/* unaligned.c: unalignment fixup handler for CPUs on which it is supported (FR451 only)
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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/config.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <linux/user.h>
#include <linux/string.h>
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/setup.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#if 0
#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdebug(fmt, ...) do {} while(0)
#endif
#define _MA_SIGNED 0x01
#define _MA_HALF 0x02
#define _MA_WORD 0x04
#define _MA_DWORD 0x08
#define _MA_SZ_MASK 0x0e
#define _MA_LOAD 0x10
#define _MA_STORE 0x20
#define _MA_UPDATE 0x40
#define _MA_IMM 0x80
#define _MA_LDxU _MA_LOAD | _MA_UPDATE
#define _MA_LDxI _MA_LOAD | _MA_IMM
#define _MA_STxU _MA_STORE | _MA_UPDATE
#define _MA_STxI _MA_STORE | _MA_IMM
static const uint8_t tbl_LDGRk_reg[0x40] = {
[0x02] = _MA_LOAD | _MA_HALF | _MA_SIGNED, /* LDSH @(GRi,GRj),GRk */
[0x03] = _MA_LOAD | _MA_HALF, /* LDUH @(GRi,GRj),GRk */
[0x04] = _MA_LOAD | _MA_WORD, /* LD @(GRi,GRj),GRk */
[0x05] = _MA_LOAD | _MA_DWORD, /* LDD @(GRi,GRj),GRk */
[0x12] = _MA_LDxU | _MA_HALF | _MA_SIGNED, /* LDSHU @(GRi,GRj),GRk */
[0x13] = _MA_LDxU | _MA_HALF, /* LDUHU @(GRi,GRj),GRk */
[0x14] = _MA_LDxU | _MA_WORD, /* LDU @(GRi,GRj),GRk */
[0x15] = _MA_LDxU | _MA_DWORD, /* LDDU @(GRi,GRj),GRk */
};
static const uint8_t tbl_STGRk_reg[0x40] = {
[0x01] = _MA_STORE | _MA_HALF, /* STH @(GRi,GRj),GRk */
[0x02] = _MA_STORE | _MA_WORD, /* ST @(GRi,GRj),GRk */
[0x03] = _MA_STORE | _MA_DWORD, /* STD @(GRi,GRj),GRk */
[0x11] = _MA_STxU | _MA_HALF, /* STHU @(GRi,GRj),GRk */
[0x12] = _MA_STxU | _MA_WORD, /* STU @(GRi,GRj),GRk */
[0x13] = _MA_STxU | _MA_DWORD, /* STDU @(GRi,GRj),GRk */
};
static const uint8_t tbl_LDSTGRk_imm[0x80] = {
[0x31] = _MA_LDxI | _MA_HALF | _MA_SIGNED, /* LDSHI @(GRi,d12),GRk */
[0x32] = _MA_LDxI | _MA_WORD, /* LDI @(GRi,d12),GRk */
[0x33] = _MA_LDxI | _MA_DWORD, /* LDDI @(GRi,d12),GRk */
[0x36] = _MA_LDxI | _MA_HALF, /* LDUHI @(GRi,d12),GRk */
[0x51] = _MA_STxI | _MA_HALF, /* STHI @(GRi,d12),GRk */
[0x52] = _MA_STxI | _MA_WORD, /* STI @(GRi,d12),GRk */
[0x53] = _MA_STxI | _MA_DWORD, /* STDI @(GRi,d12),GRk */
};
/*****************************************************************************/
/*
* see if we can handle the exception by fixing up a misaligned memory access
*/
int handle_misalignment(unsigned long esr0, unsigned long ear0, unsigned long epcr0)
{
unsigned long insn, addr, *greg;
int GRi, GRj, GRk, D12, op;
union {
uint64_t _64;
uint32_t _32[2];
uint16_t _16;
uint8_t _8[8];
} x;
if (!(esr0 & ESR0_EAV) || !(epcr0 & EPCR0_V) || !(ear0 & 7))
return -EAGAIN;
epcr0 &= EPCR0_PC;
if (__frame->pc != epcr0) {
kdebug("MISALIGN: Execution not halted on excepting instruction\n");
BUG();
}
if (__get_user(insn, (unsigned long *) epcr0) < 0)
return -EFAULT;
/* determine the instruction type first */
switch ((insn >> 18) & 0x7f) {
case 0x2:
/* LDx @(GRi,GRj),GRk */
op = tbl_LDGRk_reg[(insn >> 6) & 0x3f];
break;
case 0x3:
/* STx GRk,@(GRi,GRj) */
op = tbl_STGRk_reg[(insn >> 6) & 0x3f];
break;
default:
op = tbl_LDSTGRk_imm[(insn >> 18) & 0x7f];
break;
}
if (!op)
return -EAGAIN;
kdebug("MISALIGN: pc=%08lx insn=%08lx ad=%08lx op=%02x\n", epcr0, insn, ear0, op);
memset(&x, 0xba, 8);
/* validate the instruction parameters */
greg = (unsigned long *) &__frame->tbr;
GRi = (insn >> 12) & 0x3f;
GRk = (insn >> 25) & 0x3f;
if (GRi > 31 || GRk > 31)
return -ENOENT;
if (op & _MA_DWORD && GRk & 1)
return -EINVAL;
if (op & _MA_IMM) {
D12 = insn & 0xfff;
asm ("slli %0,#20,%0 ! srai %0,#20,%0" : "=r"(D12) : "0"(D12)); /* sign extend */
addr = (GRi ? greg[GRi] : 0) + D12;
}
else {
GRj = (insn >> 0) & 0x3f;
if (GRj > 31)
return -ENOENT;
addr = (GRi ? greg[GRi] : 0) + (GRj ? greg[GRj] : 0);
}
if (addr != ear0) {
kdebug("MISALIGN: Calculated addr (%08lx) does not match EAR0 (%08lx)\n",
addr, ear0);
return -EFAULT;
}
/* check the address is okay */
if (user_mode(__frame) && ___range_ok(ear0, 8) < 0)
return -EFAULT;
/* perform the memory op */
if (op & _MA_STORE) {
/* perform a store */
x._32[0] = 0;
if (GRk != 0) {
if (op & _MA_HALF) {
x._16 = greg[GRk];
}
else {
x._32[0] = greg[GRk];
}
}
if (op & _MA_DWORD)
x._32[1] = greg[GRk + 1];
kdebug("MISALIGN: Store GR%d { %08x:%08x } -> %08lx (%dB)\n",
GRk, x._32[1], x._32[0], addr, op & _MA_SZ_MASK);
if (__memcpy_user((void *) addr, &x, op & _MA_SZ_MASK) != 0)
return -EFAULT;
}
else {
/* perform a load */
if (__memcpy_user(&x, (void *) addr, op & _MA_SZ_MASK) != 0)
return -EFAULT;
if (op & _MA_HALF) {
if (op & _MA_SIGNED)
asm ("slli %0,#16,%0 ! srai %0,#16,%0"
: "=r"(x._32[0]) : "0"(x._16));
else
asm ("sethi #0,%0"
: "=r"(x._32[0]) : "0"(x._16));
}
kdebug("MISALIGN: Load %08lx (%dB) -> GR%d, { %08x:%08x }\n",
addr, op & _MA_SZ_MASK, GRk, x._32[1], x._32[0]);
if (GRk != 0)
greg[GRk] = x._32[0];
if (op & _MA_DWORD)
greg[GRk + 1] = x._32[1];
}
/* update the base pointer if required */
if (op & _MA_UPDATE)
greg[GRi] = addr;
/* well... we've done that insn */
__frame->pc = __frame->pc + 4;
return 0;
} /* end handle_misalignment() */
