From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [RFC PATCH 1/2] powerpc: Add a CPU feature bit for TM bug workarounds on POWER9 DD2.2 Date: Fri, 08 Dec 2017 09:15:14 -0600 Message-ID: <1512746114.9405.27.camel@au1.ibm.com> References: <20171208060803.relvzabipgl2lub6@rohan> <20171208060924.fthehkna7bsnjowx@rohan> Reply-To: benh@au1.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Gibson , Nick Piggin To: Paul Mackerras , linuxppc-dev@ozlabs.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41632 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753567AbdLHPP1 (ORCPT ); Fri, 8 Dec 2017 10:15:27 -0500 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vB8FAvjh144343 for ; Fri, 8 Dec 2017 10:15:26 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0b-001b2d01.pphosted.com with ESMTP id 2eqvyd8wvy-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 08 Dec 2017 10:15:26 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 8 Dec 2017 15:15:24 -0000 In-Reply-To: <20171208060924.fthehkna7bsnjowx@rohan> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, 2017-12-08 at 17:09 +1100, Paul Mackerras wrote: > This adds a CPU feature bit which is set for POWER9 DD2.2 processors > which will be used to enable software emulation for some transactional > memory instructions, in order to work around hardware bugs. The worry here is backward compatibility as we don't know yet which processor will fix it (if ever). Paul and Nick, can you also add it to the "new" CPU features mechanism (which we should enable now) so that we at least have a way to control this from firmware ? > Signed-off-by: Paul Mackerras > --- > arch/powerpc/include/asm/cputable.h | 5 ++++- > arch/powerpc/kernel/cputable.c | 20 ++++++++++++++++++++ > 2 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h > index 53b31c2bcdf4..70cee46c046c 100644 > --- a/arch/powerpc/include/asm/cputable.h > +++ b/arch/powerpc/include/asm/cputable.h > @@ -215,6 +215,7 @@ enum { > #define CPU_FTR_DAWR LONG_ASM_CONST(0x0400000000000000) > #define CPU_FTR_DABRX LONG_ASM_CONST(0x0800000000000000) > #define CPU_FTR_PMAO_BUG LONG_ASM_CONST(0x1000000000000000) > +#define CPU_FTR_P9_TM_EMUL LONG_ASM_CONST(0x2000000000000000) > #define CPU_FTR_POWER9_DD1 LONG_ASM_CONST(0x4000000000000000) > > #ifndef __ASSEMBLY__ > @@ -478,6 +479,7 @@ enum { > CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_ARCH_300) > #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \ > (~CPU_FTR_SAO)) > +#define CPU_FTRS_POWER9_DD2_2 (CPU_FTRS_POWER9 | CPU_FTR_P9_TM_EMUL) > #define CPU_FTRS_CELL (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \ > CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \ > CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \ > @@ -496,7 +498,8 @@ enum { > (CPU_FTRS_POWER4 | CPU_FTRS_PPC970 | CPU_FTRS_POWER5 | \ > CPU_FTRS_POWER6 | CPU_FTRS_POWER7 | CPU_FTRS_POWER8E | \ > CPU_FTRS_POWER8 | CPU_FTRS_POWER8_DD1 | CPU_FTRS_CELL | \ > - CPU_FTRS_PA6T | CPU_FTR_VSX | CPU_FTRS_POWER9 | CPU_FTRS_POWER9_DD1) > + CPU_FTRS_PA6T | CPU_FTR_VSX | CPU_FTRS_POWER9 | \ > + CPU_FTRS_POWER9_DD1 | CPU_FTRS_POWER9_DD2_2) > #endif > #else > enum { > diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c > index 760872916013..bb94bb6d9e4d 100644 > --- a/arch/powerpc/kernel/cputable.c > +++ b/arch/powerpc/kernel/cputable.c > @@ -547,6 +547,26 @@ static struct cpu_spec __initdata cpu_specs[] = { > .machine_check_early = __machine_check_early_realmode_p9, > .platform = "power9", > }, > + { /* Power9 DD2.2 */ > + .pvr_mask = 0xffffffff, > + .pvr_value = 0x004e1202, > + .cpu_name = "POWER9 (raw)", > + .cpu_features = CPU_FTRS_POWER9_DD2_2, > + .cpu_user_features = COMMON_USER_POWER9, > + .cpu_user_features2 = COMMON_USER2_POWER9, > + .mmu_features = MMU_FTRS_POWER9, > + .icache_bsize = 128, > + .dcache_bsize = 128, > + .num_pmcs = 6, > + .pmc_type = PPC_PMC_IBM, > + .oprofile_cpu_type = "ppc64/power9", > + .oprofile_type = PPC_OPROFILE_INVALID, > + .cpu_setup = __setup_cpu_power9, > + .cpu_restore = __restore_cpu_power9, > + .flush_tlb = __flush_tlb_power9, > + .machine_check_early = __machine_check_early_realmode_p9, > + .platform = "power9", > + }, > { /* Power9 */ > .pvr_mask = 0xffff0000, > .pvr_value = 0x004e0000,