vserver 1.9.5.x5

[linux-2.6.git] / arch / i386 / boot / edd.S

diff --git a/arch/i386/boot/edd.S b/arch/i386/boot/edd.S
index 8897906..027d6b3 100644 (file)
--- a/arch/i386/boot/edd.S
+++ b/arch/i386/boot/edd.S
@@ -1,5 +1,6 @@
 /*
  * BIOS Enhanced Disk Drive support
+ * Copyright (C) 2002, 2003, 2004 Dell, Inc.
  * by Matt Domsch <Matt_Domsch@dell.com> October 2002
  * conformant to T13 Committee www.t13.org
  *   projects 1572D, 1484D, 1386D, 1226DT
@@ -7,14 +8,52 @@
  *     and Andrew Wilks <Andrew_Wilks@dell.com> September 2003, June 2004
  * legacy CHS retreival by Patrick J. LoPresti <patl@users.sourceforge.net>
  *      March 2004
+ * Command line option parsing, Matt Domsch, November 2004
  */
 
 #include <linux/edd.h>
+#include <asm/setup.h>
 
 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
+       movb    $0, (EDD_MBR_SIG_NR_BUF)
+       movb    $0, (EDDNR)
+
+# Check the command line for two options:
+# edd=of  disables EDD completely  (edd=off)
+# edd=sk  skips the MBR test    (edd=skipmbr)
+       pushl   %esi
+       cmpl    $0, %cs:cmd_line_ptr
+       jz      done_cl
+       movl    %cs:(cmd_line_ptr), %esi
+# ds:esi has the pointer to the command line now
+       movl    $(COMMAND_LINE_SIZE-7), %ecx
+# loop through kernel command line one byte at a time
+cl_loop:
+       cmpl    $EDD_CL_EQUALS, (%si)
+       jz      found_edd_equals
+       incl    %esi
+       loop    cl_loop
+       jmp     done_cl
+found_edd_equals:
+# only looking at first two characters after equals
+       addl    $4, %esi
+       cmpw    $EDD_CL_OFF, (%si)      # edd=of
+       jz      do_edd_off
+       cmpw    $EDD_CL_SKIP, (%si)     # edd=sk
+       jz      do_edd_skipmbr
+       jmp     done_cl
+do_edd_skipmbr:
+       popl    %esi
+       jmp     edd_start
+do_edd_off:
+       popl    %esi
+       jmp     edd_done
+done_cl:
+       popl    %esi
+
+
 # Read the first sector of each BIOS disk device and store the 4-byte signature
 edd_mbr_sig_start:
-       movb    $0, (EDD_MBR_SIG_NR_BUF)        # zero value at EDD_MBR_SIG_NR_BUF
        movb    $0x80, %dl                      # from device 80
        movw    $EDD_MBR_SIG_BUF, %bx           # store buffer ptr in bx
 edd_mbr_sig_read:
@@ -76,7 +115,6 @@ edd_start:
                                                        # result buffer for fn48
        movw    $EDDBUF+EDDEXTSIZE, %si         # in ds:si, fn41 results
                                                # kept just before that
-       movb    $0, (EDDNR)                     # zero value at EDDNR
        movb    $0x80, %dl                      # BIOS device 0x80
 
 edd_check_ext: