projects / deliverable / linux.git / blame
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|---|---|---|
| 432c6bac PB |
1 | /* |
| 2 | * Copyright (C) 2016 Imagination Technologies | |
| 3 | * Author: Paul Burton <paul.burton@imgtec.com> | |
| 4 | * | |
| 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. | |
| 9 | */ | |
| 10 | ||
| 11 | #ifndef __MIPS_ASM_DSEMUL_H__ | |
| 12 | #define __MIPS_ASM_DSEMUL_H__ | |
| 13 | ||
| 14 | #include <asm/break.h> | |
| 15 | #include <asm/inst.h> | |
| 16 | ||
| 17 | /* Break instruction with special math emu break code set */ | |
| 18 | #define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16)) | |
| 19 | ||
| 20 | /* When used as a frame index, indicates the lack of a frame */ | |
| 21 | #define BD_EMUFRAME_NONE ((int)BIT(31)) | |
| 22 | ||
| 23 | struct mm_struct; | |
| 24 | struct pt_regs; | |
| 25 | struct task_struct; | |
| 26 | ||
| 27 | /** | |
| 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'. | |
| 33 | * | |
| 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. | |
| 38 | * | |
| 39 | * Return: Zero on success, negative if ir is a NOP, signal number on failure. | |
| 40 | */ | |
| 41 | extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir, | |
| 42 | unsigned long branch_pc, unsigned long cont_pc); | |
| 43 | ||
| 44 | /** | |
| 45 | * do_dsemulret() - Return from a delay slot 'emulation' frame | |
| 46 | * @xcp: User thread register context. | |
| 47 | * | |
| 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(). | |
| 52 | * | |
| 53 | * Return: True if an emulation frame was returned from, else false. | |
| 54 | */ | |
| 55 | extern bool do_dsemulret(struct pt_regs *xcp); | |
| 56 | ||
| 57 | /** | |
| 58 | * dsemul_thread_cleanup() - Cleanup thread 'emulation' frame | |
| 59 | * @tsk: The task structure associated with the thread | |
| 60 | * | |
| 61 | * If the thread @tsk has a branch delay slot 'emulation' frame | |
| 62 | * allocated to it then free that frame. | |
| 63 | * | |
| 64 | * Return: True if a frame was freed, else false. | |
| 65 | */ | |
| 66 | extern bool dsemul_thread_cleanup(struct task_struct *tsk); | |
| 67 | ||
| 68 | /** | |
| 69 | * dsemul_thread_rollback() - Rollback from an 'emulation' frame | |
| 70 | * @regs: User thread register context. | |
| 71 | * | |
| 72 | * If the current thread, whose register context is represented by @regs, | |
| 73 | * is executing within a delay slot 'emulation' frame then exit that | |
| 74 | * frame. The PC will be rolled back to the branch if the instruction | |
| 75 | * that was being 'emulated' has not yet executed, or advanced to the | |
| 76 | * continuation PC if it has. | |
| 77 | * | |
| 78 | * Return: True if a frame was exited, else false. | |
| 79 | */ | |
| 80 | extern bool dsemul_thread_rollback(struct pt_regs *regs); | |
| 81 | ||
| 82 | /** | |
| 83 | * dsemul_mm_cleanup() - Cleanup per-mm delay slot 'emulation' state | |
| 84 | * @mm: The struct mm_struct to cleanup state for. | |
| 85 | * | |
| 86 | * Cleanup state for the given @mm, ensuring that any memory allocated | |
| 87 | * for delay slot 'emulation' book-keeping is freed. This is to be called | |
| 88 | * before @mm is freed in order to avoid memory leaks. | |
| 89 | */ | |
| 90 | extern void dsemul_mm_cleanup(struct mm_struct *mm); | |
| 91 | ||
| 92 | #endif /* __MIPS_ASM_DSEMUL_H__ */ |