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author | bz <bz@FreeBSD.org> | 2009-08-14 21:46:54 +0000 |
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committer | bz <bz@FreeBSD.org> | 2009-08-14 21:46:54 +0000 |
commit | bf6acf798532962c108b5e0944b855cf7cfb5ff8 (patch) | |
tree | ea52f93659c64af89eda73d8980d2b5ab4e028a9 /sys | |
parent | d51166f15e1c08fdaa3df0992553ad5127da220c (diff) | |
download | FreeBSD-src-bf6acf798532962c108b5e0944b855cf7cfb5ff8.zip FreeBSD-src-bf6acf798532962c108b5e0944b855cf7cfb5ff8.tar.gz |
Add a new macro to test that a variable could be loaded atomically.
Check that the given variable is at most uintptr_t in size and that
it is aligned.
Note: ASSERT_ATOMIC_LOAD() uses ALIGN() to check for adequate
alignment -- however, the function of ALIGN() is to guarantee
alignment, and therefore may lead to stronger alignment
enforcement than necessary for types that are smaller than
sizeof(uintptr_t).
Add checks to mtx, rw and sx locks init functions to detect possible
breakage. This was used during debugging of the problem fixed with
r196118 where a pointer was on an un-aligned address in the dpcpu area.
In collaboration with: rwatson
Reviewed by: rwatson
Approved by: re (kib)
Diffstat (limited to 'sys')
-rw-r--r-- | sys/kern/kern_mutex.c | 2 | ||||
-rw-r--r-- | sys/kern/kern_rwlock.c | 2 | ||||
-rw-r--r-- | sys/kern/kern_sx.c | 2 | ||||
-rw-r--r-- | sys/sys/systm.h | 4 |
4 files changed, 10 insertions, 0 deletions
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c index fc342c5..f625098 100644 --- a/sys/kern/kern_mutex.c +++ b/sys/kern/kern_mutex.c @@ -783,6 +783,8 @@ mtx_init(struct mtx *m, const char *name, const char *type, int opts) MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0); + ASSERT_ATOMIC_LOAD(m->mtx_lock, ("%s: mtx_lock not aligned for %s: %p", + __func__, name, &m->mtx_lock)); #ifdef MUTEX_DEBUG /* Diagnostic and error correction */ diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c index c07f595..e234250 100644 --- a/sys/kern/kern_rwlock.c +++ b/sys/kern/kern_rwlock.c @@ -174,6 +174,8 @@ rw_init_flags(struct rwlock *rw, const char *name, int opts) MPASS((opts & ~(RW_DUPOK | RW_NOPROFILE | RW_NOWITNESS | RW_QUIET | RW_RECURSE)) == 0); + ASSERT_ATOMIC_LOAD(rw->rw_lock, ("%s: rw_lock not aligned for %s: %p", + __func__, name, &rw->rw_lock)); flags = LO_UPGRADABLE; if (opts & RW_DUPOK) diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c index 04c2c98..15c1c9b 100644 --- a/sys/kern/kern_sx.c +++ b/sys/kern/kern_sx.c @@ -205,6 +205,8 @@ sx_init_flags(struct sx *sx, const char *description, int opts) MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK | SX_NOPROFILE | SX_NOADAPTIVE)) == 0); + ASSERT_ATOMIC_LOAD(sx->sx_lock, ("%s: sx_lock not aligned for %s: %p", + __func__, description, &sx->sx_lock)); flags = LO_SLEEPABLE | LO_UPGRADABLE; if (opts & SX_DUPOK) diff --git a/sys/sys/systm.h b/sys/sys/systm.h index 1956a8f..2e8b9ad 100644 --- a/sys/sys/systm.h +++ b/sys/sys/systm.h @@ -89,6 +89,10 @@ extern int maxusers; /* system tune hint */ #define __CTASSERT(x, y) typedef char __assert ## y[(x) ? 1 : -1] #endif +#define ASSERT_ATOMIC_LOAD(var,msg) \ + KASSERT(sizeof(var) <= sizeof(uintptr_t) && \ + ALIGN(&(var)) == (uintptr_t)&(var), msg) + /* * XXX the hints declarations are even more misplaced than most declarations * in this file, since they are needed in one file (per arch) and only used |