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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com
Subject: [PATCH v9 18/20] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
Date: Tue,  8 Jun 2021 19:03:11 +0100	[thread overview]
Message-ID: <20210608180313.11502-19-will@kernel.org> (raw)
In-Reply-To: <20210608180313.11502-1-will@kernel.org>

Allow systems with mismatched 32-bit support at EL0 to run 32-bit
applications based on a new kernel parameter.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
 arch/arm64/kernel/cpufeature.c                  | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb89dbdedc46..a2e453919bb6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -287,6 +287,14 @@
 			do not want to use tracing_snapshot_alloc() as it needs
 			to be done where GFP_KERNEL allocations are allowed.
 
+	allow_mismatched_32bit_el0 [ARM64]
+			Allow execve() of 32-bit applications and setting of the
+			PER_LINUX32 personality on systems where only a strict
+			subset of the CPUs support 32-bit EL0. When this
+			parameter is present, the set of CPUs supporting 32-bit
+			EL0 is indicated by /sys/devices/system/cpu/aarch32_el0
+			and hot-unplug operations may be restricted.
+
 	amd_iommu=	[HW,X86-64]
 			Pass parameters to the AMD IOMMU driver in the system.
 			Possible values are:
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 854ade5b1de1..6f4aa006f130 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1298,6 +1298,13 @@ const struct cpumask *system_32bit_el0_cpumask(void)
 	return cpu_possible_mask;
 }
 
+static int __init parse_32bit_el0_param(char *str)
+{
+	allow_mismatched_32bit_el0 = true;
+	return 0;
+}
+early_param("allow_mismatched_32bit_el0", parse_32bit_el0_param);
+
 static ssize_t aarch32_el0_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
-- 
2.32.0.rc1.229.g3e70b5a671-goog


WARNING: multiple messages have this Message-ID
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com
Subject: [PATCH v9 18/20] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
Date: Tue,  8 Jun 2021 19:03:11 +0100	[thread overview]
Message-ID: <20210608180313.11502-19-will@kernel.org> (raw)
In-Reply-To: <20210608180313.11502-1-will@kernel.org>

Allow systems with mismatched 32-bit support at EL0 to run 32-bit
applications based on a new kernel parameter.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
 arch/arm64/kernel/cpufeature.c                  | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb89dbdedc46..a2e453919bb6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -287,6 +287,14 @@
 			do not want to use tracing_snapshot_alloc() as it needs
 			to be done where GFP_KERNEL allocations are allowed.
 
+	allow_mismatched_32bit_el0 [ARM64]
+			Allow execve() of 32-bit applications and setting of the
+			PER_LINUX32 personality on systems where only a strict
+			subset of the CPUs support 32-bit EL0. When this
+			parameter is present, the set of CPUs supporting 32-bit
+			EL0 is indicated by /sys/devices/system/cpu/aarch32_el0
+			and hot-unplug operations may be restricted.
+
 	amd_iommu=	[HW,X86-64]
 			Pass parameters to the AMD IOMMU driver in the system.
 			Possible values are:
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 854ade5b1de1..6f4aa006f130 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1298,6 +1298,13 @@ const struct cpumask *system_32bit_el0_cpumask(void)
 	return cpu_possible_mask;
 }
 
+static int __init parse_32bit_el0_param(char *str)
+{
+	allow_mismatched_32bit_el0 = true;
+	return 0;
+}
+early_param("allow_mismatched_32bit_el0", parse_32bit_el0_param);
+
 static ssize_t aarch32_el0_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
-- 
2.32.0.rc1.229.g3e70b5a671-goog


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  parent reply	other threads:[~2021-06-08 18:04 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 18:02 [PATCH v9 00/20] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-06-08 18:02 ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 01/20] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 02/20] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 03/20] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 04/20] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 05/20] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 06/20] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-10 12:59   ` Valentin Schneider
2021-06-10 12:59     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 07/20] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 08/20] cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-10 12:59   ` Valentin Schneider
2021-06-10 12:59     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 09/20] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 10/20] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 11/20] sched: Split the guts of sched_setaffinity() into a helper function Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 12/20] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-10 13:00   ` Valentin Schneider
2021-06-10 13:00     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 13/20] sched: Introduce dl_task_check_affinity() to check proposed affinity Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 14/20] arm64: Implement task_cpu_possible_mask() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 15/20] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 16/20] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 17/20] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` Will Deacon [this message]
2021-06-08 18:03   ` [PATCH v9 18/20] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2021-06-08 18:03 ` [PATCH v9 19/20] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 20/20] Documentation: arm64: describe asymmetric 32-bit support Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-11 16:15 ` [PATCH v9 00/20] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-06-11 16:15   ` Will Deacon

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