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1da177e4 LT |
1 | /* |
2 | * Copyright 2004 James Cleverdon, IBM. | |
3 | * Subject to the GNU Public License, v.2 | |
4 | * | |
5 | * Flat APIC subarch code. Maximum 8 CPUs, logical delivery. | |
6 | * | |
7 | * Hacked for x86-64 by James Cleverdon from i386 architecture code by | |
8 | * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and | |
9 | * James Cleverdon. | |
884d9e40 AR |
10 | * Ashok Raj <ashok.raj@intel.com> |
11 | * Removed IPI broadcast shortcut to support CPU hotplug | |
1da177e4 LT |
12 | */ |
13 | #include <linux/config.h> | |
14 | #include <linux/threads.h> | |
15 | #include <linux/cpumask.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/ctype.h> | |
19 | #include <linux/init.h> | |
20 | #include <asm/smp.h> | |
21 | #include <asm/ipi.h> | |
22 | ||
a02c4cb6 AR |
23 | /* |
24 | * The following permit choosing broadcast IPI shortcut v.s sending IPI only | |
25 | * to online cpus via the send_IPI_mask varient. | |
26 | * The mask version is my preferred option, since it eliminates a lot of | |
27 | * other extra code that would need to be written to cleanup intrs sent | |
28 | * to a CPU while offline. | |
29 | * | |
30 | * Sending broadcast introduces lots of trouble in CPU hotplug situations. | |
31 | * These IPI's are delivered to cpu's irrespective of their offline status | |
32 | * and could pickup stale intr data when these CPUS are turned online. | |
33 | * | |
34 | * Not using broadcast is a cleaner approach IMO, but Andi Kleen disagrees with | |
35 | * the idea of not using broadcast IPI's anymore. Hence the run time check | |
36 | * is introduced, on his request so we can choose an alternate mechanism. | |
37 | * | |
38 | * Initial wacky performance tests that collect cycle counts show | |
39 | * no increase in using mask v.s broadcast version. In fact they seem | |
40 | * identical in terms of cycle counts. | |
41 | * | |
42 | * if we need to use broadcast, we need to do the following. | |
43 | * | |
44 | * cli; | |
45 | * hold call_lock; | |
46 | * clear any pending IPI, just ack and clear all pending intr | |
47 | * set cpu_online_map; | |
48 | * release call_lock; | |
49 | * sti; | |
50 | * | |
51 | * The complicated dummy irq processing shown above is not required if | |
52 | * we didnt sent IPI's to wrong CPU's in the first place. | |
53 | * | |
54 | * - Ashok Raj <ashok.raj@intel.com> | |
55 | */ | |
56 | #ifdef CONFIG_HOTPLUG_CPU | |
57 | #define DEFAULT_SEND_IPI (1) | |
58 | #else | |
59 | #define DEFAULT_SEND_IPI (0) | |
60 | #endif | |
61 | ||
62 | static int no_broadcast=DEFAULT_SEND_IPI; | |
1da177e4 LT |
63 | |
64 | static cpumask_t flat_target_cpus(void) | |
65 | { | |
66 | return cpu_online_map; | |
67 | } | |
68 | ||
69 | /* | |
70 | * Set up the logical destination ID. | |
71 | * | |
72 | * Intel recommends to set DFR, LDR and TPR before enabling | |
73 | * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel | |
74 | * document number 292116). So here it goes... | |
75 | */ | |
76 | static void flat_init_apic_ldr(void) | |
77 | { | |
78 | unsigned long val; | |
79 | unsigned long num, id; | |
80 | ||
81 | num = smp_processor_id(); | |
82 | id = 1UL << num; | |
83 | x86_cpu_to_log_apicid[num] = id; | |
84 | apic_write_around(APIC_DFR, APIC_DFR_FLAT); | |
85 | val = apic_read(APIC_LDR) & ~APIC_LDR_MASK; | |
86 | val |= SET_APIC_LOGICAL_ID(id); | |
87 | apic_write_around(APIC_LDR, val); | |
88 | } | |
89 | ||
1da177e4 LT |
90 | static void flat_send_IPI_mask(cpumask_t cpumask, int vector) |
91 | { | |
92 | unsigned long mask = cpus_addr(cpumask)[0]; | |
93 | unsigned long cfg; | |
94 | unsigned long flags; | |
95 | ||
96 | local_save_flags(flags); | |
97 | local_irq_disable(); | |
98 | ||
99 | /* | |
100 | * Wait for idle. | |
101 | */ | |
102 | apic_wait_icr_idle(); | |
103 | ||
104 | /* | |
105 | * prepare target chip field | |
106 | */ | |
107 | cfg = __prepare_ICR2(mask); | |
108 | apic_write_around(APIC_ICR2, cfg); | |
109 | ||
110 | /* | |
111 | * program the ICR | |
112 | */ | |
113 | cfg = __prepare_ICR(0, vector, APIC_DEST_LOGICAL); | |
114 | ||
115 | /* | |
116 | * Send the IPI. The write to APIC_ICR fires this off. | |
117 | */ | |
118 | apic_write_around(APIC_ICR, cfg); | |
119 | local_irq_restore(flags); | |
120 | } | |
121 | ||
a02c4cb6 | 122 | static inline void __local_flat_send_IPI_allbutself(int vector) |
884d9e40 | 123 | { |
a02c4cb6 AR |
124 | if (no_broadcast) { |
125 | cpumask_t mask = cpu_online_map; | |
126 | int this_cpu = get_cpu(); | |
884d9e40 | 127 | |
a02c4cb6 | 128 | cpu_clear(this_cpu, mask); |
884d9e40 | 129 | flat_send_IPI_mask(mask, vector); |
a02c4cb6 AR |
130 | put_cpu(); |
131 | } | |
132 | else | |
133 | __send_IPI_shortcut(APIC_DEST_ALLBUT, vector, APIC_DEST_LOGICAL); | |
134 | } | |
884d9e40 | 135 | |
a02c4cb6 AR |
136 | static inline void __local_flat_send_IPI_all(int vector) |
137 | { | |
138 | if (no_broadcast) | |
139 | flat_send_IPI_mask(cpu_online_map, vector); | |
140 | else | |
141 | __send_IPI_shortcut(APIC_DEST_ALLINC, vector, APIC_DEST_LOGICAL); | |
142 | } | |
143 | ||
144 | static void flat_send_IPI_allbutself(int vector) | |
145 | { | |
146 | if (((num_online_cpus()) - 1) >= 1) | |
147 | __local_flat_send_IPI_allbutself(vector); | |
884d9e40 AR |
148 | } |
149 | ||
150 | static void flat_send_IPI_all(int vector) | |
151 | { | |
a02c4cb6 | 152 | __local_flat_send_IPI_all(vector); |
884d9e40 AR |
153 | } |
154 | ||
1da177e4 LT |
155 | static int flat_apic_id_registered(void) |
156 | { | |
157 | return physid_isset(GET_APIC_ID(apic_read(APIC_ID)), phys_cpu_present_map); | |
158 | } | |
159 | ||
160 | static unsigned int flat_cpu_mask_to_apicid(cpumask_t cpumask) | |
161 | { | |
162 | return cpus_addr(cpumask)[0] & APIC_ALL_CPUS; | |
163 | } | |
164 | ||
165 | static unsigned int phys_pkg_id(int index_msb) | |
166 | { | |
167 | u32 ebx; | |
168 | ||
169 | ebx = cpuid_ebx(1); | |
170 | return ((ebx >> 24) & 0xFF) >> index_msb; | |
171 | } | |
172 | ||
a02c4cb6 AR |
173 | static __init int no_ipi_broadcast(char *str) |
174 | { | |
175 | get_option(&str, &no_broadcast); | |
176 | printk ("Using %s mode\n", no_broadcast ? "No IPI Broadcast" : | |
177 | "IPI Broadcast"); | |
178 | return 1; | |
179 | } | |
180 | ||
181 | __setup("no_ipi_broadcast", no_ipi_broadcast); | |
182 | ||
1da177e4 LT |
183 | struct genapic apic_flat = { |
184 | .name = "flat", | |
185 | .int_delivery_mode = dest_LowestPrio, | |
186 | .int_dest_mode = (APIC_DEST_LOGICAL != 0), | |
187 | .int_delivery_dest = APIC_DEST_LOGICAL | APIC_DM_LOWEST, | |
188 | .target_cpus = flat_target_cpus, | |
189 | .apic_id_registered = flat_apic_id_registered, | |
190 | .init_apic_ldr = flat_init_apic_ldr, | |
191 | .send_IPI_all = flat_send_IPI_all, | |
192 | .send_IPI_allbutself = flat_send_IPI_allbutself, | |
193 | .send_IPI_mask = flat_send_IPI_mask, | |
194 | .cpu_mask_to_apicid = flat_cpu_mask_to_apicid, | |
195 | .phys_pkg_id = phys_pkg_id, | |
196 | }; | |
a02c4cb6 AR |
197 | |
198 | static int __init print_ipi_mode(void) | |
199 | { | |
200 | printk ("Using IPI %s mode\n", no_broadcast ? "No-Shortcut" : | |
201 | "Shortcut"); | |
202 | return 0; | |
203 | } | |
204 | ||
205 | late_initcall(print_ipi_mode); |