powerpc/sstep: Add support for divde[.] and divdeu[.] instructions

This patch adds emulation support for divde, divdeu instructions,
  - Divide Doubleword Extended (divde[.])
  - Divide Doubleword Extended Unsigned (divdeu[.])

Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200728130308.1790982-3-bala24@linux.ibm.com

arch/powerpc/lib/sstep.c

@@ -1806,7 +1806,18 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 			op->val = (int) regs->gpr[ra] /
 				(int) regs->gpr[rb];
 			goto arith_done;
-
+#ifdef __powerpc64__
+		case 425:	/* divde[.] */
+			asm volatile(PPC_DIVDE(%0, %1, %2) :
+				"=r" (op->val) : "r" (regs->gpr[ra]),
+				"r" (regs->gpr[rb]));
+			goto arith_done;
+		case 393:	/* divdeu[.] */
+			asm volatile(PPC_DIVDEU(%0, %1, %2) :
+				"=r" (op->val) : "r" (regs->gpr[ra]),
+				"r" (regs->gpr[rb]));
+			goto arith_done;
+#endif
 		case 755:	/* darn */
 			if (!cpu_has_feature(CPU_FTR_ARCH_300))
 				return -1;