Index: kernel/arch/ia64/src/mm/as.c =================================================================== --- kernel/arch/ia64/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/arch/ia64/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -37,9 +37,8 @@ #include #include +#include #include #include -#include #include -#include /** Architecture dependent address space init. */ @@ -56,10 +55,6 @@ void as_install_arch(as_t *as) { - ipl_t ipl; region_register rr; int i; - - ipl = interrupts_disable(); - spinlock_lock(&as->lock); ASSERT(as->asid != ASID_INVALID); @@ -81,7 +76,4 @@ srlz_d(); srlz_i(); - - spinlock_unlock(&as->lock); - interrupts_restore(ipl); } Index: kernel/arch/mips32/src/mm/as.c =================================================================== --- kernel/arch/mips32/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/arch/mips32/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -35,4 +35,5 @@ #include #include +#include #include #include @@ -40,5 +41,4 @@ #include #include -#include /** Architecture dependent address space init. */ @@ -58,5 +58,4 @@ { entry_hi_t hi; - ipl_t ipl; /* @@ -65,10 +64,6 @@ hi.value = cp0_entry_hi_read(); - ipl = interrupts_disable(); - spinlock_lock(&as->lock); hi.asid = as->asid; cp0_entry_hi_write(hi.value); - spinlock_unlock(&as->lock); - interrupts_restore(ipl); } Index: kernel/arch/ppc32/src/mm/as.c =================================================================== --- kernel/arch/ppc32/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/arch/ppc32/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -55,10 +55,6 @@ { asid_t asid; - ipl_t ipl; uint32_t sr; - ipl = interrupts_disable(); - spinlock_lock(&as->lock); - asid = as->asid; @@ -80,7 +76,4 @@ ); } - - spinlock_unlock(&as->lock); - interrupts_restore(ipl); } Index: kernel/arch/ppc64/src/mm/as.c =================================================================== --- kernel/arch/ppc64/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/arch/ppc64/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -27,5 +27,5 @@ */ - /** @addtogroup ppc64mm +/** @addtogroup ppc64mm * @{ */ @@ -42,5 +42,5 @@ } - /** @} +/** @} */ Index: kernel/arch/sparc64/src/mm/as.c =================================================================== --- kernel/arch/sparc64/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/arch/sparc64/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -43,5 +43,4 @@ #include #include -#include #include #include @@ -101,11 +100,5 @@ { #ifdef CONFIG_TSB - ipl_t ipl; - - ipl = interrupts_disable(); - mutex_lock_active(&as->lock); /* completely unnecessary, but polite */ tsb_invalidate(as, 0, (count_t) -1); - mutex_unlock(&as->lock); - interrupts_restore(ipl); #endif return 0; @@ -124,16 +117,15 @@ /* - * Note that we don't lock the address space. - * That's correct - we can afford it here - * because we only read members that are - * currently read-only. + * Note that we don't and may not lock the address space. That's ok + * since we only read members that are currently read-only. + * + * Moreover, the as->asid is protected by asidlock, which is being held. */ /* - * Write ASID to secondary context register. - * The primary context register has to be set - * from TL>0 so it will be filled from the - * secondary context register from the TL=1 - * code just before switch to userspace. + * Write ASID to secondary context register. The primary context + * register has to be set from TL>0 so it will be filled from the + * secondary context register from the TL=1 code just before switch to + * userspace. */ ctx.v = 0; @@ -185,8 +177,8 @@ /* - * Note that we don't lock the address space. - * That's correct - we can afford it here - * because we only read members that are - * currently read-only. + * Note that we don't and may not lock the address space. That's ok + * since we only read members that are currently read-only. + * + * Moreover, the as->asid is protected by asidlock, which is being held. */ Index: kernel/genarch/src/mm/asid.c =================================================================== --- kernel/genarch/src/mm/asid.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/genarch/src/mm/asid.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -63,12 +63,6 @@ #include #include -#include #include #include - -/** - * asidlock protects the asids_allocated counter. - */ -SPINLOCK_INITIALIZE(asidlock); static count_t asids_allocated = 0; @@ -91,5 +85,4 @@ */ - spinlock_lock(&asidlock); if (asids_allocated == ASIDS_ALLOCABLE) { @@ -109,5 +102,4 @@ as = list_get_instance(tmp, as_t, inactive_as_with_asid_link); - mutex_lock_active(&as->lock); /* @@ -131,6 +123,4 @@ as_invalidate_translation_cache(as, 0, (count_t) -1); - mutex_unlock(&as->lock); - /* * Get the system rid of the stolen ASID. @@ -157,6 +147,4 @@ } - spinlock_unlock(&asidlock); - return asid; } @@ -171,14 +159,6 @@ void asid_put(asid_t asid) { - ipl_t ipl; - - ipl = interrupts_disable(); - spinlock_lock(&asidlock); - asids_allocated--; asid_put_arch(asid); - - spinlock_unlock(&asidlock); - interrupts_restore(ipl); } Index: kernel/generic/include/mm/as.h =================================================================== --- kernel/generic/include/mm/as.h (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/generic/include/mm/as.h (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -90,4 +90,15 @@ /** Protected by asidlock. */ link_t inactive_as_with_asid_link; + /** + * Number of processors on wich is this address space active. + * Protected by asidlock. + */ + count_t cpu_refcount; + /** + * Address space identifier. + * Constant on architectures that do not support ASIDs. + * Protected by asidlock. + */ + asid_t asid; mutex_t lock; @@ -96,15 +107,6 @@ count_t refcount; - /** Number of processors on wich is this address space active. */ - count_t cpu_refcount; - /** B+tree of address space areas. */ btree_t as_area_btree; - - /** - * Address space identifier. - * Constant on architectures that do not support ASIDs. - */ - asid_t asid; /** Non-generic content. */ @@ -134,4 +136,15 @@ /** Protected by asidlock. */ link_t inactive_as_with_asid_link; + /** + * Number of processors on wich is this address space active. + * Protected by asidlock. + */ + count_t cpu_refcount; + /** + * Address space identifier. + * Constant on architectures that do not support ASIDs. + * Protected by asidlock. + */ + asid_t asid; mutex_t lock; @@ -140,15 +153,6 @@ count_t refcount; - /** Number of processors on wich is this address space active. */ - count_t cpu_refcount; - /** B+tree of address space areas. */ btree_t as_area_btree; - - /** - * Address space identifier. - * Constant on architectures that do not support ASIDs. - */ - asid_t asid; /** Non-generic content. */ @@ -250,5 +254,4 @@ #endif -SPINLOCK_EXTERN(inactive_as_with_asid_lock); extern link_t inactive_as_with_asid_head; Index: kernel/generic/src/mm/as.c =================================================================== --- kernel/generic/src/mm/as.c (revision 563c2ddc4c2e228951de3522875152bb1cf8dc51) +++ kernel/generic/src/mm/as.c (revision 879585a3fd47daccb6ab751ad240297f65de5bae) @@ -96,8 +96,11 @@ /** - * This lock protects inactive_as_with_asid_head list. It must be acquired - * before as_t mutex. - */ -SPINLOCK_INITIALIZE(inactive_as_with_asid_lock); + * This lock serializes access to the ASID subsystem. + * It protects: + * - inactive_as_with_asid_head list + * - as->asid for each as of the as_t type + * - asids_allocated counter + */ +SPINLOCK_INITIALIZE(asidlock); /** @@ -206,6 +209,7 @@ * it is safe not to lock its mutex. */ + ipl = interrupts_disable(); - spinlock_lock(&inactive_as_with_asid_lock); + spinlock_lock(&asidlock); if (as->asid != ASID_INVALID && as != AS_KERNEL) { if (as != AS && as->cpu_refcount == 0) @@ -213,5 +217,5 @@ asid_put(as->asid); } - spinlock_unlock(&inactive_as_with_asid_lock); + spinlock_unlock(&asidlock); /* @@ -861,5 +865,6 @@ * * Note that this function cannot sleep as it is essentially a part of - * scheduling. Sleeping here would lead to deadlock on wakeup. + * scheduling. Sleeping here would lead to deadlock on wakeup. Another + * thing which is forbidden in this context is locking the address space. * * @param old Old address space or NULL. @@ -868,9 +873,5 @@ void as_switch(as_t *old_as, as_t *new_as) { - ipl_t ipl; - bool needs_asid = false; - - ipl = interrupts_disable(); - spinlock_lock(&inactive_as_with_asid_lock); + spinlock_lock(&asidlock); /* @@ -878,5 +879,4 @@ */ if (old_as) { - mutex_lock_active(&old_as->lock); ASSERT(old_as->cpu_refcount); if((--old_as->cpu_refcount == 0) && (old_as != AS_KERNEL)) { @@ -891,5 +891,4 @@ &inactive_as_with_asid_head); } - mutex_unlock(&old_as->lock); /* @@ -903,34 +902,13 @@ * Second, prepare the new address space. */ - mutex_lock_active(&new_as->lock); if ((new_as->cpu_refcount++ == 0) && (new_as != AS_KERNEL)) { - if (new_as->asid != ASID_INVALID) { + if (new_as->asid != ASID_INVALID) list_remove(&new_as->inactive_as_with_asid_link); - } else { - /* - * Defer call to asid_get() until new_as->lock is released. - */ - needs_asid = true; - } + else + new_as->asid = asid_get(); } #ifdef AS_PAGE_TABLE SET_PTL0_ADDRESS(new_as->genarch.page_table); #endif - mutex_unlock(&new_as->lock); - - if (needs_asid) { - /* - * Allocation of new ASID was deferred - * until now in order to avoid deadlock. - */ - asid_t asid; - - asid = asid_get(); - mutex_lock_active(&new_as->lock); - new_as->asid = asid; - mutex_unlock(&new_as->lock); - } - spinlock_unlock(&inactive_as_with_asid_lock); - interrupts_restore(ipl); /* @@ -939,4 +917,6 @@ */ as_install_arch(new_as); + + spinlock_unlock(&asidlock); AS = new_as;