| 1 |
|
| 2 | |
| 3 | * Copyright (C) 2016 Imagination Technologies
|
| 4 | * Author: Paul Burton <[email protected]>
|
| 5 |
|
| 6 |
|
| 7 | #ifndef __MIPS_ASM_DSEMUL_H__
|
| 8 | #define __MIPS_ASM_DSEMUL_H__
|
| 9 |
|
| 10 | #include <asm/break.h>
|
| 11 | #include <asm/inst.h>
|
| 12 |
|
| 13 |
|
| 14 | #define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16))
|
| 15 |
|
| 16 |
|
| 17 | #define BD_EMUFRAME_NONE ((int)BIT(31))
|
| 18 |
|
| 19 | struct mm_struct;
|
| 20 | struct pt_regs;
|
| 21 | struct task_struct;
|
| 22 |
|
| 23 | |
| 24 | * mips_dsemul() - 'Emulate' an instruction from a branch delay slot
|
| 25 | * @regs: User thread register context.
|
| 26 | * @ir: The instruction to be 'emulated'.
|
| 27 | * @branch_pc: The PC of the branch instruction.
|
| 28 | * @cont_pc: The PC to continue at following 'emulation'.
|
| 29 | *
|
| 30 | * Emulate or execute an arbitrary MIPS instruction within the context of
|
| 31 | * the current user thread. This is used primarily to handle instructions
|
| 32 | * in the delay slots of emulated branch instructions, for example FP
|
| 33 | * branch instructions on systems without an FPU.
|
| 34 | *
|
| 35 | * Return: Zero on success, negative if ir is a NOP, signal number on failure.
|
| 36 |
|
| 37 | extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir,
|
| 38 | unsigned long branch_pc, unsigned long cont_pc);
|
| 39 |
|
| 40 | |
| 41 | * do_dsemulret() - Return from a delay slot 'emulation' frame
|
| 42 | * @xcp: User thread register context.
|
| 43 | *
|
| 44 | * Call in response to the BRK_MEMU break instruction used to return to
|
| 45 | * the kernel from branch delay slot 'emulation' frames following a call
|
| 46 | * to mips_dsemul(). Restores the user thread PC to the value that was
|
| 47 | * passed as the cpc parameter to mips_dsemul().
|
| 48 | *
|
| 49 | * Return: True if an emulation frame was returned from, else false.
|
| 50 |
|
| 51 | #ifdef CONFIG_MIPS_FP_SUPPORT
|
| 52 | extern bool do_dsemulret(struct pt_regs *xcp);
|
| 53 | #else
|
| 54 | static inline bool do_dsemulret(struct pt_regs *xcp)
|
| 55 | {
|
| 56 | return false;
|
| 57 | }
|
| 58 | #endif
|
| 59 |
|
| 60 | |
| 61 | * dsemul_thread_cleanup() - Cleanup thread 'emulation' frame
|
| 62 | * @tsk: The task structure associated with the thread
|
| 63 | *
|
| 64 | * If the thread @tsk has a branch delay slot 'emulation' frame
|
| 65 | * allocated to it then free that frame.
|
| 66 | *
|
| 67 | * Return: True if a frame was freed, else false.
|
| 68 |
|
| 69 | #ifdef CONFIG_MIPS_FP_SUPPORT
|
| 70 | extern bool dsemul_thread_cleanup(struct task_struct *tsk);
|
| 71 | #else
|
| 72 | static inline bool dsemul_thread_cleanup(struct task_struct *tsk)
|
| 73 | {
|
| 74 | return false;
|
| 75 | }
|
| 76 | #endif
|
| 77 | |
| 78 | * dsemul_thread_rollback() - Rollback from an 'emulation' frame
|
| 79 | * @regs: User thread register context.
|
| 80 | *
|
| 81 | * If the current thread, whose register context is represented by @regs,
|
| 82 | * is executing within a delay slot 'emulation' frame then exit that
|
| 83 | * frame. The PC will be rolled back to the branch if the instruction
|
| 84 | * that was being 'emulated' has not yet executed, or advanced to the
|
| 85 | * continuation PC if it has.
|
| 86 | *
|
| 87 | * Return: True if a frame was exited, else false.
|
| 88 |
|
| 89 | #ifdef CONFIG_MIPS_FP_SUPPORT
|
| 90 | extern bool dsemul_thread_rollback(struct pt_regs *regs);
|
| 91 | #else
|
| 92 | static inline bool dsemul_thread_rollback(struct pt_regs *regs)
|
| 93 | {
|
| 94 | return false;
|
| 95 | }
|
| 96 | #endif
|
| 97 |
|
| 98 | |
| 99 | * dsemul_mm_cleanup() - Cleanup per-mm delay slot 'emulation' state
|
| 100 | * @mm: The struct mm_struct to cleanup state for.
|
| 101 | *
|
| 102 | * Cleanup state for the given @mm, ensuring that any memory allocated
|
| 103 | * for delay slot 'emulation' book-keeping is freed. This is to be called
|
| 104 | * before @mm is freed in order to avoid memory leaks.
|
| 105 |
|
| 106 | #ifdef CONFIG_MIPS_FP_SUPPORT
|
| 107 | extern void dsemul_mm_cleanup(struct mm_struct *mm);
|
| 108 | #else
|
| 109 | static inline void dsemul_mm_cleanup(struct mm_struct *mm)
|
| 110 | {
|
| 111 |
|
| 112 | }
|
| 113 | #endif
|
| 114 |
|
| 115 | #endif
|