Re: in_compat_syscall() on x86

[Al Viro]

On Tue, Jan 05, 2021 at 06:03:15PM -0600, Eric W. Biederman wrote:
> > Yes, the current mainline is bloody awful in that area (PRSTATUS_SIZE and
> > SET_PR_FPVALID are not for weak stomach), but that's really not hard to
> > get into sane shape - -next had that done in last cycle and I'm currently
> > testing (well, building the test kernel) of port of that to 5.11-rc1.
> 
> That does sound interesting.  Anytime we can clean up arch specific
> weirdness so that it simply becomes generic weirdness and it can be
> tested and maintained by more people is always nice.

vfs.git #work.elf-compat, and AFAICS it works.

 arch/Kconfig                               |   3 ++
 arch/arm64/Kconfig                         |   1 -
 arch/ia64/kernel/crash.c                   |   2 +-
 arch/mips/Kconfig                          |   8 ++----
 arch/mips/include/asm/elf.h                |  56 +++++++++++++-----------------------
 arch/mips/include/asm/elfcore-compat.h     |  29 +++++++++++++++++++
 arch/mips/kernel/Makefile                  |   4 +--
 arch/mips/kernel/binfmt_elfn32.c           | 106 --------------------------------------------------------------------
 arch/mips/kernel/binfmt_elfo32.c           | 109 ----------------------------------------------------------------------
 arch/mips/kernel/scall64-n64.S             |   2 +-
 arch/parisc/Kconfig                        |   1 -
 arch/powerpc/Kconfig                       |   1 -
 arch/powerpc/platforms/powernv/opal-core.c |   6 ++--
 arch/s390/Kconfig                          |   1 -
 arch/s390/kernel/crash_dump.c              |   2 +-
 arch/sparc/Kconfig                         |   1 -
 arch/x86/Kconfig                           |   2 +-
 arch/x86/include/asm/compat.h              |  11 -------
 arch/x86/include/asm/elf.h                 |   2 +-
 arch/x86/include/asm/elfcore-compat.h      |  31 ++++++++++++++++++++
 fs/Kconfig.binfmt                          |   2 +-
 fs/binfmt_elf.c                            |  19 ++++++-------
 fs/binfmt_elf_fdpic.c                      |  22 ++++----------
 fs/compat_binfmt_elf.c                     |   7 +----
 include/linux/elfcore-compat.h             |  15 ++++++++--
 include/linux/elfcore.h                    |   7 ++++-
 kernel/kexec_core.c                        |   2 +-
 28 files changed, 128 insertions(+), 324 deletions(-)
 create mode 100644 arch/mips/include/asm/elfcore-compat.h
 delete mode 100644 arch/mips/kernel/binfmt_elfn32.c
 delete mode 100644 arch/mips/kernel/binfmt_elfo32.c
 create mode 100644 arch/x86/include/asm/elfcore-compat.h