kernel/linux.git/arch/s390/lib, branch v6.12.80

s390/xor: Fix xor_xc_2() inline assembly constraints

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

commit f775276edc0c505dc0f782773796c189f31a1123 upstream. The inline assembly constraints for xor_xc_2() are incorrect. "bytes", "p1", and "p2" are input operands, while all three of them are modified within the inline assembly. Given that the function consists only of this inline assembly it seems unlikely that this may cause any problems, however fix this in any case. Fixes: 2cfc5f9ce7f5 ("s390/xor: optimized xor routing using the XC instruction") Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Reviewed-by: Vasily Gorbik Link: https://lore.kernel.org/r/20260302133500.1560531-2-hca@linux.ibm.com Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

ftrace: Make ftrace_regs abstract from direct use

2026-03-04T12:19:36+00:00

[ Upstream commit 7888af4166d4ab07ba51234be6ba332b7807e901 ] ftrace_regs was created to hold registers that store information to save function parameters, return value and stack. Since it is a subset of pt_regs, it should only be used by its accessor functions. But because pt_regs can easily be taken from ftrace_regs (on most archs), it is tempting to use it directly. But when running on other architectures, it may fail to build or worse, build but crash the kernel! Instead, make struct ftrace_regs an empty structure and have the architectures define __arch_ftrace_regs and all the accessor functions will typecast to it to get to the actual fields. This will help avoid usage of ftrace_regs directly. Link: https://lore.kernel.org/all/20241007171027.629bdafd@gandalf.local.home/ Cc: "linux-arch@vger.kernel.org" Cc: "x86@kernel.org" Cc: Mathieu Desnoyers Cc: Mark Rutland Cc: Will Deacon Cc: Huacai Chen Cc: WANG Xuerui Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Naveen N Rao Cc: Madhavan Srinivasan Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Sven Schnelle Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Link: https://lore.kernel.org/20241008230628.958778821@goodmis.org Acked-by: Catalin Marinas Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) Acked-by: Heiko Carstens # s390 Signed-off-by: Steven Rostedt (Google) Stable-dep-of: aea251799998 ("x86/fgraph,bpf: Switch kprobe_multi program stack unwind to hw_regs path") Signed-off-by: Sasha Levin

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