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d5adb029ef
Previously, init failed to do anything meaningful;
it turns out that the reason is that FD-PIC has a readonly data
section which can be located in the XIP filesystem, and various address checks
in the kernel reject such addresses for syscall arguments. Hence, init's
execve ("/bin/sh", ...)
failed with error code EFAULT.
There's room for improvement here: in case people want to have filesystems
on flash rather than in main memory, _access_ok should be modified to
allow this.
This bug fix is also dedicated to Michael Hennerich.
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
362 lines
8.4 KiB
C
362 lines
8.4 KiB
C
/*
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* File: arch/blackfin/kernel/process.c
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* Based on:
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* Author:
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*
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* Created:
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* Description: Blackfin architecture-dependent process handling.
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*
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* Modified:
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* Copyright 2004-2006 Analog Devices Inc.
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*
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* Bugs: Enter bugs at http://blackfin.uclinux.org/
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see the file COPYING, or write
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* to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/module.h>
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#include <linux/smp_lock.h>
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#include <linux/unistd.h>
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#include <linux/user.h>
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#include <linux/uaccess.h>
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#include <linux/sched.h>
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#include <linux/tick.h>
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#include <linux/fs.h>
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#include <linux/err.h>
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#include <asm/blackfin.h>
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#include <asm/fixed_code.h>
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asmlinkage void ret_from_fork(void);
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/* Points to the SDRAM backup memory for the stack that is currently in
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* L1 scratchpad memory.
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*/
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void *current_l1_stack_save;
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/* The number of tasks currently using a L1 stack area. The SRAM is
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* allocated/deallocated whenever this changes from/to zero.
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*/
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int nr_l1stack_tasks;
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/* Start and length of the area in L1 scratchpad memory which we've allocated
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* for process stacks.
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*/
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void *l1_stack_base;
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unsigned long l1_stack_len;
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/*
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* Powermanagement idle function, if any..
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*/
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void (*pm_idle)(void) = NULL;
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EXPORT_SYMBOL(pm_idle);
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void (*pm_power_off)(void) = NULL;
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EXPORT_SYMBOL(pm_power_off);
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/*
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* The idle loop on BFIN
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*/
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#ifdef CONFIG_IDLE_L1
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static void default_idle(void)__attribute__((l1_text));
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void cpu_idle(void)__attribute__((l1_text));
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#endif
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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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static void default_idle(void)
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{
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local_irq_disable();
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if (!need_resched())
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idle_with_irq_disabled();
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local_irq_enable();
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}
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/*
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* The idle thread. We try to conserve power, while trying to keep
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* overall latency low. The architecture specific idle is passed
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* a value to indicate the level of "idleness" of the system.
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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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void (*idle)(void) = pm_idle;
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#ifdef CONFIG_HOTPLUG_CPU
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if (cpu_is_offline(smp_processor_id()))
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cpu_die();
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#endif
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if (!idle)
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idle = default_idle;
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tick_nohz_stop_sched_tick();
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while (!need_resched())
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idle();
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tick_nohz_restart_sched_tick();
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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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/* Fill in the fpu structure for a core dump. */
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int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
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{
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return 1;
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}
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/*
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* This gets run with P1 containing the
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* function to call, and R1 containing
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* the "args". Note P0 is clobbered on the way here.
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*/
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void kernel_thread_helper(void);
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__asm__(".section .text\n"
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".align 4\n"
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"_kernel_thread_helper:\n\t"
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"\tsp += -12;\n\t"
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"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".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.r1 = (unsigned long)arg;
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regs.p1 = (unsigned long)fn;
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regs.pc = (unsigned long)kernel_thread_helper;
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regs.orig_p0 = -1;
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/* Set bit 2 to tell ret_from_fork we should be returning to kernel
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mode. */
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regs.ipend = 0x8002;
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__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
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return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, 0, NULL,
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NULL);
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}
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void flush_thread(void)
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{
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}
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asmlinkage int bfin_vfork(struct pt_regs *regs)
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{
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return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
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NULL);
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}
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asmlinkage int bfin_clone(struct pt_regs *regs)
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{
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unsigned long clone_flags;
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unsigned long newsp;
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/* syscall2 puts clone_flags in r0 and usp in r1 */
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clone_flags = regs->r0;
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newsp = regs->r1;
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if (!newsp)
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newsp = rdusp();
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else
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newsp -= 12;
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return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
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}
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int
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copy_thread(int nr, unsigned long clone_flags,
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unsigned long usp, unsigned long topstk,
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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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childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
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*childregs = *regs;
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childregs->r0 = 0;
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p->thread.usp = usp;
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p->thread.ksp = (unsigned long)childregs;
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p->thread.pc = (unsigned long)ret_from_fork;
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return 0;
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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 __user *name, char __user * __user *argv, char __user * __user *envp)
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{
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int error;
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char *filename;
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struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
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lock_kernel();
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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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unlock_kernel();
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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 fp, pc;
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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 = (unsigned long)p;
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fp = p->thread.usp;
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do {
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if (fp < stack_page + sizeof(struct thread_info) ||
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fp >= 8184 + stack_page)
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return 0;
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pc = ((unsigned long *)fp)[1];
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if (!in_sched_functions(pc))
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return pc;
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fp = *(unsigned long *)fp;
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}
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while (count++ < 16);
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return 0;
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}
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void finish_atomic_sections (struct pt_regs *regs)
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{
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int __user *up0 = (int __user *)®s->p0;
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if (regs->pc < ATOMIC_SEQS_START || regs->pc >= ATOMIC_SEQS_END)
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return;
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switch (regs->pc) {
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case ATOMIC_XCHG32 + 2:
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put_user(regs->r1, up0);
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regs->pc += 2;
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break;
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case ATOMIC_CAS32 + 2:
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case ATOMIC_CAS32 + 4:
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if (regs->r0 == regs->r1)
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put_user(regs->r2, up0);
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regs->pc = ATOMIC_CAS32 + 8;
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break;
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case ATOMIC_CAS32 + 6:
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put_user(regs->r2, up0);
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regs->pc += 2;
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break;
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case ATOMIC_ADD32 + 2:
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regs->r0 = regs->r1 + regs->r0;
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/* fall through */
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case ATOMIC_ADD32 + 4:
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put_user(regs->r0, up0);
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regs->pc = ATOMIC_ADD32 + 6;
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break;
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case ATOMIC_SUB32 + 2:
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regs->r0 = regs->r1 - regs->r0;
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/* fall through */
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case ATOMIC_SUB32 + 4:
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put_user(regs->r0, up0);
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regs->pc = ATOMIC_SUB32 + 6;
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break;
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case ATOMIC_IOR32 + 2:
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regs->r0 = regs->r1 | regs->r0;
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/* fall through */
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case ATOMIC_IOR32 + 4:
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put_user(regs->r0, up0);
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regs->pc = ATOMIC_IOR32 + 6;
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break;
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case ATOMIC_AND32 + 2:
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regs->r0 = regs->r1 & regs->r0;
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/* fall through */
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case ATOMIC_AND32 + 4:
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put_user(regs->r0, up0);
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regs->pc = ATOMIC_AND32 + 6;
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break;
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case ATOMIC_XOR32 + 2:
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regs->r0 = regs->r1 ^ regs->r0;
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/* fall through */
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case ATOMIC_XOR32 + 4:
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put_user(regs->r0, up0);
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regs->pc = ATOMIC_XOR32 + 6;
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break;
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}
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}
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#if defined(CONFIG_ACCESS_CHECK)
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/* Return 1 if access to memory range is OK, 0 otherwise */
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int _access_ok(unsigned long addr, unsigned long size)
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{
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if (size == 0)
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return 1;
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if (addr > (addr + size))
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return 0;
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if (segment_eq(get_fs(), KERNEL_DS))
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return 1;
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#ifdef CONFIG_MTD_UCLINUX
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if (addr >= memory_start && (addr + size) <= memory_end)
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return 1;
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if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
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return 1;
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#ifdef CONFIG_ROMFS_MTD_FS
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/* For XIP, allow user space to use pointers within the ROMFS. */
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if (addr >= memory_mtd_start && (addr + size) <= memory_mtd_end)
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return 1;
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#endif
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#else
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if (addr >= memory_start && (addr + size) <= physical_mem_end)
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return 1;
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#endif
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if (addr >= (unsigned long)__init_begin &&
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addr + size <= (unsigned long)__init_end)
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return 1;
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if (addr >= L1_SCRATCH_START
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&& addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
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return 1;
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#if L1_CODE_LENGTH != 0
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if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
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&& addr + size <= L1_CODE_START + L1_CODE_LENGTH)
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return 1;
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#endif
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#if L1_DATA_A_LENGTH != 0
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if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
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&& addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
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return 1;
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#endif
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#if L1_DATA_B_LENGTH != 0
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if (addr >= L1_DATA_B_START
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&& addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
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return 1;
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#endif
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return 0;
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}
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EXPORT_SYMBOL(_access_ok);
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#endif /* CONFIG_ACCESS_CHECK */
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