linux-kernel - [PATCH v4 2/4] kho: replace kho_preserve_phys() with kho_preserve

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]

Message-ID: <20250917174033.3810435-3-rppt@kernel.org>
Date: Wed, 17 Sep 2025 20:40:31 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexander Graf <graf@...zon.com>,
	Baoquan He <bhe@...hat.com>,
	Changyuan Lyu <changyuanl@...gle.com>,
	Chris Li <chrisl@...nel.org>,
	Jason Gunthorpe <jgg@...dia.com>,
	Mike Rapoport <rppt@...nel.org>,
	Pasha Tatashin <pasha.tatashin@...een.com>,
	Pratyush Yadav <pratyush@...nel.org>,
	kexec@...ts.infradead.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v4 2/4] kho: replace kho_preserve_phys() with kho_preserve_pages()

From: "Mike Rapoport (Microsoft)" <rppt@...nel.org>

to make it clear that KHO operates on pages rather than on a random
physical address.

The kho_preserve_pages() will be also used in upcoming support for
vmalloc preservation.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@...nel.org>
---
 include/linux/kexec_handover.h |  5 +++--
 kernel/kexec_handover.c        | 25 +++++++++++--------------
 mm/memblock.c                  |  4 +++-
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index 348844cffb13..cc5c49b0612b 100644
--- a/include/linux/kexec_handover.h
+++ b/include/linux/kexec_handover.h
@@ -18,6 +18,7 @@ enum kho_event {
 
 struct folio;
 struct notifier_block;
+struct page;
 
 #define DECLARE_KHOSER_PTR(name, type) \
 	union {                        \
@@ -42,7 +43,7 @@ struct kho_serialization;
 bool kho_is_enabled(void);
 
 int kho_preserve_folio(struct folio *folio);
-int kho_preserve_phys(phys_addr_t phys, size_t size);
+int kho_preserve_pages(struct page *page, unsigned int nr_pages);
 struct folio *kho_restore_folio(phys_addr_t phys);
 int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt);
 int kho_retrieve_subtree(const char *name, phys_addr_t *phys);
@@ -65,7 +66,7 @@ static inline int kho_preserve_folio(struct folio *folio)
 	return -EOPNOTSUPP;
 }
 
-static inline int kho_preserve_phys(phys_addr_t phys, size_t size)
+static inline int kho_preserve_pages(struct page *page, unsigned int nr_pages)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index f421acc58c1f..3ad59c5f9eaa 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -698,26 +698,23 @@ int kho_preserve_folio(struct folio *folio)
 EXPORT_SYMBOL_GPL(kho_preserve_folio);
 
 /**
- * kho_preserve_phys - preserve a physically contiguous range across kexec.
- * @phys: physical address of the range.
- * @size: size of the range.
+ * kho_preserve_pages - preserve contiguous pages across kexec
+ * @page: first page in the list.
+ * @nr_pages: number of pages.
  *
- * Instructs KHO to preserve the memory range from @phys to @phys + @size
- * across kexec.
+ * Preserve a contiguous list of order 0 pages. Must be restored using
+ * kho_restore_page() on each order 0 page.
  *
  * Return: 0 on success, error code on failure
  */
-int kho_preserve_phys(phys_addr_t phys, size_t size)
+int kho_preserve_pages(struct page *page, unsigned int nr_pages)
 {
-	unsigned long pfn = PHYS_PFN(phys);
+	struct kho_mem_track *track = &kho_out.ser.track;
+	const unsigned long start_pfn = page_to_pfn(page);
+	const unsigned long end_pfn = start_pfn + nr_pages;
+	unsigned long pfn = start_pfn;
 	unsigned long failed_pfn = 0;
-	const unsigned long start_pfn = pfn;
-	const unsigned long end_pfn = PHYS_PFN(phys + size);
 	int err = 0;
-	struct kho_mem_track *track = &kho_out.ser.track;
-
-	if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
-		return -EINVAL;
 
 	while (pfn < end_pfn) {
 		const unsigned int order =
@@ -737,7 +734,7 @@ int kho_preserve_phys(phys_addr_t phys, size_t size)
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(kho_preserve_phys);
+EXPORT_SYMBOL_GPL(kho_preserve_pages);
 
 /* Handling for debug/kho/out */
 
diff --git a/mm/memblock.c b/mm/memblock.c
index 117d963e677c..6ec3eaa4e8d1 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2516,8 +2516,10 @@ static int reserve_mem_kho_finalize(struct kho_serialization *ser)
 
 	for (i = 0; i < reserved_mem_count; i++) {
 		struct reserve_mem_table *map = &reserved_mem_table[i];
+		struct page *page = phys_to_page(map->start);
+		unsigned int nr_pages = map->size >> PAGE_SHIFT;
 
-		err |= kho_preserve_phys(map->start, map->size);
+		err |= kho_preserve_pages(page, nr_pages);
 	}
 
 	err |= kho_preserve_folio(page_folio(kho_fdt));
-- 
2.50.1