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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m ok with this patch.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>YH<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
linuxbios-bounces@openbios.org [mailto:linuxbios-bounces@openbios.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Steven J. Magnani<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, September 09, 2005
9:35 AM<br>
<b><span style='font-weight:bold'>To:</span></b> yinghailu@gmail.com<br>
<b><span style='font-weight:bold'>Cc:</span></b> linuxbios@openbios.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [LinuxBIOS] PATCH:
relocate GDT before invoking payload</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 color=blue face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:blue'>QNX Neutrino doesn't set up its
own GDT right away. Its startup code has some defensive logic that
attempts to put the system into a known state. This causes an exception when
booted from LinuxBIOS, if its GDT got trashed when elfboot() loaded the
Neutrino image. See the hyperlink below for more discussion.</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 color=blue face=Arial><span style='font-size:
12.0pt;font-family:Arial;color:blue'>The fix seems straightforward, and the
increased amount of "table" memory very modest. Do you object to this
patch?</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 color=blue face=Arial><span style='font-size:
12.0pt;font-family:Arial;color:blue'>Steve</span></font><o:p></o:p></p>
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<blockquote style='margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> yhlu
[mailto:yinghailu@gmail.com] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, September 09, 2005
10:03 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Steven J. Magnani<br>
<b><span style='font-weight:bold'>Cc:</span></b> linuxbios@openbios.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [LinuxBIOS] PATCH:
relocate GDT before invoking payload</span></font><o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>why?<br>
<br>
The payload will have its own GDT.<br>
<br>
YH<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><span class=gmailquote><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>On 9/9/05, <b><span style='font-weight:bold'>Steven J.
Magnani</span></b> <<a href="mailto:steve@digidescorp.com">steve@digidescorp.com</a>>
wrote:</span></font></span> <o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I posted this patch previously; see<br>
<a href="http://openbios.org/pipermail/linuxbios/2005-August/012063.html">http://openbios.org/pipermail/linuxbios/2005-August/012063.html</a>
for the<br>
original issue.<br>
<br>
Here's another chance to comment before I commit it. <br>
<br>
PATCH:<br>
<br>
--- src/arch/i386/boot/tables.c.orig 2005-09-08
13:35:39.125000000<br>
-0500<br>
+++ src/arch/i386/boot/tables.c 2005-08-16 16:17:41.766000000 -0500<br>
@@ -7,6 +7,32 @@<br>
#include <arch/acpi.h> <br>
#include "linuxbios_table.h"<br>
<br>
+// Global Descriptor Table, defined in c_start.S<br>
+extern uint8_t gdt;<br>
+extern uint8_t gdt_end;<br>
+<br>
+/* i386 lgdt argument */<br>
+struct gdtarg {<br>
+ unsigned short limit; <br>
+ unsigned int base;<br>
+} __attribute__((packed));<br>
+<br>
+// Copy GDT to new location and reload it<br>
+// 2003-07 by SONE Takeshi<br>
+// Ported from Etherboot to LinuxBIOS 2005-08 by Steve Magnani<br>
+void move_gdt(unsigned long newgdt) <br>
+{<br>
+ uint16_t num_gdt_bytes = &gdt_end -
&gdt;<br>
+ struct gdtarg gdtarg;<br>
+<br>
+ printk_debug("Moving GDT to %#lx...",
newgdt);<br>
+ memcpy((void*)newgdt, &gdt, num_gdt_bytes); <br>
+ gdtarg.base = newgdt;<br>
+ gdtarg.limit = num_gdt_bytes - 1;<br>
+ __asm__ __volatile__ ("lgdt %0\n\t" : :
"m" (gdtarg));<br>
+ printk_debug("ok\n");<br>
+}<br>
+<br>
struct lb_memory *write_tables(void) <br>
{<br>
unsigned long low_table_start,
low_table_end;<br>
@@ -45,6 +71,10 @@<br>
low_table_end
= 0x500;<br>
}<br>
<br>
+ // Relocate the GDT to reserved memory,
so it won't get<br>
clobbered <br>
+ move_gdt(low_table_end);<br>
+ low_table_end += &gdt_end - &gdt;<br>
+<br>
/* The linuxbios table must be
in 0-4K or 960K-1M */<br>
write_linuxbios_table(<br>
low_table_start,
low_table_end,<br>
<br>
------------------------------------------------------------------------<br>
Steven J.
Magnani
"I claim this network for MARS!<br>
<a href="http://www.digidescorp.com">www.digidescorp.com</a> Earthling,
return my space modulator!"<br>
<br>
#include <standard.disclaimer><br>
<br>
<br>
<br>
<br>
--<br>
LinuxBIOS mailing list<br>
<a href="mailto:LinuxBIOS@openbios.org">LinuxBIOS@openbios.org</a><br>
<a href="http://www.openbios.org/mailman/listinfo/linuxbios">http://www.openbios.org/mailman/listinfo/linuxbios</a><o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</blockquote>
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