--- /dev/null
+/* 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() */
git://git.onelab.eu / linux-2.6.git / blobdiff