Ralf Baechle wrote: > On Mon, Dec 15, 2008 at 12:36:14PM +0100, Gerd Hoffmann wrote: > >> Next revision of the patch series, with the alignment issue fixed by >> swapping the last two arguments as suggested by arch maintainers. >> >> I've dropped the now-obsolete wrappers for mips. Ralf, please >> double-check. > > It fixes the alignment issue but still won't work; on MIPS 32-bit userspace > will pass the 64-bit argument in two registers but the 64-bit kernel code > will assume it to be passed in a single registers. It'd be ugly but passing > a pointer to a 64-bit argument would solve the issue; something like this: > > sys_preadv(unsigned long fd, const struct iovec __user *vec, > unsigned long vlen, loff_t __user *pos); > compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec, > unsigned long vlen, loff_t __user *pos);
Suggestion from the s390 front was to explicitly pass high and low part of pos as two arguments. A bit ugly too, but should work fine as well and it avoids the user pointer dereference. What do you think about this? > sys_splice uses loff_t __user * arguments as well and that's why it's > doesn't need any compat wrapper. Well, avoiding the compat wrapper altogether unfortunately isn't going to work because struct iovec looks different in 32 and 64 bit. > I'm surprised this works for x86; does x86-64 code really expect 64-bit > arguments as 2 32-bit arguments? Args are passed on the stack, not in registers. > Patch 1/3 looks like it's a bug fix and you may want to submit this > separate from the remainder of the series for 2.6.28? Yep, it is a separate bugfix. Spotted by Christoph while reviewing v1, but there are no other dependencies to this patch series. cheers, Gerd -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
