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SubjectRe: [PATCH 4.4 078/131] PM / Hibernate: Call flush_icache_range() on pages restored in-place
On Mon 2019-04-01 19:02:28, Greg Kroah-Hartman wrote:
> 4.4-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> [ Upstream commit f6cf0545ec697ddc278b7457b7d0c0d86a2ea88e ]
>
> 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@arm.com>
> Acked-by: Pavel Machek <pavel@ucw.cz>
> Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> [will: make clean_pages_on_* static and remove initialisers]
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

I don't think this is suitable for stable.

Catalin: Are there platforms that a) need this and b) support
hibernation in 4.4.X?

Thanks
Pavel

> @@ -36,6 +36,14 @@
>
> #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
> @@ -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.
> */

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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