18ed1c01a7
Now that we no longer rely on thread_info living at the base of the task stack to be able to access the 'current' pointer, we can wire up the generic support for moving thread_info into the task struct itself. Note that this requires us to update the cpu field in thread_info explicitly, now that the core code no longer does so. Ideally, we would switch the percpu code to access the cpu field in task_struct instead, but this unleashes #include circular dependency hell. Co-developed-by: Keith Packard <keithpac@amazon.com> Signed-off-by: Keith Packard <keithpac@amazon.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_ARM_SWITCH_TO_H
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#define __ASM_ARM_SWITCH_TO_H
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#include <linux/thread_info.h>
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/*
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* For v7 SMP cores running a preemptible kernel we may be pre-empted
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* during a TLB maintenance operation, so execute an inner-shareable dsb
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* to ensure that the maintenance completes in case we migrate to another
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* CPU.
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*/
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#if defined(CONFIG_PREEMPTION) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
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#define __complete_pending_tlbi() dsb(ish)
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#else
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#define __complete_pending_tlbi()
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#endif
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/*
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* switch_to(prev, next) should switch from task `prev' to `next'
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* `prev' will never be the same as `next'. schedule() itself
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* contains the memory barrier to tell GCC not to cache `current'.
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*/
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extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);
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static inline void set_ti_cpu(struct task_struct *p)
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{
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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/*
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* The core code no longer maintains the thread_info::cpu field once
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* CONFIG_THREAD_INFO_IN_TASK is in effect, but we rely on it for
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* raw_smp_processor_id(), which cannot access struct task_struct*
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* directly for reasons of circular #inclusion hell.
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*/
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task_thread_info(p)->cpu = task_cpu(p);
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#endif
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}
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#define switch_to(prev,next,last) \
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do { \
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__complete_pending_tlbi(); \
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set_ti_cpu(next); \
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if (IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO)) \
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__this_cpu_write(__entry_task, next); \
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last = __switch_to(prev,task_thread_info(prev), task_thread_info(next)); \
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} while (0)
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#endif /* __ASM_ARM_SWITCH_TO_H */
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