mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 10:26:42 +07:00
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>
395 lines
9.3 KiB
C
395 lines
9.3 KiB
C
/*
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* linux/arch/arm26/kernel/process.c
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*
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* Copyright (C) 2003 Ian Molton - adapted for ARM26
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* Copyright (C) 1996-2000 Russell King - Converted to ARM.
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* Origional Copyright (C) 1995 Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <stdarg.h>
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#include <linux/config.h>
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#include <linux/module.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/stddef.h>
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#include <linux/unistd.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/delay.h>
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#include <linux/reboot.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/leds.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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extern const char *processor_modes[];
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extern void setup_mm_for_reboot(char mode);
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static volatile int hlt_counter;
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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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static int __init nohlt_setup(char *__unused)
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{
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hlt_counter = 1;
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return 1;
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}
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static int __init hlt_setup(char *__unused)
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{
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hlt_counter = 0;
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return 1;
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}
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__setup("nohlt", nohlt_setup);
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__setup("hlt", hlt_setup);
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/*
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* This is our default idle handler. We need to disable
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* interrupts here to ensure we don't miss a wakeup call.
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*/
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void cpu_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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while (!need_resched())
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cpu_relax();
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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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static char reboot_mode = 'h';
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int __init reboot_setup(char *str)
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{
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reboot_mode = str[0];
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return 1;
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}
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__setup("reboot=", reboot_setup);
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/* ARM26 cant do these but we still need to define them. */
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void machine_halt(void)
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{
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}
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void machine_power_off(void)
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{
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}
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void machine_restart(char * __unused)
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{
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/*
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* Clean and disable cache, and turn off interrupts
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*/
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cpu_proc_fin();
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/*
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* Tell the mm system that we are going to reboot -
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* we may need it to insert some 1:1 mappings so that
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* soft boot works.
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*/
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setup_mm_for_reboot(reboot_mode);
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/*
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* copy branch instruction to reset location and call it
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*/
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*(unsigned long *)0 = *(unsigned long *)0x03800000;
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((void(*)(void))0)();
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/*
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* Whoops - the architecture was unable to reboot.
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* Tell the user! Should never happen...
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*/
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mdelay(1000);
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printk("Reboot failed -- System halted\n");
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while (1);
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}
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void show_regs(struct pt_regs * regs)
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{
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unsigned long flags;
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flags = condition_codes(regs);
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printk("pc : [<%08lx>] lr : [<%08lx>] %s\n"
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"sp : %08lx ip : %08lx fp : %08lx\n",
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instruction_pointer(regs),
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regs->ARM_lr, print_tainted(), regs->ARM_sp,
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regs->ARM_ip, regs->ARM_fp);
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printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
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regs->ARM_r10, regs->ARM_r9,
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regs->ARM_r8);
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printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
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regs->ARM_r7, regs->ARM_r6,
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regs->ARM_r5, regs->ARM_r4);
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printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
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regs->ARM_r3, regs->ARM_r2,
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regs->ARM_r1, regs->ARM_r0);
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printk("Flags: %c%c%c%c",
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flags & PSR_N_BIT ? 'N' : 'n',
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flags & PSR_Z_BIT ? 'Z' : 'z',
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flags & PSR_C_BIT ? 'C' : 'c',
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flags & PSR_V_BIT ? 'V' : 'v');
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printk(" IRQs o%s FIQs o%s Mode %s Segment %s\n",
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interrupts_enabled(regs) ? "n" : "ff",
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fast_interrupts_enabled(regs) ? "n" : "ff",
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processor_modes[processor_mode(regs)],
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get_fs() == get_ds() ? "kernel" : "user");
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}
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void show_fpregs(struct user_fp *regs)
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{
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int i;
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for (i = 0; i < 8; i++) {
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unsigned long *p;
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char type;
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p = (unsigned long *)(regs->fpregs + i);
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switch (regs->ftype[i]) {
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case 1: type = 'f'; break;
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case 2: type = 'd'; break;
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case 3: type = 'e'; break;
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default: type = '?'; break;
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}
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if (regs->init_flag)
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type = '?';
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printk(" f%d(%c): %08lx %08lx %08lx%c",
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i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
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}
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printk("FPSR: %08lx FPCR: %08lx\n",
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(unsigned long)regs->fpsr,
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(unsigned long)regs->fpcr);
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}
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/*
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* Task structure and kernel stack allocation.
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*/
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static unsigned long *thread_info_head;
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static unsigned int nr_thread_info;
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extern unsigned long get_page_8k(int priority);
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extern void free_page_8k(unsigned long page);
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// FIXME - is this valid?
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#define EXTRA_TASK_STRUCT 0
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#define ll_alloc_task_struct() ((struct thread_info *)get_page_8k(GFP_KERNEL))
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#define ll_free_task_struct(p) free_page_8k((unsigned long)(p))
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//FIXME - do we use *task param below looks like we dont, which is ok?
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//FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
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struct thread_info *alloc_thread_info(struct task_struct *task)
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{
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struct thread_info *thread = NULL;
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if (EXTRA_TASK_STRUCT) {
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unsigned long *p = thread_info_head;
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if (p) {
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thread_info_head = (unsigned long *)p[0];
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nr_thread_info -= 1;
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}
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thread = (struct thread_info *)p;
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}
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if (!thread)
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thread = ll_alloc_task_struct();
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#ifdef CONFIG_MAGIC_SYSRQ
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/*
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* The stack must be cleared if you want SYSRQ-T to
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* give sensible stack usage information
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*/
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if (thread) {
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char *p = (char *)thread;
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memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
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}
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#endif
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return thread;
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}
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void free_thread_info(struct thread_info *thread)
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{
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if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
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unsigned long *p = (unsigned long *)thread;
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p[0] = (unsigned long)thread_info_head;
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thread_info_head = p;
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nr_thread_info += 1;
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} else
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ll_free_task_struct(thread);
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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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}
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void flush_thread(void)
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{
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struct thread_info *thread = current_thread_info();
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struct task_struct *tsk = current;
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memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
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memset(&thread->fpstate, 0, sizeof(union fp_state));
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clear_used_math();
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}
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void release_thread(struct task_struct *dead_task)
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{
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}
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asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
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int
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copy_thread(int nr, unsigned long clone_flags, unsigned long stack_start,
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unsigned long unused, struct task_struct *p, struct pt_regs *regs)
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{
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struct thread_info *thread = p->thread_info;
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struct pt_regs *childregs;
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childregs = __get_user_regs(thread);
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*childregs = *regs;
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childregs->ARM_r0 = 0;
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childregs->ARM_sp = stack_start;
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memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
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thread->cpu_context.sp = (unsigned long)childregs;
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thread->cpu_context.pc = (unsigned long)ret_from_fork | MODE_SVC26 | PSR_I_BIT;
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return 0;
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}
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/*
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* fill in the fpe structure for a core dump...
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*/
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int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
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{
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struct thread_info *thread = current_thread_info();
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int used_math = !!used_math();
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if (used_math)
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memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
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return used_math;
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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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struct task_struct *tsk = current;
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dump->magic = CMAGIC;
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dump->start_code = tsk->mm->start_code;
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dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
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dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
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dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
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dump->u_ssize = 0;
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dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
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dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
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dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn;
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dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
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dump->u_debugreg[4] = tsk->thread.debug.nsaved;
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if (dump->start_stack < 0x04000000)
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dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
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dump->regs = *regs;
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dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
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}
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/*
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* Shuffle the argument into the correct register before calling the
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* thread function. r1 is the thread argument, r2 is the pointer to
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* the thread function, and r3 points to the exit function.
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* FIXME - make sure this is right - the older code used to zero fp
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* and cause the parent to call sys_exit (do_exit in this version)
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*/
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extern void kernel_thread_helper(void);
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asm( ".section .text\n"
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" .align\n"
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" .type kernel_thread_helper, #function\n"
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"kernel_thread_helper:\n"
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" mov r0, r1\n"
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" mov lr, r3\n"
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" mov pc, r2\n"
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" .size kernel_thread_helper, . - kernel_thread_helper\n"
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" .previous");
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/*
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* Create a kernel thread.
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*/
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pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
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{
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struct pt_regs regs;
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memset(®s, 0, sizeof(regs));
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regs.ARM_r1 = (unsigned long)arg;
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regs.ARM_r2 = (unsigned long)fn;
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regs.ARM_r3 = (unsigned long)do_exit;
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regs.ARM_pc = (unsigned long)kernel_thread_helper | MODE_SVC26;
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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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EXPORT_SYMBOL(kernel_thread);
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long fp, lr;
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unsigned long stack_page;
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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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stack_page = 4096 + (unsigned long)p;
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fp = thread_saved_fp(p);
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do {
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if (fp < stack_page || fp > 4092+stack_page)
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return 0;
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lr = pc_pointer (((unsigned long *)fp)[-1]);
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if (!in_sched_functions(lr))
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return lr;
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fp = *(unsigned long *) (fp - 12);
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} while (count ++ < 16);
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return 0;
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}
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