On Fri, 13 Dec 2019 at 02:31, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: > > On Thu, Dec 12, 2019 at 10:11:59PM +0100, Marco Elver wrote: > > On Tue, 3 Dec 2019 at 17:01, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: > > > > > > On Mon, Dec 02, 2019 at 09:30:22PM -0800, Randy Dunlap wrote: > > > > On 11/26/19 6:04 AM, Marco Elver wrote: > > > > > Prefer __always_inline for fast-path functions that are called outside > > > > > of user_access_save, to avoid generating UACCESS warnings when > > > > > optimizing for size (CC_OPTIMIZE_FOR_SIZE). It will also avoid future > > > > > surprises with compiler versions that change the inlining heuristic even > > > > > when optimizing for performance. > > > > > > > > > > Report: http://lkml.kernel.org/r/58708908-84a0-0a81-a836-ad97e33dbb62@xxxxxxxxxxxxx > > > > > Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > > > > > Signed-off-by: Marco Elver <elver@xxxxxxxxxx> > > > > > > > > Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested > > > > > > Thank you, Randy! > > > > Hoped this would have applied by now, but since KCSAN isn't in > > mainline yet, should I send a version of this patch rebased on > > -rcu/kcsan? > > It will just conflict with the style cleanup that is in > > -tip/locking/kcsan when another eventual merge happens. Alternatively, > > we can delay it for now and just have to remember to apply eventually > > (and have to live with things being messy for a bit longer :-)). > > Excellent question. ;-) > > The first several commits are in -tip already, so they will go upstream > in their current state by default. And a bunch of -tip commits have > already been merged on top of them, so it might not be easy to move them. > > So please feel free to port the patch to -rcu/ksan and let's see how that > plays out. If it gets too ugly, then maybe wait until the current set > of patches go upstream. > > Another option is to port them to the kcsan merge point in -rcu. That > would bring in v5.5-rc1. Would that help? For this patch it won't help, since it only conflicts with changes in this commit which is not in v5.5-rc1: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=locking/kcsan&id=5cbaefe9743bf14c9d3106db0cc19f8cb0a3ca22 However, for this patch there are only 3 locations in kernel/kcsan/{core.c,encoding.h} that conflict, and all of them should be trivial to resolve. For the version rebased against -rcu/kcsan, in the conflicting locations I simply carried over the better style, so that upon eventual merge the resolution should be trivial (I hope). I have sent the rebased version here: http://lkml.kernel.org/r/20191213204946.251125-1-elver@xxxxxxxxxx Unrelated to this patch, we also deferred the updated bitops patch which now applies on top of v5.5-rc1: http://lkml.kernel.org/r/20191115115524.GA77379@xxxxxxxxxx but doesn't apply to -rcu/kcsan. I think the bitops patch isn't terribly urgent, so it could wait to avoid further confusion. Many thanks, -- Marco > Thanx, Paul > > > The version as-is here applies on -tip/locking/kcsan and -next (which > > merged -tip/locking/kcsan). > > > > Thanks, > > -- Marco > > > > > > > Thanx, Paul > > > > > > > Thanks. > > > > > > > > > --- > > > > > Rebased on: locking/kcsan branch of tip tree. > > > > > --- > > > > > kernel/kcsan/atomic.h | 2 +- > > > > > kernel/kcsan/core.c | 16 +++++++--------- > > > > > kernel/kcsan/encoding.h | 14 +++++++------- > > > > > 3 files changed, 15 insertions(+), 17 deletions(-) > > > > > > > > > > diff --git a/kernel/kcsan/atomic.h b/kernel/kcsan/atomic.h > > > > > index 576e03ddd6a3..a9c193053491 100644 > > > > > --- a/kernel/kcsan/atomic.h > > > > > +++ b/kernel/kcsan/atomic.h > > > > > @@ -18,7 +18,7 @@ > > > > > * than cast to volatile. Eventually, we hope to be able to remove this > > > > > * function. > > > > > */ > > > > > -static inline bool kcsan_is_atomic(const volatile void *ptr) > > > > > +static __always_inline bool kcsan_is_atomic(const volatile void *ptr) > > > > > { > > > > > /* only jiffies for now */ > > > > > return ptr == &jiffies; > > > > > diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c > > > > > index 3314fc29e236..c616fec639cd 100644 > > > > > --- a/kernel/kcsan/core.c > > > > > +++ b/kernel/kcsan/core.c > > > > > @@ -78,10 +78,8 @@ static atomic_long_t watchpoints[CONFIG_KCSAN_NUM_WATCHPOINTS + NUM_SLOTS-1]; > > > > > */ > > > > > static DEFINE_PER_CPU(long, kcsan_skip); > > > > > > > > > > -static inline atomic_long_t *find_watchpoint(unsigned long addr, > > > > > - size_t size, > > > > > - bool expect_write, > > > > > - long *encoded_watchpoint) > > > > > +static __always_inline atomic_long_t * > > > > > +find_watchpoint(unsigned long addr, size_t size, bool expect_write, long *encoded_watchpoint) > > > > > { > > > > > const int slot = watchpoint_slot(addr); > > > > > const unsigned long addr_masked = addr & WATCHPOINT_ADDR_MASK; > > > > > @@ -146,7 +144,7 @@ insert_watchpoint(unsigned long addr, size_t size, bool is_write) > > > > > * 2. the thread that set up the watchpoint already removed it; > > > > > * 3. the watchpoint was removed and then re-used. > > > > > */ > > > > > -static inline bool > > > > > +static __always_inline bool > > > > > try_consume_watchpoint(atomic_long_t *watchpoint, long encoded_watchpoint) > > > > > { > > > > > return atomic_long_try_cmpxchg_relaxed(watchpoint, &encoded_watchpoint, CONSUMED_WATCHPOINT); > > > > > @@ -160,7 +158,7 @@ static inline bool remove_watchpoint(atomic_long_t *watchpoint) > > > > > return atomic_long_xchg_relaxed(watchpoint, INVALID_WATCHPOINT) != CONSUMED_WATCHPOINT; > > > > > } > > > > > > > > > > -static inline struct kcsan_ctx *get_ctx(void) > > > > > +static __always_inline struct kcsan_ctx *get_ctx(void) > > > > > { > > > > > /* > > > > > * In interrupts, use raw_cpu_ptr to avoid unnecessary checks, that would > > > > > @@ -169,7 +167,7 @@ static inline struct kcsan_ctx *get_ctx(void) > > > > > return in_task() ? ¤t->kcsan_ctx : raw_cpu_ptr(&kcsan_cpu_ctx); > > > > > } > > > > > > > > > > -static inline bool is_atomic(const volatile void *ptr) > > > > > +static __always_inline bool is_atomic(const volatile void *ptr) > > > > > { > > > > > struct kcsan_ctx *ctx = get_ctx(); > > > > > > > > > > @@ -193,7 +191,7 @@ static inline bool is_atomic(const volatile void *ptr) > > > > > return kcsan_is_atomic(ptr); > > > > > } > > > > > > > > > > -static inline bool should_watch(const volatile void *ptr, int type) > > > > > +static __always_inline bool should_watch(const volatile void *ptr, int type) > > > > > { > > > > > /* > > > > > * Never set up watchpoints when memory operations are atomic. > > > > > @@ -226,7 +224,7 @@ static inline void reset_kcsan_skip(void) > > > > > this_cpu_write(kcsan_skip, skip_count); > > > > > } > > > > > > > > > > -static inline bool kcsan_is_enabled(void) > > > > > +static __always_inline bool kcsan_is_enabled(void) > > > > > { > > > > > return READ_ONCE(kcsan_enabled) && get_ctx()->disable_count == 0; > > > > > } > > > > > diff --git a/kernel/kcsan/encoding.h b/kernel/kcsan/encoding.h > > > > > index b63890e86449..f03562aaf2eb 100644 > > > > > --- a/kernel/kcsan/encoding.h > > > > > +++ b/kernel/kcsan/encoding.h > > > > > @@ -59,10 +59,10 @@ encode_watchpoint(unsigned long addr, size_t size, bool is_write) > > > > > (addr & WATCHPOINT_ADDR_MASK)); > > > > > } > > > > > > > > > > -static inline bool decode_watchpoint(long watchpoint, > > > > > - unsigned long *addr_masked, > > > > > - size_t *size, > > > > > - bool *is_write) > > > > > +static __always_inline bool decode_watchpoint(long watchpoint, > > > > > + unsigned long *addr_masked, > > > > > + size_t *size, > > > > > + bool *is_write) > > > > > { > > > > > if (watchpoint == INVALID_WATCHPOINT || > > > > > watchpoint == CONSUMED_WATCHPOINT) > > > > > @@ -78,13 +78,13 @@ static inline bool decode_watchpoint(long watchpoint, > > > > > /* > > > > > * Return watchpoint slot for an address. > > > > > */ > > > > > -static inline int watchpoint_slot(unsigned long addr) > > > > > +static __always_inline int watchpoint_slot(unsigned long addr) > > > > > { > > > > > return (addr / PAGE_SIZE) % CONFIG_KCSAN_NUM_WATCHPOINTS; > > > > > } > > > > > > > > > > -static inline bool matching_access(unsigned long addr1, size_t size1, > > > > > - unsigned long addr2, size_t size2) > > > > > +static __always_inline bool matching_access(unsigned long addr1, size_t size1, > > > > > + unsigned long addr2, size_t size2) > > > > > { > > > > > unsigned long end_range1 = addr1 + size1 - 1; > > > > > unsigned long end_range2 = addr2 + size2 - 1; > > > > > > > > > > > > > > > > > -- > > > > ~Randy > > > > > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20191213013127.GE2889%40paulmck-ThinkPad-P72.
