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    SubjectRe: [PATCH 0/5] s390: rework compat wrapper generation
    On Wed, Jan 16, 2019 at 02:15:18PM +0100, Arnd Bergmann wrote:
    > Hi Heiko and Martin,
    >
    > As promised, I gave this a go and changed the SYSCALL_DEFINEx()
    > infrastructure to always include the wrappers for doing the
    > 31-bit argument conversion on s390 compat mode.
    >
    > This does three main things:
    >
    > - The UID16 rework saved a lot of duplicated code, and would
    > probably make sense by itself, but is also required as
    > we can no longer call sys_*() functions directly after the
    > last step.
    >
    > - Removing the compat_wrapper.c file is of course the main
    > goal here, in order to remove the need to maintain the
    > compat_wrapper.c file when new system calls get added.
    > Unfortunately, this requires adding some complexity in
    > syscall_wrapper.h, and trades a small reduction in source
    > code lines for a small increase in binary size for
    > unused wrappers.
    >
    > - As an added benefit, the use of syscall_wrapper.h now makes
    > it easy to change the syscall wrappers so they no longer
    > see all user space register contents, similar to changes
    > done in commits fa697140f9a2 ("syscalls/x86: Use 'struct pt_regs'
    > based syscall calling convention for 64-bit syscalls") and
    > 4378a7d4be30 ("arm64: implement syscall wrappers").
    > I leave the actual implementation of this for you, if you
    > want to do it later.
    >
    > I did not test the changes at runtime, but I looked at the
    > generated object code, which seems fine here and includes
    > the same conversions as before.

    This work is highly appreciated! I'll look into this tomorrow.

    Thanks!

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