On Wed, Jan 31, 2018 at 5:17 PM, Will Deacon <[email protected]> wrote: >> > * Will Deacon <[email protected]> wrote: >> >> e.g. for atomic[64]_read, your asm-generic header looks like: >> >> >> >> #ifndef _LINUX_ATOMIC_INSTRUMENTED_H >> >> #define _LINUX_ATOMIC_INSTRUMENTED_H >> >> >> >> #include <linux/build_bug.h> >> >> #include <linux/kasan-checks.h> >> >> >> >> static __always_inline int __atomic_read_instrumented(const atomic_t *v) >> >> { >> >> kasan_check_read(v, sizeof(*v)); >> >> return atomic_read(v); >> >> } >> >> >> >> static __always_inline s64 __atomic64_read_instrumented(const atomic64_t >> >> *v) >> >> { >> >> kasan_check_read(v, sizeof(*v)); >> >> return atomic64_read(v); >> >> } >> >> >> >> #undef atomic_read >> >> #undef atomic64_read >> >> >> >> #define atomic_read __atomic_read_instrumented >> >> #define atomic64_read __atomic64_read_instrumented >> >> >> >> #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ >> >> >> >> and the arch code just includes that in asm/atomic.h once it's done with >> >> its definitions. >> >> >> >> What do you think? Too stinky? >> > >> > Hm, so while this could work - I actually *like* the low level changes: >> > they are >> > straightforward, trivial, easy to read and they add the arch_ prefix that >> > makes it >> > abundantly clear that this isn't the highest level interface. >> > >> > The KASAN callbacks in the generic methods are also abundantly clear and >> > very easy >> > to read. I could literally verify the sanity of the series while still >> > being only >> > half awake. ;-) >> > >> > Also note that the arch renaming should be 'trivial', in the sense that any >> > missing rename results in a clear build breakage. Plus any architecture >> > making use >> > of this new KASAN feature should probably be tested before it's enabled - >> > and the >> > renaming of the low level atomic APIs kind of forces that too. >> > >> > So while this approach creates some churn, this series is IMHO a marked >> > improvement over the previous iterations. >> >> >> I think I mildly leaning towards Ingo's point. >> I guess people will first find the version in arch (because that's >> where they used to be), but that version is actually not the one that >> is called. >> The renaming is mechanical and you get build errors if anything is >> wrong. It's macros that caused hard to debug runtime crashes and >> multiple revisions of this series. > > Sure, and it sounds like you're proposing to do the arm64 changes anyway so > I'm not complaining! Just thought I'd float the alternative to see what > people think.
Any other comments? Ingo, will you take this to locking tree?
