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 v10 11/16] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Wed, 23 Jun 2021 18:38:43 +0100 [thread overview] Message-ID: <20210623173848.318-12-will@kernel.org> (raw) In-Reply-To: <20210623173848.318-1-will@kernel.org> When exec'ing a 32-bit task on a system with mismatched support for 32-bit EL0, try to ensure that it starts life on a CPU that can actually run it. Similarly, when exec'ing a 64-bit task on such a system, try to restore the old affinity mask if it was previously restricted. Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Reviewed-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/elf.h | 6 ++---- arch/arm64/kernel/process.c | 39 +++++++++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 8d1c8dcb87fd..97932fbf973d 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -213,10 +213,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; /* AArch32 EABI. */ #define EF_ARM_EABI_MASK 0xff000000 -#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \ - ((x)->e_machine == EM_ARM) && \ - ((x)->e_flags & EF_ARM_EABI_MASK)) - +int compat_elf_check_arch(const struct elf32_hdr *); +#define compat_elf_check_arch compat_elf_check_arch #define compat_start_thread compat_start_thread /* * Unlike the native SET_PERSONALITY macro, the compat version maintains diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index f4a91bf1ce0c..220134888d7e 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -22,6 +22,7 @@ #include <linux/mman.h> #include <linux/mm.h> #include <linux/nospec.h> +#include <linux/sched.h> #include <linux/stddef.h> #include <linux/sysctl.h> #include <linux/unistd.h> @@ -638,6 +639,28 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } +#ifdef CONFIG_COMPAT +int compat_elf_check_arch(const struct elf32_hdr *hdr) +{ + if (!system_supports_32bit_el0()) + return false; + + if ((hdr)->e_machine != EM_ARM) + return false; + + if (!((hdr)->e_flags & EF_ARM_EABI_MASK)) + return false; + + /* + * Prevent execve() of a 32-bit program from a deadline task + * if the restricted affinity mask would be inadmissible on an + * asymmetric system. + */ + return !static_branch_unlikely(&arm64_mismatched_32bit_el0) || + !dl_task_check_affinity(current, system_32bit_el0_cpumask()); +} +#endif + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ @@ -647,8 +670,22 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + + /* + * Restrict the CPU affinity mask for a 32-bit task so that + * it contains only 32-bit-capable CPUs. + * + * From the perspective of the task, this looks similar to + * what would happen if the 64-bit-only CPUs were hot-unplugged + * at the point of execve(), although we try a bit harder to + * honour the cpuset hierarchy. + */ + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + force_compatible_cpus_allowed_ptr(current); set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + } else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + relax_compatible_cpus_allowed_ptr(current); } current->mm->context.flags = mmflags; -- 2.32.0.93.g670b81a890-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, 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 v10 11/16] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Wed, 23 Jun 2021 18:38:43 +0100 [thread overview] Message-ID: <20210623173848.318-12-will@kernel.org> (raw) In-Reply-To: <20210623173848.318-1-will@kernel.org> When exec'ing a 32-bit task on a system with mismatched support for 32-bit EL0, try to ensure that it starts life on a CPU that can actually run it. Similarly, when exec'ing a 64-bit task on such a system, try to restore the old affinity mask if it was previously restricted. Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Reviewed-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/elf.h | 6 ++---- arch/arm64/kernel/process.c | 39 +++++++++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index 8d1c8dcb87fd..97932fbf973d 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -213,10 +213,8 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; /* AArch32 EABI. */ #define EF_ARM_EABI_MASK 0xff000000 -#define compat_elf_check_arch(x) (system_supports_32bit_el0() && \ - ((x)->e_machine == EM_ARM) && \ - ((x)->e_flags & EF_ARM_EABI_MASK)) - +int compat_elf_check_arch(const struct elf32_hdr *); +#define compat_elf_check_arch compat_elf_check_arch #define compat_start_thread compat_start_thread /* * Unlike the native SET_PERSONALITY macro, the compat version maintains diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index f4a91bf1ce0c..220134888d7e 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -22,6 +22,7 @@ #include <linux/mman.h> #include <linux/mm.h> #include <linux/nospec.h> +#include <linux/sched.h> #include <linux/stddef.h> #include <linux/sysctl.h> #include <linux/unistd.h> @@ -638,6 +639,28 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } +#ifdef CONFIG_COMPAT +int compat_elf_check_arch(const struct elf32_hdr *hdr) +{ + if (!system_supports_32bit_el0()) + return false; + + if ((hdr)->e_machine != EM_ARM) + return false; + + if (!((hdr)->e_flags & EF_ARM_EABI_MASK)) + return false; + + /* + * Prevent execve() of a 32-bit program from a deadline task + * if the restricted affinity mask would be inadmissible on an + * asymmetric system. + */ + return !static_branch_unlikely(&arm64_mismatched_32bit_el0) || + !dl_task_check_affinity(current, system_32bit_el0_cpumask()); +} +#endif + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ @@ -647,8 +670,22 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + + /* + * Restrict the CPU affinity mask for a 32-bit task so that + * it contains only 32-bit-capable CPUs. + * + * From the perspective of the task, this looks similar to + * what would happen if the 64-bit-only CPUs were hot-unplugged + * at the point of execve(), although we try a bit harder to + * honour the cpuset hierarchy. + */ + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + force_compatible_cpus_allowed_ptr(current); set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } + } else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + relax_compatible_cpus_allowed_ptr(current); } current->mm->context.flags = mmflags; -- 2.32.0.93.g670b81a890-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:[~2021-06-23 17:39 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-23 17:38 [PATCH v10 00/16] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 01/16] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 02/16] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 03/16] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 04/16] cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 05/16] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 06/16] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 07/16] sched: Split the guts of sched_setaffinity() into a helper function Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 08/16] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 09/16] sched: Introduce dl_task_check_affinity() to check proposed affinity Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 10/16] arm64: Implement task_cpu_possible_mask() Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` Will Deacon [this message] 2021-06-23 17:38 ` [PATCH v10 11/16] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon 2021-06-23 17:38 ` [PATCH v10 12/16] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 13/16] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-25 8:46 ` Greg Kroah-Hartman 2021-06-25 8:46 ` Greg Kroah-Hartman 2021-06-25 9:36 ` Will Deacon 2021-06-25 9:36 ` Will Deacon 2021-06-25 9:49 ` Greg Kroah-Hartman 2021-06-25 9:49 ` Greg Kroah-Hartman 2021-06-23 17:38 ` [PATCH v10 14/16] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 15/16] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon 2021-06-23 17:38 ` Will Deacon 2021-06-23 17:38 ` [PATCH v10 16/16] Documentation: arm64: describe asymmetric 32-bit support Will Deacon 2021-06-23 17:38 ` Will Deacon
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