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/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only 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.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <asm/user_accessible_timer.h>
#include <asm/traps.h>
#define USER_ACCESS_TIMER_OFFSET 0xf30
#define USER_ACCESS_FEATURE_OFFSET 0xf34
#define USER_ACCESS_FEATURE_FLAG 0xffff0f20
static struct vm_area_struct user_timers_vma;
static int __init user_timers_vma_init(void)
{
user_timers_vma.vm_start = CONFIG_ARM_USER_ACCESSIBLE_TIMER_BASE;
user_timers_vma.vm_end = CONFIG_ARM_USER_ACCESSIBLE_TIMER_BASE
+ PAGE_SIZE;
user_timers_vma.vm_page_prot = PAGE_READONLY;
user_timers_vma.vm_flags = VM_READ | VM_MAYREAD;
return 0;
}
arch_initcall(user_timers_vma_init);
int in_user_timers_area(struct mm_struct *mm, unsigned long addr)
{
return (addr >= user_timers_vma.vm_start) &&
(addr < user_timers_vma.vm_end);
}
EXPORT_SYMBOL(in_user_timers_area);
struct vm_area_struct *get_user_timers_vma(struct mm_struct *mm)
{
return &user_timers_vma;
}
EXPORT_SYMBOL(get_user_timers_vma);
int get_user_timer_page(struct vm_area_struct *vma,
struct mm_struct *mm, unsigned long start, unsigned int gup_flags,
struct page **pages, int idx, int *goto_next_page)
{
/* Replicates the earlier work done in mm/memory.c */
unsigned long pg = start & PAGE_MASK;
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
/* Unset this flag -- this only gets activated if the
* caller should go straight to the next_page label on
* return.
*/
*goto_next_page = 0;
/* user gate pages are read-only */
if (gup_flags & FOLL_WRITE)
return idx ? : -EFAULT;
if (pg > TASK_SIZE)
pgd = pgd_offset_k(pg);
else
pgd = pgd_offset_gate(mm, pg);
BUG_ON(pgd_none(*pgd));
pud = pud_offset(pgd, pg);
BUG_ON(pud_none(*pud));
pmd = pmd_offset(pud, pg);
if (pmd_none(*pmd))
return idx ? : -EFAULT;
VM_BUG_ON(pmd_trans_huge(*pmd));
pte = pte_offset_map(pmd, pg);
if (pte_none(*pte)) {
pte_unmap(pte);
return idx ? : -EFAULT;
}
vma = get_user_timers_vma(mm);
if (pages) {
struct page *page;
page = vm_normal_page(vma, start, *pte);
if (!page) {
if (!(gup_flags & FOLL_DUMP) &&
zero_pfn == pte_pfn(*pte))
page = pte_page(*pte);
else {
pte_unmap(pte);
return idx ? : -EFAULT;
}
}
pages[idx] = page;
get_page(page);
}
pte_unmap(pte);
/* In this case, set the next page */
*goto_next_page = 1;
return 0;
}
EXPORT_SYMBOL(get_user_timer_page);
void setup_user_timer_offset(unsigned long addr)
{
#if defined(CONFIG_CPU_USE_DOMAINS)
unsigned long vectors = CONFIG_VECTORS_BASE;
#else
unsigned long vectors = (unsigned long)vectors_page;
#endif
unsigned long *timer_offset = (unsigned long *)(vectors +
USER_ACCESS_TIMER_OFFSET);
*timer_offset = addr;
}
EXPORT_SYMBOL(setup_user_timer_offset);
void set_user_accessible_timer_flag(bool flag)
{
#if defined(CONFIG_CPU_USE_DOMAINS)
unsigned long vectors = CONFIG_VECTORS_BASE;
#else
unsigned long vectors = (unsigned long)vectors_page;
#endif
unsigned long *timer_offset = (unsigned long *)(vectors +
USER_ACCESS_FEATURE_OFFSET);
*timer_offset = (flag ? USER_ACCESS_FEATURE_FLAG : 0);
}
EXPORT_SYMBOL(set_user_accessible_timer_flag);
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