From: Will Deacon <will@kernel.org> To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@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>, kernel-team@android.com Subject: [PATCH v2 5/6] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Date: Mon, 9 Nov 2020 21:30:21 +0000 [thread overview] Message-ID: <20201109213023.15092-6-will@kernel.org> (raw) In-Reply-To: <20201109213023.15092-1-will@kernel.org> Since 32-bit applications will be killed if they are caught trying to execute on a 64-bit-only CPU in a mismatched system, advertise the set of 32-bit capable CPUs to userspace in sysfs. Signed-off-by: Will Deacon <will@kernel.org> --- .../ABI/testing/sysfs-devices-system-cpu | 9 +++++++++ arch/arm64/kernel/cpufeature.c | 19 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 1a04ca8162ad..8a2e377b0dde 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -493,6 +493,15 @@ Description: AArch64 CPU registers 'identification' directory exposes the CPU ID registers for identifying model and revision of the CPU. +What: /sys/devices/system/cpu/aarch32_el0 +Date: November 2020 +Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org> +Description: Identifies the subset of CPUs in the system that can execute + AArch32 (32-bit ARM) applications. If present, the same format as + /sys/devices/system/cpu/{offline,online,possible,present} is used. + If absent, then all or none of the CPUs can execute AArch32 + applications and execve() will behave accordingly. + What: /sys/devices/system/cpu/cpu#/cpu_capacity Date: December 2016 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 264998972627..c90f4a18768c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -67,6 +67,7 @@ #include <linux/crash_dump.h> #include <linux/sort.h> #include <linux/stop_machine.h> +#include <linux/sysfs.h> #include <linux/types.h> #include <linux/mm.h> #include <linux/cpu.h> @@ -1269,6 +1270,24 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_present_mask; } +static ssize_t aarch32_el0_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct cpumask *mask = system_32bit_el0_cpumask(); + + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask)); +} +static const DEVICE_ATTR_RO(aarch32_el0); + +static int __init aarch32_el0_sysfs_init(void) +{ + if (!allow_mismatched_32bit_el0) + return 0; + + return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0); +} +device_initcall(aarch32_el0_sysfs_init); + static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope) { if (!has_cpuid_feature(entry, scope)) -- 2.29.2.222.g5d2a92d10f8-goog
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org> To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, Marc Zyngier <maz@kernel.org>, kernel-team@android.com, Quentin Perret <qperret@google.com>, Peter Zijlstra <peterz@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Qais Yousef <qais.yousef@arm.com>, Suren Baghdasaryan <surenb@google.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Will Deacon <will@kernel.org>, Morten Rasmussen <morten.rasmussen@arm.com> Subject: [PATCH v2 5/6] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Date: Mon, 9 Nov 2020 21:30:21 +0000 [thread overview] Message-ID: <20201109213023.15092-6-will@kernel.org> (raw) In-Reply-To: <20201109213023.15092-1-will@kernel.org> Since 32-bit applications will be killed if they are caught trying to execute on a 64-bit-only CPU in a mismatched system, advertise the set of 32-bit capable CPUs to userspace in sysfs. Signed-off-by: Will Deacon <will@kernel.org> --- .../ABI/testing/sysfs-devices-system-cpu | 9 +++++++++ arch/arm64/kernel/cpufeature.c | 19 +++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 1a04ca8162ad..8a2e377b0dde 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -493,6 +493,15 @@ Description: AArch64 CPU registers 'identification' directory exposes the CPU ID registers for identifying model and revision of the CPU. +What: /sys/devices/system/cpu/aarch32_el0 +Date: November 2020 +Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org> +Description: Identifies the subset of CPUs in the system that can execute + AArch32 (32-bit ARM) applications. If present, the same format as + /sys/devices/system/cpu/{offline,online,possible,present} is used. + If absent, then all or none of the CPUs can execute AArch32 + applications and execve() will behave accordingly. + What: /sys/devices/system/cpu/cpu#/cpu_capacity Date: December 2016 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 264998972627..c90f4a18768c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -67,6 +67,7 @@ #include <linux/crash_dump.h> #include <linux/sort.h> #include <linux/stop_machine.h> +#include <linux/sysfs.h> #include <linux/types.h> #include <linux/mm.h> #include <linux/cpu.h> @@ -1269,6 +1270,24 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_present_mask; } +static ssize_t aarch32_el0_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const struct cpumask *mask = system_32bit_el0_cpumask(); + + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(mask)); +} +static const DEVICE_ATTR_RO(aarch32_el0); + +static int __init aarch32_el0_sysfs_init(void) +{ + if (!allow_mismatched_32bit_el0) + return 0; + + return device_create_file(cpu_subsys.dev_root, &dev_attr_aarch32_el0); +} +device_initcall(aarch32_el0_sysfs_init); + static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope) { if (!has_cpuid_feature(entry, scope)) -- 2.29.2.222.g5d2a92d10f8-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-09 21:30 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-09 21:30 [PATCH v2 0/6] An alternative series for asymmetric AArch32 systems Will Deacon 2020-11-09 21:30 ` Will Deacon 2020-11-09 21:30 ` [PATCH v2 1/6] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon 2020-11-09 21:30 ` Will Deacon 2020-11-09 21:30 ` [PATCH v2 2/6] arm64: Allow mismatched 32-bit EL0 support Will Deacon 2020-11-09 21:30 ` Will Deacon 2020-11-11 19:10 ` Catalin Marinas 2020-11-11 19:10 ` Catalin Marinas 2020-11-13 9:36 ` Will Deacon 2020-11-13 9:36 ` Will Deacon 2020-11-13 10:26 ` Catalin Marinas 2020-11-13 10:26 ` Catalin Marinas 2020-11-09 21:30 ` [PATCH v2 3/6] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon 2020-11-09 21:30 ` Will Deacon 2020-11-10 9:33 ` Marc Zyngier 2020-11-10 9:33 ` Marc Zyngier 2020-11-09 21:30 ` [PATCH v2 4/6] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon 2020-11-09 21:30 ` Will Deacon 2020-11-09 21:30 ` Will Deacon [this message] 2020-11-09 21:30 ` [PATCH v2 5/6] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon 2020-11-10 7:04 ` Greg Kroah-Hartman 2020-11-10 7:04 ` Greg Kroah-Hartman 2020-11-10 9:28 ` Catalin Marinas 2020-11-10 9:28 ` Catalin Marinas 2020-11-10 9:36 ` Greg Kroah-Hartman 2020-11-10 9:36 ` Greg Kroah-Hartman 2020-11-10 9:53 ` Marc Zyngier 2020-11-10 9:53 ` Marc Zyngier 2020-11-10 10:10 ` Greg Kroah-Hartman 2020-11-10 10:10 ` Greg Kroah-Hartman 2020-11-10 10:46 ` Marc Zyngier 2020-11-10 10:46 ` Marc Zyngier 2020-11-10 10:57 ` Catalin Marinas 2020-11-10 10:57 ` Catalin Marinas 2020-11-09 21:30 ` [PATCH v2 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon 2020-11-09 21:30 ` Will Deacon
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