On Tue, Jul 06, 2021 at 11:36:26AM -0700, Linus Torvalds wrote:
On Mon, Jul 5, 2021 at 9:13 PM Christoph Hellwig <hch@xxxxxx> wrote:It still needs "real" kernel-style set_fs for the mm/maccess.c routines, but adding __{get,put}_kernel_nofault should not be too hard.Yeah, it's not that it wants set-fs(), it's that I missed that m68k doesn't have HAVE_GET_KERNEL_NOFAULT. Implementing __get/put_kernel_nofault() should be fairly straightforward: they are basically the same thing as the __get/put_user() functions, except they should just use "move" instead of "moves". The m68k uaccess.h file already kind of has support for that, but it's hardcoded to the CONFIG_CPU_HAS_ADDRESS_SPACES config, rather than being available as two different versions.
So I've come up with a whole (compile tested only) series. We don't really need the preempt_disable either given the m68k saves and restores the SFC/DFC registers on context switch: http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/m68k-set_fs
