340 lines
7.7 KiB
C
340 lines
7.7 KiB
C
/*
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* arch/xtensa/kernel/process.c
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*
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* Xtensa Processor version.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001 - 2005 Tensilica Inc.
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*
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* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
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* Chris Zankel <chris@zankel.net>
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* Marc Gauthier <marc@tensilica.com, marc@alumni.uwaterloo.ca>
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* Kevin Chea
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*/
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/elf.h>
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#include <linux/init.h>
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#include <linux/prctl.h>
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#include <linux/init_task.h>
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#include <linux/module.h>
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#include <linux/mqueue.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/platform.h>
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#include <asm/mmu.h>
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#include <asm/irq.h>
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#include <linux/atomic.h>
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#include <asm/asm-offsets.h>
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#include <asm/regs.h>
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extern void ret_from_fork(void);
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struct task_struct *current_set[NR_CPUS] = {&init_task, };
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void (*pm_power_off)(void) = NULL;
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EXPORT_SYMBOL(pm_power_off);
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#if XTENSA_HAVE_COPROCESSORS
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void coprocessor_release_all(struct thread_info *ti)
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{
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unsigned long cpenable;
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int i;
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/* Make sure we don't switch tasks during this operation. */
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preempt_disable();
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/* Walk through all cp owners and release it for the requested one. */
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cpenable = ti->cpenable;
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for (i = 0; i < XCHAL_CP_MAX; i++) {
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if (coprocessor_owner[i] == ti) {
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coprocessor_owner[i] = 0;
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cpenable &= ~(1 << i);
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}
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}
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ti->cpenable = cpenable;
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coprocessor_clear_cpenable();
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preempt_enable();
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}
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void coprocessor_flush_all(struct thread_info *ti)
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{
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unsigned long cpenable;
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int i;
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preempt_disable();
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cpenable = ti->cpenable;
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for (i = 0; i < XCHAL_CP_MAX; i++) {
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if ((cpenable & 1) != 0 && coprocessor_owner[i] == ti)
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coprocessor_flush(ti, i);
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cpenable >>= 1;
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}
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preempt_enable();
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}
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#endif
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/*
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* Powermanagement idle function, if any is provided by the platform.
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*/
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void cpu_idle(void)
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{
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local_irq_enable();
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/* endless idle loop with no priority at all */
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while (1) {
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while (!need_resched())
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platform_idle();
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preempt_enable_no_resched();
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schedule();
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preempt_disable();
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}
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}
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/*
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* This is called when the thread calls exit().
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*/
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void exit_thread(void)
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{
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#if XTENSA_HAVE_COPROCESSORS
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coprocessor_release_all(current_thread_info());
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#endif
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}
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/*
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* Flush thread state. This is called when a thread does an execve()
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* Note that we flush coprocessor registers for the case execve fails.
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*/
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void flush_thread(void)
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{
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#if XTENSA_HAVE_COPROCESSORS
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struct thread_info *ti = current_thread_info();
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coprocessor_flush_all(ti);
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coprocessor_release_all(ti);
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#endif
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}
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/*
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* This is called before the thread is copied.
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*/
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void prepare_to_copy(struct task_struct *tsk)
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{
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#if XTENSA_HAVE_COPROCESSORS
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coprocessor_flush_all(task_thread_info(tsk));
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#endif
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}
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/*
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* Copy thread.
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*
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* The stack layout for the new thread looks like this:
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*
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* +------------------------+ <- sp in childregs (= tos)
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* | childregs |
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* +------------------------+ <- thread.sp = sp in dummy-frame
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* | dummy-frame | (saved in dummy-frame spill-area)
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* +------------------------+
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*
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* We create a dummy frame to return to ret_from_fork:
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* a0 points to ret_from_fork (simulating a call4)
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* sp points to itself (thread.sp)
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* a2, a3 are unused.
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*
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* Note: This is a pristine frame, so we don't need any spill region on top of
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* childregs.
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*/
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int copy_thread(unsigned long clone_flags, unsigned long usp,
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unsigned long unused,
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struct task_struct * p, struct pt_regs * regs)
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{
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struct pt_regs *childregs;
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struct thread_info *ti;
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unsigned long tos;
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int user_mode = user_mode(regs);
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/* Set up new TSS. */
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tos = (unsigned long)task_stack_page(p) + THREAD_SIZE;
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if (user_mode)
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childregs = (struct pt_regs*)(tos - PT_USER_SIZE);
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else
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childregs = (struct pt_regs*)tos - 1;
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*childregs = *regs;
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/* Create a call4 dummy-frame: a0 = 0, a1 = childregs. */
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*((int*)childregs - 3) = (unsigned long)childregs;
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*((int*)childregs - 4) = 0;
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childregs->areg[1] = tos;
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childregs->areg[2] = 0;
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p->set_child_tid = p->clear_child_tid = NULL;
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p->thread.ra = MAKE_RA_FOR_CALL((unsigned long)ret_from_fork, 0x1);
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p->thread.sp = (unsigned long)childregs;
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if (user_mode(regs)) {
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int len = childregs->wmask & ~0xf;
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childregs->areg[1] = usp;
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memcpy(&childregs->areg[XCHAL_NUM_AREGS - len/4],
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®s->areg[XCHAL_NUM_AREGS - len/4], len);
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// FIXME: we need to set THREADPTR in thread_info...
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if (clone_flags & CLONE_SETTLS)
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childregs->areg[2] = childregs->areg[6];
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} else {
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/* In kernel space, we start a new thread with a new stack. */
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childregs->wmask = 1;
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}
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#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)
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ti = task_thread_info(p);
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ti->cpenable = 0;
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#endif
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return 0;
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}
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/*
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* These bracket the sleeping functions..
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*/
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long sp, pc;
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unsigned long stack_page = (unsigned long) task_stack_page(p);
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int count = 0;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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sp = p->thread.sp;
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pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
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do {
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if (sp < stack_page + sizeof(struct task_struct) ||
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sp >= (stack_page + THREAD_SIZE) ||
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pc == 0)
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return 0;
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if (!in_sched_functions(pc))
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return pc;
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/* Stack layout: sp-4: ra, sp-3: sp' */
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pc = MAKE_PC_FROM_RA(*(unsigned long*)sp - 4, sp);
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sp = *(unsigned long *)sp - 3;
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} while (count++ < 16);
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return 0;
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}
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/*
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* xtensa_gregset_t and 'struct pt_regs' are vastly different formats
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* of processor registers. Besides different ordering,
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* xtensa_gregset_t contains non-live register information that
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* 'struct pt_regs' does not. Exception handling (primarily) uses
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* 'struct pt_regs'. Core files and ptrace use xtensa_gregset_t.
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*
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*/
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void xtensa_elf_core_copy_regs (xtensa_gregset_t *elfregs, struct pt_regs *regs)
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{
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unsigned long wb, ws, wm;
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int live, last;
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wb = regs->windowbase;
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ws = regs->windowstart;
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wm = regs->wmask;
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ws = ((ws >> wb) | (ws << (WSBITS - wb))) & ((1 << WSBITS) - 1);
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/* Don't leak any random bits. */
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memset(elfregs, 0, sizeof (elfregs));
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/* Note: PS.EXCM is not set while user task is running; its
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* being set in regs->ps is for exception handling convenience.
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*/
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elfregs->pc = regs->pc;
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elfregs->ps = (regs->ps & ~(1 << PS_EXCM_BIT));
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elfregs->lbeg = regs->lbeg;
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elfregs->lend = regs->lend;
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elfregs->lcount = regs->lcount;
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elfregs->sar = regs->sar;
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elfregs->windowstart = ws;
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live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
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last = XCHAL_NUM_AREGS - (wm >> 4) * 4;
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memcpy(elfregs->a, regs->areg, live * 4);
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memcpy(elfregs->a + last, regs->areg + last, (wm >> 4) * 16);
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}
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int dump_fpu(void)
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{
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return 0;
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}
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asmlinkage
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long xtensa_clone(unsigned long clone_flags, unsigned long newsp,
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void __user *parent_tid, void *child_tls,
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void __user *child_tid, long a5,
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struct pt_regs *regs)
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{
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if (!newsp)
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newsp = regs->areg[1];
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return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
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}
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/*
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* xtensa_execve() executes a new program.
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*/
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asmlinkage
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long xtensa_execve(const char __user *name,
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const char __user *const __user *argv,
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const char __user *const __user *envp,
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long a3, long a4, long a5,
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struct pt_regs *regs)
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{
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long error;
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char * filename;
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filename = getname(name);
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error = PTR_ERR(filename);
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if (IS_ERR(filename))
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goto out;
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error = do_execve(filename, argv, envp, regs);
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putname(filename);
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out:
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return error;
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}
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