272 lines
6.5 KiB
C
272 lines
6.5 KiB
C
/*
|
|
* Copyright 2007-2008 Paul Mackerras, IBM Corp.
|
|
*
|
|
* This program 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.
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/types.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/syscalls.h>
|
|
|
|
#include <asm/pgtable.h>
|
|
#include <linux/uaccess.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
/*
|
|
* Free all pages allocated for subpage protection maps and pointers.
|
|
* Also makes sure that the subpage_prot_table structure is
|
|
* reinitialized for the next user.
|
|
*/
|
|
void subpage_prot_free(struct mm_struct *mm)
|
|
{
|
|
struct subpage_prot_table *spt = &mm->context.spt;
|
|
unsigned long i, j, addr;
|
|
u32 **p;
|
|
|
|
for (i = 0; i < 4; ++i) {
|
|
if (spt->low_prot[i]) {
|
|
free_page((unsigned long)spt->low_prot[i]);
|
|
spt->low_prot[i] = NULL;
|
|
}
|
|
}
|
|
addr = 0;
|
|
for (i = 0; i < (TASK_SIZE_USER64 >> 43); ++i) {
|
|
p = spt->protptrs[i];
|
|
if (!p)
|
|
continue;
|
|
spt->protptrs[i] = NULL;
|
|
for (j = 0; j < SBP_L2_COUNT && addr < spt->maxaddr;
|
|
++j, addr += PAGE_SIZE)
|
|
if (p[j])
|
|
free_page((unsigned long)p[j]);
|
|
free_page((unsigned long)p);
|
|
}
|
|
spt->maxaddr = 0;
|
|
}
|
|
|
|
void subpage_prot_init_new_context(struct mm_struct *mm)
|
|
{
|
|
struct subpage_prot_table *spt = &mm->context.spt;
|
|
|
|
memset(spt, 0, sizeof(*spt));
|
|
}
|
|
|
|
static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,
|
|
int npages)
|
|
{
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
spinlock_t *ptl;
|
|
|
|
pgd = pgd_offset(mm, addr);
|
|
if (pgd_none(*pgd))
|
|
return;
|
|
pud = pud_offset(pgd, addr);
|
|
if (pud_none(*pud))
|
|
return;
|
|
pmd = pmd_offset(pud, addr);
|
|
if (pmd_none(*pmd))
|
|
return;
|
|
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
|
|
arch_enter_lazy_mmu_mode();
|
|
for (; npages > 0; --npages) {
|
|
pte_update(mm, addr, pte, 0, 0, 0);
|
|
addr += PAGE_SIZE;
|
|
++pte;
|
|
}
|
|
arch_leave_lazy_mmu_mode();
|
|
pte_unmap_unlock(pte - 1, ptl);
|
|
}
|
|
|
|
/*
|
|
* Clear the subpage protection map for an address range, allowing
|
|
* all accesses that are allowed by the pte permissions.
|
|
*/
|
|
static void subpage_prot_clear(unsigned long addr, unsigned long len)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct subpage_prot_table *spt = &mm->context.spt;
|
|
u32 **spm, *spp;
|
|
unsigned long i;
|
|
size_t nw;
|
|
unsigned long next, limit;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
limit = addr + len;
|
|
if (limit > spt->maxaddr)
|
|
limit = spt->maxaddr;
|
|
for (; addr < limit; addr = next) {
|
|
next = pmd_addr_end(addr, limit);
|
|
if (addr < 0x100000000UL) {
|
|
spm = spt->low_prot;
|
|
} else {
|
|
spm = spt->protptrs[addr >> SBP_L3_SHIFT];
|
|
if (!spm)
|
|
continue;
|
|
}
|
|
spp = spm[(addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];
|
|
if (!spp)
|
|
continue;
|
|
spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);
|
|
|
|
i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
|
|
nw = PTRS_PER_PTE - i;
|
|
if (addr + (nw << PAGE_SHIFT) > next)
|
|
nw = (next - addr) >> PAGE_SHIFT;
|
|
|
|
memset(spp, 0, nw * sizeof(u32));
|
|
|
|
/* now flush any existing HPTEs for the range */
|
|
hpte_flush_range(mm, addr, nw);
|
|
}
|
|
up_write(&mm->mmap_sem);
|
|
}
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
|
|
unsigned long end, struct mm_walk *walk)
|
|
{
|
|
struct vm_area_struct *vma = walk->vma;
|
|
split_huge_pmd(vma, pmd, addr);
|
|
return 0;
|
|
}
|
|
|
|
static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
|
|
unsigned long len)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct mm_walk subpage_proto_walk = {
|
|
.mm = mm,
|
|
.pmd_entry = subpage_walk_pmd_entry,
|
|
};
|
|
|
|
/*
|
|
* We don't try too hard, we just mark all the vma in that range
|
|
* VM_NOHUGEPAGE and split them.
|
|
*/
|
|
vma = find_vma(mm, addr);
|
|
/*
|
|
* If the range is in unmapped range, just return
|
|
*/
|
|
if (vma && ((addr + len) <= vma->vm_start))
|
|
return;
|
|
|
|
while (vma) {
|
|
if (vma->vm_start >= (addr + len))
|
|
break;
|
|
vma->vm_flags |= VM_NOHUGEPAGE;
|
|
walk_page_vma(vma, &subpage_proto_walk);
|
|
vma = vma->vm_next;
|
|
}
|
|
}
|
|
#else
|
|
static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
|
|
unsigned long len)
|
|
{
|
|
return;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Copy in a subpage protection map for an address range.
|
|
* The map has 2 bits per 4k subpage, so 32 bits per 64k page.
|
|
* Each 2-bit field is 0 to allow any access, 1 to prevent writes,
|
|
* 2 or 3 to prevent all accesses.
|
|
* Note that the normal page protections also apply; the subpage
|
|
* protection mechanism is an additional constraint, so putting 0
|
|
* in a 2-bit field won't allow writes to a page that is otherwise
|
|
* write-protected.
|
|
*/
|
|
SYSCALL_DEFINE3(subpage_prot, unsigned long, addr,
|
|
unsigned long, len, u32 __user *, map)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct subpage_prot_table *spt = &mm->context.spt;
|
|
u32 **spm, *spp;
|
|
unsigned long i;
|
|
size_t nw;
|
|
unsigned long next, limit;
|
|
int err;
|
|
|
|
if (radix_enabled())
|
|
return -ENOENT;
|
|
|
|
/* Check parameters */
|
|
if ((addr & ~PAGE_MASK) || (len & ~PAGE_MASK) ||
|
|
addr >= mm->task_size || len >= mm->task_size ||
|
|
addr + len > mm->task_size)
|
|
return -EINVAL;
|
|
|
|
if (is_hugepage_only_range(mm, addr, len))
|
|
return -EINVAL;
|
|
|
|
if (!map) {
|
|
/* Clear out the protection map for the address range */
|
|
subpage_prot_clear(addr, len);
|
|
return 0;
|
|
}
|
|
|
|
if (!access_ok(VERIFY_READ, map, (len >> PAGE_SHIFT) * sizeof(u32)))
|
|
return -EFAULT;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
subpage_mark_vma_nohuge(mm, addr, len);
|
|
for (limit = addr + len; addr < limit; addr = next) {
|
|
next = pmd_addr_end(addr, limit);
|
|
err = -ENOMEM;
|
|
if (addr < 0x100000000UL) {
|
|
spm = spt->low_prot;
|
|
} else {
|
|
spm = spt->protptrs[addr >> SBP_L3_SHIFT];
|
|
if (!spm) {
|
|
spm = (u32 **)get_zeroed_page(GFP_KERNEL);
|
|
if (!spm)
|
|
goto out;
|
|
spt->protptrs[addr >> SBP_L3_SHIFT] = spm;
|
|
}
|
|
}
|
|
spm += (addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1);
|
|
spp = *spm;
|
|
if (!spp) {
|
|
spp = (u32 *)get_zeroed_page(GFP_KERNEL);
|
|
if (!spp)
|
|
goto out;
|
|
*spm = spp;
|
|
}
|
|
spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);
|
|
|
|
local_irq_disable();
|
|
demote_segment_4k(mm, addr);
|
|
local_irq_enable();
|
|
|
|
i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
|
|
nw = PTRS_PER_PTE - i;
|
|
if (addr + (nw << PAGE_SHIFT) > next)
|
|
nw = (next - addr) >> PAGE_SHIFT;
|
|
|
|
up_write(&mm->mmap_sem);
|
|
if (__copy_from_user(spp, map, nw * sizeof(u32)))
|
|
return -EFAULT;
|
|
map += nw;
|
|
down_write(&mm->mmap_sem);
|
|
|
|
/* now flush any existing HPTEs for the range */
|
|
hpte_flush_range(mm, addr, nw);
|
|
}
|
|
if (limit > spt->maxaddr)
|
|
spt->maxaddr = limit;
|
|
err = 0;
|
|
out:
|
|
up_write(&mm->mmap_sem);
|
|
return err;
|
|
}
|