x86: fix crash due to missing debugctlmsr on AMD K6-3

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@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 9304bfba7d450fae5dc61ffa627a49fe1fdfeae6..c308d6147b7e9bef3c70839d3c413370dbb7425c 100644 (file)
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -409,4 +409,4 @@ 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)