43,6 → 43,10 |
* ASID from an address space that has not been active for |
* a while. |
* |
* This code depends on the fact that ASIDS_ALLOCABLE |
* is greater than number of supported CPUs (i.e. the |
* amount of concurently active address spaces). |
* |
* Architectures that don't have hardware support for address |
* spaces do not compile with this file. |
*/ |
57,33 → 61,21 |
#include <debug.h> |
|
/** |
* asidlock protects both the asids_allocated counter |
* and the list of address spaces that were already |
* assigned ASID. |
* asidlock protects the asids_allocated counter. |
*/ |
SPINLOCK_INITIALIZE(asidlock); |
|
static count_t asids_allocated = 0; |
|
/** |
* List of address spaces with assigned ASID. |
* When the system runs short of allocable |
* ASIDS, inactive address spaces are guaranteed |
* to be at the beginning of the list. |
*/ |
LIST_INITIALIZE(as_with_asid_head); |
|
|
/** Allocate free address space identifier. |
* |
* This code depends on the fact that ASIDS_ALLOCABLE |
* is greater than number of supported CPUs. |
* Interrupts must be disabled and as_lock must be held |
* prior to this call |
* |
* @return New ASID. |
*/ |
asid_t asid_get(void) |
{ |
ipl_t ipl; |
asid_t asid; |
link_t *tmp; |
as_t *as; |
92,7 → 84,6 |
* Check if there is an unallocated ASID. |
*/ |
|
ipl = interrupts_disable(); |
spinlock_lock(&asidlock); |
if (asids_allocated == ASIDS_ALLOCABLE) { |
|
106,11 → 97,11 |
* It is guaranteed to belong to an |
* inactive address space. |
*/ |
tmp = as_with_asid_head.next; |
ASSERT(tmp != &as_with_asid_head); |
ASSERT(!list_empty(&inactive_as_with_asid_head)); |
tmp = inactive_as_with_asid_head.next; |
list_remove(tmp); |
|
as = list_get_instance(tmp, as_t, as_with_asid_link); |
as = list_get_instance(tmp, as_t, inactive_as_with_asid_link); |
spinlock_lock(&as->lock); |
|
/* |
145,7 → 136,6 |
} |
|
spinlock_unlock(&asidlock); |
interrupts_restore(ipl); |
|
return asid; |
} |
170,57 → 160,3 |
spinlock_unlock(&asidlock); |
interrupts_restore(ipl); |
} |
|
/** Install ASID. |
* |
* This function is to be executed on each address space switch. |
* |
* @param as Address space. |
*/ |
void asid_install(as_t *as) |
{ |
ipl_t ipl; |
|
ipl = interrupts_disable(); |
spinlock_lock(&asidlock); |
spinlock_lock(&as->lock); |
|
if (as->asid != ASID_KERNEL) { |
if (as->asid != ASID_INVALID) { |
/* |
* This address space has valid ASID. |
* Remove 'as' from the list of address spaces |
* with assigned ASID, so that it can be later |
* appended to the tail of the same list. |
* This is to prevent stealing of ASIDs from |
* recently installed address spaces. |
*/ |
list_remove(&as->as_with_asid_link); |
} else { |
spinlock_unlock(&as->lock); |
spinlock_unlock(&asidlock); |
|
/* |
* This address space doesn't have ASID assigned. |
* It was stolen or the address space is being |
* installed for the first time. |
* Allocate new ASID for it. |
*/ |
as->asid = asid_get(); |
spinlock_lock(&asidlock); |
spinlock_lock(&as->lock); |
} |
|
/* |
* Now it is sure that 'as' has ASID. |
* It is therefore appended to the list |
* of address spaces from which it can |
* be stolen. |
*/ |
list_append(&as->as_with_asid_link, &as_with_asid_head); |
} |
|
spinlock_unlock(&as->lock); |
spinlock_unlock(&asidlock); |
interrupts_restore(ipl); |
} |