linux-kernel - [PATCH v1 16/18] xtensa/mm: convert check_tlb

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue,  9 Apr 2024 21:22:59 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	linux-doc@...r.kernel.org,
	cgroups@...r.kernel.org,
	linux-sh@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Peter Xu <peterx@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Yin Fengwei <fengwei.yin@...el.com>,
	Yang Shi <shy828301@...il.com>,
	Zi Yan <ziy@...dia.com>,
	Jonathan Corbet <corbet@....net>,
	Hugh Dickins <hughd@...gle.com>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	Rich Felker <dalias@...c.org>,
	John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
	Chris Zankel <chris@...kel.net>,
	Max Filippov <jcmvbkbc@...il.com>,
	Muchun Song <muchun.song@...ux.dev>,
	Miaohe Lin <linmiaohe@...wei.com>,
	Naoya Horiguchi <naoya.horiguchi@....com>,
	Richard Chang <richardycc@...gle.com>
Subject: [PATCH v1 16/18] xtensa/mm: convert check_tlb_entry() to sanity check folios

We want to limit the use of page_mapcount() to the places where it is
absolutely necessary. So let's convert check_tlb_entry() to perform
sanity checks on folios instead of pages.

This essentially already happened: page_count() is mapped to
folio_ref_count(), and page_mapped() to folio_mapped() internally.
However, we would have printed the page_mapount(), which
does not really match what page_mapped() would have checked.

Let's simply print the folio mapcount to avoid using page_mapcount(). For
small folios there is no change.

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 arch/xtensa/mm/tlb.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/xtensa/mm/tlb.c b/arch/xtensa/mm/tlb.c
index 4f974b74883c..d8b60d6e50a8 100644
--- a/arch/xtensa/mm/tlb.c
+++ b/arch/xtensa/mm/tlb.c
@@ -256,12 +256,13 @@ static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
 					dtlb ? 'D' : 'I', w, e, r0, r1, pte);
 			if (pte == 0 || !pte_present(__pte(pte))) {
 				struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
-				pr_err("page refcount: %d, mapcount: %d\n",
-						page_count(p),
-						page_mapcount(p));
-				if (!page_count(p))
+				struct folio *f = page_folio(p);
+
+				pr_err("folio refcount: %d, mapcount: %d\n",
+					folio_ref_count(f), folio_mapcount(f));
+				if (!folio_ref_count(f))
 					rc |= TLB_INSANE;
-				else if (page_mapcount(p))
+				else if (folio_mapped(f))
 					rc |= TLB_SUSPICIOUS;
 			} else {
 				rc |= TLB_INSANE;
-- 
2.44.0