From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758270AbaGOIsF (ORCPT ); Tue, 15 Jul 2014 04:48:05 -0400 Received: from mail-bn1lp0145.outbound.protection.outlook.com ([207.46.163.145]:41697 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757982AbaGOIrw (ORCPT ); Tue, 15 Jul 2014 04:47:52 -0400 From: Ley Foon Tan To: , , CC: Ley Foon Tan , , Subject: [PATCH v2 09/29] nios2: Process management Date: Tue, 15 Jul 2014 16:45:36 +0800 Message-ID: <1405413956-2772-10-git-send-email-lftan@altera.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1405413956-2772-1-git-send-email-lftan@altera.com> References: <1405413956-2772-1-git-send-email-lftan@altera.com> MIME-Version: 1.0 Content-Type: text/plain X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:66.35.236.227;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(6009001)(189002)(199002)(22564002)(43544003)(50226001)(77982001)(4396001)(68736004)(74502001)(31966008)(48376002)(50986999)(229853001)(99396002)(77156001)(76176999)(19580395003)(92726001)(92566001)(86362001)(88136002)(79102001)(105596002)(97736001)(102836001)(6806004)(84676001)(83072002)(36756003)(106466001)(19580405001)(107046002)(44976005)(74662001)(85852003)(89996001)(83322001)(21056001)(76482001)(20776003)(104166001)(47776003)(87286001)(87936001)(81342001)(93916002)(62966002)(2201001)(46102001)(77096002)(64706001)(85306003)(80022001)(81542001)(95666004)(42186005)(33646002);DIR:OUT;SFP:;SCL:1;SRVR:BLUPR03MB036;H:sj-itexedge03.altera.priv.altera.com;FPR:;MLV:sfv;PTR:InfoDomainNonexistent;MX:1;LANG:en; X-Microsoft-Antispam: BCL:0;PCL:0;RULEID: X-Forefront-PRVS: 027367F73D Authentication-Results: spf=softfail (sender IP is 66.35.236.227) smtp.mailfrom=lftan@altera.com; X-OriginatorOrg: altera.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds support for thread creation and context switching. Signed-off-by: Ley Foon Tan --- arch/nios2/include/asm/mmu_context.h | 66 +++++++++ arch/nios2/include/asm/processor.h | 102 ++++++++++++++ arch/nios2/include/asm/switch_to.h | 31 +++++ arch/nios2/include/asm/thread_info.h | 120 ++++++++++++++++ arch/nios2/kernel/process.c | 262 +++++++++++++++++++++++++++++++++++ arch/nios2/mm/mmu_context.c | 116 ++++++++++++++++ 6 files changed, 697 insertions(+) create mode 100644 arch/nios2/include/asm/mmu_context.h create mode 100644 arch/nios2/include/asm/processor.h create mode 100644 arch/nios2/include/asm/switch_to.h create mode 100644 arch/nios2/include/asm/thread_info.h create mode 100644 arch/nios2/kernel/process.c create mode 100644 arch/nios2/mm/mmu_context.c diff --git a/arch/nios2/include/asm/mmu_context.h b/arch/nios2/include/asm/mmu_context.h new file mode 100644 index 0000000..294b4b1 --- /dev/null +++ b/arch/nios2/include/asm/mmu_context.h @@ -0,0 +1,66 @@ +/* + * Copyright (C) 2010 Tobias Klauser + * Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle + * Copyright (C) 1999 Silicon Graphics, Inc. + * + * based on MIPS asm/mmu_context.h + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#ifndef _ASM_NIOS2_MMU_CONTEXT_H +#define _ASM_NIOS2_MMU_CONTEXT_H + +#include + +extern void mmu_context_init(void); +extern unsigned long get_pid_from_context(mm_context_t *ctx); + +/* + * For the fast tlb miss handlers, we keep a pointer to the current pgd. + * processor. + */ +extern pgd_t *pgd_current; + +static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ +} + +/* + * Initialize the context related info for a new mm_struct instance. + * + * Set all new contexts to 0, that way the generation will never match + * the currently running generation when this context is switched in. + */ +static inline int init_new_context(struct task_struct *tsk, + struct mm_struct *mm) +{ + mm->context = 0; + return 0; +} + +/* + * Destroy context related info for an mm_struct that is about + * to be put to rest. + */ +static inline void destroy_context(struct mm_struct *mm) +{ +} + +void switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk); + +static inline void deactivate_mm(struct task_struct *tsk, + struct mm_struct *mm) +{ +} + +/* + * After we have set current->mm to a new value, this activates + * the context for the new mm so we see the new mappings. + */ +void activate_mm(struct mm_struct *prev, struct mm_struct *next); + +#endif /* _ASM_NIOS2_MMU_CONTEXT_H */ diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h new file mode 100644 index 0000000..cff9b2d --- /dev/null +++ b/arch/nios2/include/asm/processor.h @@ -0,0 +1,102 @@ +/* + * Copyright (C) 2013 Altera Corporation + * Copyright (C) 2010 Tobias Klauser + * Copyright (C) 2004 Microtronix Datacom Ltd + * Copyright (C) 2001 Ken Hill (khill@microtronix.com) + * Vic Phillips (vic@microtronix.com) + * + * based on SPARC asm/processor_32.h which is: + * + * Copyright (C) 1994 David S. Miller + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#ifndef _ASM_NIOS2_PROCESSOR_H +#define _ASM_NIOS2_PROCESSOR_H + +#include +#include +#include + +#define NIOS2_FLAG_KTHREAD 0x00000001 /* task is a kernel thread */ + +#define NIOS2_OP_NOP 0x1883a +#define NIOS2_OP_BREAK 0x3da03a + +#ifdef __KERNEL__ + +#define STACK_TOP TASK_SIZE +#define STACK_TOP_MAX STACK_TOP + +#endif /* __KERNEL__ */ + +/* Kuser helpers is mapped to this user space address */ +#define KUSER_BASE 0x1000 +#define KUSER_SIZE (PAGE_SIZE) +#ifndef __ASSEMBLY__ + +/* + * Default implementation of macro that returns current + * instruction pointer ("program counter"). + */ +#define current_text_addr() ({ __label__ _l; _l: &&_l; }) + +# define TASK_SIZE 0x7FFF0000UL +# define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3)) + +/* The Nios processor specific thread struct. */ +struct thread_struct { + struct pt_regs *kregs; + + /* Context switch saved kernel state. */ + unsigned long ksp; + unsigned long kpsr; +}; + +#define INIT_MMAP \ + { &init_mm, (0), (0), __pgprot(0x0), VM_READ | VM_WRITE | VM_EXEC } + +# define INIT_THREAD { \ + .kregs = NULL, \ + .ksp = 0, \ + .kpsr = 0, \ +} + +extern void start_thread(struct pt_regs *regs, unsigned long pc, + unsigned long sp); + +struct task_struct; + +/* Free all resources held by a thread. */ +static inline void release_thread(struct task_struct *dead_task) +{ +} + +/* Free current thread data structures etc.. */ +static inline void exit_thread(void) +{ +} + +/* Return saved PC of a blocked thread. */ +#define thread_saved_pc(tsk) ((tsk)->thread.kregs->ea) + +extern unsigned long get_wchan(struct task_struct *p); + +/* Prepare to copy thread state - unlazy all lazy status */ +#define prepare_to_copy(tsk) do { } while (0) + +#define task_pt_regs(p) \ + ((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1) + +/* Used by procfs */ +#define KSTK_EIP(tsk) ((tsk)->thread.kregs->ea) +#define KSTK_ESP(tsk) ((tsk)->thread.kregs->sp) + +#define cpu_relax() barrier() + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_NIOS2_PROCESSOR_H */ diff --git a/arch/nios2/include/asm/switch_to.h b/arch/nios2/include/asm/switch_to.h new file mode 100644 index 0000000..c47b3f4 --- /dev/null +++ b/arch/nios2/include/asm/switch_to.h @@ -0,0 +1,31 @@ +/* + * Copyright (C) 2004 Microtronix Datacom Ltd. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#ifndef _ASM_NIOS2_SWITCH_TO_H +#define _ASM_NIOS2_SWITCH_TO_H + +/* + * switch_to(n) should switch tasks to task ptr, first checking that + * ptr isn't the current task, in which case it does nothing. This + * also clears the TS-flag if the task we switched to has used the + * math co-processor latest. + */ +#define switch_to(prev, next, last) \ +{ \ + void *_last; \ + __asm__ __volatile__ ( \ + "mov r4, %1\n" \ + "mov r5, %2\n" \ + "call resume\n" \ + "mov %0,r4\n" \ + : "=r" (_last) \ + : "r" (prev), "r" (next) \ + : "r4", "r5", "r7", "r8", "ra"); \ + (last) = _last; \ +} + +#endif /* _ASM_NIOS2_SWITCH_TO_H */ diff --git a/arch/nios2/include/asm/thread_info.h b/arch/nios2/include/asm/thread_info.h new file mode 100644 index 0000000..1f26657 --- /dev/null +++ b/arch/nios2/include/asm/thread_info.h @@ -0,0 +1,120 @@ +/* + * NiosII low-level thread information + * + * Copyright (C) 2011 Tobias Klauser + * Copyright (C) 2004 Microtronix Datacom Ltd. + * + * Based on asm/thread_info_no.h from m68k which is: + * + * Copyright (C) 2002 David Howells + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#ifndef _ASM_NIOS2_THREAD_INFO_H +#define _ASM_NIOS2_THREAD_INFO_H + +#ifdef __KERNEL__ + +/* + * Size of the kernel stack for each process. + */ +#define THREAD_SIZE_ORDER 1 +#define THREAD_SIZE 8192 /* 2 * PAGE_SIZE */ + +#ifndef __ASSEMBLY__ + +typedef struct { + unsigned long seg; +} mm_segment_t; + +/* + * low level task data that entry.S needs immediate access to + * - this struct should fit entirely inside of one cache line + * - this struct shares the supervisor stack pages + * - if the contents of this structure are changed, the assembly constants + * must also be changed + */ +struct thread_info { + struct task_struct *task; /* main task structure */ + struct exec_domain *exec_domain; /* execution domain */ + unsigned long flags; /* low level flags */ + __u32 cpu; /* current CPU */ + int preempt_count; /* 0 => preemptable,<0 => BUG */ + mm_segment_t addr_limit; /* thread address space: + 0-0x7FFFFFFF for user-thead + 0-0xFFFFFFFF for kernel-thread + */ + struct restart_block restart_block; + struct pt_regs *regs; +}; + +/* + * macros/functions for gaining access to the thread information structure + * + * preempt_count needs to be 1 initially, until the scheduler is functional. + */ +#define INIT_THREAD_INFO(tsk) \ +{ \ + .task = &tsk, \ + .exec_domain = &default_exec_domain, \ + .flags = 0, \ + .cpu = 0, \ + .preempt_count = INIT_PREEMPT_COUNT, \ + .addr_limit = KERNEL_DS, \ + .restart_block = { \ + .fn = do_no_restart_syscall, \ + }, \ +} + +#define init_thread_info (init_thread_union.thread_info) +#define init_stack (init_thread_union.stack) + +/* how to get the thread information struct from C */ +static inline struct thread_info *current_thread_info(void) +{ + register unsigned long sp asm("sp"); + + return (struct thread_info *)(sp & ~(THREAD_SIZE - 1)); +} +#endif /* !__ASSEMBLY__ */ + +/* + * thread information flags + * - these are process state flags that various assembly files may need to + * access + * - pending work-to-be-done flags are in LSW + * - other flags in MSW + */ +#define TIF_SYSCALL_TRACE 0 /* syscall trace active */ +#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */ +#define TIF_SIGPENDING 2 /* signal pending */ +#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ +#define TIF_MEMDIE 4 /* is terminating due to OOM killer */ +#define TIF_SECCOMP 5 /* secure computing */ +#define TIF_SYSCALL_AUDIT 6 /* syscall auditing active */ +#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */ + +#define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling + TIF_NEED_RESCHED */ + +#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) +#define _TIF_SIGPENDING (1 << TIF_SIGPENDING) +#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) +#define _TIF_SECCOMP (1 << TIF_SECCOMP) +#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) +#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK) +#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) + +/* work to do on interrupt/exception return */ +#define _TIF_WORK_MASK 0x0000FFFE + +/* work to do on any return to u-space */ +# define _TIF_ALLWORK_MASK 0x0000FFFF + +#endif /* __KERNEL__ */ + +#endif /* _ASM_NIOS2_THREAD_INFO_H */ diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c new file mode 100644 index 0000000..162b3f0 --- /dev/null +++ b/arch/nios2/kernel/process.c @@ -0,0 +1,262 @@ +/* + * Architecture-dependent parts of process handling. + * + * Copyright (C) 2013 Altera Corporation + * Copyright (C) 2010 Tobias Klauser + * Copyright (C) 2009 Wind River Systems Inc + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com + * Copyright (C) 2004 Microtronix Datacom Ltd + * + * based on arch/m68knommu/kernel/process.c which is: + * + * Copyright (C) 2000-2002 David McCullough + * Copyright (C) 1995 Hamish Macdonald + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include +#include +#include +#include + +#include +#include +#include + +asmlinkage void ret_from_fork(void); +asmlinkage void ret_from_kernel_thread(void); + +void (*pm_power_off)(void) = NULL; +EXPORT_SYMBOL(pm_power_off); + +void arch_cpu_idle(void) +{ + local_irq_enable(); +} + +/* + * The development boards have no way to pull a board reset. Just jump to the + * cpu reset address and let the boot loader or the code in head.S take care of + * resetting peripherals. + */ +void machine_restart(char *__unused) +{ + pr_notice("Machine restart (%08x)...\n", cpuinfo.reset_addr); + local_irq_disable(); + __asm__ __volatile__ ( + "jmp %0\n\t" + : + : "r" (cpuinfo.reset_addr) + : "r4"); +} + +void machine_halt(void) +{ + pr_notice("Machine halt...\n"); + local_irq_disable(); + for (;;) + ; +} + +/* + * There is no way to power off the development boards. So just spin for now. If + * we ever have a way of resetting a board using a GPIO we should add that here. + */ +void machine_power_off(void) +{ + pr_notice("Machine power off...\n"); + local_irq_disable(); + for (;;) + ; +} + +void show_regs(struct pt_regs *regs) +{ + pr_notice("\n"); + show_regs_print_info(KERN_DEFAULT); + + pr_notice("r1: %08lx r2: %08lx r3: %08lx r4: %08lx\n", + regs->r1, regs->r2, regs->r3, regs->r4); + + pr_notice("r5: %08lx r6: %08lx r7: %08lx r8: %08lx\n", + regs->r5, regs->r6, regs->r7, regs->r8); + + pr_notice("r9: %08lx r10: %08lx r11: %08lx r12: %08lx\n", + regs->r9, regs->r10, regs->r11, regs->r12); + + pr_notice("r13: %08lx r14: %08lx r15: %08lx\n", + regs->r13, regs->r14, regs->r15); + + pr_notice("ra: %08lx fp: %08lx sp: %08lx gp: %08lx\n", + regs->ra, regs->fp, regs->sp, regs->gp); + + pr_notice("ea: %08lx estatus: %08lx\n", + regs->ea, regs->estatus); +} + +void flush_thread(void) +{ + set_fs(USER_DS); +} + +int copy_thread(unsigned long clone_flags, + unsigned long usp, unsigned long arg, struct task_struct *p) +{ + struct pt_regs *childregs = task_pt_regs(p); + struct pt_regs *regs; + struct switch_stack *stack; + struct switch_stack *childstack = + ((struct switch_stack *)childregs) - 1; + + if (unlikely(p->flags & PF_KTHREAD)) { + memset(childstack, 0, + sizeof(struct switch_stack) + sizeof(struct pt_regs)); + + childstack->r16 = usp; /* fn */ + childstack->r17 = arg; + childstack->ra = (unsigned long) ret_from_kernel_thread; + childregs->estatus = STATUS_PIE; + childregs->sp = (unsigned long) childstack; + + p->thread.ksp = (unsigned long) childstack; + p->thread.kregs = childregs; + return 0; + } + + regs = current_pt_regs(); + *childregs = *regs; + childregs->r2 = 0; /* Set the return value for the child. */ + childregs->r7 = 0; + + stack = ((struct switch_stack *) regs) - 1; + *childstack = *stack; + childstack->ra = (unsigned long)ret_from_fork; + p->thread.kregs = childregs; + p->thread.ksp = (unsigned long) childstack; + + if (usp) + childregs->sp = usp; + + /* Initialize tls register. */ + if (clone_flags & CLONE_SETTLS) + childstack->r23 = regs->r8; + + return 0; +} + +/* + * Generic dumping code. Used for panic and debug. + */ +void dump(struct pt_regs *fp) +{ + unsigned long *sp; + unsigned char *tp; + int i; + + pr_emerg("\nCURRENT PROCESS:\n\n"); + pr_emerg("COMM=%s PID=%d\n", current->comm, current->pid); + + if (current->mm) { + pr_emerg("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n", + (int) current->mm->start_code, + (int) current->mm->end_code, + (int) current->mm->start_data, + (int) current->mm->end_data, + (int) current->mm->end_data, + (int) current->mm->brk); + pr_emerg("USER-STACK=%08x KERNEL-STACK=%08x\n\n", + (int) current->mm->start_stack, + (int)(((unsigned long) current) + THREAD_SIZE)); + } + + pr_emerg("PC: %08lx\n", fp->ea); + pr_emerg(KERN_EMERG "SR: %08lx SP: %08lx\n", + (long) fp->estatus, (long) fp); + + pr_emerg("r1: %08lx r2: %08lx r3: %08lx\n", + fp->r1, fp->r2, fp->r3); + + pr_emerg("r4: %08lx r5: %08lx r6: %08lx r7: %08lx\n", + fp->r4, fp->r5, fp->r6, fp->r7); + pr_emerg("r8: %08lx r9: %08lx r10: %08lx r11: %08lx\n", + fp->r8, fp->r9, fp->r10, fp->r11); + pr_emerg("r12: %08lx r13: %08lx r14: %08lx r15: %08lx\n", + fp->r12, fp->r13, fp->r14, fp->r15); + pr_emerg("or2: %08lx ra: %08lx fp: %08lx sp: %08lx\n", + fp->orig_r2, fp->ra, fp->fp, fp->sp); + pr_emerg("\nUSP: %08x TRAPFRAME: %08x\n", + (unsigned int) fp->sp, (unsigned int) fp); + + pr_emerg("\nCODE:"); + tp = ((unsigned char *) fp->ea) - 0x20; + for (sp = (unsigned long *) tp, i = 0; (i < 0x40); i += 4) { + if ((i % 0x10) == 0) + pr_emerg("\n%08x: ", (int) (tp + i)); + pr_emerg("%08x ", (int) *sp++); + } + pr_emerg("\n"); + + pr_emerg("\nKERNEL STACK:"); + tp = ((unsigned char *) fp) - 0x40; + for (sp = (unsigned long *) tp, i = 0; (i < 0xc0); i += 4) { + if ((i % 0x10) == 0) + pr_emerg("\n%08x: ", (int) (tp + i)); + pr_emerg("%08x ", (int) *sp++); + } + pr_emerg("\n"); + pr_emerg("\n"); + + pr_emerg("\nUSER STACK:"); + tp = (unsigned char *) (fp->sp - 0x10); + for (sp = (unsigned long *) tp, i = 0; (i < 0x80); i += 4) { + if ((i % 0x10) == 0) + pr_emerg("\n%08x: ", (int) (tp + i)); + pr_emerg("%08x ", (int) *sp++); + } + pr_emerg("\n\n"); +} + +unsigned long get_wchan(struct task_struct *p) +{ + unsigned long fp, pc; + unsigned long stack_page; + int count = 0; + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + + stack_page = (unsigned long)p; + fp = ((struct switch_stack *)p->thread.ksp)->fp; /* ;dgt2 */ + do { + if (fp < stack_page+sizeof(struct task_struct) || + fp >= 8184+stack_page) /* ;dgt2;tmp */ + return 0; + pc = ((unsigned long *)fp)[1]; + if (!in_sched_functions(pc)) + return pc; + fp = *(unsigned long *) fp; + } while (count++ < 16); /* ;dgt2;tmp */ + return 0; +} + +/* + * Do necessary setup to start up a newly executed thread. + * Will startup in user mode (status_extension = 0). + */ +void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp) +{ + memset((void *) regs, 0, sizeof(struct pt_regs)); + regs->estatus = ESTATUS_EPIE | ESTATUS_EU; + regs->ea = pc; + regs->sp = sp; +} + +#include + +/* Fill in the FPU structure for a core dump. */ +int dump_fpu(struct pt_regs *regs, elf_fpregset_t *r) +{ + return 0; /* Nios2 has no FPU and thus no FPU registers */ +} diff --git a/arch/nios2/mm/mmu_context.c b/arch/nios2/mm/mmu_context.c new file mode 100644 index 0000000..45d6b9c --- /dev/null +++ b/arch/nios2/mm/mmu_context.c @@ -0,0 +1,116 @@ +/* + * MMU context handling. + * + * Copyright (C) 2011 Tobias Klauser + * Copyright (C) 2009 Wind River Systems Inc + * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include + +#include +#include +#include + +/* The pids position and mask in context */ +#define PID_SHIFT 0 +#define PID_BITS (cpuinfo.tlb_pid_num_bits) +#define PID_MASK ((1UL << PID_BITS) - 1) + +/* The versions position and mask in context */ +#define VERSION_BITS (32 - PID_BITS) +#define VERSION_SHIFT (PID_SHIFT + PID_BITS) +#define VERSION_MASK ((1UL << VERSION_BITS) - 1) + +/* Return the version part of a context */ +#define CTX_VERSION(c) (((c) >> VERSION_SHIFT) & VERSION_MASK) + +/* Return the pid part of a context */ +#define CTX_PID(c) (((c) >> PID_SHIFT) & PID_MASK) + +/* Value of the first context (version 1, pid 0) */ +#define FIRST_CTX ((1UL << VERSION_SHIFT) | (0 << PID_SHIFT)) + +static mm_context_t next_mmu_context; + +/* + * Initialize MMU context management stuff. + */ +void __init mmu_context_init(void) +{ + /* We need to set this here because the value depends on runtime data + * from cpuinfo */ + next_mmu_context = FIRST_CTX; +} + +/* + * Set new context (pid), keep way + */ +static void set_context(mm_context_t context) +{ + set_mmu_pid(CTX_PID(context)); +} + +static mm_context_t get_new_context(void) +{ + /* Return the next pid */ + next_mmu_context += (1UL << PID_SHIFT); + + /* If the pid field wraps around we increase the version and + * flush the tlb */ + if (unlikely(CTX_PID(next_mmu_context) == 0)) { + /* Version is incremented since the pid increment above + * overflows info version */ + flush_cache_all(); + flush_tlb_all(); + } + + /* If the version wraps we start over with the first generation, we do + * not need to flush the tlb here since it's always done above */ + if (unlikely(CTX_VERSION(next_mmu_context) == 0)) + next_mmu_context = FIRST_CTX; + + return next_mmu_context; +} + +void switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ + unsigned long flags; + + local_irq_save(flags); + + /* If the process context we are swapping in has a different context + * generation then we have it should get a new generation/pid */ + if (unlikely(CTX_VERSION(next->context) != + CTX_VERSION(next_mmu_context))) + next->context = get_new_context(); + + /* Save the current pgd so the fast tlb handler can find it */ + pgd_current = next->pgd; + + /* Set the current context */ + set_context(next->context); + + local_irq_restore(flags); +} + +/* + * After we have set current->mm to a new value, this activates + * the context for the new mm so we see the new mappings. + */ +void activate_mm(struct mm_struct *prev, struct mm_struct *next) +{ + next->context = get_new_context(); + set_context(next->context); + pgd_current = next->pgd; +} + +unsigned long get_pid_from_context(mm_context_t *context) +{ + return CTX_PID((*context)); +} -- 1.8.2.1