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kernel-ark/arch/mips/math-emu/cp1emu.c
Ralf Baechle 51d943f07d MIPS: Fix for warning from FPU emulation code 
The default implementation of 'cpu_has_fpu' macro calls
smp_processor_id() which causes this warning to be printed when
preemption is enabled:

[    4.664000] Algorithmics/MIPS FPU Emulator v1.5
[    4.676000] BUG: using smp_processor_id() in preemptible [00000000] code: ini
[    4.700000] caller is fpu_emulator_cop1Handler+0x434/0x27b8

This problem got introduced in November 2009 by
af1d2af877ef6c36990671bc86a5b9c5bb50b1da (lmo) [MIPS: Fix emulation of
64-bit FPU on 64-bit CPUs.] rsp.  da0bac3341
(kernel.org) [MIPS: Fix emulation of 64-bit FPU on FPU-less 64-bit CPUs.]
in 2.6.32.

Fixed by rewriting cop1_64bit() to return a constant whenever possible
but most importantly avoid the use pf cpu_has_fpu entirely.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Jayachandran C <jchandra@broadcom.com>
Initial-patch-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: https://patchwork.linux-mips.org/patch/4225/
2012-12-13 18:15:27 +01:00

1414 lines
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/*
* cp1emu.c: a MIPS coprocessor 1 (fpu) instruction emulator
*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd.
*
* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
* Copyright (C) 2000 MIPS Technologies, Inc.
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* A complete emulator for MIPS coprocessor 1 instructions. This is
* required for #float(switch) or #float(trap), where it catches all
* COP1 instructions via the "CoProcessor Unusable" exception.
*
* More surprisingly it is also required for #float(ieee), to help out
* the hardware fpu at the boundaries of the IEEE-754 representation
* (denormalised values, infinities, underflow, etc). It is made
* quite nasty because emulation of some non-COP1 instructions is
* required, e.g. in branch delay slots.
*
* Note if you know that you won't have an fpu, then you'll get much
* better performance by compiling with -msoft-float!
*/
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/perf_event.h>
#include <asm/inst.h>
#include <asm/bootinfo.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/signal.h>
#include <asm/mipsregs.h>
#include <asm/fpu_emulator.h>
#include <asm/uaccess.h>
#include <asm/branch.h>
#include "ieee754.h"
/* Strap kernel emulator for full MIPS IV emulation */
#ifdef __mips
#undef __mips
#endif
#define __mips 4
/* Function which emulates a floating point instruction. */
static int fpu_emu(struct pt_regs *, struct mips_fpu_struct *,
mips_instruction);
#if __mips >= 4 && __mips != 32
static int fpux_emu(struct pt_regs *,
struct mips_fpu_struct *, mips_instruction, void *__user *);
#endif
/* Further private data for which no space exists in mips_fpu_struct */
#ifdef CONFIG_DEBUG_FS
DEFINE_PER_CPU(struct mips_fpu_emulator_stats, fpuemustats);
#endif
/* Control registers */
#define FPCREG_RID 0 /* $0 = revision id */
#define FPCREG_CSR 31 /* $31 = csr */
/* Determine rounding mode from the RM bits of the FCSR */
#define modeindex(v) ((v) & FPU_CSR_RM)
/* Convert Mips rounding mode (0..3) to IEEE library modes. */
static const unsigned char ieee_rm[4] = {
[FPU_CSR_RN] = IEEE754_RN,
[FPU_CSR_RZ] = IEEE754_RZ,
[FPU_CSR_RU] = IEEE754_RU,
[FPU_CSR_RD] = IEEE754_RD,
};
/* Convert IEEE library modes to Mips rounding mode (0..3). */
static const unsigned char mips_rm[4] = {
[IEEE754_RN] = FPU_CSR_RN,
[IEEE754_RZ] = FPU_CSR_RZ,
[IEEE754_RD] = FPU_CSR_RD,
[IEEE754_RU] = FPU_CSR_RU,
};
#if __mips >= 4
/* convert condition code register number to csr bit */
static const unsigned int fpucondbit[8] = {
FPU_CSR_COND0,
FPU_CSR_COND1,
FPU_CSR_COND2,
FPU_CSR_COND3,
FPU_CSR_COND4,
FPU_CSR_COND5,
FPU_CSR_COND6,
FPU_CSR_COND7
};
#endif
/*
* 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;
}
/*
* In the Linux kernel, we support selection of FPR format on the
* basis of the Status.FR bit. If an FPU is not present, the FR bit
* is hardwired to zero, which would imply a 32-bit FPU even for
* 64-bit CPUs so we rather look at TIF_32BIT_REGS.
* FPU emu is slow and bulky and optimizing this function offers fairly
* sizeable benefits so we try to be clever and make this function return
* a constant whenever possible, that is on 64-bit kernels without O32
* compatibility enabled and on 32-bit kernels.
*/
static inline int cop1_64bit(struct pt_regs *xcp)
{
#if defined(CONFIG_64BIT) && !defined(CONFIG_MIPS32_O32)
return 1;
#elif defined(CONFIG_64BIT) && defined(CONFIG_MIPS32_O32)
return !test_thread_flag(TIF_32BIT_REGS);
#else
return 0;
#endif
}
#define SIFROMREG(si, x) ((si) = cop1_64bit(xcp) || !(x & 1) ? \
(int)ctx->fpr[x] : (int)(ctx->fpr[x & ~1] >> 32))
#define SITOREG(si, x) (ctx->fpr[x & ~(cop1_64bit(xcp) == 0)] = \
cop1_64bit(xcp) || !(x & 1) ? \
ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
#define DIFROMREG(di, x) ((di) = ctx->fpr[x & ~(cop1_64bit(xcp) == 0)])
#define DITOREG(di, x) (ctx->fpr[x & ~(cop1_64bit(xcp) == 0)] = (di))
#define SPFROMREG(sp, x) SIFROMREG((sp).bits, x)
#define SPTOREG(sp, x) SITOREG((sp).bits, x)
#define DPFROMREG(dp, x) DIFROMREG((dp).bits, x)
#define DPTOREG(dp, x) DITOREG((dp).bits, x)
/*
* Emulate the single floating point instruction pointed at by EPC.
* Two instructions if the instruction is in a branch delay slot.
*/
static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
void *__user *fault_addr)
{
mips_instruction ir;
unsigned long emulpc, contpc;
unsigned int cond;
if (!access_ok(VERIFY_READ, xcp->cp0_epc, sizeof(mips_instruction))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGBUS;
}
if (__get_user(ir, (mips_instruction __user *) xcp->cp0_epc)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGSEGV;
}
/* 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 = xcp->cp0_epc + 4; /* Snapshot emulation target */
if (__compute_return_epc(xcp) < 0) {
#ifdef CP1DBG
printk("failed to emulate branch at %p\n",
(void *) (xcp->cp0_epc));
#endif
return SIGILL;
}
if (!access_ok(VERIFY_READ, emulpc, sizeof(mips_instruction))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)emulpc;
return SIGBUS;
}
if (__get_user(ir, (mips_instruction __user *) emulpc)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)emulpc;
return SIGSEGV;
}
/* __compute_return_epc() will have updated cp0_epc */
contpc = xcp->cp0_epc;
/* In order not to confuse ptrace() et al, tweak context */
xcp->cp0_epc = emulpc - 4;
} else {
emulpc = xcp->cp0_epc;
contpc = xcp->cp0_epc + 4;
}
emul:
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, xcp, 0);
MIPS_FPU_EMU_INC_STATS(emulated);
switch (MIPSInst_OPCODE(ir)) {
case ldc1_op:{
u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
MIPSInst_SIMM(ir));
u64 val;
MIPS_FPU_EMU_INC_STATS(loads);
if (!access_ok(VERIFY_READ, va, sizeof(u64))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__get_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
DITOREG(val, MIPSInst_RT(ir));
break;
}
case sdc1_op:{
u64 __user *va = (u64 __user *) (xcp->regs[MIPSInst_RS(ir)] +
MIPSInst_SIMM(ir));
u64 val;
MIPS_FPU_EMU_INC_STATS(stores);
DIFROMREG(val, MIPSInst_RT(ir));
if (!access_ok(VERIFY_WRITE, va, sizeof(u64))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__put_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
break;
}
case lwc1_op:{
u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
MIPSInst_SIMM(ir));
u32 val;
MIPS_FPU_EMU_INC_STATS(loads);
if (!access_ok(VERIFY_READ, va, sizeof(u32))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__get_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
SITOREG(val, MIPSInst_RT(ir));
break;
}
case swc1_op:{
u32 __user *va = (u32 __user *) (xcp->regs[MIPSInst_RS(ir)] +
MIPSInst_SIMM(ir));
u32 val;
MIPS_FPU_EMU_INC_STATS(stores);
SIFROMREG(val, MIPSInst_RT(ir));
if (!access_ok(VERIFY_WRITE, va, sizeof(u32))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__put_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
break;
}
case cop1_op:
switch (MIPSInst_RS(ir)) {
#if defined(__mips64)
case dmfc_op:
/* copregister fs -> gpr[rt] */
if (MIPSInst_RT(ir) != 0) {
DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
MIPSInst_RD(ir));
}
break;
case dmtc_op:
/* copregister fs <- rt */
DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
break;
#endif
case mfc_op:
/* copregister rd -> gpr[rt] */
if (MIPSInst_RT(ir) != 0) {
SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
MIPSInst_RD(ir));
}
break;
case mtc_op:
/* copregister rd <- rt */
SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
break;
case cfc_op:{
/* cop control register rd -> gpr[rt] */
u32 value;
if (MIPSInst_RD(ir) == FPCREG_CSR) {
value = ctx->fcr31;
value = (value & ~FPU_CSR_RM) |
mips_rm[modeindex(value)];
#ifdef CSRTRACE
printk("%p gpr[%d]<-csr=%08x\n",
(void *) (xcp->cp0_epc),
MIPSInst_RT(ir), value);
#endif
}
else if (MIPSInst_RD(ir) == FPCREG_RID)
value = 0;
else
value = 0;
if (MIPSInst_RT(ir))
xcp->regs[MIPSInst_RT(ir)] = value;
break;
}
case ctc_op:{
/* copregister rd <- rt */
u32 value;
if (MIPSInst_RT(ir) == 0)
value = 0;
else
value = xcp->regs[MIPSInst_RT(ir)];
/* we only have one writable control reg
*/
if (MIPSInst_RD(ir) == FPCREG_CSR) {
#ifdef CSRTRACE
printk("%p gpr[%d]->csr=%08x\n",
(void *) (xcp->cp0_epc),
MIPSInst_RT(ir), value);
#endif
/*
* Don't write reserved bits,
* and convert to ieee library modes
*/
ctx->fcr31 = (value &
~(FPU_CSR_RSVD | FPU_CSR_RM)) |
ieee_rm[modeindex(value)];
}
if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
return SIGFPE;
}
break;
}
case bc_op:{
int likely = 0;
if (xcp->cp0_cause & CAUSEF_BD)
return SIGILL;
#if __mips >= 4
cond = ctx->fcr31 & fpucondbit[MIPSInst_RT(ir) >> 2];
#else
cond = ctx->fcr31 & FPU_CSR_COND;
#endif
switch (MIPSInst_RT(ir) & 3) {
case bcfl_op:
likely = 1;
case bcf_op:
cond = !cond;
break;
case bctl_op:
likely = 1;
case bct_op:
break;
default:
/* thats an illegal instruction */
return SIGILL;
}
xcp->cp0_cause |= CAUSEF_BD;
if (cond) {
/* branch taken: emulate dslot
* instruction
*/
xcp->cp0_epc += 4;
contpc = (xcp->cp0_epc +
(MIPSInst_SIMM(ir) << 2));
if (!access_ok(VERIFY_READ, xcp->cp0_epc,
sizeof(mips_instruction))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGBUS;
}
if (__get_user(ir,
(mips_instruction __user *) xcp->cp0_epc)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGSEGV;
}
switch (MIPSInst_OPCODE(ir)) {
case lwc1_op:
case swc1_op:
#if (__mips >= 2 || defined(__mips64))
case ldc1_op:
case sdc1_op:
#endif
case cop1_op:
#if __mips >= 4 && __mips != 32
case cop1x_op:
#endif
/* its one of ours */
goto emul;
#if __mips >= 4
case spec_op:
if (MIPSInst_FUNC(ir) == movc_op)
goto emul;
break;
#endif
}
/*
* Single step the non-cp1
* instruction in the dslot
*/
return mips_dsemul(xcp, ir, contpc);
}
else {
/* branch not taken */
if (likely) {
/*
* branch likely nullifies
* dslot if not taken
*/
xcp->cp0_epc += 4;
contpc += 4;
/*
* else continue & execute
* dslot as normal insn
*/
}
}
break;
}
default:
if (!(MIPSInst_RS(ir) & 0x10))
return SIGILL;
{
int sig;
/* a real fpu computation instruction */
if ((sig = fpu_emu(xcp, ctx, ir)))
return sig;
}
}
break;
#if __mips >= 4 && __mips != 32
case cop1x_op:{
int sig = fpux_emu(xcp, ctx, ir, fault_addr);
if (sig)
return sig;
break;
}
#endif
#if __mips >= 4
case spec_op:
if (MIPSInst_FUNC(ir) != movc_op)
return SIGILL;
cond = fpucondbit[MIPSInst_RT(ir) >> 2];
if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
xcp->regs[MIPSInst_RD(ir)] =
xcp->regs[MIPSInst_RS(ir)];
break;
#endif
default:
return SIGILL;
}
/* we did it !! */
xcp->cp0_epc = contpc;
xcp->cp0_cause &= ~CAUSEF_BD;
return 0;
}
/*
* Conversion table from MIPS compare ops 48-63
* cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
*/
static const unsigned char cmptab[8] = {
0, /* cmp_0 (sig) cmp_sf */
IEEE754_CUN, /* cmp_un (sig) cmp_ngle */
IEEE754_CEQ, /* cmp_eq (sig) cmp_seq */
IEEE754_CEQ | IEEE754_CUN, /* cmp_ueq (sig) cmp_ngl */
IEEE754_CLT, /* cmp_olt (sig) cmp_lt */
IEEE754_CLT | IEEE754_CUN, /* cmp_ult (sig) cmp_nge */
IEEE754_CLT | IEEE754_CEQ, /* cmp_ole (sig) cmp_le */
IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN, /* cmp_ule (sig) cmp_ngt */
};
#if __mips >= 4 && __mips != 32
/*
* Additional MIPS4 instructions
*/
#define DEF3OP(name, p, f1, f2, f3) \
static ieee754##p fpemu_##p##_##name(ieee754##p r, ieee754##p s, \
ieee754##p t) \
{ \
struct _ieee754_csr ieee754_csr_save; \
s = f1(s, t); \
ieee754_csr_save = ieee754_csr; \
s = f2(s, r); \
ieee754_csr_save.cx |= ieee754_csr.cx; \
ieee754_csr_save.sx |= ieee754_csr.sx; \
s = f3(s); \
ieee754_csr.cx |= ieee754_csr_save.cx; \
ieee754_csr.sx |= ieee754_csr_save.sx; \
return s; \
}
static ieee754dp fpemu_dp_recip(ieee754dp d)
{
return ieee754dp_div(ieee754dp_one(0), d);
}
static ieee754dp fpemu_dp_rsqrt(ieee754dp d)
{
return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
}
static ieee754sp fpemu_sp_recip(ieee754sp s)
{
return ieee754sp_div(ieee754sp_one(0), s);
}
static ieee754sp fpemu_sp_rsqrt(ieee754sp s)
{
return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
}
DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add, );
DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub, );
DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add, );
DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub, );
DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);
static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
mips_instruction ir, void *__user *fault_addr)
{
unsigned rcsr = 0; /* resulting csr */
MIPS_FPU_EMU_INC_STATS(cp1xops);
switch (MIPSInst_FMA_FFMT(ir)) {
case s_fmt:{ /* 0 */
ieee754sp(*handler) (ieee754sp, ieee754sp, ieee754sp);
ieee754sp fd, fr, fs, ft;
u32 __user *va;
u32 val;
switch (MIPSInst_FUNC(ir)) {
case lwxc1_op:
va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
xcp->regs[MIPSInst_FT(ir)]);
MIPS_FPU_EMU_INC_STATS(loads);
if (!access_ok(VERIFY_READ, va, sizeof(u32))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__get_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
SITOREG(val, MIPSInst_FD(ir));
break;
case swxc1_op:
va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
xcp->regs[MIPSInst_FT(ir)]);
MIPS_FPU_EMU_INC_STATS(stores);
SIFROMREG(val, MIPSInst_FS(ir));
if (!access_ok(VERIFY_WRITE, va, sizeof(u32))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (put_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
break;
case madd_s_op:
handler = fpemu_sp_madd;
goto scoptop;
case msub_s_op:
handler = fpemu_sp_msub;
goto scoptop;
case nmadd_s_op:
handler = fpemu_sp_nmadd;
goto scoptop;
case nmsub_s_op:
handler = fpemu_sp_nmsub;
goto scoptop;
scoptop:
SPFROMREG(fr, MIPSInst_FR(ir));
SPFROMREG(fs, MIPSInst_FS(ir));
SPFROMREG(ft, MIPSInst_FT(ir));
fd = (*handler) (fr, fs, ft);
SPTOREG(fd, MIPSInst_FD(ir));
copcsr:
if (ieee754_cxtest(IEEE754_INEXACT))
rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
if (ieee754_cxtest(IEEE754_UNDERFLOW))
rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
if (ieee754_cxtest(IEEE754_OVERFLOW))
rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
/*printk ("SIGFPE: fpu csr = %08x\n",
ctx->fcr31); */
return SIGFPE;
}
break;
default:
return SIGILL;
}
break;
}
case d_fmt:{ /* 1 */
ieee754dp(*handler) (ieee754dp, ieee754dp, ieee754dp);
ieee754dp fd, fr, fs, ft;
u64 __user *va;
u64 val;
switch (MIPSInst_FUNC(ir)) {
case ldxc1_op:
va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
xcp->regs[MIPSInst_FT(ir)]);
MIPS_FPU_EMU_INC_STATS(loads);
if (!access_ok(VERIFY_READ, va, sizeof(u64))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__get_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
DITOREG(val, MIPSInst_FD(ir));
break;
case sdxc1_op:
va = (void __user *) (xcp->regs[MIPSInst_FR(ir)] +
xcp->regs[MIPSInst_FT(ir)]);
MIPS_FPU_EMU_INC_STATS(stores);
DIFROMREG(val, MIPSInst_FS(ir));
if (!access_ok(VERIFY_WRITE, va, sizeof(u64))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGBUS;
}
if (__put_user(val, va)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = va;
return SIGSEGV;
}
break;
case madd_d_op:
handler = fpemu_dp_madd;
goto dcoptop;
case msub_d_op:
handler = fpemu_dp_msub;
goto dcoptop;
case nmadd_d_op:
handler = fpemu_dp_nmadd;
goto dcoptop;
case nmsub_d_op:
handler = fpemu_dp_nmsub;
goto dcoptop;
dcoptop:
DPFROMREG(fr, MIPSInst_FR(ir));
DPFROMREG(fs, MIPSInst_FS(ir));
DPFROMREG(ft, MIPSInst_FT(ir));
fd = (*handler) (fr, fs, ft);
DPTOREG(fd, MIPSInst_FD(ir));
goto copcsr;
default:
return SIGILL;
}
break;
}
case 0x7: /* 7 */
if (MIPSInst_FUNC(ir) != pfetch_op) {
return SIGILL;
}
/* ignore prefx operation */
break;
default:
return SIGILL;
}
return 0;
}
#endif
/*
* Emulate a single COP1 arithmetic instruction.
*/
static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
mips_instruction ir)
{
int rfmt; /* resulting format */
unsigned rcsr = 0; /* resulting csr */
unsigned cond;
union {
ieee754dp d;
ieee754sp s;
int w;
#ifdef __mips64
s64 l;
#endif
} rv; /* resulting value */
MIPS_FPU_EMU_INC_STATS(cp1ops);
switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
case s_fmt:{ /* 0 */
union {
ieee754sp(*b) (ieee754sp, ieee754sp);
ieee754sp(*u) (ieee754sp);
} handler;
switch (MIPSInst_FUNC(ir)) {
/* binary ops */
case fadd_op:
handler.b = ieee754sp_add;
goto scopbop;
case fsub_op:
handler.b = ieee754sp_sub;
goto scopbop;
case fmul_op:
handler.b = ieee754sp_mul;
goto scopbop;
case fdiv_op:
handler.b = ieee754sp_div;
goto scopbop;
/* unary ops */
#if __mips >= 2 || defined(__mips64)
case fsqrt_op:
handler.u = ieee754sp_sqrt;
goto scopuop;
#endif
#if __mips >= 4 && __mips != 32
case frsqrt_op:
handler.u = fpemu_sp_rsqrt;
goto scopuop;
case frecip_op:
handler.u = fpemu_sp_recip;
goto scopuop;
#endif
#if __mips >= 4
case fmovc_op:
cond = fpucondbit[MIPSInst_FT(ir) >> 2];
if (((ctx->fcr31 & cond) != 0) !=
((MIPSInst_FT(ir) & 1) != 0))
return 0;
SPFROMREG(rv.s, MIPSInst_FS(ir));
break;
case fmovz_op:
if (xcp->regs[MIPSInst_FT(ir)] != 0)
return 0;
SPFROMREG(rv.s, MIPSInst_FS(ir));
break;
case fmovn_op:
if (xcp->regs[MIPSInst_FT(ir)] == 0)
return 0;
SPFROMREG(rv.s, MIPSInst_FS(ir));
break;
#endif
case fabs_op:
handler.u = ieee754sp_abs;
goto scopuop;
case fneg_op:
handler.u = ieee754sp_neg;
goto scopuop;
case fmov_op:
/* an easy one */
SPFROMREG(rv.s, MIPSInst_FS(ir));
goto copcsr;
/* binary op on handler */
scopbop:
{
ieee754sp fs, ft;
SPFROMREG(fs, MIPSInst_FS(ir));
SPFROMREG(ft, MIPSInst_FT(ir));
rv.s = (*handler.b) (fs, ft);
goto copcsr;
}
scopuop:
{
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
rv.s = (*handler.u) (fs);
goto copcsr;
}
copcsr:
if (ieee754_cxtest(IEEE754_INEXACT))
rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
if (ieee754_cxtest(IEEE754_UNDERFLOW))
rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
if (ieee754_cxtest(IEEE754_OVERFLOW))
rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
if (ieee754_cxtest(IEEE754_ZERO_DIVIDE))
rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
break;
/* unary conv ops */
case fcvts_op:
return SIGILL; /* not defined */
case fcvtd_op:{
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
rv.d = ieee754dp_fsp(fs);
rfmt = d_fmt;
goto copcsr;
}
case fcvtw_op:{
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
rv.w = ieee754sp_tint(fs);
rfmt = w_fmt;
goto copcsr;
}
#if __mips >= 2 || defined(__mips64)
case fround_op:
case ftrunc_op:
case fceil_op:
case ffloor_op:{
unsigned int oldrm = ieee754_csr.rm;
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
rv.w = ieee754sp_tint(fs);
ieee754_csr.rm = oldrm;
rfmt = w_fmt;
goto copcsr;
}
#endif /* __mips >= 2 */
#if defined(__mips64)
case fcvtl_op:{
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
rv.l = ieee754sp_tlong(fs);
rfmt = l_fmt;
goto copcsr;
}
case froundl_op:
case ftruncl_op:
case fceill_op:
case ffloorl_op:{
unsigned int oldrm = ieee754_csr.rm;
ieee754sp fs;
SPFROMREG(fs, MIPSInst_FS(ir));
ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
rv.l = ieee754sp_tlong(fs);
ieee754_csr.rm = oldrm;
rfmt = l_fmt;
goto copcsr;
}
#endif /* defined(__mips64) */
default:
if (MIPSInst_FUNC(ir) >= fcmp_op) {
unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
ieee754sp fs, ft;
SPFROMREG(fs, MIPSInst_FS(ir));
SPFROMREG(ft, MIPSInst_FT(ir));
rv.w = ieee754sp_cmp(fs, ft,
cmptab[cmpop & 0x7], cmpop & 0x8);
rfmt = -1;
if ((cmpop & 0x8) && ieee754_cxtest
(IEEE754_INVALID_OPERATION))
rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
else
goto copcsr;
}
else {
return SIGILL;
}
break;
}
break;
}
case d_fmt:{
union {
ieee754dp(*b) (ieee754dp, ieee754dp);
ieee754dp(*u) (ieee754dp);
} handler;
switch (MIPSInst_FUNC(ir)) {
/* binary ops */
case fadd_op:
handler.b = ieee754dp_add;
goto dcopbop;
case fsub_op:
handler.b = ieee754dp_sub;
goto dcopbop;
case fmul_op:
handler.b = ieee754dp_mul;
goto dcopbop;
case fdiv_op:
handler.b = ieee754dp_div;
goto dcopbop;
/* unary ops */
#if __mips >= 2 || defined(__mips64)
case fsqrt_op:
handler.u = ieee754dp_sqrt;
goto dcopuop;
#endif
#if __mips >= 4 && __mips != 32
case frsqrt_op:
handler.u = fpemu_dp_rsqrt;
goto dcopuop;
case frecip_op:
handler.u = fpemu_dp_recip;
goto dcopuop;
#endif
#if __mips >= 4
case fmovc_op:
cond = fpucondbit[MIPSInst_FT(ir) >> 2];
if (((ctx->fcr31 & cond) != 0) !=
((MIPSInst_FT(ir) & 1) != 0))
return 0;
DPFROMREG(rv.d, MIPSInst_FS(ir));
break;
case fmovz_op:
if (xcp->regs[MIPSInst_FT(ir)] != 0)
return 0;
DPFROMREG(rv.d, MIPSInst_FS(ir));
break;
case fmovn_op:
if (xcp->regs[MIPSInst_FT(ir)] == 0)
return 0;
DPFROMREG(rv.d, MIPSInst_FS(ir));
break;
#endif
case fabs_op:
handler.u = ieee754dp_abs;
goto dcopuop;
case fneg_op:
handler.u = ieee754dp_neg;
goto dcopuop;
case fmov_op:
/* an easy one */
DPFROMREG(rv.d, MIPSInst_FS(ir));
goto copcsr;
/* binary op on handler */
dcopbop:{
ieee754dp fs, ft;
DPFROMREG(fs, MIPSInst_FS(ir));
DPFROMREG(ft, MIPSInst_FT(ir));
rv.d = (*handler.b) (fs, ft);
goto copcsr;
}
dcopuop:{
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
rv.d = (*handler.u) (fs);
goto copcsr;
}
/* unary conv ops */
case fcvts_op:{
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
rv.s = ieee754sp_fdp(fs);
rfmt = s_fmt;
goto copcsr;
}
case fcvtd_op:
return SIGILL; /* not defined */
case fcvtw_op:{
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
rv.w = ieee754dp_tint(fs); /* wrong */
rfmt = w_fmt;
goto copcsr;
}
#if __mips >= 2 || defined(__mips64)
case fround_op:
case ftrunc_op:
case fceil_op:
case ffloor_op:{
unsigned int oldrm = ieee754_csr.rm;
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
rv.w = ieee754dp_tint(fs);
ieee754_csr.rm = oldrm;
rfmt = w_fmt;
goto copcsr;
}
#endif
#if defined(__mips64)
case fcvtl_op:{
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
rv.l = ieee754dp_tlong(fs);
rfmt = l_fmt;
goto copcsr;
}
case froundl_op:
case ftruncl_op:
case fceill_op:
case ffloorl_op:{
unsigned int oldrm = ieee754_csr.rm;
ieee754dp fs;
DPFROMREG(fs, MIPSInst_FS(ir));
ieee754_csr.rm = ieee_rm[modeindex(MIPSInst_FUNC(ir))];
rv.l = ieee754dp_tlong(fs);
ieee754_csr.rm = oldrm;
rfmt = l_fmt;
goto copcsr;
}
#endif /* __mips >= 3 */
default:
if (MIPSInst_FUNC(ir) >= fcmp_op) {
unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
ieee754dp fs, ft;
DPFROMREG(fs, MIPSInst_FS(ir));
DPFROMREG(ft, MIPSInst_FT(ir));
rv.w = ieee754dp_cmp(fs, ft,
cmptab[cmpop & 0x7], cmpop & 0x8);
rfmt = -1;
if ((cmpop & 0x8)
&&
ieee754_cxtest
(IEEE754_INVALID_OPERATION))
rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
else
goto copcsr;
}
else {
return SIGILL;
}
break;
}
break;
}
case w_fmt:{
ieee754sp fs;
switch (MIPSInst_FUNC(ir)) {
case fcvts_op:
/* convert word to single precision real */
SPFROMREG(fs, MIPSInst_FS(ir));
rv.s = ieee754sp_fint(fs.bits);
rfmt = s_fmt;
goto copcsr;
case fcvtd_op:
/* convert word to double precision real */
SPFROMREG(fs, MIPSInst_FS(ir));
rv.d = ieee754dp_fint(fs.bits);
rfmt = d_fmt;
goto copcsr;
default:
return SIGILL;
}
break;
}
#if defined(__mips64)
case l_fmt:{
switch (MIPSInst_FUNC(ir)) {
case fcvts_op:
/* convert long to single precision real */
rv.s = ieee754sp_flong(ctx->fpr[MIPSInst_FS(ir)]);
rfmt = s_fmt;
goto copcsr;
case fcvtd_op:
/* convert long to double precision real */
rv.d = ieee754dp_flong(ctx->fpr[MIPSInst_FS(ir)]);
rfmt = d_fmt;
goto copcsr;
default:
return SIGILL;
}
break;
}
#endif
default:
return SIGILL;
}
/*
* Update the fpu CSR register for this operation.
* If an exception is required, generate a tidy SIGFPE exception,
* without updating the result register.
* Note: cause exception bits do not accumulate, they are rewritten
* for each op; only the flag/sticky bits accumulate.
*/
ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
/*printk ("SIGFPE: fpu csr = %08x\n",ctx->fcr31); */
return SIGFPE;
}
/*
* Now we can safely write the result back to the register file.
*/
switch (rfmt) {
case -1:{
#if __mips >= 4
cond = fpucondbit[MIPSInst_FD(ir) >> 2];
#else
cond = FPU_CSR_COND;
#endif
if (rv.w)
ctx->fcr31 |= cond;
else
ctx->fcr31 &= ~cond;
break;
}
case d_fmt:
DPTOREG(rv.d, MIPSInst_FD(ir));
break;
case s_fmt:
SPTOREG(rv.s, MIPSInst_FD(ir));
break;
case w_fmt:
SITOREG(rv.w, MIPSInst_FD(ir));
break;
#if defined(__mips64)
case l_fmt:
DITOREG(rv.l, MIPSInst_FD(ir));
break;
#endif
default:
return SIGILL;
}
return 0;
}
int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
int has_fpu, void *__user *fault_addr)
{
unsigned long oldepc, prevepc;
mips_instruction insn;
int sig = 0;
oldepc = xcp->cp0_epc;
do {
prevepc = xcp->cp0_epc;
if (!access_ok(VERIFY_READ, xcp->cp0_epc, sizeof(mips_instruction))) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGBUS;
}
if (__get_user(insn, (mips_instruction __user *) xcp->cp0_epc)) {
MIPS_FPU_EMU_INC_STATS(errors);
*fault_addr = (mips_instruction __user *)xcp->cp0_epc;
return SIGSEGV;
}
if (insn == 0)
xcp->cp0_epc += 4; /* skip nops */
else {
/*
* The 'ieee754_csr' is an alias of
* ctx->fcr31. No need to copy ctx->fcr31 to
* ieee754_csr. But ieee754_csr.rm is ieee
* library modes. (not mips rounding mode)
*/
/* convert to ieee library modes */
ieee754_csr.rm = ieee_rm[ieee754_csr.rm];
sig = cop1Emulate(xcp, ctx, fault_addr);
/* revert to mips rounding mode */
ieee754_csr.rm = mips_rm[ieee754_csr.rm];
}
if (has_fpu)
break;
if (sig)
break;
cond_resched();
} while (xcp->cp0_epc > prevepc);
/* SIGILL indicates a non-fpu instruction */
if (sig == SIGILL && xcp->cp0_epc != oldepc)
/* but if epc has advanced, then ignore it */
sig = 0;
return sig;
}
#ifdef CONFIG_DEBUG_FS
static int fpuemu_stat_get(void *data, u64 *val)
{
int cpu;
unsigned long sum = 0;
for_each_online_cpu(cpu) {
struct mips_fpu_emulator_stats *ps;
local_t *pv;
ps = &per_cpu(fpuemustats, cpu);
pv = (void *)ps + (unsigned long)data;
sum += local_read(pv);
}
*val = sum;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_fpuemu_stat, fpuemu_stat_get, NULL, "%llu\n");
extern struct dentry *mips_debugfs_dir;
static int __init debugfs_fpuemu(void)
{
struct dentry *d, *dir;
if (!mips_debugfs_dir)
return -ENODEV;
dir = debugfs_create_dir("fpuemustats", mips_debugfs_dir);
if (!dir)
return -ENOMEM;
#define FPU_STAT_CREATE(M) \
do { \
d = debugfs_create_file(#M , S_IRUGO, dir, \
(void *)offsetof(struct mips_fpu_emulator_stats, M), \
&fops_fpuemu_stat); \
if (!d) \
return -ENOMEM; \
} while (0)
FPU_STAT_CREATE(emulated);
FPU_STAT_CREATE(loads);
FPU_STAT_CREATE(stores);
FPU_STAT_CREATE(cp1ops);
FPU_STAT_CREATE(cp1xops);
FPU_STAT_CREATE(errors);
return 0;
}
__initcall(debugfs_fpuemu);
#endif
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