"Nicholas Piggin" <npig...@gmail.com> writes: > On Mon Jun 5, 2023 at 6:58 PM AEST, Christophe Leroy wrote: >> Looking at generated code for handle_signal32() shows calls to a >> function called __unsafe_save_user_regs.constprop.0 while user access >> is open. >> >> And that __unsafe_save_user_regs.constprop.0 function has two nops at >> the begining, allowing it to be traced, which is unexpected during >> user access open window. >> >> The solution could be to mark __unsafe_save_user_regs() no trace, but >> to be on the safe side the most efficient is to flag it __always_inline >> as already done for function __unsafe_restore_general_regs(). The >> function is relatively small and only called twice, so the size >> increase will remain in the noise. >> >> Do the same with save_tm_user_regs_unsafe() as it may suffer the >> same issue. > > Could you put a comment so someone doesn't uninline it later?
I think the "unsafe" in the name is probably sufficient to warn people off, but you never know. Still I'd happily take a patch to add comments :) > Marking it notrace as well would be sufficient for a comment, if that works. I nearly did that when applying, but I'm not sure it won't change the code generation, so I left it as-is. cheers
