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-rw-r--r--arch/x86/math-emu/errors.c686
1 files changed, 686 insertions, 0 deletions
diff --git a/arch/x86/math-emu/errors.c b/arch/x86/math-emu/errors.c
new file mode 100644
index 000000000..ec071cbb0
--- /dev/null
+++ b/arch/x86/math-emu/errors.c
@@ -0,0 +1,686 @@
+// SPDX-License-Identifier: GPL-2.0
+/*---------------------------------------------------------------------------+
+ | errors.c |
+ | |
+ | The error handling functions for wm-FPU-emu |
+ | |
+ | Copyright (C) 1992,1993,1994,1996 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
+ | E-mail billm@jacobi.maths.monash.edu.au |
+ | |
+ | |
+ +---------------------------------------------------------------------------*/
+
+/*---------------------------------------------------------------------------+
+ | Note: |
+ | The file contains code which accesses user memory. |
+ | Emulator static data may change when user memory is accessed, due to |
+ | other processes using the emulator while swapping is in progress. |
+ +---------------------------------------------------------------------------*/
+
+#include <linux/signal.h>
+
+#include <linux/uaccess.h>
+
+#include "fpu_emu.h"
+#include "fpu_system.h"
+#include "exception.h"
+#include "status_w.h"
+#include "control_w.h"
+#include "reg_constant.h"
+#include "version.h"
+
+/* */
+#undef PRINT_MESSAGES
+/* */
+
+#if 0
+void Un_impl(void)
+{
+ u_char byte1, FPU_modrm;
+ unsigned long address = FPU_ORIG_EIP;
+
+ RE_ENTRANT_CHECK_OFF;
+ /* No need to check access_ok(), we have previously fetched these bytes. */
+ printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
+ if (FPU_CS == __USER_CS) {
+ while (1) {
+ FPU_get_user(byte1, (u_char __user *) address);
+ if ((byte1 & 0xf8) == 0xd8)
+ break;
+ printk("[%02x]", byte1);
+ address++;
+ }
+ printk("%02x ", byte1);
+ FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
+
+ if (FPU_modrm >= 0300)
+ printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
+ FPU_modrm & 7);
+ else
+ printk("/%d\n", (FPU_modrm >> 3) & 7);
+ } else {
+ printk("cs selector = %04x\n", FPU_CS);
+ }
+
+ RE_ENTRANT_CHECK_ON;
+
+ EXCEPTION(EX_Invalid);
+
+}
+#endif /* 0 */
+
+/*
+ Called for opcodes which are illegal and which are known to result in a
+ SIGILL with a real 80486.
+ */
+void FPU_illegal(void)
+{
+ math_abort(FPU_info, SIGILL);
+}
+
+void FPU_printall(void)
+{
+ int i;
+ static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
+ "DeNorm", "Inf", "NaN"
+ };
+ u_char byte1, FPU_modrm;
+ unsigned long address = FPU_ORIG_EIP;
+
+ RE_ENTRANT_CHECK_OFF;
+ /* No need to check access_ok(), we have previously fetched these bytes. */
+ printk("At %p:", (void *)address);
+ if (FPU_CS == __USER_CS) {
+#define MAX_PRINTED_BYTES 20
+ for (i = 0; i < MAX_PRINTED_BYTES; i++) {
+ FPU_get_user(byte1, (u_char __user *) address);
+ if ((byte1 & 0xf8) == 0xd8) {
+ printk(" %02x", byte1);
+ break;
+ }
+ printk(" [%02x]", byte1);
+ address++;
+ }
+ if (i == MAX_PRINTED_BYTES)
+ printk(" [more..]\n");
+ else {
+ FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
+
+ if (FPU_modrm >= 0300)
+ printk(" %02x (%02x+%d)\n", FPU_modrm,
+ FPU_modrm & 0xf8, FPU_modrm & 7);
+ else
+ printk(" /%d, mod=%d rm=%d\n",
+ (FPU_modrm >> 3) & 7,
+ (FPU_modrm >> 6) & 3, FPU_modrm & 7);
+ }
+ } else {
+ printk("%04x\n", FPU_CS);
+ }
+
+ partial_status = status_word();
+
+#ifdef DEBUGGING
+ if (partial_status & SW_Backward)
+ printk("SW: backward compatibility\n");
+ if (partial_status & SW_C3)
+ printk("SW: condition bit 3\n");
+ if (partial_status & SW_C2)
+ printk("SW: condition bit 2\n");
+ if (partial_status & SW_C1)
+ printk("SW: condition bit 1\n");
+ if (partial_status & SW_C0)
+ printk("SW: condition bit 0\n");
+ if (partial_status & SW_Summary)
+ printk("SW: exception summary\n");
+ if (partial_status & SW_Stack_Fault)
+ printk("SW: stack fault\n");
+ if (partial_status & SW_Precision)
+ printk("SW: loss of precision\n");
+ if (partial_status & SW_Underflow)
+ printk("SW: underflow\n");
+ if (partial_status & SW_Overflow)
+ printk("SW: overflow\n");
+ if (partial_status & SW_Zero_Div)
+ printk("SW: divide by zero\n");
+ if (partial_status & SW_Denorm_Op)
+ printk("SW: denormalized operand\n");
+ if (partial_status & SW_Invalid)
+ printk("SW: invalid operation\n");
+#endif /* DEBUGGING */
+
+ printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", partial_status & 0x8000 ? 1 : 0, /* busy */
+ (partial_status & 0x3800) >> 11, /* stack top pointer */
+ partial_status & 0x80 ? 1 : 0, /* Error summary status */
+ partial_status & 0x40 ? 1 : 0, /* Stack flag */
+ partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */
+ partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */
+ partial_status & SW_Precision ? 1 : 0,
+ partial_status & SW_Underflow ? 1 : 0,
+ partial_status & SW_Overflow ? 1 : 0,
+ partial_status & SW_Zero_Div ? 1 : 0,
+ partial_status & SW_Denorm_Op ? 1 : 0,
+ partial_status & SW_Invalid ? 1 : 0);
+
+ printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n",
+ control_word & 0x1000 ? 1 : 0,
+ (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
+ (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
+ control_word & 0x80 ? 1 : 0,
+ control_word & SW_Precision ? 1 : 0,
+ control_word & SW_Underflow ? 1 : 0,
+ control_word & SW_Overflow ? 1 : 0,
+ control_word & SW_Zero_Div ? 1 : 0,
+ control_word & SW_Denorm_Op ? 1 : 0,
+ control_word & SW_Invalid ? 1 : 0);
+
+ for (i = 0; i < 8; i++) {
+ FPU_REG *r = &st(i);
+ u_char tagi = FPU_gettagi(i);
+
+ switch (tagi) {
+ case TAG_Empty:
+ continue;
+ case TAG_Zero:
+ case TAG_Special:
+ /* Update tagi for the printk below */
+ tagi = FPU_Special(r);
+ fallthrough;
+ case TAG_Valid:
+ printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
+ getsign(r) ? '-' : '+',
+ (long)(r->sigh >> 16),
+ (long)(r->sigh & 0xFFFF),
+ (long)(r->sigl >> 16),
+ (long)(r->sigl & 0xFFFF),
+ exponent(r) - EXP_BIAS + 1);
+ break;
+ default:
+ printk("Whoops! Error in errors.c: tag%d is %d ", i,
+ tagi);
+ continue;
+ }
+ printk("%s\n", tag_desc[(int)(unsigned)tagi]);
+ }
+
+ RE_ENTRANT_CHECK_ON;
+
+}
+
+static struct {
+ int type;
+ const char *name;
+} exception_names[] = {
+ {
+ EX_StackOver, "stack overflow"}, {
+ EX_StackUnder, "stack underflow"}, {
+ EX_Precision, "loss of precision"}, {
+ EX_Underflow, "underflow"}, {
+ EX_Overflow, "overflow"}, {
+ EX_ZeroDiv, "divide by zero"}, {
+ EX_Denormal, "denormalized operand"}, {
+ EX_Invalid, "invalid operation"}, {
+ EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
+ 0, NULL}
+};
+
+/*
+ EX_INTERNAL is always given with a code which indicates where the
+ error was detected.
+
+ Internal error types:
+ 0x14 in fpu_etc.c
+ 0x1nn in a *.c file:
+ 0x101 in reg_add_sub.c
+ 0x102 in reg_mul.c
+ 0x104 in poly_atan.c
+ 0x105 in reg_mul.c
+ 0x107 in fpu_trig.c
+ 0x108 in reg_compare.c
+ 0x109 in reg_compare.c
+ 0x110 in reg_add_sub.c
+ 0x111 in fpe_entry.c
+ 0x112 in fpu_trig.c
+ 0x113 in errors.c
+ 0x115 in fpu_trig.c
+ 0x116 in fpu_trig.c
+ 0x117 in fpu_trig.c
+ 0x118 in fpu_trig.c
+ 0x119 in fpu_trig.c
+ 0x120 in poly_atan.c
+ 0x121 in reg_compare.c
+ 0x122 in reg_compare.c
+ 0x123 in reg_compare.c
+ 0x125 in fpu_trig.c
+ 0x126 in fpu_entry.c
+ 0x127 in poly_2xm1.c
+ 0x128 in fpu_entry.c
+ 0x129 in fpu_entry.c
+ 0x130 in get_address.c
+ 0x131 in get_address.c
+ 0x132 in get_address.c
+ 0x133 in get_address.c
+ 0x140 in load_store.c
+ 0x141 in load_store.c
+ 0x150 in poly_sin.c
+ 0x151 in poly_sin.c
+ 0x160 in reg_ld_str.c
+ 0x161 in reg_ld_str.c
+ 0x162 in reg_ld_str.c
+ 0x163 in reg_ld_str.c
+ 0x164 in reg_ld_str.c
+ 0x170 in fpu_tags.c
+ 0x171 in fpu_tags.c
+ 0x172 in fpu_tags.c
+ 0x180 in reg_convert.c
+ 0x2nn in an *.S file:
+ 0x201 in reg_u_add.S
+ 0x202 in reg_u_div.S
+ 0x203 in reg_u_div.S
+ 0x204 in reg_u_div.S
+ 0x205 in reg_u_mul.S
+ 0x206 in reg_u_sub.S
+ 0x207 in wm_sqrt.S
+ 0x208 in reg_div.S
+ 0x209 in reg_u_sub.S
+ 0x210 in reg_u_sub.S
+ 0x211 in reg_u_sub.S
+ 0x212 in reg_u_sub.S
+ 0x213 in wm_sqrt.S
+ 0x214 in wm_sqrt.S
+ 0x215 in wm_sqrt.S
+ 0x220 in reg_norm.S
+ 0x221 in reg_norm.S
+ 0x230 in reg_round.S
+ 0x231 in reg_round.S
+ 0x232 in reg_round.S
+ 0x233 in reg_round.S
+ 0x234 in reg_round.S
+ 0x235 in reg_round.S
+ 0x236 in reg_round.S
+ 0x240 in div_Xsig.S
+ 0x241 in div_Xsig.S
+ 0x242 in div_Xsig.S
+ */
+
+asmlinkage __visible void FPU_exception(int n)
+{
+ int i, int_type;
+
+ int_type = 0; /* Needed only to stop compiler warnings */
+ if (n & EX_INTERNAL) {
+ int_type = n - EX_INTERNAL;
+ n = EX_INTERNAL;
+ /* Set lots of exception bits! */
+ partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward);
+ } else {
+ /* Extract only the bits which we use to set the status word */
+ n &= (SW_Exc_Mask);
+ /* Set the corresponding exception bit */
+ partial_status |= n;
+ /* Set summary bits iff exception isn't masked */
+ if (partial_status & ~control_word & CW_Exceptions)
+ partial_status |= (SW_Summary | SW_Backward);
+ if (n & (SW_Stack_Fault | EX_Precision)) {
+ if (!(n & SW_C1))
+ /* This bit distinguishes over- from underflow for a stack fault,
+ and roundup from round-down for precision loss. */
+ partial_status &= ~SW_C1;
+ }
+ }
+
+ RE_ENTRANT_CHECK_OFF;
+ if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) {
+ /* Get a name string for error reporting */
+ for (i = 0; exception_names[i].type; i++)
+ if ((exception_names[i].type & n) ==
+ exception_names[i].type)
+ break;
+
+ if (exception_names[i].type) {
+#ifdef PRINT_MESSAGES
+ printk("FP Exception: %s!\n", exception_names[i].name);
+#endif /* PRINT_MESSAGES */
+ } else
+ printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);
+
+ if (n == EX_INTERNAL) {
+ printk("FPU emulator: Internal error type 0x%04x\n",
+ int_type);
+ FPU_printall();
+ }
+#ifdef PRINT_MESSAGES
+ else
+ FPU_printall();
+#endif /* PRINT_MESSAGES */
+
+ /*
+ * The 80486 generates an interrupt on the next non-control FPU
+ * instruction. So we need some means of flagging it.
+ * We use the ES (Error Summary) bit for this.
+ */
+ }
+ RE_ENTRANT_CHECK_ON;
+
+#ifdef __DEBUG__
+ math_abort(FPU_info, SIGFPE);
+#endif /* __DEBUG__ */
+
+}
+
+/* Real operation attempted on a NaN. */
+/* Returns < 0 if the exception is unmasked */
+int real_1op_NaN(FPU_REG *a)
+{
+ int signalling, isNaN;
+
+ isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);
+
+ /* The default result for the case of two "equal" NaNs (signs may
+ differ) is chosen to reproduce 80486 behaviour */
+ signalling = isNaN && !(a->sigh & 0x40000000);
+
+ if (!signalling) {
+ if (!isNaN) { /* pseudo-NaN, or other unsupported? */
+ if (control_word & CW_Invalid) {
+ /* Masked response */
+ reg_copy(&CONST_QNaN, a);
+ }
+ EXCEPTION(EX_Invalid);
+ return (!(control_word & CW_Invalid) ? FPU_Exception :
+ 0) | TAG_Special;
+ }
+ return TAG_Special;
+ }
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */
+ reg_copy(&CONST_QNaN, a);
+ }
+ /* ensure a Quiet NaN */
+ a->sigh |= 0x40000000;
+ }
+
+ EXCEPTION(EX_Invalid);
+
+ return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
+}
+
+/* Real operation attempted on two operands, one a NaN. */
+/* Returns < 0 if the exception is unmasked */
+int real_2op_NaN(FPU_REG const *b, u_char tagb,
+ int deststnr, FPU_REG const *defaultNaN)
+{
+ FPU_REG *dest = &st(deststnr);
+ FPU_REG const *a = dest;
+ u_char taga = FPU_gettagi(deststnr);
+ FPU_REG const *x;
+ int signalling, unsupported;
+
+ if (taga == TAG_Special)
+ taga = FPU_Special(a);
+ if (tagb == TAG_Special)
+ tagb = FPU_Special(b);
+
+ /* TW_NaN is also used for unsupported data types. */
+ unsupported = ((taga == TW_NaN)
+ && !((exponent(a) == EXP_OVER)
+ && (a->sigh & 0x80000000)))
+ || ((tagb == TW_NaN)
+ && !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
+ if (unsupported) {
+ if (control_word & CW_Invalid) {
+ /* Masked response */
+ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
+ }
+ EXCEPTION(EX_Invalid);
+ return (!(control_word & CW_Invalid) ? FPU_Exception : 0) |
+ TAG_Special;
+ }
+
+ if (taga == TW_NaN) {
+ x = a;
+ if (tagb == TW_NaN) {
+ signalling = !(a->sigh & b->sigh & 0x40000000);
+ if (significand(b) > significand(a))
+ x = b;
+ else if (significand(b) == significand(a)) {
+ /* The default result for the case of two "equal" NaNs (signs may
+ differ) is chosen to reproduce 80486 behaviour */
+ x = defaultNaN;
+ }
+ } else {
+ /* return the quiet version of the NaN in a */
+ signalling = !(a->sigh & 0x40000000);
+ }
+ } else
+#ifdef PARANOID
+ if (tagb == TW_NaN)
+#endif /* PARANOID */
+ {
+ signalling = !(b->sigh & 0x40000000);
+ x = b;
+ }
+#ifdef PARANOID
+ else {
+ signalling = 0;
+ EXCEPTION(EX_INTERNAL | 0x113);
+ x = &CONST_QNaN;
+ }
+#endif /* PARANOID */
+
+ if ((!signalling) || (control_word & CW_Invalid)) {
+ if (!x)
+ x = b;
+
+ if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */
+ x = &CONST_QNaN;
+
+ FPU_copy_to_regi(x, TAG_Special, deststnr);
+
+ if (!signalling)
+ return TAG_Special;
+
+ /* ensure a Quiet NaN */
+ dest->sigh |= 0x40000000;
+ }
+
+ EXCEPTION(EX_Invalid);
+
+ return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
+}
+
+/* Invalid arith operation on Valid registers */
+/* Returns < 0 if the exception is unmasked */
+asmlinkage __visible int arith_invalid(int deststnr)
+{
+
+ EXCEPTION(EX_Invalid);
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
+ }
+
+ return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid;
+
+}
+
+/* Divide a finite number by zero */
+asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign)
+{
+ FPU_REG *dest = &st(deststnr);
+ int tag = TAG_Valid;
+
+ if (control_word & CW_ZeroDiv) {
+ /* The masked response */
+ FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr);
+ setsign(dest, sign);
+ tag = TAG_Special;
+ }
+
+ EXCEPTION(EX_ZeroDiv);
+
+ return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag;
+
+}
+
+/* This may be called often, so keep it lean */
+int set_precision_flag(int flags)
+{
+ if (control_word & CW_Precision) {
+ partial_status &= ~(SW_C1 & flags);
+ partial_status |= flags; /* The masked response */
+ return 0;
+ } else {
+ EXCEPTION(flags);
+ return 1;
+ }
+}
+
+/* This may be called often, so keep it lean */
+asmlinkage __visible void set_precision_flag_up(void)
+{
+ if (control_word & CW_Precision)
+ partial_status |= (SW_Precision | SW_C1); /* The masked response */
+ else
+ EXCEPTION(EX_Precision | SW_C1);
+}
+
+/* This may be called often, so keep it lean */
+asmlinkage __visible void set_precision_flag_down(void)
+{
+ if (control_word & CW_Precision) { /* The masked response */
+ partial_status &= ~SW_C1;
+ partial_status |= SW_Precision;
+ } else
+ EXCEPTION(EX_Precision);
+}
+
+asmlinkage __visible int denormal_operand(void)
+{
+ if (control_word & CW_Denormal) { /* The masked response */
+ partial_status |= SW_Denorm_Op;
+ return TAG_Special;
+ } else {
+ EXCEPTION(EX_Denormal);
+ return TAG_Special | FPU_Exception;
+ }
+}
+
+asmlinkage __visible int arith_overflow(FPU_REG *dest)
+{
+ int tag = TAG_Valid;
+
+ if (control_word & CW_Overflow) {
+ /* The masked response */
+/* ###### The response here depends upon the rounding mode */
+ reg_copy(&CONST_INF, dest);
+ tag = TAG_Special;
+ } else {
+ /* Subtract the magic number from the exponent */
+ addexponent(dest, (-3 * (1 << 13)));
+ }
+
+ EXCEPTION(EX_Overflow);
+ if (control_word & CW_Overflow) {
+ /* The overflow exception is masked. */
+ /* By definition, precision is lost.
+ The roundup bit (C1) is also set because we have
+ "rounded" upwards to Infinity. */
+ EXCEPTION(EX_Precision | SW_C1);
+ return tag;
+ }
+
+ return tag;
+
+}
+
+asmlinkage __visible int arith_underflow(FPU_REG *dest)
+{
+ int tag = TAG_Valid;
+
+ if (control_word & CW_Underflow) {
+ /* The masked response */
+ if (exponent16(dest) <= EXP_UNDER - 63) {
+ reg_copy(&CONST_Z, dest);
+ partial_status &= ~SW_C1; /* Round down. */
+ tag = TAG_Zero;
+ } else {
+ stdexp(dest);
+ }
+ } else {
+ /* Add the magic number to the exponent. */
+ addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias);
+ }
+
+ EXCEPTION(EX_Underflow);
+ if (control_word & CW_Underflow) {
+ /* The underflow exception is masked. */
+ EXCEPTION(EX_Precision);
+ return tag;
+ }
+
+ return tag;
+
+}
+
+void FPU_stack_overflow(void)
+{
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ top--;
+ FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
+ }
+
+ EXCEPTION(EX_StackOver);
+
+ return;
+
+}
+
+void FPU_stack_underflow(void)
+{
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
+ }
+
+ EXCEPTION(EX_StackUnder);
+
+ return;
+
+}
+
+void FPU_stack_underflow_i(int i)
+{
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
+ }
+
+ EXCEPTION(EX_StackUnder);
+
+ return;
+
+}
+
+void FPU_stack_underflow_pop(int i)
+{
+
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
+ FPU_pop();
+ }
+
+ EXCEPTION(EX_StackUnder);
+
+ return;
+
+}
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