[PATCH v6 16/21] arm64: Implement task_cpu_possible_mask()
From: Will Deacon <will@kernel.org>
Date: 2021-05-18 09:49:28
Also in:
linux-arm-kernel, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Provide an implementation of 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@kernel.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 d3cef9133539..bb9b7510f334 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h@@ -231,6 +231,19 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, update_saved_ttbr0(tsk, next); } +static inline const struct cpumask * +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 task_cpu_possible_mask task_cpu_possible_mask + void verify_cpu_asid_bits(void); void post_ttbr_update_workaround(void);
--
2.31.1.751.gd2f1c929bd-goog