static void unmap_area_sections(unsigned long virt, unsigned long size)
{
unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
pgd_t *pgd;
pud_t *pud;
pmd_t *pmdp;
flush_cache_vunmap(addr, end);
pgd = pgd_offset_k(addr);
pud = pud_offset(pgd, addr);
pmdp = pmd_offset(pud, addr);
do {
pmd_t pmd = *pmdp;
if (!pmd_none(pmd)) {
pmd_clear(pmdp);
init_mm.context.kvm_seq++;
if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
}
addr += PMD_SIZE;
pmdp += 2;
} while (addr < end);
if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
__check_kvm_seq(current->active_mm);
flush_tlb_kernel_range(virt, end);
}
/*
* Section support is unsafe on SMP - If you iounmap and ioremap a region,
* the other CPUs will not see this change until their next context switch.
* Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
* which requires the new ioremap'd region to be referenced, the CPU will
* reference the _old_ region.
*
* Note that get_vm_area_caller() allocates a guard 4K page, so we need to
* mask the size back to 1MB aligned or we will overflow in the loop below.
*/
static void unmap_area_sections(unsigned long virt, unsigned long size)
{
unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
pgd_t *pgd;
pud_t *pud;
pmd_t *pmdp;
flush_cache_vunmap(addr, end);
pgd = pgd_offset_k(addr);
pud = pud_offset(pgd, addr);
pmdp = pmd_offset(pud, addr);
do {
pmd_t pmd = *pmdp;
if (!pmd_none(pmd)) {
/*
* Clear the PMD from the page table, and
* increment the kvm sequence so others
* notice this change.
*
* Note: this is still racy on SMP machines.
*/
pmd_clear(pmdp);
init_mm.context.kvm_seq++;
/*
* Free the page table, if there was one.
*/
if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
}
addr += PMD_SIZE;
pmdp += 2;
} while (addr < end);
/*
* Ensure that the active_mm is up to date - we want to
* catch any use-after-iounmap cases.
*/
if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
__check_kvm_seq(current->active_mm);
flush_tlb_kernel_range(virt, end);
}
