[Xen-devel] [PATCH] xen/arch/x86: Fix early boot command line parsing

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

There is no reliable way to encode nul character as a character so encode
it as a number. Read: http://sourceware.org/binutils/docs/as/Characters.html.
Octal and hex encoding does not work on at least my system (GNU assembler
version 2.22 (x86_64-linux-gnu) using BFD version (GNU Binutils for Debian) 
2.22).
Without this fix e.g. no-real-mode option at the end of xen.gz command line
is not detected. Additionally, encode other characters accordingly to
the gas documentation.

Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
 xen/arch/x86/boot/cmdline.S |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/boot/cmdline.S b/xen/arch/x86/boot/cmdline.S
index 05ffb94..4ea56b3 100644
--- a/xen/arch/x86/boot/cmdline.S
+++ b/xen/arch/x86/boot/cmdline.S
@@ -138,11 +138,11 @@
         call    .Lstrlen
         add     $4,%esp
         xadd    %eax,%ebx
-        cmpb    $'\0',(%ebx)
+        cmpb    $0,(%ebx)
         je      3f
-        cmpb    $' ',(%ebx)
+        cmpb    $' ,(%ebx)
         je      3f
-        cmpb    $'=',(%ebx)
+        cmpb    $'=,(%ebx)
         jne     1b
 3:      pop     %ebx
         ret
-- 
1.7.10.4


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