linux.git/arch/s390/lib, branch v6.12

s390/alternatives: Rework to allow for callbacks

2024-07-23T14:02:31+00:00

Rework alternatives to allow for callbacks. With this every
alternative entry has additional data encoded:

- When (aka context) an alternative is supposed to be applied

- The type of an alternative, which allows for type specific handling
  and callbacks

- Extra type specific payload (patch information), which can be passed
  to callbacks in order to decide if an alternative should be applied
  or not

With this only the "late" context is implemented, which means there is
no change to the previous behaviour. All code is just converted to the
more generic new infrastructure.

Reviewed-by: Alexander Gordeev 
Tested-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/lib: Add missing MODULE_DESCRIPTION() macros

2024-06-28T12:52:30+00:00

With ARCH=s390, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in arch/s390/lib/test_kprobes_s390.o
WARNING: modpost: missing MODULE_DESCRIPTION() in arch/s390/lib/test_unwind.o
WARNING: modpost: missing MODULE_DESCRIPTION() in arch/s390/lib/test_modules.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Acked-by: Heiko Carstens 
Signed-off-by: Jeff Johnson 
Link: https://lore.kernel.org/r/20240615-md-s390-arch-s390-lib-v1-1-d7424b943973@quicinc.com
Signed-off-by: Vasily Gorbik 
Signed-off-by: Alexander Gordeev

s390: Replace S390_lowcore by get_lowcore()

2024-06-18T15:01:33+00:00

Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

Acked-by: Heiko Carstens 
Signed-off-by: Sven Schnelle 
Signed-off-by: Vasily Gorbik

s390/expoline: Make modules use kernel expolines

2024-04-17T11:38:03+00:00

Currently, kernel modules contain their own set of expoline thunks. In
the case of EXPOLINE_EXTERN, this involves postlinking of precompiled
expoline.o. expoline.o is also necessary for out-of-source tree module
builds.

Now that the kernel modules area is less than 4 GB away from
kernel expoline thunks, make modules use kernel expolines. Also make
EXPOLINE_EXTERN the default if the compiler supports it. This simplifies
build and aligns with the approach adopted by other architectures.

Signed-off-by: Vasily Gorbik 
Signed-off-by: Alexander Gordeev

s390/checksum: provide csum_partial_copy_nocheck()

2024-02-16T13:30:17+00:00

With csum_partial(), which reads all bytes into registers it is easy to
also implement csum_partial_copy_nocheck() which copies the buffer while
calculating its checksum.

For a 512 byte buffer this reduces the runtime by 19%. Compared to the old
generic variant (memcpy() + cksm instruction) runtime is reduced by 42%).

Signed-off-by: Heiko Carstens

s390/checksum: provide vector register variant of csum_partial()

2024-02-16T13:30:17+00:00

Provide a faster variant of csum_partial() which uses vector registers
instead of the cksm instruction.

Signed-off-by: Heiko Carstens

s390/nmi: implement and use local_mcck_save() / local_mcck_restore()

2023-12-11T13:33:05+00:00

Instead of using local_mcck_disable() / local_mcck_enable() implement and
use local_mcck_save() / local_mcck_restore() to disable machine checks, and
restoring the previous state.

The problem with using local_mcck_disable() / local_mcck_enable() is that
there is an assumption that machine checks are always enabled. While this
is currently the case the code still looks quite odd, readers need to
double check if the code is correct.

In order to increase readability save and then restore the old machine
check mask bit, instead of assuming that it must have been enabled.

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/ctlreg: add struct ctlreg

2023-09-19T11:26:56+00:00

Add struct ctlreg to enforce strict type checking / usage for control
register functions.

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/ctlreg: use local_ctl_load() and local_ctl_store() where possible

2023-09-19T11:26:56+00:00

Convert all single control register usages of __local_ctl_load() and
__local_ctl_store() to local_ctl_load() and local_ctl_store().

This also requires to change the type of some struct lowcore members
from __u64 to unsigned long.

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/ctlreg: add local and system prefix to some functions

2023-09-19T11:26:56+00:00

Add local and system prefix to some functions to clarify they change
control register contents on either the local CPU or the on all CPUs.

This results in the following API:

Two defines which load and save multiple control registers.
The defines correlate with the following C prototypes:

void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high);
void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high);

Two functions which locally set or clear one bit for a specified
control register:

void local_ctl_set_bit(unsigned int cr, unsigned int bit);
void local_ctl_clear_bit(unsigned int cr, unsigned int bit);

Two functions which set or clear one bit for a specified control
register on all CPUs:

void system_ctl_set_bit(unsigned int cr, unsigned int bit);
void system_ctl_clear_bit(unsigend int cr, unsigned int bit);

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik