On Mon, Jul 23, 2018 at 5:38 AM, Dave Hansen <dave.han...@linux.intel.com> wrote: > On 07/22/2018 10:45 AM, Andy Lutomirski wrote: >> + /* >> + * sp2 is scratch space used by the SYSCALL64 handler. Linux does >> + * not use rung 2, so sp2 is not otherwise needed. >> + */ >> u64 sp2; > > Could we call out the actual thing that we use this slot for, and the > symbol name so folks can find the corresponding code that does this? > While I know the spot in entry_64 you're talking about, it might not be > patently obvious to everyone, and it's also a bit more challenging to > grep for than normal C code. > > Maybe: > > /* > * Since Linux does not use ring 2, the 'sp2' slot is unused. > * entry_SYSCALL_64 uses this as scratch space to stash the user > * %RSP value. > */
I'll improve this for v2.
