path: root/arch/tile/kernel/hardwall.c

/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/rwsem.h>
#include <linux/kprobes.h>
#include <linux/sched.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
#include <linux/smp.h>
#include <linux/cdev.h>
#include <linux/compat.h>
#include <asm/hardwall.h>
#include <asm/traps.h>
#include <asm/siginfo.h>
#include <asm/irq_regs.h>

#include <arch/interrupts.h>
#include <arch/spr_def.h>


/*
 * Implement a per-cpu "hardwall" resource class such as UDN or IPI.
 * We use "hardwall" nomenclature throughout for historical reasons.
 * The lock here controls access to the list data structure as well as
 * to the items on the list.
 */
struct hardwall_type {
	int index;
	int is_xdn;
	int is_idn;
	int disabled;
	const char *name;
	struct list_head list;
	spinlock_t lock;
	struct proc_dir_entry *proc_dir;
};

enum hardwall_index {
	HARDWALL_UDN = 0,
#ifndef __tilepro__
	HARDWALL_IDN = 1,
	HARDWALL_IPI = 2,
#endif
	_HARDWALL_TYPES
};

static struct hardwall_type hardwall_types[] = {
	{  /* user-space access to UDN */
		0,
		1,
		0,
		0,
		"udn",
		LIST_HEAD_INIT(hardwall_types[HARDWALL_UDN].list),
		__SPIN_LOCK_INITIALIZER(hardwall_types[HARDWALL_UDN].lock),
		NULL
	},
#ifndef __tilepro__
	{  /* user-space access to IDN */
		1,
		1,
		1,
		1,  /* disabled pending hypervisor support */
		"idn",
		LIST_HEAD_INIT(hardwall_types[HARDWALL_IDN].list),
		__SPIN_LOCK_INITIALIZER(hardwall_types[HARDWALL_IDN].lock),
		NULL
	},
	{  /* access to user-space IPI */
		2,
		0,
		0,
		0,
		"ipi",
		LIST_HEAD_INIT(hardwall_types[HARDWALL_IPI].list),
		__SPIN_LOCK_INITIALIZER(hardwall_types[HARDWALL_IPI].lock),
		NULL
	},
#endif
};

/*
 * This data structure tracks the cpu data, etc., associated
 * one-to-one with a "struct file *" from opening a hardwall device file.
 * Note that the file's private data points back to this structure.
 */
struct hardwall_info {
	struct list_head list;             /* for hardwall_types.list */
	struct list_head task_head;        /* head of tasks in this hardwall */
	struct hardwall_type *type;        /* type of this resource */
	struct cpumask cpumask;            /* cpus reserved */
	int id;                            /* integer id for this hardwall */
	int teardown_in_progress;          /* are we tearing this one down? */

	/* Remaining fields only valid for user-network resources. */
	int ulhc_x;                        /* upper left hand corner x coord */
	int ulhc_y;                        /* upper left hand corner y coord */
	int width;                         /* rectangle width */
	int height;                        /* rectangle height */
#if CHIP_HAS_REV1_XDN()
	atomic_t xdn_pending_count;        /* cores in phase 1 of drain */
#endif
};


/* /proc/tile/hardwall */
static struct proc_dir_entry *hardwall_proc_dir;

/* Functions to manage files in /proc/tile/hardwall. */
static void hardwall_add_proc(struct hardwall_info *);
static void hardwall_remove_proc(struct hardwall_info *);

/* Allow disabling UDN access. */
static int __init noudn(char *str)
{
	pr_info("User-space UDN access is disabled\n");
	hardwall_types[HARDWALL_UDN].disabled = 1;
	return 0;
}
early_param("noudn", noudn);

#ifndef __tilepro__
/* Allow disabling IDN access. */
static int __init noidn(char *str)
{
	pr_info("User-space IDN access is disabled\n");
	hardwall_types[HARDWALL_IDN].disabled = 1;
	return 0;
}
early_param("noidn", noidn);

/* Allow disabling IPI access. */
static int __init noipi(char *str)
{
	pr_info("User-space IPI access is disabled\n");
	hardwall_types[HARDWALL_IPI].disabled = 1;
	return 0;
}
early_param("noipi", noipi);
#endif


/*
 * Low-level primitives for UDN/IDN
 */

#ifdef __tilepro__
#define mtspr_XDN(hwt, name, val) \
	do { (void)(hwt); __insn_mtspr(SPR_UDN_##name, (val)); } while (0)
#define mtspr_MPL_XDN(hwt, name, val) \
	do { (void)(hwt); __insn_mtspr(SPR_MPL_UDN_##name, (val)); } while (0)
#define mfspr_XDN(hwt, name) \
	((void)(hwt), __insn_mfspr(SPR_UDN_##name))
#else
#define mtspr_XDN(hwt, name, val)					\
	do {								\
		if ((hwt)->is_idn)					\
			__insn_mtspr(SPR_IDN_##name, (val));		\
		else							\
			__insn_mtspr(SPR_UDN_##name, (val));		\
	} while (0)
#define mtspr_MPL_XDN(hwt, name, val)					\
	do {								\
		if ((hwt)->is_idn)					\
			__insn_mtspr(SPR_MPL_IDN_##name, (val));	\
		else							\
			__insn_mtspr(SPR_MPL_UDN_##name, (val));	\
	} while (0)
#define mfspr_XDN(hwt, name) \
  ((hwt)->is_idn ? __insn_mfspr(SPR_IDN_##name) : __insn_mfspr(SPR_UDN_##name))
#endif

/* Set a CPU bit if the CPU is online. */
#define cpu_online_set(cpu, dst) do { \
	if (cpu_online(cpu))          \
		cpumask_set_cpu(cpu, dst);    \
} while (0)


/* Does the given rectangle contain the given x,y coordinate? */