[34-longterm 139/247] x86: Use u32 instead of long to set reset vector back to 0

Paul Gortmaker
2011-06-23T18:05:55Z

From: Don Zickus <dzickus@redhat.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

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: Paul Gortmaker <paul.gortmaker@windriver.com>
---
arch/x86/include/asm/smpboot_hooks.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/smpboot_hooks.h b/arch/x86/include/asm/smpboot_hooks.h
index 1def601..cfdc6c8 100644
--- a/arch/x86/include/asm/smpboot_hooks.h
+++ b/arch/x86/include/asm/smpboot_hooks.h
@@ -34,7 +34,7 @@ static inline void smpboot_restore_warm_reset_vector(void)
*/
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)
--
1.7.4.4