On 11/22/2012 12:50 PM, H. Peter Anvin wrote:
On 11/22/2012 12:18 PM, Yinghai Lu wrote:

If we can get the sentinel hack to work that would probably be
useful, but
we need to understand the exact pathology.

for kexec bzImage --real-mode-entry, code after setup_header will be
executed.

so we could clear value before setup_header after copy 16bit section
from bzImage...

Index: kexec-tools/kexec/arch/i386/kexec-bzImage.c
===================================================================
--- kexec-tools.orig/kexec/arch/i386/kexec-bzImage.c
+++ kexec-tools/kexec/arch/i386/kexec-bzImage.c
@@ -212,6 +212,16 @@ int do_bzImage_load(struct kexec_info *i
      setup_size = kern16_size + command_line_len +
PURGATORY_CMDLINE_SIZE;
      real_mode = xmalloc(setup_size);
      memcpy(real_mode, kernel, kern16_size);
+    /*
+     * clear value before header
+     * not not clear value after header, --real-mode-entry
+     * need code after header.
+     */
+    memset(real_mode, 0, 0x1f1);
+    if (!real_mode_entry) {
+        /* clear value after setup_header  */
+        memset((unsigned char *)real_mode + 0x290, 0, kern16_size -
0x290);
+    }


You really should move the memset() into the if() clause as well...
doesn't matter at the moment, but that is the protocol.

The limit is 0x280, not 0x290, or -- better -- you can use the byte at
0x201 to get the size.


Not doing so would be wrong, in fact.


--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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