From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=52189 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P3oJk-0005lM-Ge for qemu-devel@nongnu.org; Thu, 07 Oct 2010 07:07:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P3oJi-0004ft-M4 for qemu-devel@nongnu.org; Thu, 07 Oct 2010 07:07:20 -0400 Received: from mail-ew0-f45.google.com ([209.85.215.45]:61718) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P3oJi-0004fT-ES for qemu-devel@nongnu.org; Thu, 07 Oct 2010 07:07:18 -0400 Received: by ewy19 with SMTP id 19so113168ewy.4 for ; Thu, 07 Oct 2010 04:07:17 -0700 (PDT) Date: Thu, 7 Oct 2010 13:07:13 +0200 From: "Edgar E. Iglesias" Subject: Re: [Qemu-devel] [PATCH 07/11] cris: avoid write only variables Message-ID: <20101007110713.GE16104@laped.lan> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Blue Swirl , qemu-devel On Thu, Oct 07, 2010 at 12:08:05PM +0200, Markus Armbruster wrote: > Blue Swirl writes: > > > Compiling with GCC 4.6.0 20100925 produced warnings: > > /src/qemu/target-cris/op_helper.c: In function 'helper_movl_sreg_reg': > > /src/qemu/target-cris/op_helper.c:145:8: error: variable 'tlb_v' set > > but not used [-Werror=unused-but-set-variable] > > In file included from /src/qemu/target-cris/translate.c:3154:0: > > /src/qemu/target-cris/translate_v10.c: In function 'dec10_prep_move_m': > > /src/qemu/target-cris/translate_v10.c:111:22: error: variable 'rd' set > > but not used [-Werror=unused-but-set-variable] > > > > Fix by making the variable declarations and their uses also conditional > > to debug definition, delete rd. > > > > Signed-off-by: Blue Swirl > > --- > > target-cris/op_helper.c | 6 ++++++ > > target-cris/translate_v10.c | 5 ++--- > > 2 files changed, 8 insertions(+), 3 deletions(-) > > > > diff --git a/target-cris/op_helper.c b/target-cris/op_helper.c > > index a60da94..28c79b1 100644 > > --- a/target-cris/op_helper.c > > +++ b/target-cris/op_helper.c > > @@ -142,7 +142,9 @@ void helper_movl_sreg_reg (uint32_t sreg, uint32_t reg) > > uint32_t idx; > > uint32_t lo, hi; > > uint32_t vaddr; > > +#ifdef CRIS_OP_HELPER_DEBUG > > int tlb_v; > > +#endif > > > > idx = set = env->sregs[SFR_RW_MM_TLB_SEL]; > > set >>= 4; > > @@ -157,13 +159,17 @@ void helper_movl_sreg_reg (uint32_t sreg, uint32_t reg) > > vaddr = EXTRACT_FIELD(env->tlbsets[srs-1][set][idx].hi, > > 13, 31); > > vaddr <<= TARGET_PAGE_BITS; > > +#ifdef CRIS_OP_HELPER_DEBUG > > tlb_v = EXTRACT_FIELD(env->tlbsets[srs-1][set][idx].lo, > > 3, 3); > > +#endif > > env->tlbsets[srs - 1][set][idx].lo = lo; > > env->tlbsets[srs - 1][set][idx].hi = hi; > > > > +#ifdef CRIS_OP_HELPER_DEBUG > > D_LOG("tlb flush vaddr=%x v=%d pc=%x\n", > > vaddr, tlb_v, env->pc); > > +#endif > > tlb_flush_page(env, vaddr); > > } > > } > > Could we eliminate the bothersome variable instead? > > diff --git a/target-cris/op_helper.c b/target-cris/op_helper.c > index a60da94..94e3e27 100644 > --- a/target-cris/op_helper.c > +++ b/target-cris/op_helper.c > @@ -142,7 +142,6 @@ void helper_movl_sreg_reg (uint32_t sreg, uint32_t reg) > uint32_t idx; > uint32_t lo, hi; > uint32_t vaddr; > - int tlb_v; > > idx = set = env->sregs[SFR_RW_MM_TLB_SEL]; > set >>= 4; > @@ -157,13 +156,14 @@ void helper_movl_sreg_reg (uint32_t sreg, uint32_t reg) > vaddr = EXTRACT_FIELD(env->tlbsets[srs-1][set][idx].hi, > 13, 31); > vaddr <<= TARGET_PAGE_BITS; > - tlb_v = EXTRACT_FIELD(env->tlbsets[srs-1][set][idx].lo, > + D_LOG("tlb flush vaddr=%x v=%d pc=%x\n", > + vaddr, > + EXTRACT_FIELD(env->tlbsets[srs-1][set][idx].lo, > 3, 3); > + env->pc); > env->tlbsets[srs - 1][set][idx].lo = lo; > env->tlbsets[srs - 1][set][idx].hi = hi; > > - D_LOG("tlb flush vaddr=%x v=%d pc=%x\n", > - vaddr, tlb_v, env->pc); > tlb_flush_page(env, vaddr); > } > } Hi, Sorry for the late answer. Markus, I agree that removing tlb_v would have been better than ifdefs, but i think that the intent I originally had in mind was that there should not be a need to flush the entry from the QEMU TLB if the old guest entry was not valid. The following patch works on my side: diff --git a/target-cris/op_helper.c b/target-cris/op_helper.c index a60da94..be9eb06 100644 --- a/target-cris/op_helper.c +++ b/target-cris/op_helper.c @@ -164,7 +164,9 @@ void helper_movl_sreg_reg (uint32_t sreg, uint32_t reg) D_LOG("tlb flush vaddr=%x v=%d pc=%x\n", vaddr, tlb_v, env->pc); - tlb_flush_page(env, vaddr); + if (tlb_v) { + tlb_flush_page(env, vaddr); + } } } #endif The target-cris/translate_v10.c hunk looks good. Blue, can you incorporate the tlb_v change in your patch set? Or if you prefer, I can commit that part on my side. Cheers