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/interrupt.h>
23 #include <linux/delay.h>
24 #include <linux/cpu.h>
25 #include <asm/system.h>
28 #include <asm/firmware.h>
29 #include <asm/machdep.h>
30 #include <asm/vdso_datapage.h>
31 #include <asm/pSeries_reconfig.h>
33 #include "plpar_wrappers.h"
34 #include "offline_states.h"
36 /* This version can't take the spinlock, because it never returns */
37 static struct rtas_args rtas_stop_self_args
= {
38 .token
= RTAS_UNKNOWN_SERVICE
,
41 .rets
= &rtas_stop_self_args
.args
[0],
44 static DEFINE_PER_CPU(enum cpu_state_vals
, preferred_offline_state
) =
46 static DEFINE_PER_CPU(enum cpu_state_vals
, current_state
) = CPU_STATE_OFFLINE
;
48 static enum cpu_state_vals default_offline_state
= CPU_STATE_OFFLINE
;
50 static int cede_offline_enabled __read_mostly
= 1;
53 * Enable/disable cede_offline when available.
55 static int __init
setup_cede_offline(char *str
)
57 if (!strcmp(str
, "off"))
58 cede_offline_enabled
= 0;
59 else if (!strcmp(str
, "on"))
60 cede_offline_enabled
= 1;
66 __setup("cede_offline=", setup_cede_offline
);
68 enum cpu_state_vals
get_cpu_current_state(int cpu
)
70 return per_cpu(current_state
, cpu
);
73 void set_cpu_current_state(int cpu
, enum cpu_state_vals state
)
75 per_cpu(current_state
, cpu
) = state
;
78 enum cpu_state_vals
get_preferred_offline_state(int cpu
)
80 return per_cpu(preferred_offline_state
, cpu
);
83 void set_preferred_offline_state(int cpu
, enum cpu_state_vals state
)
85 per_cpu(preferred_offline_state
, cpu
) = state
;
88 void set_default_offline_state(int cpu
)
90 per_cpu(preferred_offline_state
, cpu
) = default_offline_state
;
93 static void rtas_stop_self(void)
95 struct rtas_args
*args
= &rtas_stop_self_args
;
99 BUG_ON(args
->token
== RTAS_UNKNOWN_SERVICE
);
101 printk("cpu %u (hwid %u) Ready to die...\n",
102 smp_processor_id(), hard_smp_processor_id());
103 enter_rtas(__pa(args
));
105 panic("Alas, I survived.\n");
108 static void pseries_mach_cpu_die(void)
110 unsigned int cpu
= smp_processor_id();
111 unsigned int hwcpu
= hard_smp_processor_id();
112 u8 cede_latency_hint
= 0;
118 if (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
119 set_cpu_current_state(cpu
, CPU_STATE_INACTIVE
);
120 if (ppc_md
.suspend_disable_cpu
)
121 ppc_md
.suspend_disable_cpu();
123 cede_latency_hint
= 2;
125 get_lppaca()->idle
= 1;
126 if (!get_lppaca()->shared_proc
)
127 get_lppaca()->donate_dedicated_cpu
= 1;
129 while (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
130 extended_cede_processor(cede_latency_hint
);
133 if (!get_lppaca()->shared_proc
)
134 get_lppaca()->donate_dedicated_cpu
= 0;
135 get_lppaca()->idle
= 0;
137 if (get_preferred_offline_state(cpu
) == CPU_STATE_ONLINE
) {
138 unregister_slb_shadow(hwcpu
, __pa(get_slb_shadow()));
141 * Call to start_secondary_resume() will not return.
142 * Kernel stack will be reset and start_secondary()
143 * will be called to continue the online operation.
145 start_secondary_resume();
149 /* Requested state is CPU_STATE_OFFLINE at this point */
150 WARN_ON(get_preferred_offline_state(cpu
) != CPU_STATE_OFFLINE
);
152 set_cpu_current_state(cpu
, CPU_STATE_OFFLINE
);
153 unregister_slb_shadow(hwcpu
, __pa(get_slb_shadow()));
156 /* Should never get here... */
161 static int pseries_cpu_disable(void)
163 int cpu
= smp_processor_id();
165 set_cpu_online(cpu
, false);
166 vdso_data
->processorCount
--;
168 /*fix boot_cpuid here*/
169 if (cpu
== boot_cpuid
)
170 boot_cpuid
= cpumask_any(cpu_online_mask
);
172 /* FIXME: abstract this to not be platform specific later on */
173 xics_migrate_irqs_away();
178 * pseries_cpu_die: Wait for the cpu to die.
179 * @cpu: logical processor id of the CPU whose death we're awaiting.
181 * This function is called from the context of the thread which is performing
182 * the cpu-offline. Here we wait for long enough to allow the cpu in question
183 * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
186 * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
189 static void pseries_cpu_die(unsigned int cpu
)
193 unsigned int pcpu
= get_hard_smp_processor_id(cpu
);
195 if (get_preferred_offline_state(cpu
) == CPU_STATE_INACTIVE
) {
197 for (tries
= 0; tries
< 5000; tries
++) {
198 if (get_cpu_current_state(cpu
) == CPU_STATE_INACTIVE
) {
204 } else if (get_preferred_offline_state(cpu
) == CPU_STATE_OFFLINE
) {
206 for (tries
= 0; tries
< 25; tries
++) {
207 cpu_status
= smp_query_cpu_stopped(pcpu
);
208 if (cpu_status
== QCSS_STOPPED
||
209 cpu_status
== QCSS_HARDWARE_ERROR
)
215 if (cpu_status
!= 0) {
216 printk("Querying DEAD? cpu %i (%i) shows %i\n",
217 cpu
, pcpu
, cpu_status
);
220 /* Isolation and deallocation are definitely done by
221 * drslot_chrp_cpu. If they were not they would be
222 * done here. Change isolate state to Isolate and
223 * change allocation-state to Unusable.
225 paca
[cpu
].cpu_start
= 0;
229 * Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
230 * here is that a cpu device node may represent up to two logical cpus
231 * in the SMT case. We must honor the assumption in other code that
232 * the logical ids for sibling SMT threads x and y are adjacent, such
233 * that x^1 == y and y^1 == x.
235 static int pseries_add_processor(struct device_node
*np
)
238 cpumask_var_t candidate_mask
, tmp
;
239 int err
= -ENOSPC
, len
, nthreads
, i
;
242 intserv
= of_get_property(np
, "ibm,ppc-interrupt-server#s", &len
);
246 zalloc_cpumask_var(&candidate_mask
, GFP_KERNEL
);
247 zalloc_cpumask_var(&tmp
, GFP_KERNEL
);
249 nthreads
= len
/ sizeof(u32
);
250 for (i
= 0; i
< nthreads
; i
++)
251 cpumask_set_cpu(i
, tmp
);
253 cpu_maps_update_begin();
255 BUG_ON(!cpumask_subset(cpu_present_mask
, cpu_possible_mask
));
257 /* Get a bitmap of unoccupied slots. */
258 cpumask_xor(candidate_mask
, cpu_possible_mask
, cpu_present_mask
);
259 if (cpumask_empty(candidate_mask
)) {
260 /* If we get here, it most likely means that NR_CPUS is
261 * less than the partition's max processors setting.
263 printk(KERN_ERR
"Cannot add cpu %s; this system configuration"
264 " supports %d logical cpus.\n", np
->full_name
,
265 cpumask_weight(cpu_possible_mask
));
269 while (!cpumask_empty(tmp
))
270 if (cpumask_subset(tmp
, candidate_mask
))
271 /* Found a range where we can insert the new cpu(s) */
274 cpumask_shift_left(tmp
, tmp
, nthreads
);
276 if (cpumask_empty(tmp
)) {
277 printk(KERN_ERR
"Unable to find space in cpu_present_mask for"
278 " processor %s with %d thread(s)\n", np
->name
,
283 for_each_cpu(cpu
, tmp
) {
284 BUG_ON(cpu_present(cpu
));
285 set_cpu_present(cpu
, true);
286 set_hard_smp_processor_id(cpu
, *intserv
++);
290 cpu_maps_update_done();
291 free_cpumask_var(candidate_mask
);
292 free_cpumask_var(tmp
);
297 * Update the present map for a cpu node which is going away, and set
298 * the hard id in the paca(s) to -1 to be consistent with boot time
299 * convention for non-present cpus.
301 static void pseries_remove_processor(struct device_node
*np
)
304 int len
, nthreads
, i
;
307 intserv
= of_get_property(np
, "ibm,ppc-interrupt-server#s", &len
);
311 nthreads
= len
/ sizeof(u32
);
313 cpu_maps_update_begin();
314 for (i
= 0; i
< nthreads
; i
++) {
315 for_each_present_cpu(cpu
) {
316 if (get_hard_smp_processor_id(cpu
) != intserv
[i
])
318 BUG_ON(cpu_online(cpu
));
319 set_cpu_present(cpu
, false);
320 set_hard_smp_processor_id(cpu
, -1);
323 if (cpu
>= nr_cpu_ids
)
324 printk(KERN_WARNING
"Could not find cpu to remove "
325 "with physical id 0x%x\n", intserv
[i
]);
327 cpu_maps_update_done();
330 static int pseries_smp_notifier(struct notifier_block
*nb
,
331 unsigned long action
, void *node
)
336 case PSERIES_RECONFIG_ADD
:
337 if (pseries_add_processor(node
))
340 case PSERIES_RECONFIG_REMOVE
:
341 pseries_remove_processor(node
);
350 static struct notifier_block pseries_smp_nb
= {
351 .notifier_call
= pseries_smp_notifier
,
354 #define MAX_CEDE_LATENCY_LEVELS 4
355 #define CEDE_LATENCY_PARAM_LENGTH 10
356 #define CEDE_LATENCY_PARAM_MAX_LENGTH \
357 (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
358 #define CEDE_LATENCY_TOKEN 45
360 static char cede_parameters
[CEDE_LATENCY_PARAM_MAX_LENGTH
];
362 static int parse_cede_parameters(void)
364 memset(cede_parameters
, 0, CEDE_LATENCY_PARAM_MAX_LENGTH
);
365 return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
368 __pa(cede_parameters
),
369 CEDE_LATENCY_PARAM_MAX_LENGTH
);
372 static int __init
pseries_cpu_hotplug_init(void)
374 struct device_node
*np
;
379 for_each_node_by_name(np
, "interrupt-controller") {
380 typep
= of_get_property(np
, "compatible", NULL
);
381 if (strstr(typep
, "open-pic")) {
384 printk(KERN_INFO
"CPU Hotplug not supported on "
385 "systems using MPIC\n");
390 rtas_stop_self_args
.token
= rtas_token("stop-self");
391 qcss_tok
= rtas_token("query-cpu-stopped-state");
393 if (rtas_stop_self_args
.token
== RTAS_UNKNOWN_SERVICE
||
394 qcss_tok
== RTAS_UNKNOWN_SERVICE
) {
395 printk(KERN_INFO
"CPU Hotplug not supported by firmware "
400 ppc_md
.cpu_die
= pseries_mach_cpu_die
;
401 smp_ops
->cpu_disable
= pseries_cpu_disable
;
402 smp_ops
->cpu_die
= pseries_cpu_die
;
404 /* Processors can be added/removed only on LPAR */
405 if (firmware_has_feature(FW_FEATURE_LPAR
)) {
406 pSeries_reconfig_notifier_register(&pseries_smp_nb
);
407 cpu_maps_update_begin();
408 if (cede_offline_enabled
&& parse_cede_parameters() == 0) {
409 default_offline_state
= CPU_STATE_INACTIVE
;
410 for_each_online_cpu(cpu
)
411 set_default_offline_state(cpu
);
413 cpu_maps_update_done();
418 arch_initcall(pseries_cpu_hotplug_init
);