From: Jeff Dike <jdike@addtoit.com> Noticed by Al Viro <viro@parcelfarce.linux.theplanet.co.uk> - SMP on x86_64 is fundamentally broken due to UML's reuse of the host arch's percpu stuff. This is OK on x86, but the x86_64 pda stuff just won't work for UML. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> --- arch/um/Kconfig | 2 +- arch/um/Kconfig.x86_64 | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff -puN arch/um/Kconfig~uml-mark-smp-on-uml-x86_64-as-broken arch/um/Kconfig --- devel/arch/um/Kconfig~uml-mark-smp-on-uml-x86_64-as-broken 2005-08-30 00:11:15.000000000 -0700 +++ devel-akpm/arch/um/Kconfig 2005-08-30 00:11:15.000000000 -0700 @@ -196,7 +196,7 @@ config HOST_2G_2G config SMP bool "Symmetric multi-processing support (EXPERIMENTAL)" default n - depends on MODE_TT && EXPERIMENTAL + depends on (MODE_TT && EXPERIMENTAL && !SMP_BROKEN) || (BROKEN && SMP_BROKEN) help This option enables UML SMP support. It is NOT related to having a real SMP box. Not directly, at least. diff -puN arch/um/Kconfig.x86_64~uml-mark-smp-on-uml-x86_64-as-broken arch/um/Kconfig.x86_64 --- devel/arch/um/Kconfig.x86_64~uml-mark-smp-on-uml-x86_64-as-broken 2005-08-30 00:11:15.000000000 -0700 +++ devel-akpm/arch/um/Kconfig.x86_64 2005-08-30 00:11:15.000000000 -0700 @@ -37,3 +37,7 @@ config ARCH_HAS_SC_SIGNALS config ARCH_REUSE_HOST_VSYSCALL_AREA bool default n + +config SMP_BROKEN + bool + default y _