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1/*
2 * General MIPS MT support routines, usable in AP/SP, SMVP, or SMTC kernels
3 * Copyright (C) 2005 Mips Technologies, Inc
4 */
5#include <linux/cpu.h>
6#include <linux/cpuset.h>
7#include <linux/cpumask.h>
8#include <linux/delay.h>
9#include <linux/kernel.h>
10#include <linux/init.h>
11#include <linux/sched.h>
12#include <linux/security.h>
13#include <linux/types.h>
14#include <asm/uaccess.h>
15
16/*
17 * CPU mask used to set process affinity for MT VPEs/TCs with FPUs
18 */
19cpumask_t mt_fpu_cpumask;
20
21static int fpaff_threshold = -1;
22unsigned long mt_fpemul_threshold;
23
24/*
25 * Replacement functions for the sys_sched_setaffinity() and
26 * sys_sched_getaffinity() system calls, so that we can integrate
27 * FPU affinity with the user's requested processor affinity.
28 * This code is 98% identical with the sys_sched_setaffinity()
29 * and sys_sched_getaffinity() system calls, and should be
30 * updated when kernel/sched.c changes.
31 */
32
33/*
34 * find_process_by_pid - find a process with a matching PID value.
35 * used in sys_sched_set/getaffinity() in kernel/sched.c, so
36 * cloned here.
37 */
38static inline struct task_struct *find_process_by_pid(pid_t pid)
39{
40 return pid ? find_task_by_vpid(pid) : current;
41}
42
43/*
44 * check the target process has a UID that matches the current process's
45 */
46static bool check_same_owner(struct task_struct *p)
47{
48 const struct cred *cred = current_cred(), *pcred;
49 bool match;
50
51 rcu_read_lock();
52 pcred = __task_cred(p);
53 match = (cred->euid == pcred->euid ||
54 cred->euid == pcred->uid);
55 rcu_read_unlock();
56 return match;
57}
58
59/*
60 * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
61 */
62asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
63 unsigned long __user *user_mask_ptr)
64{
65 cpumask_var_t cpus_allowed, new_mask, effective_mask;
66 struct thread_info *ti;
67 struct task_struct *p;
68 int retval;
69
70 if (len < sizeof(new_mask))
71 return -EINVAL;
72
73 if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
74 return -EFAULT;
75
76 get_online_cpus();
77 rcu_read_lock();
78
79 p = find_process_by_pid(pid);
80 if (!p) {
81 rcu_read_unlock();
82 put_online_cpus();
83 return -ESRCH;
84 }
85
86 /* Prevent p going away */
87 get_task_struct(p);
88 rcu_read_unlock();
89
90 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
91 retval = -ENOMEM;
92 goto out_put_task;
93 }
94 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
95 retval = -ENOMEM;
96 goto out_free_cpus_allowed;
97 }
98 if (!alloc_cpumask_var(&effective_mask, GFP_KERNEL)) {
99 retval = -ENOMEM;
100 goto out_free_new_mask;
101 }
102 retval = -EPERM;
103 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
104 goto out_unlock;
105
106 retval = security_task_setscheduler(p);
107 if (retval)
108 goto out_unlock;
109
110 /* Record new user-specified CPU set for future reference */
111 cpumask_copy(&p->thread.user_cpus_allowed, new_mask);
112
113 again:
114 /* Compute new global allowed CPU set if necessary */
115 ti = task_thread_info(p);
116 if (test_ti_thread_flag(ti, TIF_FPUBOUND) &&
117 cpus_intersects(*new_mask, mt_fpu_cpumask)) {
118 cpus_and(*effective_mask, *new_mask, mt_fpu_cpumask);
119 retval = set_cpus_allowed_ptr(p, effective_mask);
120 } else {
121 cpumask_copy(effective_mask, new_mask);
122 clear_ti_thread_flag(ti, TIF_FPUBOUND);
123 retval = set_cpus_allowed_ptr(p, new_mask);
124 }
125
126 if (!retval) {
127 cpuset_cpus_allowed(p, cpus_allowed);
128 if (!cpumask_subset(effective_mask, cpus_allowed)) {
129 /*
130 * We must have raced with a concurrent cpuset
131 * update. Just reset the cpus_allowed to the
132 * cpuset's cpus_allowed
133 */
134 cpumask_copy(new_mask, cpus_allowed);
135 goto again;
136 }
137 }
138out_unlock:
139 free_cpumask_var(effective_mask);
140out_free_new_mask:
141 free_cpumask_var(new_mask);
142out_free_cpus_allowed:
143 free_cpumask_var(cpus_allowed);
144out_put_task:
145 put_task_struct(p);
146 put_online_cpus();
147 return retval;
148}
149
150/*
151 * mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
152 */
153asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
154 unsigned long __user *user_mask_ptr)
155{
156 unsigned int real_len;
157 cpumask_t mask;
158 int retval;
159 struct task_struct *p;
160
161 real_len = sizeof(mask);
162 if (len < real_len)
163 return -EINVAL;
164
165 get_online_cpus();
166 read_lock(&tasklist_lock);
167
168 retval = -ESRCH;
169 p = find_process_by_pid(pid);
170 if (!p)
171 goto out_unlock;
172 retval = security_task_getscheduler(p);
173 if (retval)
174 goto out_unlock;
175
176 cpus_and(mask, p->thread.user_cpus_allowed, cpu_possible_map);
177
178out_unlock:
179 read_unlock(&tasklist_lock);
180 put_online_cpus();
181 if (retval)
182 return retval;
183 if (copy_to_user(user_mask_ptr, &mask, real_len))
184 return -EFAULT;
185 return real_len;
186}
187
188
189static int __init fpaff_thresh(char *str)
190{
191 get_option(&str, &fpaff_threshold);
192 return 1;
193}
194__setup("fpaff=", fpaff_thresh);
195
196/*
197 * FPU Use Factor empirically derived from experiments on 34K
198 */
199#define FPUSEFACTOR 2000
200
201static __init int mt_fp_affinity_init(void)
202{
203 if (fpaff_threshold >= 0) {
204 mt_fpemul_threshold = fpaff_threshold;
205 } else {
206 mt_fpemul_threshold =
207 (FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
208 }
209 printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
210 mt_fpemul_threshold);
211
212 return 0;
213}
214arch_initcall(mt_fp_affinity_init);
1/*
2 * General MIPS MT support routines, usable in AP/SP and SMVP.
3 * Copyright (C) 2005 Mips Technologies, Inc
4 */
5#include <linux/cpu.h>
6#include <linux/cpuset.h>
7#include <linux/cpumask.h>
8#include <linux/delay.h>
9#include <linux/kernel.h>
10#include <linux/init.h>
11#include <linux/sched.h>
12#include <linux/security.h>
13#include <linux/types.h>
14#include <asm/uaccess.h>
15
16/*
17 * CPU mask used to set process affinity for MT VPEs/TCs with FPUs
18 */
19cpumask_t mt_fpu_cpumask;
20
21static int fpaff_threshold = -1;
22unsigned long mt_fpemul_threshold;
23
24/*
25 * Replacement functions for the sys_sched_setaffinity() and
26 * sys_sched_getaffinity() system calls, so that we can integrate
27 * FPU affinity with the user's requested processor affinity.
28 * This code is 98% identical with the sys_sched_setaffinity()
29 * and sys_sched_getaffinity() system calls, and should be
30 * updated when kernel/sched/core.c changes.
31 */
32
33/*
34 * find_process_by_pid - find a process with a matching PID value.
35 * used in sys_sched_set/getaffinity() in kernel/sched/core.c, so
36 * cloned here.
37 */
38static inline struct task_struct *find_process_by_pid(pid_t pid)
39{
40 return pid ? find_task_by_vpid(pid) : current;
41}
42
43/*
44 * check the target process has a UID that matches the current process's
45 */
46static bool check_same_owner(struct task_struct *p)
47{
48 const struct cred *cred = current_cred(), *pcred;
49 bool match;
50
51 rcu_read_lock();
52 pcred = __task_cred(p);
53 match = (uid_eq(cred->euid, pcred->euid) ||
54 uid_eq(cred->euid, pcred->uid));
55 rcu_read_unlock();
56 return match;
57}
58
59/*
60 * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
61 */
62asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
63 unsigned long __user *user_mask_ptr)
64{
65 cpumask_var_t cpus_allowed, new_mask, effective_mask;
66 struct thread_info *ti;
67 struct task_struct *p;
68 int retval;
69
70 if (len < sizeof(new_mask))
71 return -EINVAL;
72
73 if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
74 return -EFAULT;
75
76 get_online_cpus();
77 rcu_read_lock();
78
79 p = find_process_by_pid(pid);
80 if (!p) {
81 rcu_read_unlock();
82 put_online_cpus();
83 return -ESRCH;
84 }
85
86 /* Prevent p going away */
87 get_task_struct(p);
88 rcu_read_unlock();
89
90 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
91 retval = -ENOMEM;
92 goto out_put_task;
93 }
94 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
95 retval = -ENOMEM;
96 goto out_free_cpus_allowed;
97 }
98 if (!alloc_cpumask_var(&effective_mask, GFP_KERNEL)) {
99 retval = -ENOMEM;
100 goto out_free_new_mask;
101 }
102 retval = -EPERM;
103 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
104 goto out_unlock;
105
106 retval = security_task_setscheduler(p);
107 if (retval)
108 goto out_unlock;
109
110 /* Record new user-specified CPU set for future reference */
111 cpumask_copy(&p->thread.user_cpus_allowed, new_mask);
112
113 again:
114 /* Compute new global allowed CPU set if necessary */
115 ti = task_thread_info(p);
116 if (test_ti_thread_flag(ti, TIF_FPUBOUND) &&
117 cpumask_intersects(new_mask, &mt_fpu_cpumask)) {
118 cpumask_and(effective_mask, new_mask, &mt_fpu_cpumask);
119 retval = set_cpus_allowed_ptr(p, effective_mask);
120 } else {
121 cpumask_copy(effective_mask, new_mask);
122 clear_ti_thread_flag(ti, TIF_FPUBOUND);
123 retval = set_cpus_allowed_ptr(p, new_mask);
124 }
125
126 if (!retval) {
127 cpuset_cpus_allowed(p, cpus_allowed);
128 if (!cpumask_subset(effective_mask, cpus_allowed)) {
129 /*
130 * We must have raced with a concurrent cpuset
131 * update. Just reset the cpus_allowed to the
132 * cpuset's cpus_allowed
133 */
134 cpumask_copy(new_mask, cpus_allowed);
135 goto again;
136 }
137 }
138out_unlock:
139 free_cpumask_var(effective_mask);
140out_free_new_mask:
141 free_cpumask_var(new_mask);
142out_free_cpus_allowed:
143 free_cpumask_var(cpus_allowed);
144out_put_task:
145 put_task_struct(p);
146 put_online_cpus();
147 return retval;
148}
149
150/*
151 * mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
152 */
153asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
154 unsigned long __user *user_mask_ptr)
155{
156 unsigned int real_len;
157 cpumask_t allowed, mask;
158 int retval;
159 struct task_struct *p;
160
161 real_len = sizeof(mask);
162 if (len < real_len)
163 return -EINVAL;
164
165 get_online_cpus();
166 read_lock(&tasklist_lock);
167
168 retval = -ESRCH;
169 p = find_process_by_pid(pid);
170 if (!p)
171 goto out_unlock;
172 retval = security_task_getscheduler(p);
173 if (retval)
174 goto out_unlock;
175
176 cpumask_or(&allowed, &p->thread.user_cpus_allowed, &p->cpus_allowed);
177 cpumask_and(&mask, &allowed, cpu_active_mask);
178
179out_unlock:
180 read_unlock(&tasklist_lock);
181 put_online_cpus();
182 if (retval)
183 return retval;
184 if (copy_to_user(user_mask_ptr, &mask, real_len))
185 return -EFAULT;
186 return real_len;
187}
188
189
190static int __init fpaff_thresh(char *str)
191{
192 get_option(&str, &fpaff_threshold);
193 return 1;
194}
195__setup("fpaff=", fpaff_thresh);
196
197/*
198 * FPU Use Factor empirically derived from experiments on 34K
199 */
200#define FPUSEFACTOR 2000
201
202static __init int mt_fp_affinity_init(void)
203{
204 if (fpaff_threshold >= 0) {
205 mt_fpemul_threshold = fpaff_threshold;
206 } else {
207 mt_fpemul_threshold =
208 (FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
209 }
210 printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
211 mt_fpemul_threshold);
212
213 return 0;
214}
215arch_initcall(mt_fp_affinity_init);