From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bkNYg-0005tU-CF for qemu-devel@nongnu.org; Wed, 14 Sep 2016 23:41:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bkNYe-0004lG-3L for qemu-devel@nongnu.org; Wed, 14 Sep 2016 23:41:53 -0400 Date: Thu, 15 Sep 2016 11:07:35 +1000 From: David Gibson Message-ID: <20160915010735.GI15077@voom.fritz.box> References: <1473662506-27441-1-git-send-email-nikunj@linux.vnet.ibm.com> <1473662506-27441-12-git-send-email-nikunj@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Er/3qITiDpnrteFh" Content-Disposition: inline In-Reply-To: <1473662506-27441-12-git-send-email-nikunj@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH RESEND v2 11/17] target-ppc: implement darn instruction List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nikunj A Dadhania Cc: qemu-ppc@nongnu.org, rth@twiddle.net, qemu-devel@nongnu.org, benh@kernel.crashing.org, Ravi Bangoria --Er/3qITiDpnrteFh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Sep 12, 2016 at 12:11:40PM +0530, Nikunj A Dadhania wrote: > From: Ravi Bangoria >=20 > darn: Deliver A Random Number >=20 > Currently return invalid random number for all the case. This needs > proper algorithm to provide cryptographically suitable random data. > Reading from /dev/random can block and that is not an expected behaviour > while the cpu instruction is getting executed. Moreover, /dev/random > would only work for linux-user >=20 > Signed-off-by: Ravi Bangoria > Signed-off-by: Nikunj A Dadhania > --- > target-ppc/helper.h | 2 ++ > target-ppc/int_helper.c | 16 ++++++++++++++++ > target-ppc/translate.c | 18 ++++++++++++++++++ > 3 files changed, 36 insertions(+) >=20 > diff --git a/target-ppc/helper.h b/target-ppc/helper.h > index e75d070..966f2ce 100644 > --- a/target-ppc/helper.h > +++ b/target-ppc/helper.h > @@ -50,6 +50,8 @@ DEF_HELPER_FLAGS_1(cnttzd, TCG_CALL_NO_RWG_SE, tl, tl) > DEF_HELPER_FLAGS_1(popcntd, TCG_CALL_NO_RWG_SE, tl, tl) > DEF_HELPER_FLAGS_2(bpermd, TCG_CALL_NO_RWG_SE, i64, i64, i64) > DEF_HELPER_3(srad, tl, env, tl, tl) > +DEF_HELPER_0(darn32, tl) > +DEF_HELPER_0(darn64, tl) > #endif > =20 > DEF_HELPER_FLAGS_1(cntlsw32, TCG_CALL_NO_RWG_SE, i32, i32) > diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c > index 291fba0..51a9ac5 100644 > --- a/target-ppc/int_helper.c > +++ b/target-ppc/int_helper.c > @@ -182,6 +182,22 @@ target_ulong helper_cnttzd(target_ulong t) > { > return ctz64(t); > } > + > +/* Return invalid random number. > + * > + * FIXME: Add rng backend or other mechanism to get cryptographically su= itable > + * random number > + */ > +target_ulong helper_darn32(void) > +{ > + return -1; > +} > + > +target_ulong helper_darn64(void) > +{ > + return -1; > +} > + TBH, I think you're going to want a single helper for both 32-bit and 64-bit cases. > #endif > =20 > #if defined(TARGET_PPC64) > diff --git a/target-ppc/translate.c b/target-ppc/translate.c > index 133c531..e9dad3f 100644 > --- a/target-ppc/translate.c > +++ b/target-ppc/translate.c > @@ -528,6 +528,8 @@ EXTRACT_HELPER(FPW, 16, 1); > =20 > /* addpcis */ > EXTRACT_HELPER_DXFORM(DX, 10, 6, 6, 5, 16, 1, 1, 0, 0) > +/* darn */ > +EXTRACT_HELPER(L, 16, 2); > =20 > /*** Jump target decoding = ***/ > /* Immediate address */ > @@ -1895,6 +1897,21 @@ static void gen_cnttzd(DisasContext *ctx) > gen_set_Rc0(ctx, cpu_gpr[rA(ctx->opcode)]); > } > } > + > +/* darn */ > +static void gen_darn(DisasContext *ctx) > +{ > + int l =3D L(ctx->opcode); > + > + if (l =3D=3D 0) { > + gen_helper_darn32(cpu_gpr[rD(ctx->opcode)]); > + } else if (l <=3D 2) { > + /* Return 64-bit random for both CRN and RRN */ > + gen_helper_darn64(cpu_gpr[rD(ctx->opcode)]); So it might be simpler to just leave out the helper stubs for now, and always return the invalid value from the generated code. > + } else { > + tcg_gen_movi_i64(cpu_gpr[rD(ctx->opcode)], -1); > + } > +} > #endif > =20 > /*** Integer rotate = ***/ > @@ -6212,6 +6229,7 @@ GEN_HANDLER_E(prtyw, 0x1F, 0x1A, 0x04, 0x0000F801, = PPC_NONE, PPC2_ISA205), > GEN_HANDLER(popcntd, 0x1F, 0x1A, 0x0F, 0x0000F801, PPC_POPCNTWD), > GEN_HANDLER(cntlzd, 0x1F, 0x1A, 0x01, 0x00000000, PPC_64B), > GEN_HANDLER_E(cnttzd, 0x1F, 0x1A, 0x11, 0x00000000, PPC_NONE, PPC2_ISA30= 0), > +GEN_HANDLER_E(darn, 0x1F, 0x13, 0x17, 0x001CF801, PPC_NONE, PPC2_ISA300), > GEN_HANDLER_E(prtyd, 0x1F, 0x1A, 0x05, 0x0000F801, PPC_NONE, PPC2_ISA205= ), > GEN_HANDLER_E(bpermd, 0x1F, 0x1C, 0x07, 0x00000001, PPC_NONE, PPC2_PERM_= ISA206), > #endif --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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