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    Subject[PATCH 3.10 47/53] arm64: fix building without CONFIG_UID16
    Date
    3.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Arnd Bergmann <arnd@arndb.de>

    commit fbc416ff86183e2203cdf975e2881d7c164b0271 upstream.

    As reported by Michal Simek, building an ARM64 kernel with CONFIG_UID16
    disabled currently fails because the system call table still needs to
    reference the individual function entry points that are provided by
    kernel/sys_ni.c in this case, and the declarations are hidden inside
    of #ifdef CONFIG_UID16:

    arch/arm64/include/asm/unistd32.h:57:8: error: 'sys_lchown16' undeclared here (not in a function)
    __SYSCALL(__NR_lchown, sys_lchown16)

    I believe this problem only exists on ARM64, because older architectures
    tend to not need declarations when their system call table is built
    in assembly code, while newer architectures tend to not need UID16
    support. ARM64 only uses these system calls for compatibility with
    32-bit ARM binaries.

    This changes the CONFIG_UID16 check into CONFIG_HAVE_UID16, which is
    set unconditionally on ARM64 with CONFIG_COMPAT, so we see the
    declarations whenever we need them, but otherwise the behavior is
    unchanged.

    Fixes: af1839eb4bd4 ("Kconfig: clean up the long arch list for the UID16 config option")
    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Acked-by: Will Deacon <will.deacon@arm.com>
    Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/linux/syscalls.h | 2 +-
    include/linux/types.h | 2 +-
    2 files changed, 2 insertions(+), 2 deletions(-)

    --- a/include/linux/syscalls.h
    +++ b/include/linux/syscalls.h
    @@ -498,7 +498,7 @@ asmlinkage long sys_chown(const char __u
    asmlinkage long sys_lchown(const char __user *filename,
    uid_t user, gid_t group);
    asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group);
    -#ifdef CONFIG_UID16
    +#ifdef CONFIG_HAVE_UID16
    asmlinkage long sys_chown16(const char __user *filename,
    old_uid_t user, old_gid_t group);
    asmlinkage long sys_lchown16(const char __user *filename,
    --- a/include/linux/types.h
    +++ b/include/linux/types.h
    @@ -35,7 +35,7 @@ typedef __kernel_gid16_t gid16_t;

    typedef unsigned long uintptr_t;

    -#ifdef CONFIG_UID16
    +#ifdef CONFIG_HAVE_UID16
    /* This is defined by include/asm-{arch}/posix_types.h */
    typedef __kernel_old_uid_t old_uid_t;
    typedef __kernel_old_gid_t old_gid_t;

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