5bfb5d690f
Run idle threads with preempt disabled. Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()). How did it ever work before? Might fix the CPU hotplugging hang which Nigel Cunningham noted. We think the bug hits if the idle thread is preempted after checking need_resched() and before going to sleep, then the CPU offlined. After calling stop_machine_run, the CPU eventually returns from preemption and into the idle thread and goes to sleep. The CPU will continue executing previous idle and have no chance to call play_dead. By disabling preemption until we are ready to explicitly schedule, this bug is fixed and the idle threads generally become more robust. From: alexs <ashepard@u.washington.edu> PPC build fix From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> MIPS build fix Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
527 lines
12 KiB
C
527 lines
12 KiB
C
/* $Id: process.c,v 1.28 2004/05/05 16:54:23 lethal Exp $
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*
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* linux/arch/sh/kernel/process.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*
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* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
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*/
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/*
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* This file handles the architecture-dependent parts of process handling..
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*/
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#include <linux/module.h>
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#include <linux/unistd.h>
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#include <linux/mm.h>
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#include <linux/elfcore.h>
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#include <linux/slab.h>
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#include <linux/a.out.h>
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#include <linux/ptrace.h>
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#include <linux/platform.h>
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#include <linux/kallsyms.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/elf.h>
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#if defined(CONFIG_SH_HS7751RVOIP)
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#include <asm/hs7751rvoip/hs7751rvoip.h>
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#elif defined(CONFIG_SH_RTS7751R2D)
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#include <asm/rts7751r2d/rts7751r2d.h>
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#endif
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static int hlt_counter=0;
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int ubc_usercnt = 0;
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#define HARD_IDLE_TIMEOUT (HZ / 3)
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void disable_hlt(void)
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{
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hlt_counter++;
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}
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EXPORT_SYMBOL(disable_hlt);
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void enable_hlt(void)
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{
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hlt_counter--;
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}
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EXPORT_SYMBOL(enable_hlt);
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void default_idle(void)
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{
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/* endless idle loop with no priority at all */
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while (1) {
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if (hlt_counter) {
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while (1)
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if (need_resched())
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break;
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} else {
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while (!need_resched())
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cpu_sleep();
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}
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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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void cpu_idle(void)
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{
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default_idle();
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}
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void machine_restart(char * __unused)
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{
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/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
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asm volatile("ldc %0, sr\n\t"
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"mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
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}
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void machine_halt(void)
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{
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#if defined(CONFIG_SH_HS7751RVOIP)
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unsigned short value;
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value = ctrl_inw(PA_OUTPORTR);
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ctrl_outw((value & 0xffdf), PA_OUTPORTR);
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#elif defined(CONFIG_SH_RTS7751R2D)
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ctrl_outw(0x0001, PA_POWOFF);
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#endif
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while (1)
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cpu_sleep();
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}
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void machine_power_off(void)
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{
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#if defined(CONFIG_SH_HS7751RVOIP)
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unsigned short value;
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value = ctrl_inw(PA_OUTPORTR);
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ctrl_outw((value & 0xffdf), PA_OUTPORTR);
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#elif defined(CONFIG_SH_RTS7751R2D)
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ctrl_outw(0x0001, PA_POWOFF);
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#endif
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}
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void show_regs(struct pt_regs * regs)
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{
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printk("\n");
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printk("Pid : %d, Comm: %20s\n", current->pid, current->comm);
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print_symbol("PC is at %s\n", regs->pc);
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printk("PC : %08lx SP : %08lx SR : %08lx ",
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regs->pc, regs->regs[15], regs->sr);
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#ifdef CONFIG_MMU
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printk("TEA : %08x ", ctrl_inl(MMU_TEA));
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#else
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printk(" ");
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#endif
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printk("%s\n", print_tainted());
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printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n",
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regs->regs[0],regs->regs[1],
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regs->regs[2],regs->regs[3]);
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printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n",
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regs->regs[4],regs->regs[5],
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regs->regs[6],regs->regs[7]);
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printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n",
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regs->regs[8],regs->regs[9],
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regs->regs[10],regs->regs[11]);
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printk("R12 : %08lx R13 : %08lx R14 : %08lx\n",
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regs->regs[12],regs->regs[13],
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regs->regs[14]);
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printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n",
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regs->mach, regs->macl, regs->gbr, regs->pr);
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/*
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* If we're in kernel mode, dump the stack too..
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*/
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if (!user_mode(regs)) {
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extern void show_task(unsigned long *sp);
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unsigned long sp = regs->regs[15];
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show_task((unsigned long *)sp);
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}
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}
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/*
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* Create a kernel thread
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*/
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/*
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* This is the mechanism for creating a new kernel thread.
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*
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*/
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extern void kernel_thread_helper(void);
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__asm__(".align 5\n"
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"kernel_thread_helper:\n\t"
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"jsr @r5\n\t"
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" nop\n\t"
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"mov.l 1f, r1\n\t"
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"jsr @r1\n\t"
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" mov r0, r4\n\t"
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".align 2\n\t"
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"1:.long do_exit");
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int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
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{ /* Don't use this in BL=1(cli). Or else, CPU resets! */
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.regs[4] = (unsigned long) arg;
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regs.regs[5] = (unsigned long) fn;
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regs.pc = (unsigned long) kernel_thread_helper;
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regs.sr = (1 << 30);
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/* Ok, create the new process.. */
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
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}
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/*
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* Free current thread data structures etc..
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*/
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void exit_thread(void)
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{
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if (current->thread.ubc_pc) {
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current->thread.ubc_pc = 0;
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ubc_usercnt -= 1;
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}
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}
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void flush_thread(void)
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{
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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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struct pt_regs *regs = (struct pt_regs *)
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((unsigned long)tsk->thread_info
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+ THREAD_SIZE - sizeof(struct pt_regs)
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- sizeof(unsigned long));
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/* Forget lazy FPU state */
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clear_fpu(tsk, regs);
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clear_used_math();
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#endif
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}
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void release_thread(struct task_struct *dead_task)
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{
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/* do nothing */
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}
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/* Fill in the fpu structure for a core dump.. */
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
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{
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int fpvalid = 0;
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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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fpvalid = !!tsk_used_math(tsk);
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if (fpvalid) {
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unlazy_fpu(tsk, regs);
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memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
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}
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#endif
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return fpvalid;
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}
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/*
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* Capture the user space registers if the task is not running (in user space)
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*/
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int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
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{
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struct pt_regs ptregs;
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ptregs = *(struct pt_regs *)
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((unsigned long)tsk->thread_info + THREAD_SIZE
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- sizeof(struct pt_regs)
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#ifdef CONFIG_SH_DSP
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- sizeof(struct pt_dspregs)
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#endif
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- sizeof(unsigned long));
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elf_core_copy_regs(regs, &ptregs);
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return 1;
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}
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int
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dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *fpu)
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{
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int fpvalid = 0;
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#if defined(CONFIG_SH_FPU)
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fpvalid = !!tsk_used_math(tsk);
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if (fpvalid) {
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struct pt_regs *regs = (struct pt_regs *)
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((unsigned long)tsk->thread_info
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+ THREAD_SIZE - sizeof(struct pt_regs)
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- sizeof(unsigned long));
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unlazy_fpu(tsk, regs);
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memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu));
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}
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#endif
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return fpvalid;
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}
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asmlinkage void ret_from_fork(void);
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int copy_thread(int nr, 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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#if defined(CONFIG_SH_FPU)
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struct task_struct *tsk = current;
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unlazy_fpu(tsk, regs);
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p->thread.fpu = tsk->thread.fpu;
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copy_to_stopped_child_used_math(p);
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#endif
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childregs = ((struct pt_regs *)
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(THREAD_SIZE + (unsigned long) p->thread_info)
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#ifdef CONFIG_SH_DSP
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- sizeof(struct pt_dspregs)
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#endif
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- sizeof(unsigned long)) - 1;
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*childregs = *regs;
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if (user_mode(regs)) {
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childregs->regs[15] = usp;
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} else {
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childregs->regs[15] = (unsigned long)p->thread_info + THREAD_SIZE;
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}
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if (clone_flags & CLONE_SETTLS) {
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childregs->gbr = childregs->regs[0];
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}
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childregs->regs[0] = 0; /* Set return value for child */
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p->thread.sp = (unsigned long) childregs;
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p->thread.pc = (unsigned long) ret_from_fork;
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p->thread.ubc_pc = 0;
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return 0;
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}
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/*
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* fill in the user structure for a core dump..
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*/
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void dump_thread(struct pt_regs * regs, struct user * dump)
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{
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dump->magic = CMAGIC;
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dump->start_code = current->mm->start_code;
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dump->start_data = current->mm->start_data;
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dump->start_stack = regs->regs[15] & ~(PAGE_SIZE - 1);
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dump->u_tsize = (current->mm->end_code - dump->start_code) >> PAGE_SHIFT;
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dump->u_dsize = (current->mm->brk + (PAGE_SIZE-1) - dump->start_data) >> PAGE_SHIFT;
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dump->u_ssize = (current->mm->start_stack - dump->start_stack +
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PAGE_SIZE - 1) >> PAGE_SHIFT;
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/* Debug registers will come here. */
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dump->regs = *regs;
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dump->u_fpvalid = dump_fpu(regs, &dump->fpu);
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}
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/* Tracing by user break controller. */
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static void
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ubc_set_tracing(int asid, unsigned long pc)
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{
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ctrl_outl(pc, UBC_BARA);
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/* We don't have any ASID settings for the SH-2! */
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if (cpu_data->type != CPU_SH7604)
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ctrl_outb(asid, UBC_BASRA);
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ctrl_outl(0, UBC_BAMRA);
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if (cpu_data->type == CPU_SH7729) {
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ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA);
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ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR);
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} else {
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ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA);
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ctrl_outw(BRCR_PCBA, UBC_BRCR);
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}
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}
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/*
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* switch_to(x,y) should switch tasks from x to y.
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*
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*/
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struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)
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{
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#if defined(CONFIG_SH_FPU)
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struct pt_regs *regs = (struct pt_regs *)
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((unsigned long)prev->thread_info
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+ THREAD_SIZE - sizeof(struct pt_regs)
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- sizeof(unsigned long));
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unlazy_fpu(prev, regs);
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#endif
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#ifdef CONFIG_PREEMPT
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{
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unsigned long flags;
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struct pt_regs *regs;
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local_irq_save(flags);
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regs = (struct pt_regs *)
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((unsigned long)prev->thread_info
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+ THREAD_SIZE - sizeof(struct pt_regs)
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#ifdef CONFIG_SH_DSP
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- sizeof(struct pt_dspregs)
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#endif
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- sizeof(unsigned long));
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if (user_mode(regs) && regs->regs[15] >= 0xc0000000) {
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int offset = (int)regs->regs[15];
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/* Reset stack pointer: clear critical region mark */
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regs->regs[15] = regs->regs[1];
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if (regs->pc < regs->regs[0])
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/* Go to rewind point */
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regs->pc = regs->regs[0] + offset;
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}
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local_irq_restore(flags);
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}
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#endif
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/*
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* Restore the kernel mode register
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* k7 (r7_bank1)
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*/
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asm volatile("ldc %0, r7_bank"
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: /* no output */
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: "r" (next->thread_info));
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#ifdef CONFIG_MMU
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/* If no tasks are using the UBC, we're done */
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if (ubc_usercnt == 0)
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/* If no tasks are using the UBC, we're done */;
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else if (next->thread.ubc_pc && next->mm) {
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ubc_set_tracing(next->mm->context & MMU_CONTEXT_ASID_MASK,
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next->thread.ubc_pc);
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} else {
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ctrl_outw(0, UBC_BBRA);
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ctrl_outw(0, UBC_BBRB);
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}
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#endif
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return prev;
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}
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asmlinkage int sys_fork(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs regs)
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{
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#ifdef CONFIG_MMU
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return do_fork(SIGCHLD, regs.regs[15], ®s, 0, NULL, NULL);
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#else
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/* fork almost works, enough to trick you into looking elsewhere :-( */
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return -EINVAL;
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#endif
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}
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asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
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unsigned long parent_tidptr,
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unsigned long child_tidptr,
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struct pt_regs regs)
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{
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if (!newsp)
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newsp = regs.regs[15];
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return do_fork(clone_flags, newsp, ®s, 0,
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(int __user *)parent_tidptr, (int __user *)child_tidptr);
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}
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/*
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* This is trivial, and on the face of it looks like it
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* could equally well be done in user mode.
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*
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* Not so, for quite unobvious reasons - register pressure.
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* In user mode vfork() cannot have a stack frame, and if
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* done by calling the "clone()" system call directly, you
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* do not have enough call-clobbered registers to hold all
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* the information you need.
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*/
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asmlinkage int sys_vfork(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs regs)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.regs[15], ®s,
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0, NULL, NULL);
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}
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/*
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* sys_execve() executes a new program.
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*/
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asmlinkage int sys_execve(char *ufilename, char **uargv,
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char **uenvp, unsigned long r7,
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struct pt_regs regs)
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{
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int error;
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char *filename;
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filename = getname((char __user *)ufilename);
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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,
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(char __user * __user *)uargv,
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(char __user * __user *)uenvp,
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®s);
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if (error == 0) {
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task_lock(current);
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current->ptrace &= ~PT_DTRACE;
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task_unlock(current);
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}
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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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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long schedule_frame;
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unsigned long pc;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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/*
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* The same comment as on the Alpha applies here, too ...
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*/
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pc = thread_saved_pc(p);
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if (in_sched_functions(pc)) {
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schedule_frame = ((unsigned long *)(long)p->thread.sp)[1];
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return (unsigned long)((unsigned long *)schedule_frame)[1];
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}
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return pc;
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}
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asmlinkage void break_point_trap(unsigned long r4, unsigned long r5,
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unsigned long r6, unsigned long r7,
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struct pt_regs regs)
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|
{
|
|
/* Clear tracing. */
|
|
ctrl_outw(0, UBC_BBRA);
|
|
ctrl_outw(0, UBC_BBRB);
|
|
current->thread.ubc_pc = 0;
|
|
ubc_usercnt -= 1;
|
|
|
|
force_sig(SIGTRAP, current);
|
|
}
|
|
|
|
asmlinkage void break_point_trap_software(unsigned long r4, unsigned long r5,
|
|
unsigned long r6, unsigned long r7,
|
|
struct pt_regs regs)
|
|
{
|
|
regs.pc -= 2;
|
|
force_sig(SIGTRAP, current);
|
|
}
|