> > A FRED stack frame could contain different amount of information for > > different event types, or perhaps even for different instances of the > > same event type. Thus we need to eliminate the need of any advance > > information of the stack frame size to allow dynamic stack frame size. > > > > Implement it through: > > 1) add a new field user_pt_regs to thread_info, and initialize it > > with a pointer to a virtual pt_regs structure at the top of a > > thread stack. > > 2) save a pointer to the user-space pt_regs structure created by > > fred_entrypoint_user() to user_pt_regs in fred_entry_from_user(). > > 3) initialize the init_thread_info's user_pt_regs with a pointer to > > a virtual pt_regs structure at the top of init stack. > > > > This approach also works for IDT, thus we unify the code. > > And thereby remove the useful comment and replace it with an undocumented > macro mess. > > I'm simply refusing to review this. It's not my job to understand this > undocumented hackery. > I believe it's a nice idea to allow dynamic stack frame size, at least for FRED. It's totally my bad that I didn't make it meet the minimum standards, I will rewrite the commit message and add better comments. After a second thought, I probably should only apply the change to FRED for 2 reasons, the change seems problematic with ESPFIX (which FRED doesn't need), and such corner cases are hard to test (self-tests needed?). Thanks! Xin
