[PATCH] ARM: 2680/1: refine TLS reg availability some more again
Patch from Nicolas Pitre
Not all ARMv6 processors implement the TLS register.
Signed-off-by: Nicolas Pitre
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 07646d2..48bac7d 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -412,21 +412,20 @@
config TLS_REG_EMUL
bool
- default y if (SMP || CPU_32v6) && (CPU_32v5 || CPU_32v4 || CPU_32v3)
+ default y if SMP && (CPU_32v5 || CPU_32v4 || CPU_32v3)
help
- We might be running on an ARMv6+ processor which should have the TLS
- register but for some reason we can't use it, or maybe an SMP system
- using a pre-ARMv6 processor (there are apparently a few prototypes
- like that in existence) and therefore access to that register must
- be emulated.
+ An SMP system using a pre-ARMv6 processor (there are apparently
+ a few prototypes like that in existence) and therefore access to
+ that required register must be emulated.
config HAS_TLS_REG
bool
- depends on CPU_32v6
- default y if !TLS_REG_EMUL
+ depends on !TLS_REG_EMUL
+ default y if SMP || CPU_32v7
help
This selects support for the CP15 thread register.
- It is defined to be available on ARMv6 or later. If a particular
- ARMv6 or later CPU doesn't support it then it must include "select
- TLS_REG_EMUL" along with its other characteristics.
+ It is defined to be available on some ARMv6 processors (including
+ all SMP capable ARMv6's) or later processors. User space may
+ assume directly accessing that register and always obtain the
+ expected value only on ARMv7 and above.