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Message-Id: <20201124155039.13804-14-will@kernel.org>
Date: Tue, 24 Nov 2020 15:50:38 +0000
From: Will Deacon <will@...nel.org>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Marc Zyngier <maz@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Morten Rasmussen <morten.rasmussen@....com>,
Qais Yousef <qais.yousef@....com>,
Suren Baghdasaryan <surenb@...gle.com>,
Quentin Perret <qperret@...gle.com>, Tejun Heo <tj@...nel.org>,
Li Zefan <lizefan@...wei.com>,
Johannes Weiner <hannes@...xchg.org>,
Ingo Molnar <mingo@...hat.com>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
kernel-team@...roid.com
Subject: [PATCH v4 13/14] arm64: Implement arch_task_cpu_possible_mask()
Provide an implementation of arch_task_cpu_possible_mask() so that we
can prevent 64-bit-only cores being added to the 'cpus_mask' for compat
tasks on systems with mismatched 32-bit support at EL0,
Signed-off-by: Will Deacon <will@...nel.org>
---
arch/arm64/include/asm/mmu_context.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 0672236e1aea..641dff35a56f 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -251,6 +251,19 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev,next) switch_mm(prev, next, current)
+static inline const struct cpumask *
+arch_task_cpu_possible_mask(struct task_struct *p)
+{
+ if (!static_branch_unlikely(&arm64_mismatched_32bit_el0))
+ return cpu_possible_mask;
+
+ if (!is_compat_thread(task_thread_info(p)))
+ return cpu_possible_mask;
+
+ return system_32bit_el0_cpumask();
+}
+#define arch_task_cpu_possible_mask arch_task_cpu_possible_mask
+
void verify_cpu_asid_bits(void);
void post_ttbr_update_workaround(void);
--
2.29.2.454.gaff20da3a2-goog
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