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There is need for figuring out how to manage struct thread_info data when IRQ stack is introduced. struct thread_info information should be copied to IRQ stack under the current thread_info calculation logic whenever context switching is invoked. This is too expensive to keep supporting the approach. Instead, this patch pays attention to sp_el0 which is an unused scratch register in EL1 context. sp_el0 utilization not only simplifies the management, but also prevents text section size from being increased largely due to static allocated IRQ stack as removing masking operation using THREAD_SIZE in many places. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
143 lines
4.2 KiB
C
143 lines
4.2 KiB
C
/*
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* Based on arch/arm/include/asm/thread_info.h
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*
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* Copyright (C) 2002 Russell King.
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_THREAD_INFO_H
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#define __ASM_THREAD_INFO_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#ifdef CONFIG_ARM64_4K_PAGES
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#define THREAD_SIZE_ORDER 2
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#elif defined(CONFIG_ARM64_16K_PAGES)
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#define THREAD_SIZE_ORDER 0
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#endif
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#define THREAD_SIZE 16384
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#define THREAD_START_SP (THREAD_SIZE - 16)
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#ifndef __ASSEMBLY__
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struct task_struct;
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#include <asm/types.h>
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typedef unsigned long mm_segment_t;
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/*
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* low level task data that entry.S needs immediate access to.
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* __switch_to() assumes cpu_context follows immediately after cpu_domain.
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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mm_segment_t addr_limit; /* address limit */
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struct task_struct *task; /* main task structure */
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int preempt_count; /* 0 => preemptable, <0 => bug */
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int cpu; /* cpu */
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};
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.task = &tsk, \
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.flags = 0, \
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.preempt_count = INIT_PREEMPT_COUNT, \
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.addr_limit = KERNEL_DS, \
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}
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#define init_thread_info (init_thread_union.thread_info)
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#define init_stack (init_thread_union.stack)
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/*
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* how to get the current stack pointer from C
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*/
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register unsigned long current_stack_pointer asm ("sp");
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/*
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* how to get the thread information struct from C
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*/
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static inline struct thread_info *current_thread_info(void) __attribute_const__;
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/*
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* struct thread_info can be accessed directly via sp_el0.
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*/
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static inline struct thread_info *current_thread_info(void)
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{
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unsigned long sp_el0;
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asm ("mrs %0, sp_el0" : "=r" (sp_el0));
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return (struct thread_info *)sp_el0;
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}
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#define thread_saved_pc(tsk) \
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((unsigned long)(tsk->thread.cpu_context.pc))
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#define thread_saved_sp(tsk) \
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((unsigned long)(tsk->thread.cpu_context.sp))
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#define thread_saved_fp(tsk) \
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((unsigned long)(tsk->thread.cpu_context.fp))
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#endif
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/*
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* thread information flags:
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* TIF_SYSCALL_TRACE - syscall trace active
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* TIF_SYSCALL_TRACEPOINT - syscall tracepoint for ftrace
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* TIF_SYSCALL_AUDIT - syscall auditing
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* TIF_SECOMP - syscall secure computing
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* TIF_SIGPENDING - signal pending
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* TIF_NEED_RESCHED - rescheduling necessary
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* TIF_NOTIFY_RESUME - callback before returning to user
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* TIF_USEDFPU - FPU was used by this task this quantum (SMP)
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*/
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#define TIF_SIGPENDING 0
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#define TIF_NEED_RESCHED 1
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#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
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#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
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#define TIF_NOHZ 7
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#define TIF_SYSCALL_TRACE 8
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#define TIF_SYSCALL_AUDIT 9
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#define TIF_SYSCALL_TRACEPOINT 10
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#define TIF_SECCOMP 11
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#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
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#define TIF_FREEZE 19
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#define TIF_RESTORE_SIGMASK 20
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#define TIF_SINGLESTEP 21
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#define TIF_32BIT 22 /* 32bit process */
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#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
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#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
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#define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE)
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#define _TIF_NOHZ (1 << TIF_NOHZ)
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#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
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#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
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#define _TIF_SECCOMP (1 << TIF_SECCOMP)
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#define _TIF_32BIT (1 << TIF_32BIT)
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#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
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_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
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#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
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_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
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_TIF_NOHZ)
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#endif /* __KERNEL__ */
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#endif /* __ASM_THREAD_INFO_H */
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