diff options
Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/kernel/uaccess.c')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/kernel/uaccess.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/kernel/uaccess.c b/target/linux/ubicom32/files/arch/ubicom32/kernel/uaccess.c new file mode 100644 index 000000000..2fe5f5f87 --- /dev/null +++ b/target/linux/ubicom32/files/arch/ubicom32/kernel/uaccess.c @@ -0,0 +1,109 @@ +/* + * arch/ubicom32/include/asm/uaccess.c + * User space memory access functions for Ubicom32 architecture. + * + * (C) Copyright 2009, Ubicom, Inc. + * + * This file is part of the Ubicom32 Linux Kernel Port. + * + * The Ubicom32 Linux Kernel Port is free software: you can redistribute + * it and/or modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, either version 2 of the + * License, or (at your option) any later version. + * + * The Ubicom32 Linux Kernel Port is distributed in the hope that it + * will be useful, but WITHOUT ANY WARRANTY; without even the implied + * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with the Ubicom32 Linux Kernel Port. If not, + * see <http://www.gnu.org/licenses/>. + * + * Ubicom32 implementation derived from (with many thanks): + * arch/m68knommu + * arch/blackfin + * arch/parisc + */ + +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/module.h> + +#include <asm/segment.h> +#include <asm/uaccess.h> + +extern int _stext, _etext, _sdata, _edata, _sbss, _ebss, _end; + +/* + * __access_ok() + * Check that the address is in the current processes. + * + * NOTE: The kernel uses "pretend" user addresses that wind + * up calling access_ok() so this approach has only marginal + * value because you wind up with lots of false positives. + */ +int __access_ok(unsigned long addr, unsigned long size) +{ + // struct vm_area_struct *vma; + + /* + * Don't do anything if we are not a running system yet. + */ + if (system_state != SYSTEM_RUNNING) { + return 1; + } + + /* + * It appears that Linux will call this function even when we are not + * in the context of a user space application that has a VM address + * space. So we must check that current and mm are valid before + * performing the check. + */ + if ((!current) || (!current->mm)) { + return 1; + } + + /* + * We perform some basic checks on the address to ensure that it + * is at least within the range of DRAM. + */ + if ((addr < (int)&_etext) || (addr > memory_end)) { + printk(KERN_WARNING "pid=%d[%s]: range [%lx - %lx] not in memory area: [%lx - %lx]\n", + current->pid, current->comm, + addr, addr + size, + memory_start, memory_end); + return 0; + } + + /* + * For nommu Linux we can check this by looking at the allowed + * memory map for the process. + * + * TODO: Since the kernel passes addresses in it's own space as though + * they were user address, we can not validate the addresses this way. + */ +#if 0 + if (!down_read_trylock(¤t->mm->mmap_sem)) { + return 1; + } + vma = find_vma(current->mm, addr); + if (!vma) { + up_read(¤t->mm->mmap_sem); + printk(KERN_WARNING "pid=%d[%s]: possible invalid acesss on range: [%lx - %lx]\n", + current->pid, current->comm, addr, addr + size); + return 1; + } + if ((addr + size) > vma->vm_end) { + up_read(¤t->mm->mmap_sem); + printk(KERN_WARNING "pid=%d[%s]: possible invalid length on range: [%lx - %lx]\n", + current->pid, current->comm, addr, addr + size); + return 1; + } + up_read(¤t->mm->mmap_sem); +#endif + return 1; +} + +EXPORT_SYMBOL(__access_ok); |