27  * |      process ID         |   ASID    |
32  * The ASID is used to tag entries in the CPU caches and TLBs.
56 	u64 context_id, asid;  in a15_erratum_get_cpumask()  local
65 		 * running the same ASID as the one being invalidated.  in a15_erratum_get_cpumask()
67 		asid = per_cpu(active_asids, cpu).counter;  in a15_erratum_get_cpumask()
68 		if (asid == 0)  in a15_erratum_get_cpumask()
69 			asid = per_cpu(reserved_asids, cpu);  in a15_erratum_get_cpumask()
70 		if (context_id == asid)  in a15_erratum_get_cpumask()
79  * With LPAE, the ASID and page tables are updated atomicly, so there is
80  * no need for a reserved set of tables (the active ASID tracking prevents
139 	u64 asid;  in flush_context()  local
141 	/* Update the list of reserved ASIDs and the ASID bitmap. */  in flush_context()
144 		asid = atomic64_xchg(&per_cpu(active_asids, i), 0);  in flush_context()
149 		 * ASID, as this is the only trace we have of  in flush_context()
152 		if (asid == 0)  in flush_context()
153 			asid = per_cpu(reserved_asids, i);  in flush_context()
154 		__set_bit(asid & ~ASID_MASK, asid_map);  in flush_context()
155 		per_cpu(reserved_asids, i) = asid;  in flush_context()
165 static bool check_update_reserved_asid(u64 asid, u64 newasid)  in check_update_reserved_asid()  argument
173 	 * (i.e. the same ASID in the current generation) but we can't  in check_update_reserved_asid()
175 	 * of the old ASID are updated to reflect the mm. Failure to do  in check_update_reserved_asid()
176 	 * so could result in us missing the reserved ASID in a future  in check_update_reserved_asid()
180 		if (per_cpu(reserved_asids, cpu) == asid) {  in check_update_reserved_asid()
192 	u64 asid = atomic64_read(&mm->context.id);  in new_context()  local
195 	if (asid != 0) {  in new_context()
196 		u64 newasid = generation | (asid & ~ASID_MASK);  in new_context()
199 		 * If our current ASID was active during a rollover, we  in new_context()
202 		if (check_update_reserved_asid(asid, newasid))  in new_context()
206 		 * We had a valid ASID in a previous life, so try to re-use  in new_context()
209 		asid &= ~ASID_MASK;  in new_context()
210 		if (!__test_and_set_bit(asid, asid_map))  in new_context()
215 	 * Allocate a free ASID. If we can't find one, take a note of the  in new_context()
217 	 * We always count from ASID #1, as we reserve ASID #0 to switch  in new_context()
223 	asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, cur_idx);  in new_context()
224 	if (asid == NUM_USER_ASIDS) {  in new_context()
228 		asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, 1);  in new_context()
231 	__set_bit(asid, asid_map);  in new_context()
232 	cur_idx = asid;  in new_context()
234 	return asid | generation;  in new_context()
241 	u64 asid;  in check_and_switch_context()  local
246 	 * We cannot update the pgd and the ASID atomicly with classic  in check_and_switch_context()
252 	asid = atomic64_read(&mm->context.id);  in check_and_switch_context()
253 	if (!((asid ^ atomic64_read(&asid_generation)) >> ASID_BITS)  in check_and_switch_context()
254 	    && atomic64_xchg(&per_cpu(active_asids, cpu), asid))  in check_and_switch_context()
258 	/* Check that our ASID belongs to the current generation. */  in check_and_switch_context()
259 	asid = atomic64_read(&mm->context.id);  in check_and_switch_context()
260 	if ((asid ^ atomic64_read(&asid_generation)) >> ASID_BITS) {  in check_and_switch_context()
261 		asid = new_context(mm, cpu);  in check_and_switch_context()
262 		atomic64_set(&mm->context.id, asid);  in check_and_switch_context()
270 	atomic64_set(&per_cpu(active_asids, cpu), asid);  in check_and_switch_context()