From 02c0f62a60b67d6c9bfe9429cbe3aa034b6c6676 Mon Sep 17 00:00:00 2001
From: Matt Brown <matthew.brown.dev@gmail.com>
Date: Mon, 31 Jul 2017 10:58:22 +1000
Subject: powerpc/lib/sstep: Add cmpb instruction emulation
This patch adds emulation of the cmpb instruction, enabling xmon to
emulate this instruction.
Tested for correctness against the cmpb asm instruction on ppc64le.
Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/lib/sstep.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
(limited to 'arch/powerpc/lib')
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ee33327686ae..cc6327b8f589 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -596,6 +596,22 @@ static nokprobe_inline void do_cmp_unsigned(struct pt_regs *regs, unsigned long
regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
}
+static nokprobe_inline void do_cmpb(struct pt_regs *regs, unsigned long v1,
+ unsigned long v2, int rd)
+{
+ unsigned long long out_val, mask;
+ int i;
+
+ out_val = 0;
+ for (i = 0; i < 8; i++) {
+ mask = 0xffUL << (i * 8);
+ if ((v1 & mask) == (v2 & mask))
+ out_val |= mask;
+ }
+
+ regs->gpr[rd] = out_val;
+}
+
static nokprobe_inline int trap_compare(long v1, long v2)
{
int ret = 0;
@@ -1064,6 +1080,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
do_cmp_unsigned(regs, val, val2, rd >> 2);
goto instr_done;
+ case 508: /* cmpb */
+ do_cmpb(regs, regs->gpr[rd], regs->gpr[rb], ra);
+ goto instr_done;
+
/*
* Arithmetic instructions
*/
--
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