path: root/arch/blackfin/mach-common/entry.S

/*
 * File:         arch/blackfin/mach-common/entry.S
 * Based on:
 * Author:       Linus Torvalds
 *
 * Created:      ?
 * Description:  contains the system-call and fault low-level handling routines.
 *               This also contains the timer-interrupt handler, as well as all
 *               interrupts and faults that can result in a task-switch.
 *
 * Modified:
 *               Copyright 2004-2006 Analog Devices Inc.
 *
 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

/*
 * 25-Dec-2004 - LG Soft India
 * 	1. Fix in return_from_int, to make sure any pending
 *	system call in ILAT for this process to get
 *	executed, otherwise in case context switch happens,
 *	system call of first process (i.e in ILAT) will be
 *	carried forward to the switched process.
 *	2. Removed Constant references for the following
 *		a.  IPEND
 *		b.  EXCAUSE mask
 *		c.  PAGE Mask
 */

/*
 * NOTE: This code handles signal-recognition, which happens every time
 * after a timer-interrupt and after each system call.
 */


#include <linux/linkage.h>
#include <asm/blackfin.h>
#include <asm/unistd.h>
#include <asm/errno.h>
#include <asm/thread_info.h>  /* TIF_NEED_RESCHED */
#include <asm/asm-offsets.h>

#include <asm/mach-common/context.S>

#ifdef CONFIG_DEBUG_BFIN_NO_KERN_HWTRACE
	/*
	 * TODO: this should be proper save/restore, but for now
	 * we'll just cheat and use 0x1/0x13
	 */
# define DEBUG_START_HWTRACE \
	P5.l = LO(TBUFCTL); \
	P5.h = HI(TBUFCTL); \
	R7 = 0x13; \
	[P5] = R7;
# define DEBUG_STOP_HWTRACE \
	P5.l = LO(TBUFCTL); \
	P5.h = HI(TBUFCTL); \
	R7 = 0x01; \
	[P5] = R7;
#else
# define DEBUG_START_HWTRACE
# define DEBUG_STOP_HWTRACE
#endif

#ifdef CONFIG_EXCPT_IRQ_SYSC_L1
.section .l1.text
#else
.text
#endif

/* Slightly simplified and streamlined entry point for CPLB misses.
 * This one does not lower the level to IRQ5, and thus can be used to
 * patch up CPLB misses on the kernel stack.
 */
ENTRY(_ex_dcplb)
#if defined(ANOMALY_05000261)
	/*
	 * Work around an anomaly: if we see a new DCPLB fault, return
	 * without doing anything.  Then, if we get the same fault again,
	 * handle it.
	 */
	p5.l = _last_cplb_fault_retx;
	p5.h = _last_cplb_fault_retx;
	r7 = [p5];
	r6 = retx;
	[p5] = r6;
	cc = r6 == r7;
	if !cc jump _return_from_exception;
	/* fall through */
#endif

ENTRY(_ex_icplb)
	(R7:6,P5:4) = [sp++];
	ASTAT = [sp++];
	SAVE_ALL_SYS
	call __cplb_hdr;
	DEBUG_START_HWTRACE
	RESTORE_ALL_SYS
	SP = RETN;
	rtx;

ENTRY(_ex_spinlock)
	/* Transform this into a syscall - twiddle the syscall vector.  */
	p5.l = lo(EVT15);
	p5.h = hi(EVT15);
	r7.l = _spinlock_bh;
	r7.h = _spinlock_bh;
	[p5] = r7;
	csync;
	/* Fall through.  */

ENTRY(_ex_syscall)
	DEBUG_START_HWTRACE
	(R7:6,P5:4) = [sp++];
	ASTAT = [sp++];
	raise 15;		/* invoked by TRAP #0, for sys call */
	sp = retn;
	rtx

ENTRY(_spinlock_bh)
	SAVE_ALL_SYS
	/* To end up here, vector 15 was changed - so we have to change it
	 * back.
	 */
	p0.l = lo(EVT15);
	p0.h = hi(EVT15);
	p1.l = _evt_system_call;
	p1.h = _evt_system_call;
	[p0] = p1;
	csync;
	r0 = [sp + PT_R0];
	sp += -12;
	call _sys_bfin_spinlock;
	sp += 12;
	[SP + PT_R0] = R0;
	RESTORE_ALL_SYS
	rti;

ENTRY(_ex_soft_bp)
	<