x86: Support HAVE_CONTEXT_TRACKING_OFFSTACK

A lot of ground work has been performed on x86 entry code. Fragile path
between user_enter() and user_exit() have IRQs disabled. Uses of RCU and
intrumentation in these fragile areas have been explicitly annotated
and protected.

This architecture doesn't need exception_enter()/exception_exit()
anymore and has therefore earned CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201117151637.259084-6-frederic@kernel.org

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f6946b81f74a95da92bce9f483dcbd6ca6aa7cff..d793361839b589d1dc773fcc2ff14b920e07205a 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -162,6 +162,7 @@ config X86
        select HAVE_CMPXCHG_DOUBLE
        select HAVE_CMPXCHG_LOCAL
        select HAVE_CONTEXT_TRACKING            if X86_64
+       select HAVE_CONTEXT_TRACKING_OFFSTACK   if HAVE_CONTEXT_TRACKING
        select HAVE_C_RECORDMCOUNT
        select HAVE_DEBUG_KMEMLEAK
        select HAVE_DMA_CONTIGUOUS