path: root/arch/powerpc/kernel/align.c

/* align.c - handle alignment exceptions for the Power PC.
 *
 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au>
 * Copyright (c) 1998-1999 TiVo, Inc.
 *   PowerPC 403GCX modifications.
 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
 *   PowerPC 403GCX/405GP modifications.
 * Copyright (c) 2001-2002 PPC64 team, IBM Corp
 *   64-bit and Power4 support
 * Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp
 *                    <benh@kernel.crashing.org>
 *   Merge ppc32 and ppc64 implementations
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/cache.h>
#include <asm/cputable.h>
#include <asm/emulated_ops.h>
#include <asm/switch_to.h>

struct aligninfo {
	unsigned char len;
	unsigned char flags;
};

#define IS_XFORM(inst)	(((inst) >> 26) == 31)
#define IS_DSFORM(inst)	(((inst) >> 26) >= 56)

#define INVALID	{ 0, 0 }

/* Bits in the flags field */
#define LD	0	/* load */
#define ST	1	/* store */
#define SE	2	/* sign-extend value, or FP ld/st as word */
#define F	4	/* to/from fp regs */
#define U	8	/* update index register */
#define M	0x10	/* multiple load/store */
#define SW	0x20	/* byte swap */
#define S	0x40	/* single-precision fp or... */
#define SX	0x40	/* ... byte count in XER */
#define HARD	0x80	/* string, stwcx. */
#define E4	0x40	/* SPE endianness is word */
#define E8	0x80	/* SPE endianness is double word */
#define SPLT	0x80	/* VSX SPLAT load */

/* DSISR bits reported for a DCBZ instruction: */
#define DCBZ	0x5f	/* 8xx/82xx dcbz faults when cache not enabled */

/*
 * The PowerPC stores certain bits of the instruction that caused the
 * alignment exception in the DSISR register.  This array maps those
 * bits to information about the operand length and what the
 * instruction would do.
 */
static struct aligninfo aligninfo[128] = {
	{ 4, LD },		/* 00 0 0000: lwz / lwarx */
	INVALID,		/* 00 0 0001 */
	{ 4, ST },		/* 00 0 0010: stw */
	INVALID,		/* 00 0 0011 */
	{ 2, LD },		/* 00 0 0100: lhz */
	{ 2, LD+SE },		/* 00 0 0101: lha */
	{ 2, ST },		/* 00 0 0110: sth */
	{ 4, LD+M },		/* 00 0 0111: lmw */
	{ 4, LD+F+S },		/* 00 0 1000: lfs */
	{ 8, LD+F },		/* 00 0 1001: lfd */
	{ 4, ST+F+S },		/* 00 0 1010: stfs */
	{ 8, ST+F },		/* 00 0 1011: stfd */
	{ 16, LD },		/* 00 0 1100: lq */
	{ 8, LD },		/* 00 0 1101: ld/ldu/lwa */
	INVALID,		/* 00 0 1110 */
	{ 8, ST },		/* 00 0 1111: std/stdu */
	{ 4, LD+U },		/* 00 1 0000: lwzu */
	INVALID,		/* 00 1 0001 */
	{ 4, ST+U },		/* 00 1 0010: stwu */
	INVALID,		/* 00 1 0011 */
	{ 2, LD+U },		/* 00 1 0100: lhzu */
	{ 2, LD+SE+U },		/* 00 1 0101: lhau */
	{ 2, ST+U },		/* 00 1 0110: sthu */
	{ 4, ST+M },		/* 00 1 0111: stmw */
	{ 4, LD+F+S+U },	/* 00 1 1000: lfsu */
	{ 8, LD+F+U },		/* 00 1 1001: lfdu */
	{ 4, ST+F+S+U },	/* 00 1 1010: stfsu */
	{ 8, ST+F+U },		/* 00 1 1011: stfdu */
	{ 16, LD+F },		/* 00 1 1100: lfdp */
	INVALID,		/* 00 1 1101 */
	{ 16, ST+F },		/* 00 1 1110: stfdp */
	INVALID,		/* 00 1 1111 */
	{ 8, LD },		/* 01 0 0000: ldx */
	INVALID,		/* 01 0 0001 */
	{ 8, ST },		/* 01 0 0010: stdx */
	INVALID,		/* 01 0 0011 */
	INVALID,		/* 01 0 0100 */
	{ 4, LD+SE },		/* 01 0 0101: lwax */
	INVALID,		/* 01 0 0110 */
	INVALID,		/* 01 0 0111 */
	{ 4, LD+M+HARD+SX },	/* 01 0 1000: lswx */
	{ 4, LD+M+HARD },	/* 01 0 1001: lswi */
	{ 4, ST+M+HARD+SX },	/* 01 0 1010: stswx */
	{ 4, ST+M+HARD },	/* 01 0 1011: stswi */
	INVALID,		/* 01 0 1100 */
	{ 8, LD+U },		/* 01 0 1101: ldu */
	INVALID,		/* 01 0 1110 */
	{ 8, ST+U },		/* 01 0 1111: stdu */
	{ 8, LD+U },		/* 01 1 0000: ldux */
	INVALID,		/* 01 1 0001 */
	{ 8, ST+U },		/* 01 1 0010: stdux */
	INVALID,		/* 01 1 0011 */
	INVALID,		/* 01 1 0100 */
	{ 4, LD+SE+U },		/* 01 1 0101: lwaux */
	INVALID,