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s390/vmem: do not silently ignore mapping limit

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The only interface that allows drivers establishing
liner mappings is vmem_add_mapping(). It does check
a requested range against allowed limits and a call
to modify_pagetable() with an invalid mapping range
is impossible.

Hence, an attempt to map an address range outside of
the identity mapping or vmemmap array could only be
kernel bug.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2023-09-01 08:11:14 +02:00 committed by Heiko Carstens
parent f59ec04d38
commit 06fc3b0d22
1 changed files with 3 additions and 15 deletions
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18
arch/s390/mm/vmem.c
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@ -290,14 +290,9 @@ out:
static void try_free_pmd_table(pud_t *pud, unsigned long start)
{
const unsigned long end = start + PUD_SIZE;
pmd_t *pmd;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
pmd = pmd_offset(pud, start);
for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
if (!pmd_none(*pmd))
@ -362,14 +357,9 @@ out:
static void try_free_pud_table(p4d_t *p4d, unsigned long start)
{
const unsigned long end = start + P4D_SIZE;
pud_t *pud;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
pud = pud_offset(p4d, start);
for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
if (!pud_none(*pud))
@ -412,14 +402,9 @@ out:
static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
{
const unsigned long end = start + PGDIR_SIZE;
p4d_t *p4d;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
p4d = p4d_offset(pgd, start);
for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
if (!p4d_none(*p4d))
@ -439,6 +424,9 @@ static int modify_pagetable(unsigned long start, unsigned long end, bool add,
if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
return -EINVAL;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (WARN_ON_ONCE(end > VMALLOC_START))
return -EINVAL;
for (addr = start; addr < end; addr = next) {
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);