Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'x86_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
- Use a GB page for identity mapping only when memory of this size is
requested so that mapping of reserved regions is prevented which
would otherwise lead to system crashes on UV machines
* tag 'x86_urgent_for_v6.8_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
+18
-5
+18
-5
arch/x86/mm/ident_map.c
+18
-5
arch/x86/mm/ident_map.c
···
26
26
for (; addr < end; addr = next) {
27
27
pud_t *pud = pud_page + pud_index(addr);
28
28
pmd_t *pmd;
29
+
bool use_gbpage;
29
30
30
31
next = (addr & PUD_MASK) + PUD_SIZE;
31
32
if (next > end)
32
33
next = end;
33
34
34
-
if (info->direct_gbpages) {
35
+
/* if this is already a gbpage, this portion is already mapped */
36
+
if (pud_large(*pud))
37
+
continue;
38
+
39
+
/* Is using a gbpage allowed? */
40
+
use_gbpage = info->direct_gbpages;
41
+
42
+
/* Don't use gbpage if it maps more than the requested region. */
43
+
/* at the begining: */
44
+
use_gbpage &= ((addr & ~PUD_MASK) == 0);
45
+
/* ... or at the end: */
46
+
use_gbpage &= ((next & ~PUD_MASK) == 0);
47
+
48
+
/* Never overwrite existing mappings */
49
+
use_gbpage &= !pud_present(*pud);
50
+
51
+
if (use_gbpage) {
35
52
pud_t pudval;
36
53
37
-
if (pud_present(*pud))
38
-
continue;
39
-
40
-
addr &= PUD_MASK;
41
54
pudval = __pud((addr - info->offset) | info->page_flag);
42
55
set_pud(pud, pudval);
43
56
continue;