* Change the scope of the ASSERT_ATOMIC_LOAD() from a generic check to
a pointer-fetching specific operation check. Consequently, rename the operation ASSERT_ATOMIC_LOAD_PTR(). * Fix the implementation of ASSERT_ATOMIC_LOAD_PTR() by checking directly alignment on the word boundry, for all the given specific architectures. That's a bit too strict for some common case, but it assures safety. * Add a comment explaining the scope of the macro * Add a new stub in the lockmgr specific implementation Tested by: marcel (initial version), marius Reviewed by: rwatson, jhb (comment specific review) Approved by: re (kib)
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=196334
@ -334,6 +334,9 @@ lockinit(struct lock *lk, int pri, const char *wmesg, int timo, int flags)
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int iflags;
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MPASS((flags & ~LK_INIT_MASK) == 0);
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ASSERT_ATOMIC_LOAD_PTR(lk->lk_lock,
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("%s: lockmgr not aligned for %s: %p", __func__, wmesg,
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&lk->lk_lock));
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iflags = LO_SLEEPABLE | LO_UPGRADABLE;
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if (flags & LK_CANRECURSE)
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@ -783,8 +783,9 @@ mtx_init(struct mtx *m, const char *name, const char *type, int opts)
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MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
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MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0);
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ASSERT_ATOMIC_LOAD(m->mtx_lock, ("%s: mtx_lock not aligned for %s: %p",
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__func__, name, &m->mtx_lock));
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ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
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("%s: mtx_lock not aligned for %s: %p", __func__, name,
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&m->mtx_lock));
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#ifdef MUTEX_DEBUG
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/* Diagnostic and error correction */
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@ -174,8 +174,9 @@ rw_init_flags(struct rwlock *rw, const char *name, int opts)
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MPASS((opts & ~(RW_DUPOK | RW_NOPROFILE | RW_NOWITNESS | RW_QUIET |
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RW_RECURSE)) == 0);
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ASSERT_ATOMIC_LOAD(rw->rw_lock, ("%s: rw_lock not aligned for %s: %p",
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__func__, name, &rw->rw_lock));
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ASSERT_ATOMIC_LOAD_PTR(rw->rw_lock,
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("%s: rw_lock not aligned for %s: %p", __func__, name,
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&rw->rw_lock));
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flags = LO_UPGRADABLE;
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if (opts & RW_DUPOK)
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@ -205,8 +205,9 @@ sx_init_flags(struct sx *sx, const char *description, int opts)
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MPASS((opts & ~(SX_QUIET | SX_RECURSE | SX_NOWITNESS | SX_DUPOK |
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SX_NOPROFILE | SX_NOADAPTIVE)) == 0);
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ASSERT_ATOMIC_LOAD(sx->sx_lock, ("%s: sx_lock not aligned for %s: %p",
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__func__, description, &sx->sx_lock));
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ASSERT_ATOMIC_LOAD_PTR(sx->sx_lock,
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("%s: sx_lock not aligned for %s: %p", __func__, description,
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&sx->sx_lock));
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flags = LO_SLEEPABLE | LO_UPGRADABLE;
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if (opts & SX_DUPOK)
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@ -89,9 +89,16 @@ extern int maxusers; /* system tune hint */
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#define __CTASSERT(x, y) typedef char __assert ## y[(x) ? 1 : -1]
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#endif
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#define ASSERT_ATOMIC_LOAD(var,msg) \
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KASSERT(sizeof(var) <= sizeof(uintptr_t) && \
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ALIGN(&(var)) == (uintptr_t)&(var), msg)
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/*
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* Assert that a pointer can be loaded from memory atomically.
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*
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* This assertion enforces stronger alignment than necessary. For example,
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* on some architectures, atomicity for unaligned loads will depend on
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* whether or not the load spans multiple cache lines.
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*/
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#define ASSERT_ATOMIC_LOAD_PTR(var, msg) \
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KASSERT(sizeof(var) == sizeof(void *) && \
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((uintptr_t)&(var) & (sizeof(void *) - 1)) == 0, msg)
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/*
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* XXX the hints declarations are even more misplaced than most declarations
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