On Mon, Sep 25, 2023 at 02:57:31PM +0200, Arnd Bergmann wrote: > On Wed, Sep 13, 2023, at 17:22, Miklos Szeredi wrote: > > > asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, > > struct statfs64 __user *buf); > > +asmlinkage long sys_statmnt(u64 mnt_id, u64 mask, > > + struct statmnt __user *buf, size_t bufsize, > > + unsigned int flags); > > This definition is problematic on 32-bit architectures for two > reasons: > > - 64-bit register arguments are passed in pairs of registers > on two architectures, so anything passing those needs to > have a separate entry point for compat syscalls on 64-bit > architectures. I would suggest also using the same one on > 32-bit ones, so you don't rely on the compiler splitting > up the long arguments into pairs. > > - There is a limit of six argument registers for system call > entry points, but with two pairs and three single registers > you end up with seven of them. > > The listmnt syscall in patch 3 also has the first problem, > but not the second. Both fields could also just be moved into the struct itself just like we did for clone3() and others.