From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45162) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fTqGX-0001oy-BJ for qemu-devel@nongnu.org; Fri, 15 Jun 2018 11:03:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fTqGW-0007Da-Bc for qemu-devel@nongnu.org; Fri, 15 Jun 2018 11:03:53 -0400 Received: from mail-lf0-x244.google.com ([2a00:1450:4010:c07::244]:35399) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fTqGW-0007D7-4q for qemu-devel@nongnu.org; Fri, 15 Jun 2018 11:03:52 -0400 Received: by mail-lf0-x244.google.com with SMTP id i15-v6so15120526lfc.2 for ; Fri, 15 Jun 2018 08:03:51 -0700 (PDT) From: "Edgar E. Iglesias" Date: Fri, 15 Jun 2018 17:03:43 +0200 Message-Id: <20180615150343.4937-3-edgar.iglesias@gmail.com> In-Reply-To: <20180615150343.4937-1-edgar.iglesias@gmail.com> References: <20180615150343.4937-1-edgar.iglesias@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PULL v1 2/2] target-microblaze: Rework NOP/zero instruction handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, edgar.iglesias@xilinx.com From: "Edgar E. Iglesias" Remove the abort on a sequence of NOP/zero instructions. Always return early and avoid decoding NOP/zero instructions. This fixes Coverity CID 1391443. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Edgar E. Iglesias --- target/microblaze/translate.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/target/microblaze/translate.c b/target/microblaze/translate.c index 6c64946398..78ca265b04 100644 --- a/target/microblaze/translate.c +++ b/target/microblaze/translate.c @@ -90,7 +90,6 @@ typedef struct DisasContext { uint32_t jmp_pc; int abort_at_next_insn; - int nr_nops; struct TranslationBlock *tb; int singlestep_enabled; } DisasContext; @@ -1576,17 +1575,12 @@ static inline void decode(DisasContext *dc, uint32_t ir) dc->ir = ir; LOG_DIS("%8.8x\t", dc->ir); - if (dc->ir) - dc->nr_nops = 0; - else { + if (ir == 0) { trap_illegal(dc, dc->cpu->env.pvr.regs[2] & PVR2_OPCODE_0x0_ILL_MASK); - - LOG_DIS("nr_nops=%d\t", dc->nr_nops); - dc->nr_nops++; - if (dc->nr_nops > 4) { - cpu_abort(CPU(dc->cpu), "fetching nop sequence\n"); - } + /* Don't decode nop/zero instructions any further. */ + return; } + /* bit 2 seems to indicate insn type. */ dc->type_b = ir & (1 << 29); @@ -1633,7 +1627,6 @@ void gen_intermediate_code(CPUState *cs, struct TranslationBlock *tb) dc->singlestep_enabled = cs->singlestep_enabled; dc->cpustate_changed = 0; dc->abort_at_next_insn = 0; - dc->nr_nops = 0; if (pc_start & 3) { cpu_abort(cs, "Microblaze: unaligned PC=%x\n", pc_start); -- 2.14.1