/* 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
*
* 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/system.h>
#include <asm/cache.h>
#include <asm/cputable.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 }
#define LD 1 /* load */
#define ST 2 /* store */
#define SE 4 /* sign-extend value */
#define F 8 /* to/from fp regs */
#define U 0x10 /* update index register */
#define M 0x20 /* multiple load/store */
#define SW 0x40 /* byte swap */
#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 }, /* 00 0 1000: lfs */
{ 8, LD+F }, /* 00 0 1001: lfd */
{ 4, ST+F }, /* 00 0 1010: stfs */
{ 8, ST+F }, /* 00 0 1011: stfd */
INVALID, /* 00 0 1100 */
{ 8, LD }, /* 00 0 1101: ld */
INVALID, /* 00 0 1110 */
{ 8, ST }, /* 00 0 1111: std */
{ 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+U }, /* 00 1 1000: lfsu */
{ 8, LD+F+U }, /* 00 1 1001: lfdu */
{ 4, ST+F+U }, /* 00 1 1010: stfsu */
{ 8, ST+F+U }, /* 00 1 1011: stfdu */
INVALID, /* 00 1 1100 */
INVALID, /* 00 1 1101 */
INVALID, /* 00 1 1110 */
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 */
{ 0, LD }, /* 01 0 1000: lswx */
{ 0, LD }, /* 01 0 1001: lswi */
{ 0, ST }, /* 01 0 1010: stswx */
{ 0, ST }, /* 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, /* 01 1 0110 */
INVALID, /* 01 1 0111 */
INVALID, /* 01 1 1000 */
INVALID, /* 01 1 1001 */
INVALID, /* 01 1 1010 */
INVALID, /* 01 1 1011 */
INVALID, /* 01 1 1100 */
INVALID, /* 01 1 1101 */
INVALID, /* 01 1 1110 */
INVALID, /* 01 1 1111 */
INVALID, /* 10 0 0000 */
INVALID, /* 10 0 0001 */
{ 0, ST }, /* 10 0 0010: stwcx. */
INVALID, /* 10 0 0011 */
INVALID, /* 10 0 0100 */
INVALID, /* 10 0 0101 */
INVALID, /* 10 0 0110 */
INVALID, /* 10 0 0111 */
{ 4, LD+SW }, /* 10 0 1000: lwbrx */
INVALID, /* 10 0 1001 */
{ 4, ST+SW }, /* 10 0 1010: stwbrx */
INVALID, /* 10 0 1011 */
{ 2, LD+SW }, /* 10 0 1100: lhbrx */
{ 4, LD+SE }, /* 10 0 1101 lwa */
{ 2, ST+SW }, /* 10 0 1110: sthbrx */
INVALID, /* 10 0 1111 */
INVALID, /* 10 1 0000 */
INVALID, /* 10 1 0001 */
INVALID, /* 10 1 0010 */
INVALID, /* 10 1 0011 */
INVALID, /* 10 1 0100 */
INVALID, /* 10 1 0101 */
INVALID, /* 10 1 0110 */
INVALID, /* 10 1 0111 */
INVALID, /* 10 1 1000 */
INVALID, /* 10 1 1001 */
INVALID, /* 10 1 1010 */
INVALID, /* 10 1 1011 */
INVALID, /* 10 1 1100 */
INVALID, /* 10 1 1101 */
INVALID, /* 10 1 1110 */
{ L1_CACHE_BYTES, ST }, /* 10 1 1111: dcbz */
{ 4, LD }, /* 11 0 0000: lwzx */
INVALID, /* 11 0 0001 */
{ 4, ST }, /* 11 0 0010: stwx */
INVALID, /* 11 0 0011 */
{ 2, LD }, /* 11 0 0100: lhzx */
{ 2, LD+SE }, /* 11 0 0101: lhax */
{ 2, ST }, /* 11 0 0110: sthx */
INVALID, /* 11 0 0111 */
{ 4, LD+F }, /* 11 0 1000: lfsx */
{ 8, LD+F }, /* 11 0 1001: lfdx */
{ 4, ST+F }, /* 11 0 1010: stfsx */
{ 8, ST+F }, /* 11 0 1011: stfdx */
INVALID, /* 11 0 1100 */
{ 8, LD+M }, /* 11 0 1101: lmd */
INVALID, /* 11 0 1110 */
{ 8, ST+M }, /* 11 0 1111: stmd */
{ 4, LD+U }, /* 11 1 0000: lwzux */
INVALID, /* 11 1 0001 */
{ 4, ST+U }, /* 11 1 0010: stwux */
INVALID, /* 11 1 0011 */
{ 2, LD+U }, /* 11 1 0100: lhzux */
{ 2, LD+SE+U }, /* 11 1 0101: lhaux */
{ 2, ST+U }, /* 11 1 0110: sthux */
INVALID, /* 11 1 0111 */
{ 4, LD+F+U }, /* 11 1 1000: lfsux */
{ 8, LD+F+U }, /* 11 1 1001: lfdux */
{ 4, ST+F+U }, /* 11 1 1010: stfsux */
{ 8, ST+F+U }, /* 11 1 1011: stfdux */
INVALID, /* 11 1 1100 */
INVALID, /* 11 1 1101 */
INVALID, /* 11 1 1110 */
INVALID, /* 11 1 1111 */
};
#define SWAP(a, b) (t = (a), (a) = (b), (b) = t)
static inline unsigned make_dsisr(unsigned instr)
{
unsigned dsisr;
/* create a DSISR value from the instruction */
dsisr = (instr & 0x03ff0000) >> 16; /* bits 6:15 --> 22:31 */
if ( IS_XFORM(instr) ) {
dsisr |= (instr & 0x00000006) << 14; /* bits 29:30 --> 15:16 */
dsisr |= (instr & 0x00000040) << 8; /* bit 25 --> 17 */
dsisr |= (instr & 0x00000780) << 3; /* bits 21:24 --> 18:21 */
}
else {
dsisr |= (instr & 0x04000000) >> 12; /* bit 5 --> 17 */
dsisr |= (instr & 0x78000000) >> 17; /* bits 1: 4 --> 18:21 */
if ( IS_DSFORM(instr) ) {
dsisr |= (instr & 0x00000003) << 18; /* bits 30:31 --> 12:13 */
}
}
return dsisr;
}
int
fix_alignment(struct pt_regs *regs)
{
unsigned int instr, nb, flags;
int t;
unsigned long reg, areg;
unsigned long i;
int ret;
unsigned dsisr;
unsigned char __user *addr;
unsigned char __user *p;
unsigned long __user *lp;
union {
long ll;
double dd;
unsigned char v[8];
struct {
unsigned hi32;
int low32;
} x32;
struct {
unsigned char hi48[6];
short low16;
} x16;
} data;
/*
* Return 1 on success
* Return 0 if unable to handle the interrupt
* Return -EFAULT if data address is bad
*/
dsisr = regs->dsisr;
if (cpu_has_feature(CPU_FTR_NODSISRALIGN)) {
unsigned int real_instr;
if (__get_user(real_instr, (unsigned int __user *)regs->nip))
return 0;
dsisr = make_dsisr(real_instr);
}
/* extract the operation and registers from the dsisr */
reg = (dsisr >> 5) & 0x1f; /* source/dest register */
areg = dsisr & 0x1f; /* register to update */
instr = (dsisr >> 10) & 0x7f;
instr |= (dsisr >> 13) & 0x60;
/* Lookup the operation in our table */
nb = aligninfo[instr].len;
flags = aligninfo[instr].flags;
/* DAR has the operand effective address */
addr = (unsigned char __user *)regs->dar;
/* A size of 0 indicates an instruction we don't support */
/* we also don't support the multiples (lmw, stmw, lmd, stmd) */
if ((nb == 0) || (flags & M))
return 0; /* too hard or invalid instruction */
/*
* Special handling for dcbz
* dcbz may give an alignment exception for accesses to caching inhibited
* storage
*/
if (instr == DCBZ)
addr = (unsigned char __user *) ((unsigned long)addr & -L1_CACHE_BYTES);
/* Verify the address of the operand */
if (user_mode(regs)) {
if (!access_ok((flags & ST? VERIFY_WRITE: VERIFY_READ), addr, nb))
return -EFAULT; /* bad address */
}
/* Force the fprs into the save area so we can reference them */
if (flags & F) {
if (!user_mode(regs))
return 0;
flush_fp_to_thread(current);
}
/* If we are loading, get the data from user space */
if (flags & LD) {
data.ll = 0;
ret = 0;
p = addr;
switch (nb) {
case 8:
ret |= __get_user(data.v[0], p++);
ret |= __get_user(data.v[1], p++);
ret |= __get_user(data.v[2], p++);
ret |= __get_user(data.v[3], p++);
case 4:
ret |= __get_user(data.v[4], p++);
ret |= __get_user(data.v[5], p++);
case 2:
ret |= __get_user(data.v[6], p++);
ret |= __get_user(data.v[7], p++);
if (ret)
return -EFAULT;
}
}
/* If we are storing, get the data from the saved gpr or fpr */
if (flags & ST) {
if (flags & F) {
if (nb == 4) {
/* Doing stfs, have to convert to single */
preempt_disable();
enable_kernel_fp();
cvt_df(¤t->thread.fpr[reg], (float *)&data.v[4], ¤t->thread.fpscr);
disable_kernel_fp();
preempt_enable();
}
else
data.dd = current->thread.fpr[reg];
}
else
data.ll = regs->gpr[reg];
}
/* Swap bytes as needed */
if (flags & SW) {
if (nb == 2)
SWAP(data.v[6], data.v[7]);
else { /* nb must be 4 */
SWAP(data.v[4], data.v[7]);
SWAP(data.v[5], data.v[6]);
}
}
/* Sign extend as needed */
if (flags & SE) {
if ( nb == 2 )
data.ll = data.x16.low16;
else /* nb must be 4 */
data.ll = data.x32.low32;
}
/* If we are loading, move the data to the gpr or fpr */
if (flags & LD) {
if (flags & F) {
if (nb == 4) {
/* Doing lfs, have to convert to double */
preempt_disable();
enable_kernel_fp();
cvt_fd((float *)&data.v[4], ¤t->thread.fpr[reg], ¤t->thread.fpscr);
disable_kernel_fp();
preempt_enable();
}
else
current->thread.fpr[reg] = data.dd;
}
else
regs->gpr[reg] = data.ll;
}
/* If we are storing, copy the data to the user */
if (flags & ST) {
ret = 0;
p = addr;
switch (nb) {
case 128: /* Special case - must be dcbz */
lp = (unsigned long __user *)p;
for (i = 0; i < L1_CACHE_BYTES / sizeof(long); ++i)
ret |= __put_user(0, lp++);
break;
case 8:
ret |= __put_user(data.v[0], p++);
ret |= __put_user(data.v[1], p++);
ret |= __put_user(data.v[2], p++);
ret |= __put_user(data.v[3], p++);
case 4:
ret |= __put_user(data.v[4], p++);
ret |= __put_user(data.v[5], p++);
case 2:
ret |= __put_user(data.v[6], p++);
ret |= __put_user(data.v[7], p++);
}
if (ret)
return -EFAULT;
}
/* Update RA as needed */
if (flags & U) {
regs->gpr[areg] = regs->dar;
}
return 1;
}
