[patch 25/62] x86: fix crash due to missing debugctlmsr on AMD K6-3

From: Greg KH
Date: Wed Jul 30 2008 - 20:13:42 EST


2.6.26 -stable review patch. If anyone has any objections, please let
us know.

------------------
From: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>

commit d536b1f86591fb081c7a56eab04e711eb4dab951 upstream

currently if you use PTRACE_SINGLEBLOCK on AMD K6-3 (i586) it will crash.
Kernel now wrongly assumes existing DEBUGCTLMSR MSR register there.

Removed the assumption also for some other non-K6 CPUs but I am not sure there
(but it can only bring small inefficiency there if my assumption is wrong).

Based on info from Roland McGrath, Chuck Ebbert and Mikulas Patocka.
More info at:
https://bugzilla.redhat.com/show_bug.cgi?id=456175

Signed-off-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
arch/x86/Kconfig.cpu | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -414,4 +414,4 @@ config X86_MINIMUM_CPU_FAMILY

config X86_DEBUGCTLMSR
def_bool y
- depends on !(M586MMX || M586TSC || M586 || M486 || M386)
+ depends on !(MK6 || MWINCHIPC6 || MWINCHIP2 || MWINCHIP3D || MCYRIXIII || M586MMX || M586TSC || M586 || M486 || M386)

--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/