On Thu, Mar 29, 2018 at 07:20:27AM -0700, Matthew Wilcox wrote: > On Thu, Mar 29, 2018 at 01:22:37PM +0200, Dominik Brodowski wrote: > > At least on 64-bit x86, it will likely be a hard requirement from v4.17 > > onwards to not call system call functions in the kernel: It is better to > > use use a different calling convention for system calls there, where > > struct pt_regs is decoded on-the-fly in a syscall wrapper which then hands > > processing over to the actual syscall function. This means that only those > > parameters which are actually needed for a specific syscall are passed on > > during syscall entry, instead of filling in six CPU registers with random > > user space content all the time (which may cause serious trouble down the > > call chain).[*] > > How do we stop new ones from springing up? Some kind of linker trick > like was used to, er, "dissuade" people from using gets()? Once the patches which modify the syscall calling convention are merged, it won't compile on 64-bit x86, but bark loudly. That should frighten anyone. Meow. Thanks, Dominik
