Commit 5b2189ab authored by Noam Camus's avatar Noam Camus Committed by Vineet Gupta
Browse files

ARC: [plat-eznps] handle extra aux regs #1: save/restore on context switch 



save EFLAGS, and GPA1 auxiliary registers during context switch,
since they may be changed by the new task in kernel mode, while using atomic
ops e.g. cmpxchg.

Signed-off-by: default avatarNoam Camus <noamc@ezchip.com>
Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 3f9cd874

arch/arc/include/asm/processor.h

+10 −0
Original line number Diff line number Diff line
@@ -27,6 +27,13 @@ struct arc_fpu { 
};

#endif



#ifdef CONFIG_ARC_PLAT_EZNPS

struct eznps_dp {

	unsigned int eflags;

	unsigned int gpa1;

};

#endif



/* Arch specific stuff which needs to be saved per task.

 * However these items are not so important so as to earn a place in

 * struct thread_info
@@ -38,6 +45,9 @@ struct thread_struct { 
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE

	struct arc_fpu fpu;

#endif

#ifdef CONFIG_ARC_PLAT_EZNPS

	struct eznps_dp dp;

#endif

};



#define INIT_THREAD  {                          \

arch/arc/include/asm/switch_to.h

+9 −0
Original line number Diff line number Diff line
@@ -26,10 +26,19 @@ extern void fpu_save_restore(struct task_struct *p, struct task_struct *n); 


#endif /* !CONFIG_ARC_FPU_SAVE_RESTORE */



#ifdef CONFIG_ARC_PLAT_EZNPS

extern void dp_save_restore(struct task_struct *p, struct task_struct *n);

#define ARC_EZNPS_DP_PREV(p, n)      dp_save_restore(p, n)

#else

#define ARC_EZNPS_DP_PREV(p, n)



#endif /* !CONFIG_ARC_PLAT_EZNPS */



struct task_struct *__switch_to(struct task_struct *p, struct task_struct *n);



#define switch_to(prev, next, last)	\

do {					\

	ARC_EZNPS_DP_PREV(prev, next);	\

	ARC_FPU_PREV(prev, next);	\

	last = __switch_to(prev, next);\

	ARC_FPU_NEXT(next);		\

arch/arc/plat-eznps/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,6 +2,6 @@ 
# Makefile for the linux kernel.

#



obj-y := entry.o platform.o

obj-y := entry.o platform.o ctop.o

obj-$(CONFIG_SMP) += smp.o

obj-$(CONFIG_EZNPS_MTM_EXT) += mtm.o

arch/arc/plat-eznps/ctop.c

0 → 100644
+32 −0
Original line number Diff line number Diff line 
/*

 * Copyright(c) 2015 EZchip Technologies.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 * The full GNU General Public License is included in this distribution in

 * the file called "COPYING".

 */



#include <linux/sched.h>

#include <asm/processor.h>

#include <plat/ctop.h>



void dp_save_restore(struct task_struct *prev, struct task_struct *next)

{

	struct eznps_dp *prev_task_dp = &prev->thread.dp;

	struct eznps_dp *next_task_dp = &next->thread.dp;



	/* Here we save all Data Plane related auxiliary registers */

	prev_task_dp->eflags = read_aux_reg(CTOP_AUX_EFLAGS);

	write_aux_reg(CTOP_AUX_EFLAGS, next_task_dp->eflags);



	prev_task_dp->gpa1 = read_aux_reg(CTOP_AUX_GPA1);

	write_aux_reg(CTOP_AUX_GPA1, next_task_dp->gpa1);

}