1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
365 lines
8.8 KiB
C
365 lines
8.8 KiB
C
/*
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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) 1994 - 1999, 2000 by Ralf Baechle and others.
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* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
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* Copyright (C) 2004 Thiemo Seufer
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*/
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#include <linux/config.h>
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#include <linux/errno.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/mman.h>
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#include <linux/personality.h>
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#include <linux/sys.h>
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#include <linux/user.h>
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#include <linux/a.out.h>
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#include <linux/init.h>
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#include <linux/completion.h>
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#include <asm/bootinfo.h>
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#include <asm/cpu.h>
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#include <asm/fpu.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/mipsregs.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <asm/elf.h>
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#include <asm/isadep.h>
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#include <asm/inst.h>
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/*
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* We use this if we don't have any better idle routine..
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* (This to kill: kernel/platform.c.
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*/
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void default_idle (void)
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{
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}
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/*
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* The idle thread. There's no useful work to be done, so just try to conserve
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* power and have a low exit latency (ie sit in a loop waiting for somebody to
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* say that they'd like to reschedule)
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*/
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ATTRIB_NORET 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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if (cpu_wait)
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(*cpu_wait)();
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schedule();
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}
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}
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asmlinkage void ret_from_fork(void);
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void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
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{
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unsigned long status;
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/* New thread loses kernel privileges. */
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status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|KU_MASK);
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#ifdef CONFIG_MIPS64
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status &= ~ST0_FR;
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status |= (current->thread.mflags & MF_32BIT_REGS) ? 0 : ST0_FR;
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#endif
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status |= KU_USER;
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regs->cp0_status = status;
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clear_used_math();
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lose_fpu();
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regs->cp0_epc = pc;
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regs->regs[29] = sp;
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current_thread_info()->addr_limit = USER_DS;
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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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}
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int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
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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 *ti = p->thread_info;
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struct pt_regs *childregs;
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long childksp;
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childksp = (unsigned long)ti + THREAD_SIZE - 32;
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preempt_disable();
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if (is_fpu_owner()) {
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save_fp(p);
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}
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preempt_enable();
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/* set up new TSS. */
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childregs = (struct pt_regs *) childksp - 1;
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*childregs = *regs;
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childregs->regs[7] = 0; /* Clear error flag */
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#if defined(CONFIG_BINFMT_IRIX)
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if (current->personality != PER_LINUX) {
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/* Under IRIX things are a little different. */
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childregs->regs[3] = 1;
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regs->regs[3] = 0;
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}
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#endif
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childregs->regs[2] = 0; /* Child gets zero as return value */
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regs->regs[2] = p->pid;
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if (childregs->cp0_status & ST0_CU0) {
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childregs->regs[28] = (unsigned long) ti;
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childregs->regs[29] = childksp;
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ti->addr_limit = KERNEL_DS;
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} else {
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childregs->regs[29] = usp;
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ti->addr_limit = USER_DS;
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}
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p->thread.reg29 = (unsigned long) childregs;
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p->thread.reg31 = (unsigned long) ret_from_fork;
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/*
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* New tasks lose permission to use the fpu. This accelerates context
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* switching for most programs since they don't use the fpu.
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*/
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p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1);
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childregs->cp0_status &= ~(ST0_CU2|ST0_CU1);
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clear_tsk_thread_flag(p, TIF_USEDFPU);
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return 0;
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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 *r)
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{
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memcpy(r, ¤t->thread.fpu, sizeof(current->thread.fpu));
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return 1;
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}
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void dump_regs(elf_greg_t *gp, struct pt_regs *regs)
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{
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int i;
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for (i = 0; i < EF_R0; i++)
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gp[i] = 0;
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gp[EF_R0] = 0;
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for (i = 1; i <= 31; i++)
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gp[EF_R0 + i] = regs->regs[i];
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gp[EF_R26] = 0;
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gp[EF_R27] = 0;
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gp[EF_LO] = regs->lo;
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gp[EF_HI] = regs->hi;
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gp[EF_CP0_EPC] = regs->cp0_epc;
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gp[EF_CP0_BADVADDR] = regs->cp0_badvaddr;
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gp[EF_CP0_STATUS] = regs->cp0_status;
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gp[EF_CP0_CAUSE] = regs->cp0_cause;
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#ifdef EF_UNUSED0
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gp[EF_UNUSED0] = 0;
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#endif
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}
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int dump_task_fpu (struct task_struct *t, elf_fpregset_t *fpr)
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{
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memcpy(fpr, &t->thread.fpu, sizeof(current->thread.fpu));
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return 1;
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}
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/*
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* Create a kernel thread
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*/
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ATTRIB_NORET void kernel_thread_helper(void *arg, int (*fn)(void *))
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{
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do_exit(fn(arg));
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}
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long 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.regs[4] = (unsigned long) arg;
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regs.regs[5] = (unsigned long) fn;
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regs.cp0_epc = (unsigned long) kernel_thread_helper;
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regs.cp0_status = read_c0_status();
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#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
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regs.cp0_status &= ~(ST0_KUP | ST0_IEC);
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regs.cp0_status |= ST0_IEP;
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#else
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regs.cp0_status |= ST0_EXL;
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#endif
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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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struct mips_frame_info {
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int frame_offset;
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int pc_offset;
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};
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static struct mips_frame_info schedule_frame;
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static struct mips_frame_info schedule_timeout_frame;
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static struct mips_frame_info sleep_on_frame;
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static struct mips_frame_info sleep_on_timeout_frame;
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static struct mips_frame_info wait_for_completion_frame;
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static int mips_frame_info_initialized;
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static int __init get_frame_info(struct mips_frame_info *info, void *func)
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{
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int i;
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union mips_instruction *ip = (union mips_instruction *)func;
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info->pc_offset = -1;
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info->frame_offset = -1;
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for (i = 0; i < 128; i++, ip++) {
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/* if jal, jalr, jr, stop. */
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if (ip->j_format.opcode == jal_op ||
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(ip->r_format.opcode == spec_op &&
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(ip->r_format.func == jalr_op ||
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ip->r_format.func == jr_op)))
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break;
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if (
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#ifdef CONFIG_MIPS32
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ip->i_format.opcode == sw_op &&
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#endif
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#ifdef CONFIG_MIPS64
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ip->i_format.opcode == sd_op &&
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#endif
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ip->i_format.rs == 29)
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{
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/* sw / sd $ra, offset($sp) */
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if (ip->i_format.rt == 31) {
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if (info->pc_offset != -1)
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break;
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info->pc_offset =
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ip->i_format.simmediate / sizeof(long);
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}
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/* sw / sd $s8, offset($sp) */
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if (ip->i_format.rt == 30) {
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if (info->frame_offset != -1)
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break;
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info->frame_offset =
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ip->i_format.simmediate / sizeof(long);
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}
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}
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}
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if (info->pc_offset == -1 || info->frame_offset == -1) {
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printk("Can't analyze prologue code at %p\n", func);
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info->pc_offset = -1;
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info->frame_offset = -1;
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return -1;
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}
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return 0;
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}
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static int __init frame_info_init(void)
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{
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mips_frame_info_initialized =
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!get_frame_info(&schedule_frame, schedule) &&
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!get_frame_info(&schedule_timeout_frame, schedule_timeout) &&
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!get_frame_info(&sleep_on_frame, sleep_on) &&
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!get_frame_info(&sleep_on_timeout_frame, sleep_on_timeout) &&
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!get_frame_info(&wait_for_completion_frame, wait_for_completion);
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return 0;
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}
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arch_initcall(frame_info_init);
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/*
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* Return saved PC of a blocked thread.
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*/
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unsigned long thread_saved_pc(struct task_struct *tsk)
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{
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struct thread_struct *t = &tsk->thread;
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/* New born processes are a special case */
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if (t->reg31 == (unsigned long) ret_from_fork)
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return t->reg31;
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if (schedule_frame.pc_offset < 0)
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return 0;
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return ((unsigned long *)t->reg29)[schedule_frame.pc_offset];
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}
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/* get_wchan - a maintenance nightmare^W^Wpain in the ass ... */
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unsigned long get_wchan(struct task_struct *p)
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{
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unsigned long frame, pc;
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if (!p || p == current || p->state == TASK_RUNNING)
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return 0;
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if (!mips_frame_info_initialized)
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return 0;
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pc = thread_saved_pc(p);
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if (!in_sched_functions(pc))
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goto out;
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if (pc >= (unsigned long) sleep_on_timeout)
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goto schedule_timeout_caller;
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if (pc >= (unsigned long) sleep_on)
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goto schedule_caller;
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if (pc >= (unsigned long) interruptible_sleep_on_timeout)
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goto schedule_timeout_caller;
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if (pc >= (unsigned long)interruptible_sleep_on)
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goto schedule_caller;
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if (pc >= (unsigned long)wait_for_completion)
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goto schedule_caller;
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goto schedule_timeout_caller;
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schedule_caller:
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frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
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if (pc >= (unsigned long) sleep_on)
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pc = ((unsigned long *)frame)[sleep_on_frame.pc_offset];
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else
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pc = ((unsigned long *)frame)[wait_for_completion_frame.pc_offset];
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goto out;
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schedule_timeout_caller:
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/*
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* The schedule_timeout frame
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*/
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frame = ((unsigned long *)p->thread.reg30)[schedule_frame.frame_offset];
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/*
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* frame now points to sleep_on_timeout's frame
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*/
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pc = ((unsigned long *)frame)[schedule_timeout_frame.pc_offset];
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if (in_sched_functions(pc)) {
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/* schedule_timeout called by [interruptible_]sleep_on_timeout */
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frame = ((unsigned long *)frame)[schedule_timeout_frame.frame_offset];
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pc = ((unsigned long *)frame)[sleep_on_timeout_frame.pc_offset];
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}
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out:
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#ifdef CONFIG_MIPS64
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if (current->thread.mflags & MF_32BIT_REGS) /* Kludge for 32-bit ps */
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pc &= 0xffffffffUL;
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#endif
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return pc;
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}
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EXPORT_SYMBOL(get_wchan);
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