Contributors: 15
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Paul Mackerras |
987 |
72.79% |
1 |
4.00% |
| Aneesh Kumar K.V |
266 |
19.62% |
8 |
32.00% |
| Al Viro |
19 |
1.40% |
1 |
4.00% |
| Christoph Hellwig |
17 |
1.25% |
2 |
8.00% |
| Mike Rapoport |
17 |
1.25% |
2 |
8.00% |
| David Gibson |
12 |
0.88% |
1 |
4.00% |
| Anshuman Khandual |
9 |
0.66% |
1 |
4.00% |
| Joe MacDonald |
8 |
0.59% |
1 |
4.00% |
| Michel Lespinasse |
7 |
0.52% |
2 |
8.00% |
| SF Markus Elfring |
4 |
0.29% |
1 |
4.00% |
| Kirill A. Shutemov |
3 |
0.22% |
1 |
4.00% |
| Naoya Horiguchi |
2 |
0.15% |
1 |
4.00% |
| Anton Blanchard |
2 |
0.15% |
1 |
4.00% |
| Thomas Gleixner |
2 |
0.15% |
1 |
4.00% |
| Linus Torvalds |
1 |
0.07% |
1 |
4.00% |
| Total |
1356 |
|
25 |
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2007-2008 Paul Mackerras, IBM Corp.
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/types.h>
#include <linux/pagewalk.h>
#include <linux/hugetlb.h>
#include <linux/syscalls.h>
#include <linux/pgtable.h>
#include <linux/uaccess.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_ctx_subpage_prot(&mm->context);
unsigned long i, j, addr;
u32 **p;
if (!spt)
return;
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;
kfree(spt);
}
static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,
int npages)
{
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
pgd = pgd_offset(mm, addr);
p4d = p4d_offset(pgd, addr);
if (p4d_none(*p4d))
return;
pud = pud_offset(p4d, 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;
u32 **spm, *spp;
unsigned long i;
size_t nw;
unsigned long next, limit;
mmap_write_lock(mm);
spt = mm_ctx_subpage_prot(&mm->context);
if (!spt)
goto err_out;
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);
}
err_out:
mmap_write_unlock(mm);
}
#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 const struct mm_walk_ops subpage_walk_ops = {
.pmd_entry = subpage_walk_pmd_entry,
};
static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
struct vm_area_struct *vma;
/*
* 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_walk_ops, NULL);
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;
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(map, (len >> PAGE_SHIFT) * sizeof(u32)))
return -EFAULT;
mmap_write_lock(mm);
spt = mm_ctx_subpage_prot(&mm->context);
if (!spt) {
/*
* Allocate subpage prot table if not already done.
* Do this with mmap_lock held
*/
spt = kzalloc(sizeof(struct subpage_prot_table), GFP_KERNEL);
if (!spt) {
err = -ENOMEM;
goto out;
}
mm->context.hash_context->spt = spt;
}
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;
mmap_write_unlock(mm);
if (__copy_from_user(spp, map, nw * sizeof(u32)))
return -EFAULT;
map += nw;
mmap_write_lock(mm);
/* now flush any existing HPTEs for the range */
hpte_flush_range(mm, addr, nw);
}
if (limit > spt->maxaddr)
spt->maxaddr = limit;
err = 0;
out:
mmap_write_unlock(mm);
return err;
}