kernel/linux.git/arch/s390/include/asm/thread_info.h, branch linux-7.0.y

s390: Remove compat support

2025-11-17T10:10:38+00:00

There shouldn't be any 31 bit code around anymore that matters. Remove the compat layer support required to run 31 bit code. Reason for removal is code simplification and reduced test effort. Note that this comes without any deprecation warnings added to config options, or kernel messages, since most likely those would be ignored anyway. If it turns out there is still a reason to keep the compat layer this can be reverted at any time in the future. Reviewed-by: Arnd Bergmann Signed-off-by: Heiko Carstens

s390/entry: Remove unused TIF flags

2025-09-17T06:14:04+00:00

The conversion of s390 to generic entry missed to remove the TIF_SYSCALL*/TIF_SECCOMP flags. Remove them as they are unused now. Fixes: 56e62a737028 ("s390: convert to generic entry") Signed-off-by: Sven Schnelle Signed-off-by: Thomas Gleixner Acked-by: Heiko Carstens

s390: Use generic TIF bits

2025-09-17T06:14:04+00:00

No point in defining generic items and the upcoming RSEQ optimizations are only available with this _and_ the generic entry infrastructure, which is already used by s390. So no further action required here. This leaves a comment about the AUDIT/TRACE/SECCOMP bits which are handled by SYSCALL_WORK in the generic code, so they seem redundant, but that's a problem for the s390 wizards to think about. Signed-off-by: Thomas Gleixner Acked-by: Heiko Carstens

s390: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-06-16T14:23:02+00:00

While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembler code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This is bad since macros starting with two underscores are names that are reserved by the C language. It can also be very confusing for the developers when switching between userspace and kernelspace coding, or when dealing with uapi headers that rather should use __ASSEMBLER__ instead. So let's now standardize on the __ASSEMBLER__ macro that is provided by the compilers. This is a completely mechanical patch (done with a simple "sed -i" statement), with some manual fixups done later while rebasing the patch. Signed-off-by: Thomas Huth Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20250611140046.137739-3-thuth@redhat.com Signed-off-by: Alexander Gordeev

s390/thread_info: Cleanup header includes

2025-05-17T08:55:00+00:00

asm/thread_info.h requires PAGE_SIZE, which is defined in vdso/page.h, but doesn't need to include asm/lowcore.h or asm/page.h. Therefore change the includes accordingly and reduce header dependencies. Signed-off-by: Heiko Carstens

s390/mm: Reimplement lazy ASCE handling

2025-04-14T09:23:21+00:00

Reduce system call overhead time (round trip time for invoking a non-existent system call) by 25%. With the removal of set_fs() [1] lazy control register handling was removed in order to keep kernel entry and exit simple. However this made system calls slower. With the conversion to generic entry [2] and numerous follow up changes which simplified the entry code significantly, adding support for lazy asce handling doesn't add much complexity to the entry code anymore. In particular this means: - On kernel entry the primary asce is not modified and contains the user asce - Kernel accesses which require secondary-space mode (for example futex operations) are surrounded by enable_sacf_uaccess() and disable_sacf_uaccess() calls. enable_sacf_uaccess() sets the primary asce to kernel asce so that the sacf instruction can be used to switch to secondary-space mode. The primary asce is changed back to user asce with disable_sacf_uaccess(). The state of the control register which contains the primary asce is reflected with a new TIF_ASCE_PRIMARY bit. This is required on context switch so that the correct asce is restored for the scheduled in process. In result address spaces are now setup like this: CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE -----------------------------|-----------|-----------|----------- user space | user | user | kernel kernel (no sacf) | user | user | kernel kernel (during sacf uaccess) | kernel | user | kernel kernel (kvm guest execution) | guest | user | kernel In result cr1 control register content is not changed except for: - futex system calls - legacy s390 PCI system calls - the kvm specific cmpxchg_user_key() uaccess helper This leads to faster system call execution. [1] 87d598634521 ("s390/mm: remove set_fs / rework address space handling") [2] 56e62a737028 ("s390: convert to generic entry") Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens

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: Remove 2k vs 4k page table leftovers

2025-03-18T16:13:05+00:00

Since commit d08d4e7cd6bf ("s390/mm: use full 4KB page for 2KB PTE") always 4k page tables are allocated, however there is still some (now) obsolete code left which deals with switching from 2k to 4k page tables for qemu/kvm processes. Reviewed-by: Alexander Gordeev Remove the not needed code. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: Add ARCH_HAS_PREEMPT_LAZY support

2024-11-24T15:59:42+00:00

Just add the required TIF bit for ARCH_HAS_PREEMPT_LAZY support. Shuffle TIF bits to get TIF_NEED_RESCHED_LAZY next to TIF_NEED_RESCHED. Signed-off-by: Heiko Carstens

s390: Add missing _TIF defines