[patch] Fix crash due to missing debugctlmsr on AMD K6-3

From: Jan Kratochvil
Date: Tue Jul 22 2008 - 08:10:09 EST


Hi,

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

Please Cc me in a reply.


Regards,
Jan
Signed-off-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>

--- linux-2.6.26/arch/x86/Kconfig.cpu-orig 2008-07-13 23:51:29.000000000 +0200
+++ linux-2.6.26/arch/x86/Kconfig.cpu 2008-07-22 13:44:19.000000000 +0200
@@ -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)