kernel/linux.git/arch/s390/include/asm/processor.h, branch v6.12.80

s390/stackleak: Fix __stackleak_poison() inline assembly constraint

2026-03-25T10:08:46+00:00

commit 674c5ff0f440a051ebf299d29a4c013133d81a65 upstream. The __stackleak_poison() inline assembly comes with a "count" operand where the "d" constraint is used. "count" is used with the exrl instruction and "d" means that the compiler may allocate any register from 0 to 15. If the compiler would allocate register 0 then the exrl instruction would not or the value of "count" into the executed instruction - resulting in a stackframe which is only partially poisoned. Use the correct "a" constraint, which excludes register 0 from register allocation. Fixes: 2a405f6bb3a5 ("s390/stackleak: provide fast __stackleak_poison() implementation") Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Reviewed-by: Vasily Gorbik Link: https://lore.kernel.org/r/20260302133500.1560531-4-hca@linux.ibm.com Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/stackleak: Use exrl instead of ex in __stackleak_poison()

2025-02-17T09:04:43+00:00

[ Upstream commit a88c26bb8e04ee5f2678225c0130a5fbc08eef85 ] exrl is present in all machines currently supported, therefore prefer it over ex. This saves one instruction and doesn't need an additional register to hold the address of the target instruction. Signed-off-by: Sven Schnelle Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

s390/smp: Add cpu capacities

2024-08-29T20:56:35+00:00

Linux scheduler allows architectures to assign capacity values to individual CPUs. This hints scheduler the performance difference between CPUs and allows more efficient task distribution them. Implement helper methods to set and get CPU capacities for s390. This is particularly helpful in vertical polarization configurations of LPARs. On vertical polarization an LPARs CPUs can get different polarization values depending on the CEC configuration. CPUs with different polarization values can perform different from each other, using CPU capacities this can be reflected to linux scheduler. Acked-by: Vasily Gorbik Signed-off-by: Mete Durlu Signed-off-by: Vasily Gorbik

s390/entry: Move SIE indicator flag to thread info

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

CIF_SIE indicates if a thread is running in SIE context. This is the state of a thread and not the CPU. Therefore move this indicator to thread info. Signed-off-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/nospec: Push down alternative handling

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

The nospec implementation is deeply integrated into the alternatives code: only for nospec an alternative facility list is implemented and used by the alternative code, while it is modified by nospec specific needs. Push down the nospec alternative handling into the nospec by introducing a new alternative type and a specific nospec callback to decide if alternatives should be applied. Also introduce a new global nobp variable which together with facility 82 can be used to decide if nobp is enabled or not. Acked-by: Alexander Gordeev Tested-by: Sven Schnelle Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

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: Move CIF flags to struct pcpu

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

To allow testing flags for offline CPUs, move the CIF flags to struct pcpu. To avoid having to calculate the array index for each access, add a pointer to the pcpu member for the current cpu to lowcore. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

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: Mark psw in __load_psw_mask() as __unitialized

2024-05-14T11:37:08+00:00

Without __unitialized, the following code is generated when INIT_STACK_ALL_ZERO is enabled: 86: d7 0f f0 a0 f0 a0 xc 160(16,%r15), 160(%r15) 8c: e3 40 f0 a0 00 24 stg %r4, 160(%r15) 92: c0 10 00 00 00 08 larl %r1, 0xa2 98: e3 10 f0 a8 00 24 stg %r1, 168(%r15) 9e: b2 b2 f0 a0 lpswe 160(%r15) The xc is not adding any security because psw is fully initialized with the following instructions. Add __unitialized to the psw definitiation to avoid the superfluous clearing of psw. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Alexander Gordeev

s390/idle: Rewrite psw_idle() in C

2024-05-14T11:37:07+00:00

To ease maintenance and further enhancements, convert the psw_idle() function to C. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Alexander Gordeev