linux-toradex.git/arch/s390/kernel/early.c, branch v6.8

s390/fpu: get rid of MACHINE_HAS_VX

2023-12-11T13:33:07+00:00

Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a
short readable wrapper for "test_facility(129)".

Facility bit 129 is set if the vector facility is present. test_facility()
returns also true for all bits which are set in the architecture level set
of the cpu that the kernel is compiled for. This means that
test_facility(129) is a compile time constant which returns true for z13
and later, since the vector facility bit is part of the z13 kernel ALS.

In result the compiled code will have less runtime checks, and less code.

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

s390/fpu: remove "novx" option

2023-12-11T13:33:06+00:00

Remove the "novx" kernel command line option: the vector code runs
without any problems since many years.

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

s390/cmma: move parsing of cmma kernel parameter to early boot code

2023-11-05T21:34:57+00:00

The "cmma=" kernel command line parameter needs to be parsed early for
upcoming changes. Therefore move the parsing code.

Note that EX_TABLE handling of cmma_test_essa() needs to be open-coded,
since the early boot code doesn't have infrastructure for handling expected
exceptions.

Reviewed-by: Claudio Imbrenda 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: use control register bit defines

2023-09-19T11:26:57+00:00

Use control register bit defines instead of plain numbers where
possible.

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

s390/early: use system_ctl_set_bit() instead of local_ctl_set_bit()

2023-09-19T11:26:57+00:00

Use system_ctl_set_bit() instead of local_ctl_set_bit() to reflect
that the control register changes are supposed to be global. This
change is just for documentation purposes, since it still results only
in local control register contents being changed.

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

s390/smp,mcck: fix early IPI handling

2023-09-19T11:26:55+00:00

Both the external call as well as the emergency signal submask bits in
control register 0 are set before any interrupt handler is registered.

Change the order and first register the interrupt handler and only then
enable the interrupts by setting the corresponding bits in control
register 0.

This prevents that the second part of the machine check handler for
early machine check handling is not executed: the machine check handler
sends an IPI to the CPU it runs on. If the corresponding interrupts are
enabled, but no interrupt handler is present, the interrupt is ignored.

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

s390/mm: simplify kernel mapping setup

2023-08-30T09:03:27+00:00

The kernel mapping is setup in two stages: in the decompressor map all
pages with RWX permissions, and within the kernel change all mappings to
their final permissions, where most of the mappings are changed from RWX to
RWNX.

Change this and map all pages RWNX from the beginning, however without
enabling noexec via control register modification. This means that
effectively all pages are used with RWX permissions like before. When the
final permissions have been applied to the kernel mapping enable noexec via
control register modification.

This allows to remove quite a bit of non-obvious code.

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

s390: remove "noexec" option

2023-08-30T09:03:27+00:00

Do the same like x86 with commit 76ea0025a214 ("x86/cpu: Remove "noexec"")
and remove the "noexec" kernel command line option.

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

s390/kasan: move shadow mapping to decompressor

2023-03-20T10:02:51+00:00

Since regular paging structs are initialized in decompressor already
move KASAN shadow mapping to decompressor as well. This helps to avoid
allocating KASAN required memory in 1 large chunk, de-duplicate paging
structs creation code and start the uncompressed kernel with KASAN
instrumentation right away. This also allows to avoid all pitfalls
accidentally calling KASAN instrumented code during KASAN initialization.

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