Remove s390 compat support to allow for code simplification and especially
reduced test effort. To the best of our knowledge there aren't any 31 bit
binaries out in the world anymore that would matter for newer kernels or
newer distributions.

Distributions do not provide compat packages since quite some time or even
have CONFIG_COMPAT disabled.

Instead of adding deprecation warnings to config option, or adding kernel
messages, just remove the code. Deprecation warnings haven't proven to be
useful. If it turns out there is still a reason to keep the compat support
this series can be reverted at any time in the future.

Arnd, we talked about this two weeks ago. I would appreciate if you could
have a look at this series, especially the last patch of this series.

Patches 1-3 are just some random cleanups / preparations.
Patches 4-6 remove compat support.
Patches 7-8 switch s390 to generic system call table generation

Thanks,
Heiko

Heiko Carstens (8):
  s390/ptrace: Rename psw_t32 to psw32_t
  s390/kvm: Use psw32_t instead of psw_compat_t
  s390/syscalls: Add pt_regs parameter to SYSCALL_DEFINE0() syscall wrapper
  tools: Remove s390 compat support
  s390: Remove compat support
  s390/uapi: Remove 31 bit support from uapi header files
  s390/syscalls: Remove system call table pointer from thread_struct
  s390/syscalls: Switch to generic system call table generation

 arch/s390/Kconfig                             |  16 -
 arch/s390/Makefile                            |   6 +-
 arch/s390/boot/ipl_data.c                     |   3 +-
 arch/s390/configs/compat.config               |   3 -
 arch/s390/hypfs/hypfs_sprp.c                  |   6 +-
 arch/s390/include/asm/compat.h                | 140 ---
 arch/s390/include/asm/elf.h                   |  47 +-
 arch/s390/include/asm/ftrace.h                |  19 +-
 arch/s390/include/asm/processor.h             |  13 +-
 arch/s390/include/asm/ptrace.h                |   2 +-
 arch/s390/include/asm/seccomp.h               |   5 -
 arch/s390/include/asm/syscall.h               |  19 +-
 arch/s390/include/asm/syscall_wrapper.h       |  95 +-
 arch/s390/include/asm/thread_info.h           |   2 -
 arch/s390/include/asm/unistd.h                |   8 +-
 arch/s390/include/asm/vdso-symbols.h          |   8 -
 arch/s390/include/uapi/asm/bitsperlong.h      |   4 -
 arch/s390/include/uapi/asm/ipcbuf.h           |   3 -
 arch/s390/include/uapi/asm/posix_types.h      |  13 -
 arch/s390/include/uapi/asm/ptrace.h           | 124 ---
 arch/s390/include/uapi/asm/sigcontext.h       |  15 -
 arch/s390/include/uapi/asm/stat.h             |  70 --
 arch/s390/include/uapi/asm/unistd.h           |   4 -
 arch/s390/kernel/Makefile                     |   4 -
 arch/s390/kernel/audit.c                      |  16 -
 arch/s390/kernel/audit.h                      |  16 -
 arch/s390/kernel/compat_audit.c               |  48 -
 arch/s390/kernel/compat_linux.c               | 289 ------
 arch/s390/kernel/compat_linux.h               | 101 ---
 arch/s390/kernel/compat_ptrace.h              |  64 --
 arch/s390/kernel/compat_signal.c              | 420 ---------
 arch/s390/kernel/entry.S                      |  17 -
 arch/s390/kernel/perf_cpum_cf.c               |   1 -
 arch/s390/kernel/perf_event.c                 |   1 -
 arch/s390/kernel/perf_regs.c                  |   3 -
 arch/s390/kernel/process.c                    |   9 +-
 arch/s390/kernel/ptrace.c                     | 524 -----------
 arch/s390/kernel/setup.c                      |   1 -
 arch/s390/kernel/signal.c                     |  23 +-
 arch/s390/kernel/stacktrace.c                 |   3 -
 arch/s390/kernel/syscall.c                    |  12 +-
 arch/s390/kernel/syscalls/Makefile            |  58 +-
 arch/s390/kernel/syscalls/syscall.tbl         | 856 ++++++++----------
 arch/s390/kernel/syscalls/syscalltbl          | 232 -----
 arch/s390/kernel/uprobes.c                    |   6 +-
 arch/s390/kernel/vdso.c                       |  26 +-
 arch/s390/kernel/vdso32/.gitignore            |   2 -
 arch/s390/kernel/vdso32/Makefile              |  64 --
 arch/s390/kernel/vdso32/gen_vdso_offsets.sh   |  15 -
 arch/s390/kernel/vdso32/note.S                |  13 -
 arch/s390/kernel/vdso32/vdso32.lds.S          | 140 ---
 arch/s390/kernel/vdso32/vdso32_wrapper.S      |  15 -
 arch/s390/kernel/vdso32/vdso_user_wrapper.S   |  22 -
 arch/s390/kvm/priv.c                          |   2 +-
 arch/s390/mm/fault.c                          |   1 -
 arch/s390/mm/mmap.c                           |   1 -
 arch/s390/pci/pci_clp.c                       |   4 +-
 drivers/s390/block/dasd.c                     |   1 -
 drivers/s390/block/dasd_eckd.c                |  11 -
 drivers/s390/block/dasd_ioctl.c               |   6 +-
 drivers/s390/char/con3270.c                   |  19 -
 drivers/s390/char/fs3270.c                    |   7 +-
 drivers/s390/char/sclp_ctl.c                  |  12 +-
 drivers/s390/char/tape_char.c                 |  26 -
 drivers/s390/char/vmcp.c                      |   7 +-
 drivers/s390/cio/chsc_sch.c                   |   7 +-
 drivers/s390/crypto/zcrypt_api.c              | 195 ----
 drivers/s390/crypto/zcrypt_card.c             |   1 -
 drivers/s390/crypto/zcrypt_queue.c            |   1 -
 drivers/s390/net/qeth_core_main.c             |   4 +-
 .../arch/s390/include/uapi/asm/bitsperlong.h  |   4 -
 tools/build/feature/test-bpf.c                |   2 +-
 tools/include/asm/barrier.h                   |   2 +-
 tools/include/nolibc/arch-s390.h              |   5 -
 tools/include/nolibc/arch.h                   |   2 +-
 tools/include/uapi/asm/bitsperlong.h          |   2 +-
 tools/include/uapi/asm/bpf_perf_event.h       |   2 +-
 tools/lib/bpf/bpf.c                           |   2 +-
 tools/lib/bpf/bpf_tracing.h                   |   2 +-
 tools/lib/bpf/libbpf.c                        |   4 -
 tools/lib/bpf/usdt.c                          |   2 -
 tools/perf/util/header.c                      |   2 +-
 tools/testing/selftests/bpf/sdt.h             |   2 +-
 tools/testing/selftests/bpf/usdt.h            |   2 +-
 .../selftests/ptrace/set_syscall_info.c       |   2 +-
 tools/testing/selftests/rseq/param_test.c     |   2 +-
 tools/testing/selftests/rseq/rseq-s390.h      |  39 -
 tools/testing/selftests/rseq/rseq.h           |   2 +-
 .../selftests/rseq/syscall_errors_test.c      |   2 +-
 tools/testing/selftests/seccomp/seccomp_bpf.c |   4 +-
 tools/testing/selftests/vDSO/vdso_config.h    |   4 -
 91 files changed, 476 insertions(+), 3545 deletions(-)
 delete mode 100644 arch/s390/configs/compat.config
 delete mode 100644 arch/s390/include/asm/compat.h
 delete mode 100644 arch/s390/kernel/audit.h
 delete mode 100644 arch/s390/kernel/compat_audit.c
 delete mode 100644 arch/s390/kernel/compat_linux.c
 delete mode 100644 arch/s390/kernel/compat_linux.h
 delete mode 100644 arch/s390/kernel/compat_ptrace.h
 delete mode 100644 arch/s390/kernel/compat_signal.c
 delete mode 100755 arch/s390/kernel/syscalls/syscalltbl
 delete mode 100644 arch/s390/kernel/vdso32/.gitignore
 delete mode 100644 arch/s390/kernel/vdso32/Makefile
 delete mode 100755 arch/s390/kernel/vdso32/gen_vdso_offsets.sh
 delete mode 100644 arch/s390/kernel/vdso32/note.S
 delete mode 100644 arch/s390/kernel/vdso32/vdso32.lds.S
 delete mode 100644 arch/s390/kernel/vdso32/vdso32_wrapper.S
 delete mode 100644 arch/s390/kernel/vdso32/vdso_user_wrapper.S

-- 
2.48.1

On Mon, Nov 10, 2025, at 19:54, Heiko Carstens wrote:
> Remove s390 compat support to allow for code simplification and especially
> reduced test effort. To the best of our knowledge there aren't any 31 bit
> binaries out in the world anymore that would matter for newer kernels or
> newer distributions.
>
> Distributions do not provide compat packages since quite some time or even
> have CONFIG_COMPAT disabled.
>
> Instead of adding deprecation warnings to config option, or adding kernel
> messages, just remove the code. Deprecation warnings haven't proven to be
> useful. If it turns out there is still a reason to keep the compat support
> this series can be reverted at any time in the future.
>
> Arnd, we talked about this two weeks ago. I would appreciate if you could
> have a look at this series, especially the last patch of this series.
>
> Patches 1-3 are just some random cleanups / preparations.
> Patches 4-6 remove compat support.
> Patches 7-8 switch s390 to generic system call table generation

Loooks good to me overall,

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

I agree it's rather unlikely that anyone is still using 31-bit
binaries, it was only really from 2000 to 2002 that commercial
distros were missing s390x support. Debian moved to 64-bit-only
much later than the others, but had both fewer user and fewer
third-party applications that might require old binaries.

      Arnd