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authorRalf Baechle <ralf@mips.com>2007-07-03 09:37:43 -0400
committerRalf Baechle <ralf@linux-mips.org>2007-07-10 12:33:04 -0400
commit295cbf6d63165fe4253cf1d9ceadcda47a318b48 (patch)
treef37a2065836ccb32a1438c57ef0eefe3aef1e82d /arch/mips/kernel/mips-mt-fpaff.c
parent5ddcb3c35be995517a32799796e2acda90a784e0 (diff)
[MIPS] Move FPU affinity code into separate file.
Gets rid of some of the CONFIG_MIPS_MT_FPAFF #ifdefery. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/mips-mt-fpaff.c')
-rw-r--r--arch/mips/kernel/mips-mt-fpaff.c176
1 files changed, 176 insertions, 0 deletions
diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c
new file mode 100644
index 000000000000..ede5d73d652e
--- /dev/null
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -0,0 +1,176 @@
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/cpumask.h>
7#include <linux/delay.h>
8#include <linux/kernel.h>
9#include <linux/init.h>
10#include <linux/sched.h>
11#include <linux/security.h>
12#include <linux/types.h>
13#include <asm/uaccess.h>
14
15/*
16 * CPU mask used to set process affinity for MT VPEs/TCs with FPUs
17 */
18cpumask_t mt_fpu_cpumask;
19
20static int fpaff_threshold = -1;
21unsigned long mt_fpemul_threshold = 0;
22
23/*
24 * Replacement functions for the sys_sched_setaffinity() and
25 * sys_sched_getaffinity() system calls, so that we can integrate
26 * FPU affinity with the user's requested processor affinity.
27 * This code is 98% identical with the sys_sched_setaffinity()
28 * and sys_sched_getaffinity() system calls, and should be
29 * updated when kernel/sched.c changes.
30 */
31
32/*
33 * find_process_by_pid - find a process with a matching PID value.
34 * used in sys_sched_set/getaffinity() in kernel/sched.c, so
35 * cloned here.
36 */
37static inline struct task_struct *find_process_by_pid(pid_t pid)
38{
39 return pid ? find_task_by_pid(pid) : current;
40}
41
42
43/*
44 * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
45 */
46asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
47 unsigned long __user *user_mask_ptr)
48{
49 cpumask_t new_mask;
50 cpumask_t effective_mask;
51 int retval;
52 struct task_struct *p;
53
54 if (len < sizeof(new_mask))
55 return -EINVAL;
56
57 if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
58 return -EFAULT;
59
60 lock_cpu_hotplug();
61 read_lock(&tasklist_lock);
62
63 p = find_process_by_pid(pid);
64 if (!p) {
65 read_unlock(&tasklist_lock);
66 unlock_cpu_hotplug();
67 return -ESRCH;
68 }
69
70 /*
71 * It is not safe to call set_cpus_allowed with the
72 * tasklist_lock held. We will bump the task_struct's
73 * usage count and drop tasklist_lock before invoking
74 * set_cpus_allowed.
75 */
76 get_task_struct(p);
77
78 retval = -EPERM;
79 if ((current->euid != p->euid) && (current->euid != p->uid) &&
80 !capable(CAP_SYS_NICE)) {
81 read_unlock(&tasklist_lock);
82 goto out_unlock;
83 }
84
85 retval = security_task_setscheduler(p, 0, NULL);
86 if (retval)
87 goto out_unlock;
88
89 /* Record new user-specified CPU set for future reference */
90 p->thread.user_cpus_allowed = new_mask;
91
92 /* Unlock the task list */
93 read_unlock(&tasklist_lock);
94
95 /* Compute new global allowed CPU set if necessary */
96 if ((p->thread.mflags & MF_FPUBOUND)
97 && cpus_intersects(new_mask, mt_fpu_cpumask)) {
98 cpus_and(effective_mask, new_mask, mt_fpu_cpumask);
99 retval = set_cpus_allowed(p, effective_mask);
100 } else {
101 p->thread.mflags &= ~MF_FPUBOUND;
102 retval = set_cpus_allowed(p, new_mask);
103 }
104
105
106out_unlock:
107 put_task_struct(p);
108 unlock_cpu_hotplug();
109 return retval;
110}
111
112/*
113 * mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
114 */
115asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
116 unsigned long __user *user_mask_ptr)
117{
118 unsigned int real_len;
119 cpumask_t mask;
120 int retval;
121 struct task_struct *p;
122
123 real_len = sizeof(mask);
124 if (len < real_len)
125 return -EINVAL;
126
127 lock_cpu_hotplug();
128 read_lock(&tasklist_lock);
129
130 retval = -ESRCH;
131 p = find_process_by_pid(pid);
132 if (!p)
133 goto out_unlock;
134 retval = security_task_getscheduler(p);
135 if (retval)
136 goto out_unlock;
137
138 cpus_and(mask, p->thread.user_cpus_allowed, cpu_possible_map);
139
140out_unlock:
141 read_unlock(&tasklist_lock);
142 unlock_cpu_hotplug();
143 if (retval)
144 return retval;
145 if (copy_to_user(user_mask_ptr, &mask, real_len))
146 return -EFAULT;
147 return real_len;
148}
149
150
151static int __init fpaff_thresh(char *str)
152{
153 get_option(&str, &fpaff_threshold);
154 return 1;
155}
156__setup("fpaff=", fpaff_thresh);
157
158/*
159 * FPU Use Factor empirically derived from experiments on 34K
160 */
161#define FPUSEFACTOR 333
162
163static __init int mt_fp_affinity_init(void)
164{
165 if (fpaff_threshold >= 0) {
166 mt_fpemul_threshold = fpaff_threshold;
167 } else {
168 mt_fpemul_threshold =
169 (FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
170 }
171 printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
172 mt_fpemul_threshold);
173
174 return 0;
175}
176arch_initcall(mt_fp_affinity_init);