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SubjectRe: Kernel Crash on Shutdown
Hi,


On 13 Jun, Menaka Lashitha Bandara wrote:
> Sorry for responding after such a long time. I had to take my
> motherboard back because there was an error with the RTC. Now I've got a
> replacement motherboard, and the kernel still crashes on "halt." When
> I first wrote the problem to this Mailing list, Alan Cox said it could
> be a bios problem. I have a new bios now (because I got a replacment
> m/b), but the kernel still crashes on shutdown. I've tried exchanging
> the CPU (to the same one) from my friend's system which shuts down
> properley, but this didn't solve anything. If it helps, here are the
> devices on my system:
>

Try the attached patch for apm. It was posted here some time apo.

I had the same problem and the patch works for me.

Georg

--
Georg Funke
Crowns & Flames SDC Cologne, Germany; http://www.geocities.com/Colosseum/4893
"Friendship is Square Dancing's greatest Reward"
--- linux/arch/i386/kernel/process.c~ Sun Feb 28 23:09:29 1999
+++ linux/arch/i386/kernel/process.c Mon Mar 1 00:04:01 1999
@@ -2,6 +2,10 @@
* linux/arch/i386/kernel/process.c
*
* Copyright (C) 1995 Linus Torvalds
+ *
+ * Change back to real mode for APM power off
+ * Walter Hofmann, March 1999
+ *
*/

/*
@@ -380,10 +384,106 @@
{
}

+#if defined(CONFIG_APM) && defined(CONFIG_APM_POWER_OFF)
+
+/* This is 16-bit protected mode code to disable paging and the cache,
+ switch to real mode and jump to the BIOS APM poweroff code. */
+
+unsigned char apm_real_mode_poweroff [] =
+{
+ 0x66, 0x0f, 0x20, 0xc0, /* movl %cr0,%eax */
+ 0x66, 0x83, 0xe0, 0x11, /* andl $0x00000011,%eax */
+ 0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */
+ 0x66, 0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */
+ 0x66, 0x0f, 0x22, 0xd8, /* movl %eax,%cr3 */
+ 0x66, 0x0f, 0x20, 0xc3, /* movl %cr0,%ebx */
+ 0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60, /* andl $0x60000000,%ebx */
+ 0x74, 0x02, /* jz f */
+ 0x0f, 0x08, /* invd */
+ 0x24, 0x10, /* f: andb $0x10,al */
+ 0x66, 0x0f, 0x22, 0xc0, /* movl %eax,%cr0 */
+ 0xea, 0xed, 0x0f, 0x00, 0x00, /* ljmp g */
+ 0xb8, 0x00, 0x10, /* g: movw $0x1000,ax */
+ 0x8e, 0xd0, /* movw ax,ss */
+ 0xbc, 0x00, 0xf0, /* movw $0xf000,sp */
+ 0xb8, 0x07, 0x53, /* movw $0x5307,ax */
+ 0xbb, 0x01, 0x00, /* movw $0x0001,bx */
+ 0xb9, 0x03, 0x00, /* movw $0x0003,cx */
+ 0xcd, 0x15 /* int $0x15 */
+};
+
+void apm_realmode_poweroff(void)
+{
+ cli ();
+
+ /* Remap the kernel at virtual address zero, as well as offset zero
+ from the kernel segment. This assumes the kernel segment starts at
+ virtual address 0xc0000000. */
+
+ memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
+ sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
+
+ /* Make sure the first page is mapped to the start of physical memory.
+ It is normally not mapped, to trap kernel NULL pointer dereferences. */
+
+ pg0 [0] = 7;
+
+ /*
+ * Use `swapper_pg_dir' as our page directory. We bother with
+ * `SET_PAGE_DIR' because although might be rebooting, but if we change
+ * the way we set root page dir in the future, then we wont break a
+ * seldom used feature ;)
+ */
+
+ SET_PAGE_DIR(current,swapper_pg_dir);
+
+ /* For the switch to real mode, copy some code to low memory. It has
+ to be in the first 64k because it is running in 16-bit mode, and it
+ has to have the same physical and virtual address, because it turns
+ off paging. Copy it near the end of the first page, out of the way
+ of BIOS variables. */
+
+ memcpy ((void *) (0x1000 - sizeof (apm_real_mode_poweroff)),
+ apm_real_mode_poweroff, sizeof (apm_real_mode_poweroff));
+
+ /* Set up the IDT for real mode. */
+
+ __asm__ __volatile__ ("lidt %0" : : "m" (real_mode_idt));
+
+ /* Set up a GDT from which we can load segment descriptors for real
+ mode. The GDT is not used in real mode; it is just needed here to
+ prepare the descriptors. */
+
+ __asm__ __volatile__ ("lgdt %0" : : "m" (real_mode_gdt));
+
+ /* Load the data segment registers, and thus the descriptors ready for
+ real mode. The base address of each segment is 0x100, 16 times the
+ selector value being loaded here. This is so that the segment
+ registers don't have to be reloaded after switching to real mode:
+ the values are consistent for real mode operation already. */
+
+ __asm__ __volatile__ ("movw $0x0010,%%ax\n"
+ "\tmovw %%ax,%%ds\n"
+ "\tmovw %%ax,%%es\n"
+ "\tmovw %%ax,%%fs\n"
+ "\tmovw %%ax,%%gs\n"
+ "\tmovw %%ax,%%ss" : : : "eax");
+
+ /* Jump to the 16-bit code that we copied earlier. It disables paging
+ and the cache, switches to real mode, and jumps to the BIOS APM
+ entry point. */
+
+ __asm__ __volatile__ ("ljmp $0x0008,%0"
+ :
+ : "i" ((void *) (0x1000 - sizeof (apm_real_mode_poweroff))));
+
+}
+#endif
+
void machine_power_off(void)
{
#if defined(CONFIG_APM) && defined(CONFIG_APM_POWER_OFF)
- apm_power_off();
+ apm_realmode_poweroff();
#endif
}
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