[PATCH 0/8] s390: Remove compat support

Heiko Carstens
2025-11-13T15:08:04Z

Changes since RFC:

- Reduce changes to tools to a minimum: only change __s390__ to __s390x__
guards if this comes with code removal. This avoids unnecessary churn and
potential merge conflicts

- Completely remove 32-bit s390 support from nolibc

- Explicitly use sys_ni_syscall as entry point for dead system calls for
which system call numbers still exists

- Add Arnd's Reviewed-by tag to all patches

RFC: https://lore.kernel.org/r/20251110185440.2667511-1-hca@linux.ibm.com/

---

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

Arnd, I added your Reviewed-by also to the first patch, even though this is
the only one of this series with some larger changes compared to the RFC.
Let me know if you are not ok with this.

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/include/nolibc/arch-s390.h | 5 -
tools/include/nolibc/arch.h | 2 +-
tools/lib/bpf/libbpf.c | 4 -
tools/lib/bpf/usdt.c | 2 -
.../testing/selftests/nolibc/Makefile.nolibc | 5 -
tools/testing/selftests/nolibc/run-tests.sh | 6 +-
tools/testing/selftests/rseq/rseq-s390.h | 39 -
tools/testing/selftests/vDSO/vdso_config.h | 4 -
79 files changed, 462 insertions(+), 3540 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