[PATCH 2/4] PM: hibernate: improve robustness of mapping pages in the direct map
From: Mike Rapoport <rppt@kernel.org>
Date: 2020-10-25 10:16:56
Also in:
linux-mm, linux-pm, linux-riscv, linux-s390, linuxppc-dev, lkml, sparclinux
Subsystem:
hibernation (aka software suspend, aka swsusp), suspend to ram, the rest · Maintainers:
"Rafael J. Wysocki", Linus Torvalds
From: Mike Rapoport <redacted>
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.
On arm64 it is possible that a page would be removed from the direct map
using set_direct_map_invalid_noflush() but __kernel_map_pages() will refuse
to map this page back if DEBUG_PAGEALLOC is disabled.
Explicitly use set_direct_map_{default,invalid}_noflush() for
ARCH_HAS_SET_DIRECT_MAP case and debug_pagealloc_map_pages() for
DEBUG_PAGEALLOC case.
While on that, rename kernel_map_pages() to hibernate_map_page() and drop
numpages parameter.
Signed-off-by: Mike Rapoport <redacted>
---
kernel/power/snapshot.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index fa499466f645..ecb7b32ce77c 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c@@ -76,16 +76,25 @@ static inline void hibernate_restore_protect_page(void *page_address) {} static inline void hibernate_restore_unprotect_page(void *page_address) {} #endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */ -#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) -static inline void -kernel_map_pages(struct page *page, int numpages, int enable) +static inline void hibernate_map_page(struct page *page, int enable) { - __kernel_map_pages(page, numpages, enable); + if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { + unsigned long addr = (unsigned long)page_address(page); + int ret; + + if (enable) + ret = set_direct_map_default_noflush(page); + else + ret = set_direct_map_invalid_noflush(page); + + if (WARN_ON(ret)) + return; + + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + } else { + debug_pagealloc_map_pages(page, 1, enable); + } } -#else -static inline void -kernel_map_pages(struct page *page, int numpages, int enable) {} -#endif static int swsusp_page_is_free(struct page *); static void swsusp_set_page_forbidden(struct page *);
@@ -1366,9 +1375,9 @@ static void safe_copy_page(void *dst, struct page *s_page) 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); } }
--
2.28.0
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