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/*
* Based on arch/arm/kernel/sys_arm.c
*
* Copyright (C) People who wrote linux/arch/i386/kernel/sys_i386.c
* Copyright (C) 1995, 1996 Russell King.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/compat.h>
#include <linux/personality.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/unistd.h>
static inline void
do_compat_cache_op(unsigned long start, unsigned long end, int flags)
{
struct mm_struct *mm = current->active_mm;
struct vm_area_struct *vma;
if (end < start || flags)
return;
down_read(&mm->mmap_sem);
vma = find_vma(mm, start);
if (vma && vma->vm_start < end) {
if (start < vma->vm_start)
start = vma->vm_start;
if (end > vma->vm_end)
end = vma->vm_end;
up_read(&mm->mmap_sem);
__flush_cache_user_range(start & PAGE_MASK, PAGE_ALIGN(end));
return;
}
up_read(&mm->mmap_sem);
}
/*
* Handle all unrecognised system calls.
*/
long compat_arm_syscall(struct pt_regs *regs)
{
unsigned int no = regs->regs[7];
switch (no) {
/*
* Flush a region from virtual address 'r0' to virtual address 'r1'
* _exclusive_. There is no alignment requirement on either address;
* user space does not need to know the hardware cache layout.
*
* r2 contains flags. It should ALWAYS be passed as ZERO until it
* is defined to be something else. For now we ignore it, but may
* the fires of hell burn in your belly if you break this rule. ;)
*
* (at a later date, we may want to allow this call to not flush
* various aspects of the cache. Passing '0' will guarantee that
* everything necessary gets flushed to maintain consistency in
* the specified region).
*/
case __ARM_NR_compat_cacheflush:
do_compat_cache_op(regs->regs[0], regs->regs[1], regs->regs[2]);
return 0;
case __ARM_NR_compat_set_tls:
current->thread.tp_value = regs->regs[0];
/*
* Protect against register corruption from context switch.
* See comment in tls_thread_flush.
*/
barrier();
asm ("msr tpidrro_el0, %0" : : "r" (regs->regs[0]));
return 0;
default:
return -ENOSYS;
}
}
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