2 * pseries CPU Hotplug infrastructure.
4 * Split out from arch/powerpc/platforms/pseries/setup.c
5 * arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c
7 * Peter Bergner, IBM March 2001.
8 * Copyright (C) 2001 IBM.
9 * Dave Engebretsen, Peter Bergner, and
10 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
11 * Plus various changes from other IBM teams...
13 * Copyright (C) 2006 Michael Ellerman, IBM Corporation
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
21 #include <linux/kernel.h>
22 #include <linux/delay.h>
23 #include <linux/cpu.h>
24 #include <asm/system.h>
27 #include <asm/firmware.h>
28 #include <asm/machdep.h>
29 #include <asm/vdso_datapage.h>
30 #include <asm/pSeries_reconfig.h>
32 #include "plpar_wrappers.h"
33 #include "offline_states.h"
35 /* This version can't take the spinlock, because it never returns */
36 static struct rtas_args rtas_stop_self_args
= {
37 .token
= RTAS_UNKNOWN_SERVICE
,
40 .rets
= &rtas_stop_self_args
.args
[0],
43 static DEFINE_PER_CPU(enum cpu_state_vals
, preferred_offline_state
) =
45 static DEFINE_PER_CPU(enum cpu_state_vals
, current_state
) = CPU_STATE_OFFLINE
;
47 static enum cpu_state_vals default_offline_state
= CPU_STATE_OFFLINE
;
49 static int cede_offline_enabled __read_mostly
= 1;
52 * Enable/disable cede_offline when available.
54 static int __init
setup_cede_offline(char *str
)
56 if (!strcmp(str
, "off"))
57 cede_offline_enabled
= 0;
58 else if (!strcmp(str
, "on"))
59 cede_offline_enabled
= 1;
65 __setup("cede_offline=", setup_cede_offline
);
67 enum cpu_state_vals
get_cpu_current_state(int cpu
)
69 return per_cpu(current_state
, cpu
);
72 void set_cpu_current_state(int cpu
, enum cpu_state_vals state
)
74 per_cpu(current_state
, cpu
) = state
;
77 enum cpu_state_vals
get_preferred_offline_state(int cpu
)
79 return per_cpu(preferred_offline_state
, cpu
);
82 void set_preferred_offline_state(int cpu
, enum cpu_state_vals state
)
84 per_cpu(preferred_offline_state
, cpu
) = state
;
87 void set_default_offline_state(int cpu
)
89 per_cpu(preferred_offline_state
, cpu
) = default_offline_state
;
92 static void rtas_stop_self(void)
94 struct rtas_args
*args
= &rtas_stop_self_args
;
98 BUG_ON(args
->token
== RTAS_UNKNOWN_SERVICE
);
100 printk("cpu %u (hwid %u) Ready to die...\n",
101 smp_processor_id(), hard_smp_processor_id());
102 enter_rtas(__pa(args
));
104 panic("Alas, I survived.\n");
107 static void pseries_mach_cpu_die(void)
109 unsigned int cpu
= smp_processor_id();
110 unsigned int hwcpu
= hard_smp_processor_id();
111 u8 cede_latency_hint
= 0;
117 if (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
118 set_cpu_current_state(cpu
, CPU_STATE_INACTIVE
);
119 cede_latency_hint
= 2;
121 get_lppaca()->idle
= 1;
122 if (!get_lppaca()->shared_proc
)
123 get_lppaca()->donate_dedicated_cpu
= 1;
126 "cpu %u (hwid %u) ceding for offline with hint %d\n",
127 cpu
, hwcpu
, cede_latency_hint
);
128 while (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
129 extended_cede_processor(cede_latency_hint
);
130 printk(KERN_INFO
"cpu %u (hwid %u) returned from cede.\n",
133 "Decrementer value = %x Timebase value = %llx\n",
134 get_dec(), get_tb());
137 printk(KERN_INFO
"cpu %u (hwid %u) got prodded to go online\n",
140 if (!get_lppaca()->shared_proc
)
141 get_lppaca()->donate_dedicated_cpu
= 0;
142 get_lppaca()->idle
= 0;
145 if (get_preferred_offline_state(cpu
) == CPU_STATE_ONLINE
) {
146 unregister_slb_shadow(hwcpu
, __pa(get_slb_shadow()));
149 * NOTE: Calling start_secondary() here for now to
151 * However, need to do it cleanly by resetting the
156 } else if (get_preferred_offline_state(cpu
) == CPU_STATE_OFFLINE
) {
158 set_cpu_current_state(cpu
, CPU_STATE_OFFLINE
);
159 unregister_slb_shadow(hard_smp_processor_id(),
160 __pa(get_slb_shadow()));
164 /* Should never get here... */
169 static int qcss_tok
; /* query-cpu-stopped-state token */
171 /* Get state of physical CPU.
173 * 0 - The processor is in the RTAS stopped state
174 * 1 - stop-self is in progress
175 * 2 - The processor is not in the RTAS stopped state
176 * -1 - Hardware Error
177 * -2 - Hardware Busy, Try again later.
179 static int query_cpu_stopped(unsigned int pcpu
)
181 int cpu_status
, status
;
183 status
= rtas_call(qcss_tok
, 1, 2, &cpu_status
, pcpu
);
186 "RTAS query-cpu-stopped-state failed: %i\n", status
);
193 static int pseries_cpu_disable(void)
195 int cpu
= smp_processor_id();
197 set_cpu_online(cpu
, false);
198 vdso_data
->processorCount
--;
200 /*fix boot_cpuid here*/
201 if (cpu
== boot_cpuid
)
202 boot_cpuid
= any_online_cpu(cpu_online_map
);
204 /* FIXME: abstract this to not be platform specific later on */
205 xics_migrate_irqs_away();
210 * pseries_cpu_die: Wait for the cpu to die.
211 * @cpu: logical processor id of the CPU whose death we're awaiting.
213 * This function is called from the context of the thread which is performing
214 * the cpu-offline. Here we wait for long enough to allow the cpu in question
215 * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
218 * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
221 static void pseries_cpu_die(unsigned int cpu
)
225 unsigned int pcpu
= get_hard_smp_processor_id(cpu
);
227 if (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
229 for (tries
= 0; tries
< 1000; tries
++) {
230 if (get_cpu_current_state(cpu
) == CPU_STATE_INACTIVE
) {
236 } else if (get_preferred_offline_state(cpu
) == CPU_STATE_OFFLINE
) {
238 for (tries
= 0; tries
< 25; tries
++) {
239 cpu_status
= query_cpu_stopped(pcpu
);
240 if (cpu_status
== 0 || cpu_status
== -1)
246 if (cpu_status
!= 0) {
247 printk("Querying DEAD? cpu %i (%i) shows %i\n",
248 cpu
, pcpu
, cpu_status
);
251 /* Isolation and deallocation are definatly done by
252 * drslot_chrp_cpu. If they were not they would be
253 * done here. Change isolate state to Isolate and
254 * change allocation-state to Unusable.
256 paca
[cpu
].cpu_start
= 0;
260 * Update cpu_present_map and paca(s) for a new cpu node. The wrinkle
261 * here is that a cpu device node may represent up to two logical cpus
262 * in the SMT case. We must honor the assumption in other code that
263 * the logical ids for sibling SMT threads x and y are adjacent, such
264 * that x^1 == y and y^1 == x.
266 static int pseries_add_processor(struct device_node
*np
)
269 cpumask_t candidate_map
, tmp
= CPU_MASK_NONE
;
270 int err
= -ENOSPC
, len
, nthreads
, i
;
273 intserv
= of_get_property(np
, "ibm,ppc-interrupt-server#s", &len
);
277 nthreads
= len
/ sizeof(u32
);
278 for (i
= 0; i
< nthreads
; i
++)
281 cpu_maps_update_begin();
283 BUG_ON(!cpus_subset(cpu_present_map
, cpu_possible_map
));
285 /* Get a bitmap of unoccupied slots. */
286 cpus_xor(candidate_map
, cpu_possible_map
, cpu_present_map
);
287 if (cpus_empty(candidate_map
)) {
288 /* If we get here, it most likely means that NR_CPUS is
289 * less than the partition's max processors setting.
291 printk(KERN_ERR
"Cannot add cpu %s; this system configuration"
292 " supports %d logical cpus.\n", np
->full_name
,
293 cpus_weight(cpu_possible_map
));
297 while (!cpus_empty(tmp
))
298 if (cpus_subset(tmp
, candidate_map
))
299 /* Found a range where we can insert the new cpu(s) */
302 cpus_shift_left(tmp
, tmp
, nthreads
);
304 if (cpus_empty(tmp
)) {
305 printk(KERN_ERR
"Unable to find space in cpu_present_map for"
306 " processor %s with %d thread(s)\n", np
->name
,
311 for_each_cpu_mask(cpu
, tmp
) {
312 BUG_ON(cpu_isset(cpu
, cpu_present_map
));
313 set_cpu_present(cpu
, true);
314 set_hard_smp_processor_id(cpu
, *intserv
++);
318 cpu_maps_update_done();
323 * Update the present map for a cpu node which is going away, and set
324 * the hard id in the paca(s) to -1 to be consistent with boot time
325 * convention for non-present cpus.
327 static void pseries_remove_processor(struct device_node
*np
)
330 int len
, nthreads
, i
;
333 intserv
= of_get_property(np
, "ibm,ppc-interrupt-server#s", &len
);
337 nthreads
= len
/ sizeof(u32
);
339 cpu_maps_update_begin();
340 for (i
= 0; i
< nthreads
; i
++) {
341 for_each_present_cpu(cpu
) {
342 if (get_hard_smp_processor_id(cpu
) != intserv
[i
])
344 BUG_ON(cpu_online(cpu
));
345 set_cpu_present(cpu
, false);
346 set_hard_smp_processor_id(cpu
, -1);
350 printk(KERN_WARNING
"Could not find cpu to remove "
351 "with physical id 0x%x\n", intserv
[i
]);
353 cpu_maps_update_done();
356 static int pseries_smp_notifier(struct notifier_block
*nb
,
357 unsigned long action
, void *node
)
362 case PSERIES_RECONFIG_ADD
:
363 if (pseries_add_processor(node
))
366 case PSERIES_RECONFIG_REMOVE
:
367 pseries_remove_processor(node
);
376 static struct notifier_block pseries_smp_nb
= {
377 .notifier_call
= pseries_smp_notifier
,
380 #define MAX_CEDE_LATENCY_LEVELS 4
381 #define CEDE_LATENCY_PARAM_LENGTH 10
382 #define CEDE_LATENCY_PARAM_MAX_LENGTH \
383 (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
384 #define CEDE_LATENCY_TOKEN 45
386 static char cede_parameters
[CEDE_LATENCY_PARAM_MAX_LENGTH
];
388 static int parse_cede_parameters(void)
390 memset(cede_parameters
, 0, CEDE_LATENCY_PARAM_MAX_LENGTH
);
391 return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
394 __pa(cede_parameters
),
395 CEDE_LATENCY_PARAM_MAX_LENGTH
);
398 static int __init
pseries_cpu_hotplug_init(void)
400 struct device_node
*np
;
404 for_each_node_by_name(np
, "interrupt-controller") {
405 typep
= of_get_property(np
, "compatible", NULL
);
406 if (strstr(typep
, "open-pic")) {
409 printk(KERN_INFO
"CPU Hotplug not supported on "
410 "systems using MPIC\n");
415 rtas_stop_self_args
.token
= rtas_token("stop-self");
416 qcss_tok
= rtas_token("query-cpu-stopped-state");
418 if (rtas_stop_self_args
.token
== RTAS_UNKNOWN_SERVICE
||
419 qcss_tok
== RTAS_UNKNOWN_SERVICE
) {
420 printk(KERN_INFO
"CPU Hotplug not supported by firmware "
425 ppc_md
.cpu_die
= pseries_mach_cpu_die
;
426 smp_ops
->cpu_disable
= pseries_cpu_disable
;
427 smp_ops
->cpu_die
= pseries_cpu_die
;
429 /* Processors can be added/removed only on LPAR */
430 if (firmware_has_feature(FW_FEATURE_LPAR
)) {
431 pSeries_reconfig_notifier_register(&pseries_smp_nb
);
432 cpu_maps_update_begin();
433 if (cede_offline_enabled
&& parse_cede_parameters() == 0) {
434 default_offline_state
= CPU_STATE_INACTIVE
;
435 for_each_online_cpu(cpu
)
436 set_default_offline_state(cpu
);
438 cpu_maps_update_done();
443 arch_initcall(pseries_cpu_hotplug_init
);