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Add support for alternative inline assemblies with input and output
arguments. This is consistent to x86.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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This is the s390 version of commit 40576e5e63ea ("x86: alternative.h:
use asm_inline for all alternative variants").
See commit eb111869301e ("compiler-types.h: add asm_inline
definition") for more details.
With this change the compiler will not generate many out-of-line
versions for the three instruction sized arch_spin_unlock() function
anymore. Due to this gcc seems to change a lot of other inline
decisions which results in a net 6k text size growth according to
bloat-o-meter (gcc 9.2 with defconfig).
But that's still better than having many out-of-line versions of
arch_spin_unlock().
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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Add the correct SPDX license to a few more files under arch/s390 and
drivers/s390 which have been missed to far.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Remove the CPU_ALTERNATIVES config option and enable the code
unconditionally. The config option was only added to avoid a conflict
with the named saved segment support. Since that code is gone there is
no reason to keep the CPU_ALTERNATIVES config option.
Just enable it unconditionally to also reduce the number of config
options and make it less likely that something breaks.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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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>
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Heiko Carstens
Heiko Carstens
Martin Schwidefsky
Vasily Gorbik