[2.4][2.5][Trivial Patch] Bug in i386/kernel/process.c?

From: Disconnect (lkml@sigkill.net)
Date: Thu Jul 03 2003 - 11:26:15 EST

I was poking into how to force a warm boot (found it easily enough) and
started reading process.c, where the details live.

We have:
static int reboot_mode;
int reboot_thru_bios;
static int __init reboot_setup(char *str)
...set reboot_mode/reboot_thru_bios according to reboot=...
__setup("reboot=", reboot_setup);

Farther down:
        /* Write 0x1234 to absolute memory location 0x472. The BIOS
           this on booting to tell it to "Bypass memory test (also warm
           boot)". This seems like a fairly standard thing that gets
set by
           REBOOT.COM programs, and the previous reset routine did this
           too. */
        *((unsigned short *)0x472) = reboot_mode;
                                                                                (similar code farther down in !reboot_thru_bios)

....but reboot_mode doesn't seem to be initialized if you don't set it
via reboot=...? (Same for reboot_thru_bios)

A simple patch to use the defaults (according to the code comments) is
below; if this is right please push accordingly:

Its against 2.4 but should apply to 2.5 as well.
--- build-dis5-final/arch/i386/kernel/process.c.orig 2003-07-03 12:15:36.000000000 -0400
+++ build-dis5-final/arch/i386/kernel/process.c 2003-07-03 12:16:46.000000000 -0400
@@ -152,8 +152,8 @@
 __setup("idle=", idle_setup);
 static long no_idt[2];
-static int reboot_mode;
-int reboot_thru_bios;
+static int reboot_mode = 0x1234;
+int reboot_thru_bios = 1;
 #ifdef CONFIG_SMP
 int reboot_smp = 0;

Disconnect <lkml@sigkill.net>

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