On Fri, Feb 11, 2022 at 1:17 AM Stafford Horne <shorne@xxxxxxxxx> wrote: > On Thu, Feb 10, 2022 at 08:31:05AM +0900, Stafford Horne wrote: > > > Looking at it again, I wonder if it would help to use the __get_kernel_nofault() > > > and __get_kernel_nofault() helpers as the default in > > > include/asm-generic/uaccess.h. > > > > That would make sense. Perhaps also the __range_ok() function from OpenRISC > > could move there as I think other architectures would also want to use that. I have now uploaded a cleanup series to https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/log/?h=set_fs This uses the same access_ok() function across almost all architectures, with the exception of those that need something else, and I then I went further and killed off set_fs for everything other than ia64. > > > I see it's identical to the openrisc version and would probably be the same > > > for some of the other architectures that have no other use for > > > set_fs(). That may > > > help to do a bulk remove of set_fs for alpha, arc, csky, h8300, hexagon, nds32, > > > nios2, um and extensa, leaving only ia64, sparc and sh. > > > > If you could add it into include/asm-generic/uaccess.h I can test changing my > > patch to use it. > > Note, I would be happy to do the work to move these into include/asm-generic/uaccess.h. > But as I see it the existing include/asm-generic/uaccess.h is for NOMMU. How > should we go about having an MMU and NOMMU version? Should we move uaccess.h to > uaccess-nommu.h? Or add more ifdefs to uaccess.h? There are two parts of asm-generic/uaccess.h: - the CONFIG_UACCESS_MEMCPYsection is fundamentally limited to nommu targets and cannot be shared. Similarly, targets with an MMU must use a custom implementation to get the correct fixups. - the put_user/get_user implementation is fairly dumb, you can use these to avoid having your own ones, but you still need copy_{to,from}_user, and a custom implementation tends to produce better code. So chances are that you won't want to use either one. In my new branch, I added the common helpers to linux/uaccess.h and asm-generic/access-ok.h, respectively, both of which are used everywhere now. Arnd
