On Thu, Nov 01, 2018 at 12:10:35PM -0700, Linus Torvalds wrote: > On Thu, Nov 1, 2018 at 11:52 AM Rich Felker <dalias@xxxxxxxx> wrote: > > > > There's no need to chain if the handler is specific to the context > > where the fault happens. You just replace the handler with the one > > relevant to the code you're about to run before you run it. > > That's much too expensive to do as a system call. See my other emails in this thread. You would register the *address* (in TLS) of a function pointer object pointing to the handler, rather than the function address of the handler. Then switching handler is just a single store in userspace, no syscalls involved. Rich
