[linux-aws-xenial][PATCH 1/2] PM / Hibernate: Call flush_icache_range() on pages restored in-place

Kamal Mostafa kamal at canonical.com
Thu Nov 15 22:06:25 UTC 2018


From: James Morse <james.morse at arm.com>

BugLink: http://bugs.launchpad.net/bugs/1803613

Some architectures require code written to memory as if it were data to be
'cleaned' from any data caches before the processor can fetch them as new
instructions.

During resume from hibernate, the snapshot code copies some pages directly,
meaning these architectures do not get a chance to perform their cache
maintenance. Modify the read and decompress code to call
flush_icache_range() on all pages that are restored, so that the restored
in-place pages are guaranteed to be executable on these architectures.

Signed-off-by: James Morse <james.morse at arm.com>
Acked-by: Pavel Machek <pavel at ucw.cz>
Acked-by: Rafael J. Wysocki <rjw at rjwysocki.net>
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
[will: make clean_pages_on_* static and remove initialisers]
Signed-off-by: Will Deacon <will.deacon at arm.com>

(cherry picked from commit f6cf0545ec697ddc278b7457b7d0c0d86a2ea88e)
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 kernel/power/swap.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 12cd989..160e100 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -37,6 +37,14 @@
 #define HIBERNATE_SIG	"S1SUSPEND"
 
 /*
+ * When reading an {un,}compressed image, we may restore pages in place,
+ * in which case some architectures need these pages cleaning before they
+ * can be executed. We don't know which pages these may be, so clean the lot.
+ */
+static bool clean_pages_on_read;
+static bool clean_pages_on_decompress;
+
+/*
  *	The swap map is a data structure used for keeping track of each page
  *	written to a swap partition.  It consists of many swap_map_page
  *	structures that contain each an array of MAP_PAGE_ENTRIES swap entries.
@@ -241,6 +249,9 @@ static void hib_end_io(struct bio *bio)
 
 	if (bio_data_dir(bio) == WRITE)
 		put_page(page);
+	else if (clean_pages_on_read)
+		flush_icache_range((unsigned long)page_address(page),
+				   (unsigned long)page_address(page) + PAGE_SIZE);
 
 	if (bio->bi_error && !hb->error)
 		hb->error = bio->bi_error;
@@ -1049,6 +1060,7 @@ static int load_image(struct swap_map_handle *handle,
 
 	hib_init_batch(&hb);
 
+	clean_pages_on_read = true;
 	printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
 		nr_to_read);
 	m = nr_to_read / 10;
@@ -1124,6 +1136,10 @@ static int lzo_decompress_threadfn(void *data)
 		d->unc_len = LZO_UNC_SIZE;
 		d->ret = lzo1x_decompress_safe(d->cmp + LZO_HEADER, d->cmp_len,
 		                               d->unc, &d->unc_len);
+		if (clean_pages_on_decompress)
+			flush_icache_range((unsigned long)d->unc,
+					   (unsigned long)d->unc + d->unc_len);
+
 		atomic_set(&d->stop, 1);
 		wake_up(&d->done);
 	}
@@ -1189,6 +1205,8 @@ static int load_image_lzo(struct swap_map_handle *handle,
 	}
 	memset(crc, 0, offsetof(struct crc_data, go));
 
+	clean_pages_on_decompress = true;
+
 	/*
 	 * Start the decompression threads.
 	 */
-- 
2.7.4




More information about the kernel-team mailing list