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.
Arnd
