[Xen-changelog] [xen-unstable] x86: allow Dom0 image to be compressed ELF

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxxxx>
# Date 1308825237 -3600
# Node ID d7644abc218d3232b9d957ce94fc4b4bcc1f456e
# Parent  584c2e5e03d96f912cdfe90f8e9f910d5d661706
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@xxxxxxxxxx>
---


diff -r 584c2e5e03d9 -r d7644abc218d xen/arch/x86/bzimage.c
--- a/xen/arch/x86/bzimage.c    Thu Jun 23 11:32:43 2011 +0100
+++ b/xen/arch/x86/bzimage.c    Thu Jun 23 11:33:57 2011 +0100
@@ -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 @@
     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;
+    }
 
-    headroom = output_length(img, hdr->payload_length);
-    if (gzip_check(img, hdr->payload_length)) {
+    if ( elf_is_elfbinary(image_start) )
+        return 0;
+
+    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 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 -r 584c2e5e03d9 -r d7644abc218d xen/include/asm-x86/bzimage.h
--- a/xen/include/asm-x86/bzimage.h     Thu Jun 23 11:32:43 2011 +0100
+++ b/xen/include/asm-x86/bzimage.h     Thu Jun 23 11:33:57 2011 +0100
@@ -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);

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