[tip: x86/mm] x86/mm/pat: Convert pmd code to use page table apis

[tip-bot2 for Vishal Moola (Oracle)]

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     6ba1917a4c5c59415c8fc3f83019d92e3f81c87c
Gitweb:        https://git.kernel.org/tip/6ba1917a4c5c59415c8fc3f83019d92e3f81c87c
Author:        Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
AuthorDate:    Tue, 03 Mar 2026 11:48:25 -08:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Wed, 04 Mar 2026 10:08:54 -08:00

x86/mm/pat: Convert pmd code to use page table apis

Use the ptdesc APIs for all page table allocation and free sites to allow
their separate allocation from struct page in the future. Convert the PMD
allocation and free sites to use the generic page table APIs, as they
already use ptdescs.

Pass through init_mm since these are kernel page tables, as
pmd_alloc_one() requires it to identify kernel page tables. Because the
generic implementation does not use the second argument, pass a
placeholder to avoid reimplementing it or risking breakage on other
architectures.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Link: https://patch.msgid.link/20260303194828.1406905-3-vishal.moola@xxxxxxxxx
---
 arch/x86/mm/pat/set_memory.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index a4b1b32..72a2600 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -1420,7 +1420,7 @@ static bool try_to_free_pmd_page(pmd_t *pmd)
 		if (!pmd_none(pmd[i]))
 			return false;
 
-	free_page((unsigned long)pmd);
+	pmd_free(&init_mm, pmd);
 	return true;
 }
 
@@ -1549,7 +1549,11 @@ static int alloc_pte_page(pmd_t *pmd)
 
 static int alloc_pmd_page(pud_t *pud)
 {
-	pmd_t *pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
+	/*
+	 * Pass 0 as a placeholder for the second argument, since the
+	 * generic implementation of pmd_alloc_one() does not use it.
+	 */
+	pmd_t *pmd = pmd_alloc_one(&init_mm, 0);
 	if (!pmd)
 		return -1;