Subject: [PATCH v3] powerpc: sstep.c: Add modsw, moduw instruction emulation

From: PrasannaKumar Muralidharan <[email-masked]>
Date: Tue, 13 Dec 2016 13:35:08 +0530

Add modsw and moduw instruction emulation support to analyse_instr.
modsw is an x-form instruction that calculates signed modulo of values
stored in registers. moduw is similar to modsw but it works with
unsigned values.

Signed-off-by: PrasannaKumar Muralidharan <[email-masked]>
Reviewed-by: Naveen N. Rao <[email-masked]>
---
Changes in v3:
Move 'Changes in v2' after '---' so that it won't appear in commit message

Changes in v2:
Don't update CR register as the instruction does not touch that
Arrange extended opcode in numerical order

 arch/powerpc/lib/sstep.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 9c78a9c..b0acdbc 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1128,6 +1128,11 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
 		case 266:	/* add */
 			regs->gpr[rd] = regs->gpr[ra] + regs->gpr[rb];
 			goto arith_done;
+
+		case 267:	/* moduw */
+			regs->gpr[rd] = (unsigned int) regs->gpr[ra] %
+				(unsigned int) regs->gpr[rb];
+			goto instr_done;
 #ifdef __powerpc64__
 		case 457:	/* divdu */
 			regs->gpr[rd] = regs->gpr[ra] / regs->gpr[rb];
@@ -1148,6 +1153,10 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
 				(int) regs->gpr[rb];
 			goto arith_done;
 
+		case 779:	/* modsw */
+			regs->gpr[rd] = (int) regs->gpr[ra] %
+				(int) regs->gpr[rb];
+			goto instr_done;
 
 /*
  * Logical instructions
-- 
2.9.3