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>
diff --git a/arch/sparc/math-emu/math_64.c b/arch/sparc/math-emu/math_64.c
index 2bbe2f2..1704068 100644
--- a/arch/sparc/math-emu/math_64.c
+++ b/arch/sparc/math-emu/math_64.c
@@ -163,7 +163,7 @@
u64 q[2];
} *argp;
-int do_mathemu(struct pt_regs *regs, struct fpustate *f)
+int do_mathemu(struct pt_regs *regs, struct fpustate *f, bool illegal_insn_trap)
{
unsigned long pc = regs->tpc;
unsigned long tstate = regs->tstate;
@@ -218,7 +218,7 @@
case FSQRTS: {
unsigned long x = current_thread_info()->xfsr[0];
- x = (x >> 14) & 0xf;
+ x = (x >> 14) & 0x7;
TYPE(x,1,1,1,1,0,0);
break;
}
@@ -226,7 +226,7 @@
case FSQRTD: {
unsigned long x = current_thread_info()->xfsr[0];
- x = (x >> 14) & 0xf;
+ x = (x >> 14) & 0x7;
TYPE(x,2,1,2,1,0,0);
break;
}
@@ -357,9 +357,17 @@
if (type) {
argp rs1 = NULL, rs2 = NULL, rd = NULL;
- freg = (current_thread_info()->xfsr[0] >> 14) & 0xf;
- if (freg != (type >> 9))
- goto err;
+ /* 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) {