From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Poimboeuf Subject: Re: [PATCH RFC 5/5] arm64/speculation: Add support for 'cpu_spec_mitigations=' cmdline options Date: Fri, 5 Apr 2019 09:43:56 -0500 Message-ID: <20190405144356.zdi7fwoanz72xduh@treble> References: <5f70df57b19bbccc4a0d5d76134b4681c9a50b0b.1554396090.git.jpoimboe@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Steven Price Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Benjamin Herrenschmidt , Heiko Carstens , Paul Mackerras , "H . Peter Anvin" , Ingo Molnar , Andrea Arcangeli , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Will Deacon , Linus Torvalds , Catalin Marinas , Waiman Long , linux-arch@vger.kernel.org, Jon Masters , Jiri Kosina , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.i List-Id: linux-arch.vger.kernel.org On Fri, Apr 05, 2019 at 03:39:58PM +0100, Steven Price wrote: > On 04/04/2019 17:44, Josh Poimboeuf wrote: > > Configure arm64 runtime CPU speculation bug mitigations in accordance > > with the 'cpu_spec_mitigations=' cmdline options. This affects > > Meltdown and Speculative Store Bypass. > > > > The default behavior is unchanged. > > > > Signed-off-by: Josh Poimboeuf > > --- > > Documentation/admin-guide/kernel-parameters.txt | 2 ++ > > arch/arm64/kernel/cpu_errata.c | 4 ++++ > > arch/arm64/kernel/cpufeature.c | 6 ++++++ > > 3 files changed, 12 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index e838af96daa4..0b54385ee7a8 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2553,11 +2553,13 @@ > > off > > Disable all speculative CPU mitigations. > > Equivalent to: nopti [x86, powerpc] > > + kpti=0 [arm64] > > nospectre_v1 [powerpc] > > nospectre_v2 [x86, powerpc, s390] > > spectre_v2_user=off [x86] > > nobp=0 [s390] > > spec_store_bypass_disable=off [x86, powerpc] > > + ssbd=force-off [arm64] > > l1tf=off [x86] > > > > auto (default) > > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > > index 9950bb0cbd52..db8d27e3fb1c 100644 > > --- a/arch/arm64/kernel/cpu_errata.c > > +++ b/arch/arm64/kernel/cpu_errata.c > > @@ -19,6 +19,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -385,6 +386,9 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, > > return false; > > } > > > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > > + ssbd_state = ARM64_SSBD_FORCE_DISABLE; > > + > > switch (psci_ops.conduit) { > > case PSCI_CONDUIT_HVC: > > arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > > index 4061de10cea6..4512b582d50f 100644 > > --- a/arch/arm64/kernel/cpufeature.c > > +++ b/arch/arm64/kernel/cpufeature.c > > @@ -25,6 +25,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -978,6 +979,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, > > __kpti_forced = -1; > > } > > > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) { > > + str = "cpu_spec_mitigations=off"; > > Might also be worth changing the initialisation of str, currently it is: > > > char const *str = "command line option"; > > But now we have two command line options, perhaps "kpti command line > option". Yes, agreed, thanks. -- Josh From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:13287 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726291AbfDEOoG (ORCPT ); Fri, 5 Apr 2019 10:44:06 -0400 Date: Fri, 5 Apr 2019 09:43:56 -0500 From: Josh Poimboeuf Subject: Re: [PATCH RFC 5/5] arm64/speculation: Add support for 'cpu_spec_mitigations=' cmdline options Message-ID: <20190405144356.zdi7fwoanz72xduh@treble> References: <5f70df57b19bbccc4a0d5d76134b4681c9a50b0b.1554396090.git.jpoimboe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Steven Price Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Benjamin Herrenschmidt , Heiko Carstens , Paul Mackerras , "H . Peter Anvin" , Ingo Molnar , Andrea Arcangeli , linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Will Deacon , Linus Torvalds , Catalin Marinas , Waiman Long , linux-arch@vger.kernel.org, Jon Masters , Jiri Kosina , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman , Tyler Hicks , Martin Schwidefsky , linuxppc-dev@lists.ozlabs.org Message-ID: <20190405144356.9p1BhXsIjOJE5oKY8oqxUMAecWPbYA158YjKfCNCYAk@z> On Fri, Apr 05, 2019 at 03:39:58PM +0100, Steven Price wrote: > On 04/04/2019 17:44, Josh Poimboeuf wrote: > > Configure arm64 runtime CPU speculation bug mitigations in accordance > > with the 'cpu_spec_mitigations=' cmdline options. This affects > > Meltdown and Speculative Store Bypass. > > > > The default behavior is unchanged. > > > > Signed-off-by: Josh Poimboeuf > > --- > > Documentation/admin-guide/kernel-parameters.txt | 2 ++ > > arch/arm64/kernel/cpu_errata.c | 4 ++++ > > arch/arm64/kernel/cpufeature.c | 6 ++++++ > > 3 files changed, 12 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index e838af96daa4..0b54385ee7a8 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2553,11 +2553,13 @@ > > off > > Disable all speculative CPU mitigations. > > Equivalent to: nopti [x86, powerpc] > > + kpti=0 [arm64] > > nospectre_v1 [powerpc] > > nospectre_v2 [x86, powerpc, s390] > > spectre_v2_user=off [x86] > > nobp=0 [s390] > > spec_store_bypass_disable=off [x86, powerpc] > > + ssbd=force-off [arm64] > > l1tf=off [x86] > > > > auto (default) > > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > > index 9950bb0cbd52..db8d27e3fb1c 100644 > > --- a/arch/arm64/kernel/cpu_errata.c > > +++ b/arch/arm64/kernel/cpu_errata.c > > @@ -19,6 +19,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -385,6 +386,9 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, > > return false; > > } > > > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > > + ssbd_state = ARM64_SSBD_FORCE_DISABLE; > > + > > switch (psci_ops.conduit) { > > case PSCI_CONDUIT_HVC: > > arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > > index 4061de10cea6..4512b582d50f 100644 > > --- a/arch/arm64/kernel/cpufeature.c > > +++ b/arch/arm64/kernel/cpufeature.c > > @@ -25,6 +25,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -978,6 +979,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, > > __kpti_forced = -1; > > } > > > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) { > > + str = "cpu_spec_mitigations=off"; > > Might also be worth changing the initialisation of str, currently it is: > > > char const *str = "command line option"; > > But now we have two command line options, perhaps "kpti command line > option". Yes, agreed, thanks. -- Josh