[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>

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 @@
+/*
+ * General MIPS MT support routines, usable in AP/SP, SMVP, or SMTC kernels
+ * Copyright (C) 2005 Mips Technologies, Inc
+ */
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/security.h>
+#include <linux/types.h>
+#include <asm/uaccess.h>
+
+/*
+ * CPU mask used to set process affinity for MT VPEs/TCs with FPUs
+ */
+cpumask_t mt_fpu_cpumask;
+
+static int fpaff_threshold = -1;
+unsigned long mt_fpemul_threshold = 0;
+
+/*
+ * Replacement functions for the sys_sched_setaffinity() and
+ * sys_sched_getaffinity() system calls, so that we can integrate
+ * FPU affinity with the user's requested processor affinity.
+ * This code is 98% identical with the sys_sched_setaffinity()
+ * and sys_sched_getaffinity() system calls, and should be
+ * updated when kernel/sched.c changes.
+ */
+
+/*
+ * find_process_by_pid - find a process with a matching PID value.
+ * used in sys_sched_set/getaffinity() in kernel/sched.c, so
+ * cloned here.
+ */
+static inline struct task_struct *find_process_by_pid(pid_t pid)
+{
+	return pid ? find_task_by_pid(pid) : current;
+}
+
+
+/*
+ * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
+ */
+asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
+				      unsigned long __user *user_mask_ptr)
+{
+	cpumask_t new_mask;
+	cpumask_t effective_mask;
+	int retval;
+	struct task_struct *p;
+
+	if (len < sizeof(new_mask))
+		return -EINVAL;
+
+	if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
+		return -EFAULT;
+
+	lock_cpu_hotplug();
+	read_lock(&tasklist_lock);
+
+	p = find_process_by_pid(pid);
+	if (!p) {
+		read_unlock(&tasklist_lock);
+		unlock_cpu_hotplug();
+		return -ESRCH;
+	}
+
+	/*
+	 * It is not safe to call set_cpus_allowed with the
+	 * tasklist_lock held.  We will bump the task_struct's
+	 * usage count and drop tasklist_lock before invoking
+	 * set_cpus_allowed.
+	 */
+	get_task_struct(p);
+
+	retval = -EPERM;
+	if ((current->euid != p->euid) && (current->euid != p->uid) &&
+			!capable(CAP_SYS_NICE)) {
+		read_unlock(&tasklist_lock);
+		goto out_unlock;
+	}
+
+	retval = security_task_setscheduler(p, 0, NULL);
+	if (retval)
+		goto out_unlock;
+
+	/* Record new user-specified CPU set for future reference */
+	p->thread.user_cpus_allowed = new_mask;
+
+	/* Unlock the task list */
+	read_unlock(&tasklist_lock);
+
+	/* Compute new global allowed CPU set if necessary */
+	if ((p->thread.mflags & MF_FPUBOUND)
+	&& cpus_intersects(new_mask, mt_fpu_cpumask)) {
+		cpus_and(effective_mask, new_mask, mt_fpu_cpumask);
+		retval = set_cpus_allowed(p, effective_mask);
+	} else {
+		p->thread.mflags &= ~MF_FPUBOUND;
+		retval = set_cpus_allowed(p, new_mask);
+	}
+
+
+out_unlock:
+	put_task_struct(p);
+	unlock_cpu_hotplug();
+	return retval;
+}
+
+/*
+ * mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
+ */
+asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
+				      unsigned long __user *user_mask_ptr)
+{
+	unsigned int real_len;
+	cpumask_t mask;
+	int retval;
+	struct task_struct *p;
+
+	real_len = sizeof(mask);
+	if (len < real_len)
+		return -EINVAL;
+
+	lock_cpu_hotplug();
+	read_lock(&tasklist_lock);
+
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	cpus_and(mask, p->thread.user_cpus_allowed, cpu_possible_map);
+
+out_unlock:
+	read_unlock(&tasklist_lock);
+	unlock_cpu_hotplug();
+	if (retval)
+		return retval;
+	if (copy_to_user(user_mask_ptr, &mask, real_len))
+		return -EFAULT;
+	return real_len;
+}
+
+
+static int __init fpaff_thresh(char *str)
+{
+	get_option(&str, &fpaff_threshold);
+	return 1;
+}
+__setup("fpaff=", fpaff_thresh);
+
+/*
+ * FPU Use Factor empirically derived from experiments on 34K
+ */
+#define FPUSEFACTOR 333
+
+static __init int mt_fp_affinity_init(void)
+{
+	if (fpaff_threshold >= 0) {
+		mt_fpemul_threshold = fpaff_threshold;
+	} else {
+		mt_fpemul_threshold =
+			(FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
+	}
+	printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
+	       mt_fpemul_threshold);
+
+	return 0;
+}
+arch_initcall(mt_fp_affinity_init);