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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
116 lines
3.5 KiB
C
116 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2016 Imagination Technologies
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* Author: Paul Burton <paul.burton@mips.com>
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*/
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#ifndef __MIPS_ASM_DSEMUL_H__
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#define __MIPS_ASM_DSEMUL_H__
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#include <asm/break.h>
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#include <asm/inst.h>
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/* Break instruction with special math emu break code set */
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#define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16))
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/* When used as a frame index, indicates the lack of a frame */
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#define BD_EMUFRAME_NONE ((int)BIT(31))
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struct mm_struct;
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struct pt_regs;
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struct task_struct;
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/**
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* mips_dsemul() - 'Emulate' an instruction from a branch delay slot
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* @regs: User thread register context.
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* @ir: The instruction to be 'emulated'.
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* @branch_pc: The PC of the branch instruction.
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* @cont_pc: The PC to continue at following 'emulation'.
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*
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* Emulate or execute an arbitrary MIPS instruction within the context of
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* the current user thread. This is used primarily to handle instructions
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* in the delay slots of emulated branch instructions, for example FP
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* branch instructions on systems without an FPU.
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*
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* Return: Zero on success, negative if ir is a NOP, signal number on failure.
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*/
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extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
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unsigned long branch_pc, unsigned long cont_pc);
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/**
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* do_dsemulret() - Return from a delay slot 'emulation' frame
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* @xcp: User thread register context.
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*
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* Call in response to the BRK_MEMU break instruction used to return to
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* the kernel from branch delay slot 'emulation' frames following a call
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* to mips_dsemul(). Restores the user thread PC to the value that was
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* passed as the cpc parameter to mips_dsemul().
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*
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* Return: True if an emulation frame was returned from, else false.
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*/
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#ifdef CONFIG_MIPS_FP_SUPPORT
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extern bool do_dsemulret(struct pt_regs *xcp);
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#else
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static inline bool do_dsemulret(struct pt_regs *xcp)
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{
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return false;
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}
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#endif
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/**
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* dsemul_thread_cleanup() - Cleanup thread 'emulation' frame
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* @tsk: The task structure associated with the thread
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*
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* If the thread @tsk has a branch delay slot 'emulation' frame
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* allocated to it then free that frame.
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*
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* Return: True if a frame was freed, else false.
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*/
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#ifdef CONFIG_MIPS_FP_SUPPORT
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extern bool dsemul_thread_cleanup(struct task_struct *tsk);
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#else
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static inline bool dsemul_thread_cleanup(struct task_struct *tsk)
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{
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return false;
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}
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#endif
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/**
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* dsemul_thread_rollback() - Rollback from an 'emulation' frame
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* @regs: User thread register context.
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*
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* If the current thread, whose register context is represented by @regs,
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* is executing within a delay slot 'emulation' frame then exit that
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* frame. The PC will be rolled back to the branch if the instruction
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* that was being 'emulated' has not yet executed, or advanced to the
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* continuation PC if it has.
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*
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* Return: True if a frame was exited, else false.
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*/
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#ifdef CONFIG_MIPS_FP_SUPPORT
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extern bool dsemul_thread_rollback(struct pt_regs *regs);
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#else
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static inline bool dsemul_thread_rollback(struct pt_regs *regs)
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{
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return false;
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}
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#endif
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/**
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* dsemul_mm_cleanup() - Cleanup per-mm delay slot 'emulation' state
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* @mm: The struct mm_struct to cleanup state for.
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*
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* Cleanup state for the given @mm, ensuring that any memory allocated
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* for delay slot 'emulation' book-keeping is freed. This is to be called
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* before @mm is freed in order to avoid memory leaks.
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*/
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#ifdef CONFIG_MIPS_FP_SUPPORT
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extern void dsemul_mm_cleanup(struct mm_struct *mm);
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#else
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static inline void dsemul_mm_cleanup(struct mm_struct *mm)
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{
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/* no-op */
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}
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#endif
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#endif /* __MIPS_ASM_DSEMUL_H__ */
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