xref: /openbmc/linux/arch/x86/kernel/apic/ipi.c (revision 4f205687)
1 #include <linux/cpumask.h>
2 #include <linux/interrupt.h>
3 
4 #include <linux/mm.h>
5 #include <linux/delay.h>
6 #include <linux/spinlock.h>
7 #include <linux/kernel_stat.h>
8 #include <linux/mc146818rtc.h>
9 #include <linux/cache.h>
10 #include <linux/cpu.h>
11 #include <linux/module.h>
12 
13 #include <asm/smp.h>
14 #include <asm/mtrr.h>
15 #include <asm/tlbflush.h>
16 #include <asm/mmu_context.h>
17 #include <asm/apic.h>
18 #include <asm/proto.h>
19 #include <asm/ipi.h>
20 
21 void __default_send_IPI_shortcut(unsigned int shortcut, int vector, unsigned int dest)
22 {
23 	/*
24 	 * Subtle. In the case of the 'never do double writes' workaround
25 	 * we have to lock out interrupts to be safe.  As we don't care
26 	 * of the value read we use an atomic rmw access to avoid costly
27 	 * cli/sti.  Otherwise we use an even cheaper single atomic write
28 	 * to the APIC.
29 	 */
30 	unsigned int cfg;
31 
32 	/*
33 	 * Wait for idle.
34 	 */
35 	__xapic_wait_icr_idle();
36 
37 	/*
38 	 * No need to touch the target chip field
39 	 */
40 	cfg = __prepare_ICR(shortcut, vector, dest);
41 
42 	/*
43 	 * Send the IPI. The write to APIC_ICR fires this off.
44 	 */
45 	native_apic_mem_write(APIC_ICR, cfg);
46 }
47 
48 /*
49  * This is used to send an IPI with no shorthand notation (the destination is
50  * specified in bits 56 to 63 of the ICR).
51  */
52 void __default_send_IPI_dest_field(unsigned int mask, int vector, unsigned int dest)
53 {
54 	unsigned long cfg;
55 
56 	/*
57 	 * Wait for idle.
58 	 */
59 	if (unlikely(vector == NMI_VECTOR))
60 		safe_apic_wait_icr_idle();
61 	else
62 		__xapic_wait_icr_idle();
63 
64 	/*
65 	 * prepare target chip field
66 	 */
67 	cfg = __prepare_ICR2(mask);
68 	native_apic_mem_write(APIC_ICR2, cfg);
69 
70 	/*
71 	 * program the ICR
72 	 */
73 	cfg = __prepare_ICR(0, vector, dest);
74 
75 	/*
76 	 * Send the IPI. The write to APIC_ICR fires this off.
77 	 */
78 	native_apic_mem_write(APIC_ICR, cfg);
79 }
80 
81 void default_send_IPI_single_phys(int cpu, int vector)
82 {
83 	unsigned long flags;
84 
85 	local_irq_save(flags);
86 	__default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid, cpu),
87 				      vector, APIC_DEST_PHYSICAL);
88 	local_irq_restore(flags);
89 }
90 
91 void default_send_IPI_mask_sequence_phys(const struct cpumask *mask, int vector)
92 {
93 	unsigned long query_cpu;
94 	unsigned long flags;
95 
96 	/*
97 	 * Hack. The clustered APIC addressing mode doesn't allow us to send
98 	 * to an arbitrary mask, so I do a unicast to each CPU instead.
99 	 * - mbligh
100 	 */
101 	local_irq_save(flags);
102 	for_each_cpu(query_cpu, mask) {
103 		__default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid,
104 				query_cpu), vector, APIC_DEST_PHYSICAL);
105 	}
106 	local_irq_restore(flags);
107 }
108 
109 void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask,
110 						 int vector)
111 {
112 	unsigned int this_cpu = smp_processor_id();
113 	unsigned int query_cpu;
114 	unsigned long flags;
115 
116 	/* See Hack comment above */
117 
118 	local_irq_save(flags);
119 	for_each_cpu(query_cpu, mask) {
120 		if (query_cpu == this_cpu)
121 			continue;
122 		__default_send_IPI_dest_field(per_cpu(x86_cpu_to_apicid,
123 				 query_cpu), vector, APIC_DEST_PHYSICAL);
124 	}
125 	local_irq_restore(flags);
126 }
127 
128 /*
129  * Helper function for APICs which insist on cpumasks
130  */
131 void default_send_IPI_single(int cpu, int vector)
132 {
133 	apic->send_IPI_mask(cpumask_of(cpu), vector);
134 }
135 
136 #ifdef CONFIG_X86_32
137 
138 void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
139 						 int vector)
140 {
141 	unsigned long flags;
142 	unsigned int query_cpu;
143 
144 	/*
145 	 * Hack. The clustered APIC addressing mode doesn't allow us to send
146 	 * to an arbitrary mask, so I do a unicasts to each CPU instead. This
147 	 * should be modified to do 1 message per cluster ID - mbligh
148 	 */
149 
150 	local_irq_save(flags);
151 	for_each_cpu(query_cpu, mask)
152 		__default_send_IPI_dest_field(
153 			early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
154 			vector, apic->dest_logical);
155 	local_irq_restore(flags);
156 }
157 
158 void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask,
159 						 int vector)
160 {
161 	unsigned long flags;
162 	unsigned int query_cpu;
163 	unsigned int this_cpu = smp_processor_id();
164 
165 	/* See Hack comment above */
166 
167 	local_irq_save(flags);
168 	for_each_cpu(query_cpu, mask) {
169 		if (query_cpu == this_cpu)
170 			continue;
171 		__default_send_IPI_dest_field(
172 			early_per_cpu(x86_cpu_to_logical_apicid, query_cpu),
173 			vector, apic->dest_logical);
174 		}
175 	local_irq_restore(flags);
176 }
177 
178 /*
179  * This is only used on smaller machines.
180  */
181 void default_send_IPI_mask_logical(const struct cpumask *cpumask, int vector)
182 {
183 	unsigned long mask = cpumask_bits(cpumask)[0];
184 	unsigned long flags;
185 
186 	if (!mask)
187 		return;
188 
189 	local_irq_save(flags);
190 	WARN_ON(mask & ~cpumask_bits(cpu_online_mask)[0]);
191 	__default_send_IPI_dest_field(mask, vector, apic->dest_logical);
192 	local_irq_restore(flags);
193 }
194 
195 void default_send_IPI_allbutself(int vector)
196 {
197 	/*
198 	 * if there are no other CPUs in the system then we get an APIC send
199 	 * error if we try to broadcast, thus avoid sending IPIs in this case.
200 	 */
201 	if (!(num_online_cpus() > 1))
202 		return;
203 
204 	__default_local_send_IPI_allbutself(vector);
205 }
206 
207 void default_send_IPI_all(int vector)
208 {
209 	__default_local_send_IPI_all(vector);
210 }
211 
212 void default_send_IPI_self(int vector)
213 {
214 	__default_send_IPI_shortcut(APIC_DEST_SELF, vector, apic->dest_logical);
215 }
216 
217 /* must come after the send_IPI functions above for inlining */
218 static int convert_apicid_to_cpu(int apic_id)
219 {
220 	int i;
221 
222 	for_each_possible_cpu(i) {
223 		if (per_cpu(x86_cpu_to_apicid, i) == apic_id)
224 			return i;
225 	}
226 	return -1;
227 }
228 
229 int safe_smp_processor_id(void)
230 {
231 	int apicid, cpuid;
232 
233 	if (!boot_cpu_has(X86_FEATURE_APIC))
234 		return 0;
235 
236 	apicid = hard_smp_processor_id();
237 	if (apicid == BAD_APICID)
238 		return 0;
239 
240 	cpuid = convert_apicid_to_cpu(apicid);
241 
242 	return cpuid >= 0 ? cpuid : 0;
243 }
244 #endif
245