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nios2: Process management

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This patch adds support for thread creation and context switching.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
This commit is contained in:
Ley Foon Tan 2014-11-06 15:19:47 +08:00
parent cbd15b3fad
commit 71995e4d00
6 changed files with 694 additions and 0 deletions
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66
arch/nios2/include/asm/mmu_context.h Normal file
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/*
* Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
* 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 <asm-generic/mm_hooks.h>
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 */

103
arch/nios2/include/asm/processor.h Normal file
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/*
* Copyright (C) 2013 Altera Corporation
* Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
* 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 <asm/ptrace.h>
#include <asm/registers.h>
#include <asm/page.h>
#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()
#define cpu_relax_lowlatency() cpu_relax()
#endif /* __ASSEMBLY__ */
#endif /* _ASM_NIOS2_PROCESSOR_H */

31
arch/nios2/include/asm/switch_to.h Normal file
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/*
* 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 */

120
arch/nios2/include/asm/thread_info.h Normal file
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/*
* NiosII low-level thread information
*
* Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2004 Microtronix Datacom Ltd.
*
* Based on asm/thread_info_no.h from m68k which is:
*
* Copyright (C) 2002 David Howells <dhowells@redhat.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.
*/
#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 */

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arch/nios2/kernel/process.c Normal file
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/*
* Architecture-dependent parts of process handling.
*
* Copyright (C) 2013 Altera Corporation
* Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009 Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
* 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.
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/tick.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/traps.h>
#include <asm/cpuinfo.h>
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("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 <linux/elfcore.h>
/* 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 */
}

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/*
* MMU context handling.
*
* Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
* 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 <linux/mm.h>
#include <asm/cpuinfo.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
/* 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));
}