linux-stable.git/arch/s390/kernel/early.c, branch linux-rolling-stable

s390: Remove KMSG_COMPONENT macro

2025-11-24T10:45:21+00:00

The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel
message catalog" which never made it upstream.

Remove the macro in order to get rid of a pointless indirection. Replace
all users with the string it defines. In almost all cases this leads to a
simple replacement like this:

 - #define KMSG_COMPONENT "appldata"
 - #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 + #define pr_fmt(fmt) "appldata: " fmt

Except for some special cases this is just mechanical/scripted work.

Acked-by: Thomas Richter 
Signed-off-by: Heiko Carstens

s390/early: Use scnprintf() instead of sprintf()

2025-10-21T08:17:30+00:00

Use scnprintf() instead of sprintf() for those cases where the destination
is an array and the size of the array is known at compile time.

This prevents theoretical buffer overflows, but also avoids that people
again and again spend time to figure out if the code is actually safe.

Reviewed-by: Jan Polensky 
Signed-off-by: Heiko Carstens

kasan: call kasan_init_generic in kasan_init

2025-09-21T21:21:58+00:00

Call kasan_init_generic() which handles Generic KASAN initialization.  For
architectures that do not select ARCH_DEFER_KASAN, this will be a no-op
for the runtime flag but will print the initialization banner.

For SW_TAGS and HW_TAGS modes, their respective init functions will handle
the flag enabling, if they are enabled/implemented.

Link: https://lkml.kernel.org/r/20250810125746.1105476-3-snovitoll@gmail.com
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049
Signed-off-by: Sabyrzhan Tasbolatov 
Tested-by: Alexandre Ghiti 	[riscv]
Acked-by: Alexander Gordeev 	[s390]
Reviewed-by: Christophe Leroy 
Cc: Alexander Potapenko 
Cc: Alexandre Ghiti 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Baoquan He 
Cc: David Gow 
Cc: Dmitriy Vyukov 
Cc: Heiko Carstens 
Cc: Huacai Chen 
Cc: Marco Elver 
Cc: Qing Zhang 
Cc: Vincenzo Frascino 
Cc: Ritesh Harjani (IBM) 
Signed-off-by: Andrew Morton

s390/early: Copy last breaking event address to pt_regs

2025-07-09T07:21:46+00:00

In case of an early crash the early program check handler also prints the
last breaking event address which is contained within the pt_regs
structure. However it is not initialized, and therefore a more or less
random value is printed in case of a crash.

Copy the last breaking event address from lowcore to pt_regs in case of an
early program check to address this. This also makes it easier to analyze
early crashes.

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

s390/nmi: Print additional information

2025-06-26T13:30:51+00:00

In case of an unrecoverable machine check only the machine check interrupt
code is printed to the console before the machine is stopped. This makes
root cause analysis sometimes hard.

Print additional machine check information to make analysis easier.
The output now looks like this:

Unrecoverable machine check, code: 00400F5F4C3B0000
6.16.0-rc2-11605-g987a9431e53a-dirty
HW: IBM 3931 A01 704 (z/VM 7.4.0)
PSW: 0706C00180000000 000003FFE0F0462E PFX: 0000000000070000
LBA: 000003FFE0F0462A EDC: 0000000000000000 FSA: 0000000000000000
CRS:
0080000014966A12 0000000087CB41C7 0000000000BFF140 0000000000000000
000000000000FFFF 0000000000BFF140 0000000071000000 0000000087CB41C7
0000000000008000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 00000000024C0007 00000000DB000000 0000000000BFF000
GPRS:
FFFFFFFF00000000 000003FFE0F0462E E10EA4F489F897A6 0000000000000000
7FFFFFF2C0413C4C 000003FFE19B7010 0000000000000000 0000000000000000
0000000000000000 00000001F76B3380 000003FFE15D4050 0000000000000005
0000000000000000 0000000000070000 000003FFE0F0586C 0000037FE00B7DA0
System stopped

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

s390/asm-offsets: Remove ASM_OFFSETS_C

2025-03-31T10:20:39+00:00

Remove ASM_OFFSETS_C which is used as guard in thread_info.h to decide if
asm-offsets can be included or not.

There is no reason to include asm-offsets.h in thread_info.h anymore.
Remove the define and the not needed include. Explicitly include
asm-offsets.h in all header files which require it, and where it used
to be included implicitly via thread_info.h.

This reduces header dependencies.

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

s390/alternatives: Add debug functionality

2025-03-04T16:18:08+00:00

Similar to x86 and loongarch add a "debug-alternative" command line
parameter, which allows for alternative debugging. The parameter
itself comes with architecture specific semantics:

"debug-alternative"
 -> print debug message for every single alternative

"debug-alternative=0;2"
-> print debug message for all alternatives with type 0 and 2

"debug-alternative=0:0-7"
-> print debug message for all alternatives with type 0 which have a
   facility number within the range of 0-7

"debug-alternative=0:!8;1"
-> print debug message for all alternatives with type 0, for all
   facility numbers, except facility 8, and in addition print all
   alternatives with type 1

A defconfig build currently results in a kernel with more than 20.000
alternatives, where the majority is for the niai alternative (spinlocks),
and the relocated lowcore alternative. The following kernel command like
options limit alternative debug output, and enable dynamic debug messages:

debug-alternative=0:!49;1:!0
earlyprintk
bootdebug
ignore_loglevel
loglevel=8
dyndbg="file alternative.c +p"

This results in output like this:

 alt: [0/ 11] 0000021b9ce8680c: c0f400000089 -> c00400000000
 alt: [0/ 64] 0000021b9ce87e60: c0f400000043 -> c00400000000
 alt: [0/133] 0000021b9ce88c56: c0f400000027 -> c00400000000
 alt: [0/ 74] 0000021b9ce89410: c0f40000002a -> c00400000000
 alt: [0/ 40] 0000021b9dc3720a: 47000000 -> b280d398
 alt: [0/193] 0000021b9dc37306: 47000000 -> b201d2b0
 alt: [0/193] 0000021b9dc37354: c00400000000 -> d20720c0d2b0
 alt: [1/  5] 0000038d720d7bf2: c0f400000016 -> c00400000000

With

[/]  oldcode -> newcode

Alternative data depends on the alternative type: for type 0
(ALT_TYPE_FACILITY) data is the facility. For type 1 (ALT_TYPE_FEATURE)
data is the corresponding machine feature.

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

s390/setup: Add decompressor_handled_param() wrapper

2025-03-04T16:18:08+00:00

Make decompressor_handled_param() a wrapper for
__decompressor_handled_param(). __decompressor_handled_param() now
takes two parameters: a function name and a parameter name, which do
not necessarily match.

This allows to use characters like "-", which are not allowed in
function names, for command line parameters which are handled by the
decompressor and should be ignored by the kernel.

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

s390/vx: Convert cpu_has_vx() to cpu feature function

2025-03-04T16:18:07+00:00

Instead of having a private cpu_has_vx() implementation use the new common
cpu feature method. Move the facility detection to the decompressor so it
matches all other cpu features.

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

s390: Convert MACHINE_IS_[LPAR|VM|KVM], etc, machine_is_[lpar|vm|kvm]()

2025-03-04T16:18:07+00:00

Move machine type detection to the decompressor and use static branches
to implement and use machine_is_[lpar|vm|kvm]() instead of a runtime check
via MACHINE_IS_[LPAR|VM|KVM].

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