x86: Use u32 instead of long to set reset vector back to 0

commit 299c56966a72b9109d47c71a6db52097098703dd upstream.

A customer of ours, complained that when setting the reset
vector back to 0, it trashed other data and hung their box.
They noticed when only 4 bytes were set to 0 instead of 8,
everything worked correctly.

Mathew pointed out:

 |
 | We're supposed to be resetting trampoline_phys_low and
 | trampoline_phys_high here, which are two 16-bit values.
 | Writing 64 bits is definitely going to overwrite space
 | that we're not supposed to be touching.
 |

So limit the area modified to u32.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
LKML-Reference: <1297139100-424-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/asm-x86/mach-default/smpboot_hooks.h b/include/asm-x86/mach-default/smpboot_hooks.h
index dbab36d64d48f2b15aa6be7dea09e9feb91f869f..4e767be7c6050c6e34810024613cfcd8ce301bef 100644 (file)
--- a/include/asm-x86/mach-default/smpboot_hooks.h
+++ b/include/asm-x86/mach-default/smpboot_hooks.h
@@ -32,7 +32,7 @@ static inline void smpboot_restore_warm_reset_vector(void)
         */
        CMOS_WRITE(0, 0xf);
 
-       *((volatile long *) phys_to_virt(0x467)) = 0;
+       *((volatile u32 *) phys_to_virt(0x467)) = 0;
 }
 
 static inline void __init smpboot_setup_io_apic(void)