This is a note to let you know that I've just added the patch titled
Revert "x86/mm/ident_map: Use gbpages only where full GB page should be mapped."
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-x86-mm-ident_map-use-gbpages-only-where-full-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 903e6b636ff957419a5c19368ffc685536b7c3b6
Author: Ingo Molnar <mingo@xxxxxxxxxx>
Date: Mon Mar 25 11:47:51 2024 +0100
Revert "x86/mm/ident_map: Use gbpages only where full GB page should be mapped."
[ Upstream commit c567f2948f57bdc03ed03403ae0234085f376b7d ]
This reverts commit d794734c9bbfe22f86686dc2909c25f5ffe1a572.
While the original change tries to fix a bug, it also unintentionally broke
existing systems, see the regressions reported at:
https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@xxxxxxxxxxxxxxx/
Since d794734c9bbf was also marked for -stable, let's back it out before
causing more damage.
Note that due to another upstream change the revert was not 100% automatic:
0a845e0f6348 mm/treewide: replace pud_large() with pud_leaf()
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Russ Anderson <rja@xxxxxxx>
Cc: Steve Wahl <steve.wahl@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/3a1b9909-45ac-4f97-ad68-d16ef1ce99db@xxxxxxxxxxxxxxx/
Fixes: d794734c9bbf ("x86/mm/ident_map: Use gbpages only where full GB page should be mapped.")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
index a204a332c71fc..968d7005f4a72 100644
--- a/arch/x86/mm/ident_map.c
+++ b/arch/x86/mm/ident_map.c
@@ -26,31 +26,18 @@ static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page,
for (; addr < end; addr = next) {
pud_t *pud = pud_page + pud_index(addr);
pmd_t *pmd;
- bool use_gbpage;
next = (addr & PUD_MASK) + PUD_SIZE;
if (next > end)
next = end;
- /* if this is already a gbpage, this portion is already mapped */
- if (pud_leaf(*pud))
- continue;
-
- /* Is using a gbpage allowed? */
- use_gbpage = info->direct_gbpages;
-
- /* Don't use gbpage if it maps more than the requested region. */
- /* at the begining: */
- use_gbpage &= ((addr & ~PUD_MASK) == 0);
- /* ... or at the end: */
- use_gbpage &= ((next & ~PUD_MASK) == 0);
-
- /* Never overwrite existing mappings */
- use_gbpage &= !pud_present(*pud);
-
- if (use_gbpage) {
+ if (info->direct_gbpages) {
pud_t pudval;
+ if (pud_present(*pud))
+ continue;
+
+ addr &= PUD_MASK;
pudval = __pud((addr - info->offset) | info->page_flag);
set_pud(pud, pudval);
continue;
