The patch titled
Subject: PM: hibernate: make direct map manipulations more explicit
has been added to the -mm tree. Its filename is
pm-hibernate-make-direct-map-manipulations-more-explicit.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/pm-hibernate-make-direct-map-manipulations-more-explicit.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/pm-hibernate-make-direct-map-manipulations-more-explicit.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Subject: PM: hibernate: make direct map manipulations more explicit
When DEBUG_PAGEALLOC or ARCH_HAS_SET_DIRECT_MAP is enabled a page may be
not present in the direct map and has to be explicitly mapped before it
could be copied.
Introduce hibernate_map_page() that will explicitly use
set_direct_map_{default,invalid}_noflush() for ARCH_HAS_SET_DIRECT_MAP
case and debug_pagealloc_map_pages() for DEBUG_PAGEALLOC case.
The remapping of the pages in safe_copy_page() presumes that it only
changes protection bits in an existing PTE and so it is safe to ignore
return value of set_direct_map_{default,invalid}_noflush().
Still, add a pr_warn() so that future changes in set_memory APIs will not
silently break hibernation.
Link: https://lkml.kernel.org/r/20201103162057.22916-3-rppt@xxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@xxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 12 ------------
kernel/power/snapshot.c | 32 ++++++++++++++++++++++++++++++--
2 files changed, 30 insertions(+), 14 deletions(-)
--- a/include/linux/mm.h~pm-hibernate-make-direct-map-manipulations-more-explicit
+++ a/include/linux/mm.h
@@ -2915,16 +2915,6 @@ static inline bool debug_pagealloc_enabl
#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP)
extern void __kernel_map_pages(struct page *page, int numpages, int enable);
-/*
- * When called in DEBUG_PAGEALLOC context, the call should most likely be
- * guarded by debug_pagealloc_enabled() or debug_pagealloc_enabled_static()
- */
-static inline void
-kernel_map_pages(struct page *page, int numpages, int enable)
-{
- __kernel_map_pages(page, numpages, enable);
-}
-
static inline void debug_pagealloc_map_pages(struct page *page,
int numpages, int enable)
{
@@ -2936,8 +2926,6 @@ static inline void debug_pagealloc_map_p
extern bool kernel_page_present(struct page *page);
#endif /* CONFIG_HIBERNATION */
#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */
-static inline void
-kernel_map_pages(struct page *page, int numpages, int enable) {}
static inline void debug_pagealloc_map_pages(struct page *page,
int numpages, int enable) {}
#ifdef CONFIG_HIBERNATION
--- a/kernel/power/snapshot.c~pm-hibernate-make-direct-map-manipulations-more-explicit
+++ a/kernel/power/snapshot.c
@@ -76,6 +76,34 @@ static inline void hibernate_restore_pro
static inline void hibernate_restore_unprotect_page(void *page_address) {}
#endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */
+static inline void hibernate_map_page(struct page *page, int enable)
+{
+ if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
+ unsigned long addr = (unsigned long)page_address(page);
+ int ret;
+
+ /*
+ * This should not fail because remapping a page here means
+ * that we only update protection bits in an existing PTE.
+ * It is still worth to have a warning here if something
+ * changes and this will no longer be the case.
+ */
+ if (enable)
+ ret = set_direct_map_default_noflush(page);
+ else
+ ret = set_direct_map_invalid_noflush(page);
+
+ if (ret) {
+ pr_warn_once("Failed to remap page\n");
+ return;
+ }
+
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+ } else {
+ debug_pagealloc_map_pages(page, 1, enable);
+ }
+}
+
static int swsusp_page_is_free(struct page *);
static void swsusp_set_page_forbidden(struct page *);
static void swsusp_unset_page_forbidden(struct page *);
@@ -1355,9 +1383,9 @@ static void safe_copy_page(void *dst, st
if (kernel_page_present(s_page)) {
do_copy_page(dst, page_address(s_page));
} else {
- kernel_map_pages(s_page, 1, 1);
+ hibernate_map_page(s_page, 1);
do_copy_page(dst, page_address(s_page));
- kernel_map_pages(s_page, 1, 0);
+ hibernate_map_page(s_page, 0);
}
}
_
Patches currently in -mm which might be from rppt@xxxxxxxxxxxxx are
mm-introduce-debug_pagealloc_map_pages-helper.patch
pm-hibernate-make-direct-map-manipulations-more-explicit.patch
arch-mm-restore-dependency-of-__kernel_map_pages-of-debug_pagealloc.patch
arch-mm-make-kernel_page_present-always-available.patch
