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linux-pinenote/arch/sparc/math-emu/math_64.c
David S. Miller 456d3d4246 sparc64: Fix several bugs in quad floating point emulation. 
UltraSPARC-T2 and later do not use the fp_exception_other trap and do
not set the floating point trap type field in the %fsr at all when you
try to execute an unimplemented FPU operation.

Instead, it uses the illegal_instruction trap and it leaves the
floating point trap type field clear.

So we should not validate the %fsr trap type field when do_mathemu()
is invoked from the illegal instruction handler.

Also, the floating point trap type field is 3 bits, not 4 bits.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-25 00:31:56 -07:00

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/*
* arch/sparc64/math-emu/math.c
*
* Copyright (C) 1997,1999 Jakub Jelinek (jj@ultra.linux.cz)
* Copyright (C) 1999 David S. Miller (davem@redhat.com)
*
* Emulation routines originate from soft-fp package, which is part
* of glibc and has appropriate copyrights in it.
*/
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/perf_event.h>
#include <asm/fpumacro.h>
#include <asm/ptrace.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include "sfp-util_64.h"
#include <math-emu/soft-fp.h>
#include <math-emu/single.h>
#include <math-emu/double.h>
#include <math-emu/quad.h>
/* QUAD - ftt == 3 */
#define FMOVQ 0x003
#define FNEGQ 0x007
#define FABSQ 0x00b
#define FSQRTQ 0x02b
#define FADDQ 0x043
#define FSUBQ 0x047
#define FMULQ 0x04b
#define FDIVQ 0x04f
#define FDMULQ 0x06e
#define FQTOX 0x083
#define FXTOQ 0x08c
#define FQTOS 0x0c7
#define FQTOD 0x0cb
#define FITOQ 0x0cc
#define FSTOQ 0x0cd
#define FDTOQ 0x0ce
#define FQTOI 0x0d3
/* SUBNORMAL - ftt == 2 */
#define FSQRTS 0x029
#define FSQRTD 0x02a
#define FADDS 0x041
#define FADDD 0x042
#define FSUBS 0x045
#define FSUBD 0x046
#define FMULS 0x049
#define FMULD 0x04a
#define FDIVS 0x04d
#define FDIVD 0x04e
#define FSMULD 0x069
#define FSTOX 0x081
#define FDTOX 0x082
#define FDTOS 0x0c6
#define FSTOD 0x0c9
#define FSTOI 0x0d1
#define FDTOI 0x0d2
#define FXTOS 0x084 /* Only Ultra-III generates this. */
#define FXTOD 0x088 /* Only Ultra-III generates this. */
#if 0 /* Optimized inline in sparc64/kernel/entry.S */
#define FITOS 0x0c4 /* Only Ultra-III generates this. */
#endif
#define FITOD 0x0c8 /* Only Ultra-III generates this. */
/* FPOP2 */
#define FCMPQ 0x053
#define FCMPEQ 0x057
#define FMOVQ0 0x003
#define FMOVQ1 0x043
#define FMOVQ2 0x083
#define FMOVQ3 0x0c3
#define FMOVQI 0x103
#define FMOVQX 0x183
#define FMOVQZ 0x027
#define FMOVQLE 0x047
#define FMOVQLZ 0x067
#define FMOVQNZ 0x0a7
#define FMOVQGZ 0x0c7
#define FMOVQGE 0x0e7
#define FSR_TEM_SHIFT 23UL
#define FSR_TEM_MASK (0x1fUL << FSR_TEM_SHIFT)
#define FSR_AEXC_SHIFT 5UL
#define FSR_AEXC_MASK (0x1fUL << FSR_AEXC_SHIFT)
#define FSR_CEXC_SHIFT 0UL
#define FSR_CEXC_MASK (0x1fUL << FSR_CEXC_SHIFT)
/* All routines returning an exception to raise should detect
* such exceptions _before_ rounding to be consistent with
* the behavior of the hardware in the implemented cases
* (and thus with the recommendations in the V9 architecture
* manual).
*
* We return 0 if a SIGFPE should be sent, 1 otherwise.
*/
static inline int record_exception(struct pt_regs *regs, int eflag)
{
u64 fsr = current_thread_info()->xfsr[0];
int would_trap;
/* Determine if this exception would have generated a trap. */
would_trap = (fsr & ((long)eflag << FSR_TEM_SHIFT)) != 0UL;
/* If trapping, we only want to signal one bit. */
if(would_trap != 0) {
eflag &= ((fsr & FSR_TEM_MASK) >> FSR_TEM_SHIFT);
if((eflag & (eflag - 1)) != 0) {
if(eflag & FP_EX_INVALID)
eflag = FP_EX_INVALID;
else if(eflag & FP_EX_OVERFLOW)
eflag = FP_EX_OVERFLOW;
else if(eflag & FP_EX_UNDERFLOW)
eflag = FP_EX_UNDERFLOW;
else if(eflag & FP_EX_DIVZERO)
eflag = FP_EX_DIVZERO;
else if(eflag & FP_EX_INEXACT)
eflag = FP_EX_INEXACT;
}
}
/* Set CEXC, here is the rule:
*
* In general all FPU ops will set one and only one
* bit in the CEXC field, this is always the case
* when the IEEE exception trap is enabled in TEM.
*/
fsr &= ~(FSR_CEXC_MASK);
fsr |= ((long)eflag << FSR_CEXC_SHIFT);
/* Set the AEXC field, rule is:
*
* If a trap would not be generated, the
* CEXC just generated is OR'd into the
* existing value of AEXC.
*/
if(would_trap == 0)
fsr |= ((long)eflag << FSR_AEXC_SHIFT);
/* If trapping, indicate fault trap type IEEE. */
if(would_trap != 0)
fsr |= (1UL << 14);
current_thread_info()->xfsr[0] = fsr;
/* If we will not trap, advance the program counter over
* the instruction being handled.
*/
if(would_trap == 0) {
regs->tpc = regs->tnpc;
regs->tnpc += 4;
}
return (would_trap ? 0 : 1);
}
typedef union {
u32 s;
u64 d;
u64 q[2];
} *argp;
int do_mathemu(struct pt_regs *regs, struct fpustate *f, bool illegal_insn_trap)
{
unsigned long pc = regs->tpc;
unsigned long tstate = regs->tstate;
u32 insn = 0;
int type = 0;
/* ftt tells which ftt it may happen in, r is rd, b is rs2 and a is rs1. The *u arg tells
whether the argument should be packed/unpacked (0 - do not unpack/pack, 1 - unpack/pack)
non-u args tells the size of the argument (0 - no argument, 1 - single, 2 - double, 3 - quad */
#define TYPE(ftt, r, ru, b, bu, a, au) type = (au << 2) | (a << 0) | (bu << 5) | (b << 3) | (ru << 8) | (r << 6) | (ftt << 9)
int freg;
static u64 zero[2] = { 0L, 0L };
int flags;
FP_DECL_EX;
FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR);
FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR);
FP_DECL_Q(QA); FP_DECL_Q(QB); FP_DECL_Q(QR);
int IR;
long XR, xfsr;
if (tstate & TSTATE_PRIV)
die_if_kernel("unfinished/unimplemented FPop from kernel", regs);
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
if (test_thread_flag(TIF_32BIT))
pc = (u32)pc;
if (get_user(insn, (u32 __user *) pc) != -EFAULT) {
if ((insn & 0xc1f80000) == 0x81a00000) /* FPOP1 */ {
switch ((insn >> 5) & 0x1ff) {
/* QUAD - ftt == 3 */
case FMOVQ:
case FNEGQ:
case FABSQ: TYPE(3,3,0,3,0,0,0); break;
case FSQRTQ: TYPE(3,3,1,3,1,0,0); break;
case FADDQ:
case FSUBQ:
case FMULQ:
case FDIVQ: TYPE(3,3,1,3,1,3,1); break;
case FDMULQ: TYPE(3,3,1,2,1,2,1); break;
case FQTOX: TYPE(3,2,0,3,1,0,0); break;
case FXTOQ: TYPE(3,3,1,2,0,0,0); break;
case FQTOS: TYPE(3,1,1,3,1,0,0); break;
case FQTOD: TYPE(3,2,1,3,1,0,0); break;
case FITOQ: TYPE(3,3,1,1,0,0,0); break;
case FSTOQ: TYPE(3,3,1,1,1,0,0); break;
case FDTOQ: TYPE(3,3,1,2,1,0,0); break;
case FQTOI: TYPE(3,1,0,3,1,0,0); break;
/* We can get either unimplemented or unfinished
* for these cases. Pre-Niagara systems generate
* unfinished fpop for SUBNORMAL cases, and Niagara
* always gives unimplemented fpop for fsqrt{s,d}.
*/
case FSQRTS: {
unsigned long x = current_thread_info()->xfsr[0];
x = (x >> 14) & 0x7;
TYPE(x,1,1,1,1,0,0);
break;
}
case FSQRTD: {
unsigned long x = current_thread_info()->xfsr[0];
x = (x >> 14) & 0x7;
TYPE(x,2,1,2,1,0,0);
break;
}
/* SUBNORMAL - ftt == 2 */
case FADDD:
case FSUBD:
case FMULD:
case FDIVD: TYPE(2,2,1,2,1,2,1); break;
case FADDS:
case FSUBS:
case FMULS:
case FDIVS: TYPE(2,1,1,1,1,1,1); break;
case FSMULD: TYPE(2,2,1,1,1,1,1); break;
case FSTOX: TYPE(2,2,0,1,1,0,0); break;
case FDTOX: TYPE(2,2,0,2,1,0,0); break;
case FDTOS: TYPE(2,1,1,2,1,0,0); break;
case FSTOD: TYPE(2,2,1,1,1,0,0); break;
case FSTOI: TYPE(2,1,0,1,1,0,0); break;
case FDTOI: TYPE(2,1,0,2,1,0,0); break;
/* Only Ultra-III generates these */
case FXTOS: TYPE(2,1,1,2,0,0,0); break;
case FXTOD: TYPE(2,2,1,2,0,0,0); break;
#if 0 /* Optimized inline in sparc64/kernel/entry.S */
case FITOS: TYPE(2,1,1,1,0,0,0); break;
#endif
case FITOD: TYPE(2,2,1,1,0,0,0); break;
}
}
else if ((insn & 0xc1f80000) == 0x81a80000) /* FPOP2 */ {
IR = 2;
switch ((insn >> 5) & 0x1ff) {
case FCMPQ: TYPE(3,0,0,3,1,3,1); break;
case FCMPEQ: TYPE(3,0,0,3,1,3,1); break;
/* Now the conditional fmovq support */
case FMOVQ0:
case FMOVQ1:
case FMOVQ2:
case FMOVQ3:
/* fmovq %fccX, %fY, %fZ */
if (!((insn >> 11) & 3))
XR = current_thread_info()->xfsr[0] >> 10;
else
XR = current_thread_info()->xfsr[0] >> (30 + ((insn >> 10) & 0x6));
XR &= 3;
IR = 0;
switch ((insn >> 14) & 0x7) {
/* case 0: IR = 0; break; */ /* Never */
case 1: if (XR) IR = 1; break; /* Not Equal */
case 2: if (XR == 1 || XR == 2) IR = 1; break; /* Less or Greater */
case 3: if (XR & 1) IR = 1; break; /* Unordered or Less */
case 4: if (XR == 1) IR = 1; break; /* Less */
case 5: if (XR & 2) IR = 1; break; /* Unordered or Greater */
case 6: if (XR == 2) IR = 1; break; /* Greater */
case 7: if (XR == 3) IR = 1; break; /* Unordered */
}
if ((insn >> 14) & 8)
IR ^= 1;
break;
case FMOVQI:
case FMOVQX:
/* fmovq %[ix]cc, %fY, %fZ */
XR = regs->tstate >> 32;
if ((insn >> 5) & 0x80)
XR >>= 4;
XR &= 0xf;
IR = 0;
freg = ((XR >> 2) ^ XR) & 2;
switch ((insn >> 14) & 0x7) {
/* case 0: IR = 0; break; */ /* Never */
case 1: if (XR & 4) IR = 1; break; /* Equal */
case 2: if ((XR & 4) || freg) IR = 1; break; /* Less or Equal */
case 3: if (freg) IR = 1; break; /* Less */
case 4: if (XR & 5) IR = 1; break; /* Less or Equal Unsigned */
case 5: if (XR & 1) IR = 1; break; /* Carry Set */
case 6: if (XR & 8) IR = 1; break; /* Negative */
case 7: if (XR & 2) IR = 1; break; /* Overflow Set */
}
if ((insn >> 14) & 8)
IR ^= 1;
break;
case FMOVQZ:
case FMOVQLE:
case FMOVQLZ:
case FMOVQNZ:
case FMOVQGZ:
case FMOVQGE:
freg = (insn >> 14) & 0x1f;
if (!freg)
XR = 0;
else if (freg < 16)
XR = regs->u_regs[freg];
else if (test_thread_flag(TIF_32BIT)) {
struct reg_window32 __user *win32;
flushw_user ();
win32 = (struct reg_window32 __user *)((unsigned long)((u32)regs->u_regs[UREG_FP]));
get_user(XR, &win32->locals[freg - 16]);
} else {
struct reg_window __user *win;
flushw_user ();
win = (struct reg_window __user *)(regs->u_regs[UREG_FP] + STACK_BIAS);
get_user(XR, &win->locals[freg - 16]);
}
IR = 0;
switch ((insn >> 10) & 3) {
case 1: if (!XR) IR = 1; break; /* Register Zero */
case 2: if (XR <= 0) IR = 1; break; /* Register Less Than or Equal to Zero */
case 3: if (XR < 0) IR = 1; break; /* Register Less Than Zero */
}
if ((insn >> 10) & 4)
IR ^= 1;
break;
}
if (IR == 0) {
/* The fmov test was false. Do a nop instead */
current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
regs->tpc = regs->tnpc;
regs->tnpc += 4;
return 1;
} else if (IR == 1) {
/* Change the instruction into plain fmovq */
insn = (insn & 0x3e00001f) | 0x81a00060;
TYPE(3,3,0,3,0,0,0);
}
}
}
if (type) {
argp rs1 = NULL, rs2 = NULL, rd = NULL;
/* Starting with UltraSPARC-T2, the cpu does not set the FP Trap
* Type field in the %fsr to unimplemented_FPop. Nor does it
* use the fp_exception_other trap. Instead it signals an
* illegal instruction and leaves the FP trap type field of
* the %fsr unchanged.
*/
if (!illegal_insn_trap) {
int ftt = (current_thread_info()->xfsr[0] >> 14) & 0x7;
if (ftt != (type >> 9))
goto err;
}
current_thread_info()->xfsr[0] &= ~0x1c000;
freg = ((insn >> 14) & 0x1f);
switch (type & 0x3) {
case 3: if (freg & 2) {
current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
goto err;
}
case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
case 1: rs1 = (argp)&f->regs[freg];
flags = (freg < 32) ? FPRS_DL : FPRS_DU;
if (!(current_thread_info()->fpsaved[0] & flags))
rs1 = (argp)&zero;
break;
}
switch (type & 0x7) {
case 7: FP_UNPACK_QP (QA, rs1); break;
case 6: FP_UNPACK_DP (DA, rs1); break;
case 5: FP_UNPACK_SP (SA, rs1); break;
}
freg = (insn & 0x1f);
switch ((type >> 3) & 0x3) {
case 3: if (freg & 2) {
current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
goto err;
}
case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
case 1: rs2 = (argp)&f->regs[freg];
flags = (freg < 32) ? FPRS_DL : FPRS_DU;
if (!(current_thread_info()->fpsaved[0] & flags))
rs2 = (argp)&zero;
break;
}
switch ((type >> 3) & 0x7) {
case 7: FP_UNPACK_QP (QB, rs2); break;
case 6: FP_UNPACK_DP (DB, rs2); break;
case 5: FP_UNPACK_SP (SB, rs2); break;
}
freg = ((insn >> 25) & 0x1f);
switch ((type >> 6) & 0x3) {
case 3: if (freg & 2) {
current_thread_info()->xfsr[0] |= (6 << 14) /* invalid_fp_register */;
goto err;
}
case 2: freg = ((freg & 1) << 5) | (freg & 0x1e);
case 1: rd = (argp)&f->regs[freg];
flags = (freg < 32) ? FPRS_DL : FPRS_DU;
if (!(current_thread_info()->fpsaved[0] & FPRS_FEF)) {
current_thread_info()->fpsaved[0] = FPRS_FEF;
current_thread_info()->gsr[0] = 0;
}
if (!(current_thread_info()->fpsaved[0] & flags)) {
if (freg < 32)
memset(f->regs, 0, 32*sizeof(u32));
else
memset(f->regs+32, 0, 32*sizeof(u32));
}
current_thread_info()->fpsaved[0] |= flags;
break;
}
switch ((insn >> 5) & 0x1ff) {
/* + */
case FADDS: FP_ADD_S (SR, SA, SB); break;
case FADDD: FP_ADD_D (DR, DA, DB); break;
case FADDQ: FP_ADD_Q (QR, QA, QB); break;
/* - */
case FSUBS: FP_SUB_S (SR, SA, SB); break;
case FSUBD: FP_SUB_D (DR, DA, DB); break;
case FSUBQ: FP_SUB_Q (QR, QA, QB); break;
/* * */
case FMULS: FP_MUL_S (SR, SA, SB); break;
case FSMULD: FP_CONV (D, S, 1, 1, DA, SA);
FP_CONV (D, S, 1, 1, DB, SB);
case FMULD: FP_MUL_D (DR, DA, DB); break;
case FDMULQ: FP_CONV (Q, D, 2, 1, QA, DA);
FP_CONV (Q, D, 2, 1, QB, DB);
case FMULQ: FP_MUL_Q (QR, QA, QB); break;
/* / */
case FDIVS: FP_DIV_S (SR, SA, SB); break;
case FDIVD: FP_DIV_D (DR, DA, DB); break;
case FDIVQ: FP_DIV_Q (QR, QA, QB); break;
/* sqrt */
case FSQRTS: FP_SQRT_S (SR, SB); break;
case FSQRTD: FP_SQRT_D (DR, DB); break;
case FSQRTQ: FP_SQRT_Q (QR, QB); break;
/* mov */
case FMOVQ: rd->q[0] = rs2->q[0]; rd->q[1] = rs2->q[1]; break;
case FABSQ: rd->q[0] = rs2->q[0] & 0x7fffffffffffffffUL; rd->q[1] = rs2->q[1]; break;
case FNEGQ: rd->q[0] = rs2->q[0] ^ 0x8000000000000000UL; rd->q[1] = rs2->q[1]; break;
/* float to int */
case FSTOI: FP_TO_INT_S (IR, SB, 32, 1); break;
case FDTOI: FP_TO_INT_D (IR, DB, 32, 1); break;
case FQTOI: FP_TO_INT_Q (IR, QB, 32, 1); break;
case FSTOX: FP_TO_INT_S (XR, SB, 64, 1); break;
case FDTOX: FP_TO_INT_D (XR, DB, 64, 1); break;
case FQTOX: FP_TO_INT_Q (XR, QB, 64, 1); break;
/* int to float */
case FITOQ: IR = rs2->s; FP_FROM_INT_Q (QR, IR, 32, int); break;
case FXTOQ: XR = rs2->d; FP_FROM_INT_Q (QR, XR, 64, long); break;
/* Only Ultra-III generates these */
case FXTOS: XR = rs2->d; FP_FROM_INT_S (SR, XR, 64, long); break;
case FXTOD: XR = rs2->d; FP_FROM_INT_D (DR, XR, 64, long); break;
#if 0 /* Optimized inline in sparc64/kernel/entry.S */
case FITOS: IR = rs2->s; FP_FROM_INT_S (SR, IR, 32, int); break;
#endif
case FITOD: IR = rs2->s; FP_FROM_INT_D (DR, IR, 32, int); break;
/* float to float */
case FSTOD: FP_CONV (D, S, 1, 1, DR, SB); break;
case FSTOQ: FP_CONV (Q, S, 2, 1, QR, SB); break;
case FDTOQ: FP_CONV (Q, D, 2, 1, QR, DB); break;
case FDTOS: FP_CONV (S, D, 1, 1, SR, DB); break;
case FQTOS: FP_CONV (S, Q, 1, 2, SR, QB); break;
case FQTOD: FP_CONV (D, Q, 1, 2, DR, QB); break;
/* comparison */
case FCMPQ:
case FCMPEQ:
FP_CMP_Q(XR, QB, QA, 3);
if (XR == 3 &&
(((insn >> 5) & 0x1ff) == FCMPEQ ||
FP_ISSIGNAN_Q(QA) ||
FP_ISSIGNAN_Q(QB)))
FP_SET_EXCEPTION (FP_EX_INVALID);
}
if (!FP_INHIBIT_RESULTS) {
switch ((type >> 6) & 0x7) {
case 0: xfsr = current_thread_info()->xfsr[0];
if (XR == -1) XR = 2;
switch (freg & 3) {
/* fcc0, 1, 2, 3 */
case 0: xfsr &= ~0xc00; xfsr |= (XR << 10); break;
case 1: xfsr &= ~0x300000000UL; xfsr |= (XR << 32); break;
case 2: xfsr &= ~0xc00000000UL; xfsr |= (XR << 34); break;
case 3: xfsr &= ~0x3000000000UL; xfsr |= (XR << 36); break;
}
current_thread_info()->xfsr[0] = xfsr;
break;
case 1: rd->s = IR; break;
case 2: rd->d = XR; break;
case 5: FP_PACK_SP (rd, SR); break;
case 6: FP_PACK_DP (rd, DR); break;
case 7: FP_PACK_QP (rd, QR); break;
}
}
if(_fex != 0)
return record_exception(regs, _fex);
/* Success and no exceptions detected. */
current_thread_info()->xfsr[0] &= ~(FSR_CEXC_MASK);
regs->tpc = regs->tnpc;
regs->tnpc += 4;
return 1;
}
err: return 0;
}
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