On Tue, 2 Apr 2019, Andy Lutomirski wrote: > > On Apr 2, 2019, at 9:48 AM, Thomas Gleixner <t...@linutronix.de> wrote: > > > >> On Tue, 2 Apr 2019, Josh Poimboeuf wrote: > >>> On Tue, Apr 02, 2019 at 12:19:46PM +0200, Thomas Gleixner wrote: > >>> +/* > >>> + * Array of exception stack page descriptors. If the stack is larger than > >>> + * PAGE_SIZE, all pages covering a particular stack will have the same > >>> + * info. > >>> + */ > >>> +static const struct estack_pages estack_pages[ESTACK_PAGES] > >>> ____cacheline_aligned = { > >>> + [CONDRANGE(DF)] = ESTACK_PAGE(DOUBLEFAULT_IST, DF), > >>> + [CONDRANGE(NMI)] = ESTACK_PAGE(NMI_IST, NMI), > >>> + [PAGERANGE(DB)] = ESTACK_PAGE(DEBUG_IST, DB), > >>> + [CONDRANGE(MCE)] = ESTACK_PAGE(MCE_IST, MCE), > >> > >> It would be nice if the *_IST macro naming aligned with the struct > >> cea_exception_stacks field naming. Then you could just do, e.g. > >> ESTACKPAGE(DF). > > > > Yes, lemme fix that up. > > > >> Also it's a bit unfortunate that some of the stack size knowledge is > >> hard-coded here, i.e #DB always being > 1 page and non-#DB being > >> sometimes 1 page. > > > > The problem is that there is no way to make this macro maze conditional on > > sizeof(). But my macro foo is rusty. > > How about a much better fix: make the DB stack be the same size as all > the others and just have 4 of them (DB0, DB1, DB2, and DB3. After all, > overflowing from one debug stack into another is just as much of a bug as > overflowing into a different IST stack.
That makes sense. Thanks, tglx