| From | Andi Kleen <> | Subject | [PATCH] [162/275] x86: Use u32 instead of long to set reset vector back to 0 | Date | Wed, 30 Mar 2011 14:06:44 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Don Zickus <dzickus@redhat.com>
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> Signed-off-by: Andi Kleen <ak@linux.intel.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>
--- arch/x86/include/asm/smpboot_hooks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.35.y/arch/x86/include/asm/smpboot_hooks.h =================================================================== --- linux-2.6.35.y.orig/arch/x86/include/asm/smpboot_hooks.h 2011-03-29 22:51:00.390713170 -0700 +++ linux-2.6.35.y/arch/x86/include/asm/smpboot_hooks.h 2011-03-29 23:03:01.622258662 -0700 @@ -34,7 +34,7 @@ */ CMOS_WRITE(0, 0xf); - *((volatile long *)phys_to_virt(apic->trampoline_phys_low)) = 0; + *((volatile u32 *)phys_to_virt(apic->trampoline_phys_low)) = 0; } static inline void __init smpboot_setup_io_apic(void)
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