s390: add zEC12 code generation support

Allow to generate code that only runs on zEC12 machines.

Also add a check which prevents the kernel to run on machines which
do not have any of the following new facilities installed:

- (48) decimal-floating-point zoned-conversion
- (49) execution-hint
- (49) load-and-trap
- (49) miscellaneous-instruction-extensions
- (49) processor-assist
- (50) constrained transactional-execution
- (73) transactional-execution

48, 49, 50 and 73 are the bit numbers of the facility indications for
each of the required facilities.

Note that we assume that user-space gets compiled with the same
compiler options, therefore we also test for a dfp facility even
if the kernel doesn't make use of it.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d385f396dfee..1bf4b294c6e9 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -169,6 +169,10 @@ config HAVE_MARCH_Z196_FEATURES
         def_bool n
         select HAVE_MARCH_Z10_FEATURES
 
+config HAVE_MARCH_ZEC12_FEATURES
+        def_bool n
+        select HAVE_MARCH_Z196_FEATURES
+
 choice
         prompt "Processor type"
         default MARCH_G5
@@ -220,6 +224,13 @@ config MARCH_Z196
           (2818 and 2817 series). The kernel will be slightly faster but will
           not work on older machines.
 
+config MARCH_ZEC12
+        bool "IBM zEC12"
+        select HAVE_MARCH_ZEC12_FEATURES if 64BIT
+        help
+          Select this to enable optimizations for IBM zEC12 (2827 series). The
+          kernel will be slightly faster but will not work on older machines.
+
 endchoice
 
 config 64BIT