diff options
Diffstat (limited to 'arch/mips/include')
| -rw-r--r-- | arch/mips/include/asm/dsemul.h | 92 | ||||
| -rw-r--r-- | arch/mips/include/asm/fpu_emulator.h | 17 | ||||
| -rw-r--r-- | arch/mips/include/asm/mmu.h | 9 | ||||
| -rw-r--r-- | arch/mips/include/asm/mmu_context.h | 6 | ||||
| -rw-r--r-- | arch/mips/include/asm/processor.h | 18 |
5 files changed, 127 insertions, 15 deletions
diff --git a/arch/mips/include/asm/dsemul.h b/arch/mips/include/asm/dsemul.h new file mode 100644 index 000000000000..a6e067801f23 --- /dev/null +++ b/arch/mips/include/asm/dsemul.h @@ -0,0 +1,92 @@ +/* + * Copyright (C) 2016 Imagination Technologies + * Author: Paul Burton <paul.burton@imgtec.com> + * + * 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. + */ + +#ifndef __MIPS_ASM_DSEMUL_H__ +#define __MIPS_ASM_DSEMUL_H__ + +#include <asm/break.h> +#include <asm/inst.h> + +/* Break instruction with special math emu break code set */ +#define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16)) + +/* When used as a frame index, indicates the lack of a frame */ +#define BD_EMUFRAME_NONE ((int)BIT(31)) + +struct mm_struct; +struct pt_regs; +struct task_struct; + +/** + * mips_dsemul() - 'Emulate' an instruction from a branch delay slot + * @regs: User thread register context. + * @ir: The instruction to be 'emulated'. + * @branch_pc: The PC of the branch instruction. + * @cont_pc: The PC to continue at following 'emulation'. + * + * Emulate or execute an arbitrary MIPS instruction within the context of + * the current user thread. This is used primarily to handle instructions + * in the delay slots of emulated branch instructions, for example FP + * branch instructions on systems without an FPU. + * + * Return: Zero on success, negative if ir is a NOP, signal number on failure. + */ +extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir, + unsigned long branch_pc, unsigned long cont_pc); + +/** + * do_dsemulret() - Return from a delay slot 'emulation' frame + * @xcp: User thread register context. + * + * Call in response to the BRK_MEMU break instruction used to return to + * the kernel from branch delay slot 'emulation' frames following a call + * to mips_dsemul(). Restores the user thread PC to the value that was + * passed as the cpc parameter to mips_dsemul(). + * + * Return: True if an emulation frame was returned from, else false. + */ +extern bool do_dsemulret(struct pt_regs *xcp); + +/** + * dsemul_thread_cleanup() - Cleanup thread 'emulation' frame + * @tsk: The task structure associated with the thread + * + * If the thread @tsk has a branch delay slot 'emulation' frame + * allocated to it then free that frame. + * + * Return: True if a frame was freed, else false. + */ +extern bool dsemul_thread_cleanup(struct task_struct *tsk); + +/** + * dsemul_thread_rollback() - Rollback from an 'emulation' frame + * @regs: User thread register context. + * + * If the current thread, whose register context is represented by @regs, + * is executing within a delay slot 'emulation' frame then exit that + * frame. The PC will be rolled back to the branch if the instruction + * that was being 'emulated' has not yet executed, or advanced to the + * continuation PC if it has. + * + * Return: True if a frame was exited, else false. + */ +extern bool dsemul_thread_rollback(struct pt_regs *regs); + +/** + * dsemul_mm_cleanup() - Cleanup per-mm delay slot 'emulation' state + * @mm: The struct mm_struct to cleanup state for. + * + * Cleanup state for the given @mm, ensuring that any memory allocated + * for delay slot 'emulation' book-keeping is freed. This is to be called + * before @mm is freed in order to avoid memory leaks. + */ +extern void dsemul_mm_cleanup(struct mm_struct *mm); + +#endif /* __MIPS_ASM_DSEMUL_H__ */ diff --git a/arch/mips/include/asm/fpu_emulator.h b/arch/mips/include/asm/fpu_emulator.h index 3225c3c0724b..355dc25172e7 100644 --- a/arch/mips/include/asm/fpu_emulator.h +++ b/arch/mips/include/asm/fpu_emulator.h @@ -24,7 +24,7 @@ #define _ASM_FPU_EMULATOR_H #include <linux/sched.h> -#include <asm/break.h> +#include <asm/dsemul.h> #include <asm/thread_info.h> #include <asm/inst.h> #include <asm/local.h> @@ -60,27 +60,16 @@ do { \ #define MIPS_FPU_EMU_INC_STATS(M) do { } while (0) #endif /* CONFIG_DEBUG_FS */ -extern int mips_dsemul(struct pt_regs *regs, mips_instruction ir, - unsigned long cpc); -extern int do_dsemulret(struct pt_regs *xcp); extern int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx, int has_fpu, void *__user *fault_addr); int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31); +int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, + unsigned long *contpc); int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, unsigned long *contpc); -/* - * Instruction inserted following the badinst to further tag the sequence - */ -#define BD_COOKIE 0x0000bd36 /* tne $0, $0 with baggage */ - -/* - * Break instruction with special math emu break code set - */ -#define BREAK_MATH(micromips) (((micromips) ? 0x7 : 0xd) | (BRK_MEMU << 16)) - #define SIGNALLING_NAN 0x7ff800007ff80000LL static inline void fpu_emulator_init_fpu(void) diff --git a/arch/mips/include/asm/mmu.h b/arch/mips/include/asm/mmu.h index 1afa1f986df8..f6ba08d77931 100644 --- a/arch/mips/include/asm/mmu.h +++ b/arch/mips/include/asm/mmu.h @@ -2,11 +2,20 @@ #define __ASM_MMU_H #include <linux/atomic.h> +#include <linux/spinlock.h> +#include <linux/wait.h> typedef struct { unsigned long asid[NR_CPUS]; void *vdso; atomic_t fp_mode_switching; + + /* lock to be held whilst modifying fp_bd_emupage_allocmap */ + spinlock_t bd_emupage_lock; + /* bitmap tracking allocation of fp_bd_emupage */ + unsigned long *bd_emupage_allocmap; + /* wait queue for threads requiring an emuframe */ + wait_queue_head_t bd_emupage_queue; } mm_context_t; #endif /* __ASM_MMU_H */ diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h index fc57e135cb0a..ddd57ade1aa8 100644 --- a/arch/mips/include/asm/mmu_context.h +++ b/arch/mips/include/asm/mmu_context.h @@ -16,6 +16,7 @@ #include <linux/smp.h> #include <linux/slab.h> #include <asm/cacheflush.h> +#include <asm/dsemul.h> #include <asm/hazards.h> #include <asm/tlbflush.h> #include <asm-generic/mm_hooks.h> @@ -128,6 +129,10 @@ init_new_context(struct task_struct *tsk, struct mm_struct *mm) atomic_set(&mm->context.fp_mode_switching, 0); + mm->context.bd_emupage_allocmap = NULL; + spin_lock_init(&mm->context.bd_emupage_lock); + init_waitqueue_head(&mm->context.bd_emupage_queue); + return 0; } @@ -162,6 +167,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, */ static inline void destroy_context(struct mm_struct *mm) { + dsemul_mm_cleanup(mm); } #define deactivate_mm(tsk, mm) do { } while (0) diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h index 7e78b6208d7d..0d36c87acbe2 100644 --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -11,12 +11,14 @@ #ifndef _ASM_PROCESSOR_H #define _ASM_PROCESSOR_H +#include <linux/atomic.h> #include <linux/cpumask.h> #include <linux/threads.h> #include <asm/cachectl.h> #include <asm/cpu.h> #include <asm/cpu-info.h> +#include <asm/dsemul.h> #include <asm/mipsregs.h> #include <asm/prefetch.h> @@ -78,7 +80,11 @@ extern unsigned int vced_count, vcei_count; #endif -#define STACK_TOP (TASK_SIZE & PAGE_MASK) +/* + * One page above the stack is used for branch delay slot "emulation". + * See dsemul.c for details. + */ +#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - PAGE_SIZE) /* * This decides where the kernel will search for a free chunk of vm @@ -256,6 +262,12 @@ struct thread_struct { /* Saved fpu/fpu emulator stuff. */ struct mips_fpu_struct fpu FPU_ALIGN; + /* Assigned branch delay slot 'emulation' frame */ + atomic_t bd_emu_frame; + /* PC of the branch from a branch delay slot 'emulation' */ + unsigned long bd_emu_branch_pc; + /* PC to continue from following a branch delay slot 'emulation' */ + unsigned long bd_emu_cont_pc; #ifdef CONFIG_MIPS_MT_FPAFF /* Emulated instruction count */ unsigned long emulated_fp; @@ -323,6 +335,10 @@ struct thread_struct { * FPU affinity state (null if not FPAFF) \ */ \ FPAFF_INIT \ + /* Delay slot emulation */ \ + .bd_emu_frame = ATOMIC_INIT(BD_EMUFRAME_NONE), \ + .bd_emu_branch_pc = 0, \ + .bd_emu_cont_pc = 0, \ /* \ * Saved DSP stuff \ */ \ |