen/arch/x86/bzimage.c b/xen/arch/x86/bzimage.c
index d1aecabe35f0b015e759a39354bafeb54dd19b5f..5adc22373506e83e4d3c858f28339e1d83a0ad89 100644 (file)
--- a/xen/arch/x86/bzimage.c
+++ b/xen/arch/x86/bzimage.c
@@ -5,6 +5,7 @@
 #include <xen/string.h>
 #include <xen/types.h>
 #include <xen/decompress.h>
+#include <xen/libelf.h>
 #include <asm/bzimage.h>
 
 #define HEAPORDER 3
@@ -200,25 +201,36 @@ static __init int bzimage_check(struct setup_header *hdr, unsigned long len)
     return 1;
 }
 
-int __init bzimage_headroom(char *image_start, unsigned long image_length)
+static unsigned long __initdata orig_image_len;
+
+unsigned long __init bzimage_headroom(char *image_start,
+                                      unsigned long image_length)
 {
     struct setup_header *hdr = (struct setup_header *)image_start;
-    char *img;
-    int err, headroom;
+    int err;
+    unsigned long headroom;
 
     err = bzimage_check(hdr, image_length);
-    if (err < 1)
+    if ( err < 0 )
         return 0;
 
-    img = image_start + (hdr->setup_sects+1) * 512;
-    img += hdr->payload_offset;
+    if ( err > 0 )
+    {
+        image_start += (hdr->setup_sects + 1) * 512 + hdr->payload_offset;
+        image_length = hdr->payload_length;
+    }
+
+    if ( elf_is_elfbinary(image_start) )
+        return 0;
 
-    headroom = output_length(img, hdr->payload_length);
-    if (gzip_check(img, hdr->payload_length)) {
+    orig_image_len = image_length;
+    headroom = output_length(image_start, image_length);
+    if (gzip_check(image_start, image_length))
+    {
         headroom += headroom >> 12; /* Add 8 bytes for every 32K input block */
         headroom += (32768 + 18); /* Add 32K + 18 bytes of extra headroom */
     } else
-        headroom += hdr->payload_length;
+        headroom += image_length;
     headroom = (headroom + 4095) & ~4095;
 
     return headroom;
@@ -230,18 +242,24 @@ int __init bzimage_parse(char *image_base, char **image_start, unsigned long *im
     int err = bzimage_check(hdr, *image_len);
     unsigned long output_len;
 
-    if (err < 1)
+    if ( err < 0 )
         return err;
 
+    if ( err > 0 )
+    {
+        *image_start += (hdr->setup_sects + 1) * 512 + hdr->payload_offset;
+        *image_len = hdr->payload_length;
+    }
+
+    if ( elf_is_elfbinary(*image_start) )
+        return 0;
+
     BUG_ON(!(image_base < *image_start));
 
-    *image_start += (hdr->setup_sects+1) * 512;
-    *image_start += hdr->payload_offset;
-    *image_len = hdr->payload_length;
-    output_len = output_length(*image_start, *image_len);
+    output_len = output_length(*image_start, orig_image_len);
 
-    if ( (err = perform_gunzip(image_base, *image_start, *image_len)) > 0 )
-        err = decompress(*image_start, *image_len, image_base);
+    if ( (err = perform_gunzip(image_base, *image_start, orig_image_len)) > 0 )
+        err = decompress(*image_start, orig_image_len, image_base);
 
     if ( !err )
     {

diff --git a/xen/include/asm-x86/bzimage.h b/xen/include/asm-x86/bzimage.h
index b6d1a81cc48bdc891eaa8a055de24b849d7e7c41..b48a2560854b5ea152696bcebb40a2eccac36aa9 100644 (file)
--- a/xen/include/asm-x86/bzimage.h
+++ b/xen/include/asm-x86/bzimage.h
@@ -4,7 +4,7 @@
 #include <xen/config.h>
 #include <xen/init.h>
 
-int bzimage_headroom(char *image_start, unsigned long image_length);
+unsigned long bzimage_headroom(char *image_start, unsigned long image_length);
 
 int bzimage_parse(char *image_base, char **image_start,
                   unsigned long *image_len);