From 02c0f62a60b67d6c9bfe9429cbe3aa034b6c6676 Mon Sep 17 00:00:00 2001 From: Matt Brown Date: Mon, 31 Jul 2017 10:58:22 +1000 Subject: [PATCH] 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 Reviewed-by: Cyril Bur Signed-off-by: Michael Ellerman --- arch/powerpc/lib/sstep.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index ee33327..cc6327b 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 */ -- 2.7.4