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Revision a0195f314a25582b38993bf30db11c300f4f4611 authored by Fenghua Yu on 17 December 2020, 22:31:19 UTC, committed by Borislav Petkov on 08 January 2021, 08:08:03 UTC 
x86/resctrl: Don't move a task to the same resource group
 
Shakeel Butt reported in [1] that a user can request a task to be moved
to a resource group even if the task is already in the group. It just
wastes time to do the move operation which could be costly to send IPI
to a different CPU.

Add a sanity check to ensure that the move operation only happens when
the task is not already in the resource group.

[1] https://lore.kernel.org/lkml/CALvZod7E9zzHwenzf7objzGKsdBmVwTgEJ0nPgs0LUFU3SN5Pw@mail.gmail.com/

Fixes: e02737d5b826 ("x86/intel_rdt: Add tasks files")
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/962ede65d8e95be793cb61102cca37f7bb018e66.1608243147.git.reinette.chatre@intel.com
1 parent ae28d1a
Raw File
hecubafb.h 
/*
 * hecubafb.h - definitions for the hecuba framebuffer driver
 *
 * Copyright (C) 2008 by Jaya Kumar
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file COPYING in the main directory of this archive for
 * more details.
 *
 */

#ifndef _LINUX_HECUBAFB_H_
#define _LINUX_HECUBAFB_H_

/* Apollo controller specific defines */
#define APOLLO_START_NEW_IMG	0xA0
#define APOLLO_STOP_IMG_DATA	0xA1
#define APOLLO_DISPLAY_IMG	0xA2
#define APOLLO_ERASE_DISPLAY	0xA3
#define APOLLO_INIT_DISPLAY	0xA4

/* Hecuba interface specific defines */
#define HCB_WUP_BIT	0x01
#define HCB_DS_BIT 	0x02
#define HCB_RW_BIT 	0x04
#define HCB_CD_BIT 	0x08
#define HCB_ACK_BIT 	0x80

/* struct used by hecuba. board specific stuff comes from *board */
struct hecubafb_par {
	struct fb_info *info;
	struct hecuba_board *board;
	void (*send_command)(struct hecubafb_par *, unsigned char);
	void (*send_data)(struct hecubafb_par *, unsigned char);
};

/* board specific routines
board drivers can implement wait_for_ack with interrupts if desired. if
wait_for_ack is called with clear=0, then go to sleep and return when ack
goes hi or if wait_for_ack with clear=1, then return when ack goes lo */
struct hecuba_board {
	struct module *owner;
	void (*remove)(struct hecubafb_par *);
	void (*set_ctl)(struct hecubafb_par *, unsigned char, unsigned char);
	void (*set_data)(struct hecubafb_par *, unsigned char);
	void (*wait_for_ack)(struct hecubafb_par *, int);
	int (*init)(struct hecubafb_par *);
};


#endif
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