/*
* Redundant with logic already in kernel/branch.c,
* embedded in compute_return_epc. At some point,
* a single subroutine should be used across both
* modules.
*/
static int isBranchInstr(mips_instruction * i)
{
switch (MIPSInst_OPCODE(*i)) {
case spec_op:
switch (MIPSInst_FUNC(*i)) {
case jalr_op:
case jr_op:
return 1;
}
break;
case bcond_op:
switch (MIPSInst_RT(*i)) {
case bltz_op:
case bgez_op:
case bltzl_op:
case bgezl_op:
case bltzal_op:
case bgezal_op:
case bltzall_op:
case bgezall_op:
return 1;
}
break;
case j_op:
case jal_op:
case jalx_op:
case beq_op:
case bne_op:
case blez_op:
case bgtz_op:
case beql_op:
case bnel_op:
case blezl_op:
case bgtzl_op:
return 1;
case cop0_op:
case cop1_op:
case cop2_op:
case cop1x_op:
if (MIPSInst_RS(*i) == bc_op)
return 1;
break;
}
return 0;
}
static int
cop1Emulate(int xcptno, struct pt_regs *xcp,
struct mips_fpu_soft_struct *ctx)
{
mips_instruction ir;
vaddr_t emulpc;
vaddr_t contpc;
unsigned int cond;
int err = 0;
ir = mips_get_word(xcp, REG_TO_VA xcp->cp0_epc, &err);
if (err) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
/* XXX NEC Vr54xx bug workaround */
if ((xcp->cp0_cause & CAUSEF_BD) && !isBranchInstr(&ir))
xcp->cp0_cause &= ~CAUSEF_BD;
if (xcp->cp0_cause & CAUSEF_BD) {
/*
* The instruction to be emulated is in a branch delay slot
* which means that we have to emulate the branch instruction
* BEFORE we do the cop1 instruction.
*
* This branch could be a COP1 branch, but in that case we
* would have had a trap for that instruction, and would not
* come through this route.
*
* Linux MIPS branch emulator operates on context, updating the
* cp0_epc.
*/
emulpc = REG_TO_VA(xcp->cp0_epc + 4); /* Snapshot emulation target */
if (__compute_return_epc(xcp)) {
#ifdef CP1DBG
printk("failed to emulate branch at %p\n",
REG_TO_VA(xcp->cp0_epc));
#endif
return SIGILL;;
}
ir = mips_get_word(xcp, emulpc, &err);
if (err) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
contpc = REG_TO_VA xcp->cp0_epc;
} else {
emulpc = REG_TO_VA xcp->cp0_epc;
contpc = REG_TO_VA xcp->cp0_epc + 4;
}
emul:
fpuemuprivate.stats.emulated++;
switch (MIPSInst_OPCODE(ir)) {
#ifdef CP0_STATUS_FR_SUPPORT
/* R4000+ 64-bit fpu registers */
#ifndef SINGLE_ONLY_FPU
case ldc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
int ft = MIPSInst_RT(ir);
if (!(xcp->cp0_status & ST0_FR))
ft &= ~1;
ctx->regs[ft] = mips_get_dword(xcp, va, &err);
fpuemuprivate.stats.loads++;
if (err) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
}
break;
case sdc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
int ft = MIPSInst_RT(ir);
if (!(xcp->cp0_status & ST0_FR))
ft &= ~1;
fpuemuprivate.stats.stores++;
if (mips_put_dword(xcp, va, ctx->regs[ft])) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
}
break;
#endif
case lwc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
fpureg_t val;
int ft = MIPSInst_RT(ir);
fpuemuprivate.stats.loads++;
val = mips_get_word(xcp, va, &err);
if (err) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
if (xcp->cp0_status & ST0_FR) {
/* load whole register */
ctx->regs[ft] = val;
} else if (ft & 1) {
/* load to m.s. 32 bits */
#ifdef SINGLE_ONLY_FPU
/* illegal register in single-float mode */
return SIGILL;
#else
ctx->regs[(ft & ~1)] &= 0xffffffff;
ctx->regs[(ft & ~1)] |= val << 32;
#endif
} else {
/* load to l.s. 32 bits */
ctx->regs[ft] &= ~0xffffffffLL;
ctx->regs[ft] |= val;
}
}
break;
case swc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
unsigned int val;
int ft = MIPSInst_RT(ir);
fpuemuprivate.stats.stores++;
if (xcp->cp0_status & ST0_FR) {
/* store whole register */
val = ctx->regs[ft];
} else if (ft & 1) {
#ifdef SINGLE_ONLY_FPU
/* illegal register in single-float mode */
return SIGILL;
#else
/* store from m.s. 32 bits */
val = ctx->regs[(ft & ~1)] >> 32;
#endif
} else {
/* store from l.s. 32 bits */
val = ctx->regs[ft];
}
if (mips_put_word(xcp, va, val)) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
}
break;
#else /* old 32-bit fpu registers */
case lwc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
ctx->regs[MIPSInst_RT(ir)] =
mips_get_word(xcp, va, &err);
fpuemuprivate.stats.loads++;
if (err) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
}
break;
case swc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
fpuemuprivate.stats.stores++;
if (mips_put_word
(xcp, va, ctx->regs[MIPSInst_RT(ir)])) {
fpuemuprivate.stats.errors++;
return SIGBUS;
}
}
break;
case ldc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
unsigned int rt = MIPSInst_RT(ir) & ~1;
int errs = 0;
fpuemuprivate.stats.loads++;
#if (defined(BYTE_ORDER) && BYTE_ORDER == BIG_ENDIAN) || defined(__MIPSEB__)
ctx->regs[rt + 1] =
mips_get_word(xcp, va + 0, &err);
errs += err;
ctx->regs[rt + 0] =
mips_get_word(xcp, va + 4, &err);
errs += err;
#else
ctx->regs[rt + 0] =
mips_get_word(xcp, va + 0, &err);
errs += err;
ctx->regs[rt + 1] =
mips_get_word(xcp, va + 4, &err);
errs += err;
#endif
if (err)
return SIGBUS;
}
break;
case sdc1_op:
{
void *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)])
+ MIPSInst_SIMM(ir);
unsigned int rt = MIPSInst_RT(ir) & ~1;
fpuemuprivate.stats.stores++;
#if (defined(BYTE_ORDER) && BYTE_ORDER == BIG_ENDIAN) || defined(__MIPSEB__)
if (mips_put_word(xcp, va + 0, ctx->regs[rt + 1]))
return SIGBUS;
if (mips_put_word(xcp, va + 4, ctx->regs[rt + 0]))
return SIGBUS;
#else
if (mips_put_word(xcp, va + 0, ctx->regs[rt + 0]))
return SIGBUS;
if (mips_put_word(xcp, va + 4, ctx->regs[rt + 1]))
return SIGBUS;
#endif
}
break;
#endif
case cop1_op:
switch (MIPSInst_RS(ir)) {
#ifdef CP0_STATUS_FR_SUPPORT
#if __mips64 && !defined(SINGLE_ONLY_FPU)
case dmfc_op:
/* copregister fs -> gpr[rt] */
if (MIPSInst_RT(ir) != 0) {
int fs = MIPSInst_RD(ir);
if (!(xcp->cp0_status & ST0_FR))
fs &= ~1;
xcp->regs[MIPSInst_RT(ir)] = ctx->regs[fs];
}
break;
case dmtc_op:
/* copregister fs <- rt */
{
fpureg_t value;
int fs = MIPSInst_RD(ir);
if (!(xcp->cp0_status & ST0_FR))
fs &= ~1;
value =
(MIPSInst_RT(ir) ==
0) ? 0 : xcp->regs[MIPSInst_RT(ir)];
ctx->regs[fs] = value;
}
break;
#endif
case mfc_op:
/* copregister rd -> gpr[rt] */
if (MIPSInst_RT(ir) != 0) {
/* default value from l.s. 32 bits */
int value = ctx->regs[MIPSInst_RD(ir)];
if (MIPSInst_RD(ir) & 1) {
#ifdef SINGLE_ONLY_FPU
/* illegal register in single-float mode */
return SIGILL;
#else
if (!(xcp->cp0_status & ST0_FR)) {
/* move from m.s. 32 bits */
value =
ctx->
regs[MIPSInst_RD(ir) &
~1] >> 32;
}
#endif
}
xcp->regs[MIPSInst_RT(ir)] = value;
}