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    SubjectRe: [PATCH 0/8] Update kernel uabi header files for x32
    On Mon, Jan 20, 2014 at 05:46:41PM +0000, H. Peter Anvin wrote:
    > On 12/28/2013 08:33 AM, Christoph Hellwig wrote:
    > > On Fri, Dec 27, 2013 at 02:14:16PM -0800, H.J. Lu wrote:
    > >> X32 uses the same kernel system call interface as x86-64 for many
    > >> system calls. However, "long" is 64-bit for x86-64 and is 32-bit for
    > >> x32. Where long or unsigned long are used in struct types for such
    > >> system calls, they are wrong for x32. __kernel_[u]long_t is [unsigned]
    > >> long for all ABIs other than x32. I am submitting 8 patches to replace
    > >> long or unsigned long with __kernel_[u]long_t so that those struct types
    > >> can be used with x32 system calls.

    Does this mean that you are changing the x32 ABI (or it hasn't been
    declared stable yet)?

    > This comment by Christoph was literally the only feedback on this
    > patchset. The definition of __kernel_[u]long_t is "the size of 'long'
    > for the native kernel for the ABI". H.J.'s patchset only affects x86
    > (specifically x86-64) since on all other platforms __kernel_[u]long_t is
    > simply defined as long/unsigned long.
    >
    > That being said, x32 is not the only ABI of this type. In particular,
    > if the MIPS N32 and ARM64 ILP32 maintainers have suggestions which would
    > make this work more applicable to them, it would be highly useful to
    > receive any such feedback.

    ILP32 for arm64 is still work in progress and subject to change. So far
    the preliminary ABI
    (http://git.kernel.org/cgit/linux/kernel/git/cmarinas/linux-aarch64.git/log/?h=ilp32)
    redefines kernel_(u)long_t is defined as (unsigned) long long. Most of
    the syscalls are 64-bit generic with ~23 routed to compat. I would like
    to simplify these further and even use native 64-bit signal handling but
    it requires some changes to generic structures.

    I'll have a look at H.J.'s patches and give comments, they may come in
    handy.

    --
    Catalin


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