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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/mips/include/asm/dsemul.h
2 * Copyright (C) 2016 Imagination Technologies
3 * Author: Paul Burton <paul.burton@mips.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
11 #ifndef __MIPS_ASM_DSEMUL_H__
12 #define __MIPS_ASM_DSEMUL_H__
14 #include <asm/break.h>
17 /* Break instruction with special math emu break code set */
18 #define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16))
20 /* When used as a frame index, indicates the lack of a frame */
21 #define BD_EMUFRAME_NONE ((int)BIT(31))
28 * mips_dsemul() - 'Emulate' an instruction from a branch delay slot
29 * @regs: User thread register context.
30 * @ir: The instruction to be 'emulated'.
31 * @branch_pc: The PC of the branch instruction.
32 * @cont_pc: The PC to continue at following 'emulation'.
34 * Emulate or execute an arbitrary MIPS instruction within the context of
35 * the current user thread. This is used primarily to handle instructions
36 * in the delay slots of emulated branch instructions, for example FP
37 * branch instructions on systems without an FPU.
39 * Return: Zero on success, negative if ir is a NOP, signal number on failure.
41 extern int mips_dsemul(struct pt_regs
*regs
, mips_instruction ir
,
42 unsigned long branch_pc
, unsigned long cont_pc
);
45 * do_dsemulret() - Return from a delay slot 'emulation' frame
46 * @xcp: User thread register context.
48 * Call in response to the BRK_MEMU break instruction used to return to
49 * the kernel from branch delay slot 'emulation' frames following a call
50 * to mips_dsemul(). Restores the user thread PC to the value that was
51 * passed as the cpc parameter to mips_dsemul().
53 * Return: True if an emulation frame was returned from, else false.
55 #ifdef CONFIG_MIPS_FP_SUPPORT
56 extern bool do_dsemulret(struct pt_regs
*xcp
);
58 static inline bool do_dsemulret(struct pt_regs
*xcp
)
65 * dsemul_thread_cleanup() - Cleanup thread 'emulation' frame
66 * @tsk: The task structure associated with the thread
68 * If the thread @tsk has a branch delay slot 'emulation' frame
69 * allocated to it then free that frame.
71 * Return: True if a frame was freed, else false.
73 #ifdef CONFIG_MIPS_FP_SUPPORT
74 extern bool dsemul_thread_cleanup(struct task_struct
*tsk
);
76 static inline bool dsemul_thread_cleanup(struct task_struct
*tsk
)
82 * dsemul_thread_rollback() - Rollback from an 'emulation' frame
83 * @regs: User thread register context.
85 * If the current thread, whose register context is represented by @regs,
86 * is executing within a delay slot 'emulation' frame then exit that
87 * frame. The PC will be rolled back to the branch if the instruction
88 * that was being 'emulated' has not yet executed, or advanced to the
89 * continuation PC if it has.
91 * Return: True if a frame was exited, else false.
93 #ifdef CONFIG_MIPS_FP_SUPPORT
94 extern bool dsemul_thread_rollback(struct pt_regs
*regs
);
96 static inline bool dsemul_thread_rollback(struct pt_regs
*regs
)
103 * dsemul_mm_cleanup() - Cleanup per-mm delay slot 'emulation' state
104 * @mm: The struct mm_struct to cleanup state for.
106 * Cleanup state for the given @mm, ensuring that any memory allocated
107 * for delay slot 'emulation' book-keeping is freed. This is to be called
108 * before @mm is freed in order to avoid memory leaks.
110 #ifdef CONFIG_MIPS_FP_SUPPORT
111 extern void dsemul_mm_cleanup(struct mm_struct
*mm
);
113 static inline void dsemul_mm_cleanup(struct mm_struct
*mm
)
119 #endif /* __MIPS_ASM_DSEMUL_H__ */