[PATCH 2/6] powerpc sstep: Add darn instruction emulation

[Sandipan Das]

This adds emulation support for the following integer instructions:
  * Deliver A Random Number (darn)

Signed-off-by: Sandipan Das <sandipan at linux.ibm.com>
---
 arch/powerpc/lib/sstep.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index b40ec18515bd..18ac0a26c4fc 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1728,6 +1728,25 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 				(int) regs->gpr[rb];
 			goto arith_done;
 
+		case 755:	/* darn */
+			if (!cpu_has_feature(CPU_FTR_ARCH_300))
+				return -1;
+			switch (ra & 0x3) {
+			case 0:
+				asm("darn %0,0" : "=r" (op->val));
+				goto compute_done;
+
+			case 1:
+				asm("darn %0,1" : "=r" (op->val));
+				goto compute_done;
+
+			case 2:
+				asm("darn %0,2" : "=r" (op->val));
+				goto compute_done;
+			}
+
+			return -1;
+
 
 /*
  * Logical instructions
-- 
2.14.4