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authorVasily Gorbik <gor@linux.vnet.ibm.com>2018-04-27 07:36:25 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-29 11:33:14 +0200
commitb44533a06fd8f50c425c9cfa3cbfa70f62c39a84 (patch)
treee9925950d485d356362a720b2f3d0b579f8c3c7a /arch/s390/kernel/Makefile
parent55c80adf0d0e528f4e4de92cecc5bf7c9201fc8a (diff)
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s390: introduce CPU alternatives
[ Upstream commit 686140a1a9c41d85a4212a1c26d671139b76404b ] Implement CPU alternatives, which allows to optionally patch newer instructions at runtime, based on CPU facilities availability. A new kernel boot parameter "noaltinstr" disables patching. Current implementation is derived from x86 alternatives. Although ideal instructions padding (when altinstr is longer then oldinstr) is added at compile time, and no oldinstr nops optimization has to be done at runtime. Also couple of compile time sanity checks are done: 1. oldinstr and altinstr must be <= 254 bytes long, 2. oldinstr and altinstr must not have an odd length. alternative(oldinstr, altinstr, facility); alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2); Both compile time and runtime padding consists of either 6/4/2 bytes nop or a jump (brcl) + 2 bytes nop filler if padding is longer then 6 bytes. .altinstructions and .altinstr_replacement sections are part of __init_begin : __init_end region and are freed after initialization. Signed-off-by: Vasily Gorbik <gor@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/kernel/Makefile')
-rw-r--r--arch/s390/kernel/Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 4ce2d05929a7..23cdabe61b77 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_FUNCTION_TRACER) += mcount.o ftrace.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_UPROBES) += uprobes.o
+obj-$(CONFIG_ALTERNATIVES) += alternative.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_cpum_cf.o perf_cpum_sf.o
obj-$(CONFIG_PERF_EVENTS) += perf_cpum_cf_events.o