From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752167Ab1HPRzG (ORCPT ); Tue, 16 Aug 2011 13:55:06 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:45447 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751373Ab1HPRzE (ORCPT ); Tue, 16 Aug 2011 13:55:04 -0400 From: "Rafael J. Wysocki" To: Martin Schwidefsky Subject: Re: [patch 1/1] [PATCH] include storage keys in hibernation image. Date: Tue, 16 Aug 2011 19:56:47 +0200 User-Agent: KMail/1.13.6 (Linux/3.1.0-rc2+; KDE/4.6.0; x86_64; ; ) Cc: linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Pavel Machek , Jiri Slaby References: <20110816141441.898339466@de.ibm.com> <20110816141541.237704940@de.ibm.com> In-Reply-To: <20110816141541.237704940@de.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Message-Id: <201108161956.47434.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, August 16, 2011, Martin Schwidefsky wrote: > From: Martin Schwidefsky > > For s390 there is one additional byte associated with each page, > the storage key. This byte contains the referenced and changed > bits and needs to be included into the hibernation image. > If the storage keys are not restored to their previous state all > original pages would appear to be dirty. This can cause > inconsistencies e.g. with read-only filesystems. > > Cc: Pavel Machek > Cc: Rafael J. Wysocki > Cc: Jiri Slaby > Cc: linux-pm@lists.linux-foundation.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-s390@vger.kernel.org > Signed-off-by: Martin Schwidefsky OK, I don't have any complaints. Do you want me to take this patch or do you want to push it through the s390 tree? Rafael > --- > > arch/s390/Kconfig | 1 > arch/s390/kernel/suspend.c | 118 ++++++++++++++++++++++++++++++++++++++++ > arch/s390/kernel/swsusp_asm64.S | 3 + > include/linux/suspend.h | 34 +++++++++++ > kernel/power/Kconfig | 3 + > kernel/power/snapshot.c | 18 ++++++ > 6 files changed, 177 insertions(+) > > Index: hibernate-2.6/arch/s390/Kconfig > =================================================================== > --- hibernate-2.6.orig/arch/s390/Kconfig 2011-08-09 17:40:09.220010373 +0200 > +++ hibernate-2.6/arch/s390/Kconfig 2011-08-16 16:06:09.845540931 +0200 > @@ -91,6 +91,7 @@ > select HAVE_ARCH_MUTEX_CPU_RELAX > select HAVE_ARCH_JUMP_LABEL if !MARCH_G5 > select HAVE_RCU_TABLE_FREE if SMP > + select ARCH_SAVE_PAGE_KEYS if HIBERNATION > select ARCH_INLINE_SPIN_TRYLOCK > select ARCH_INLINE_SPIN_TRYLOCK_BH > select ARCH_INLINE_SPIN_LOCK > Index: hibernate-2.6/arch/s390/kernel/suspend.c > =================================================================== > --- hibernate-2.6.orig/arch/s390/kernel/suspend.c 2009-09-24 09:06:44.000000000 +0200 > +++ hibernate-2.6/arch/s390/kernel/suspend.c 2011-08-16 16:06:09.845540931 +0200 > @@ -7,6 +7,7 @@ > */ > > #include > +#include > #include > > /* > @@ -14,6 +15,123 @@ > */ > extern const void __nosave_begin, __nosave_end; > > +/* > + * The restore of the saved pages in an hibernation image will set > + * the change and referenced bits in the storage key for each page. > + * Overindication of the referenced bits after an hibernation cycle > + * does not cause any harm but the overindication of the change bits > + * would cause trouble. > + * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each > + * page to the most significant byte of the associated page frame > + * number in the hibernation image. > + */ > + > +/* > + * Key storage is allocated as a linked list of pages. > + * The size of the keys array is (PAGE_SIZE - sizeof(long)) > + */ > +struct page_key_data { > + struct page_key_data *next; > + unsigned char data[]; > +}; > + > +#define PAGE_KEY_DATA_SIZE (PAGE_SIZE - sizeof(struct page_key_data *)) > + > +static struct page_key_data *page_key_data; > +static struct page_key_data *page_key_rp, *page_key_wp; > +static unsigned long page_key_rx, page_key_wx; > + > +/* > + * For each page in the hibernation image one additional byte is > + * stored in the most significant byte of the page frame number. > + * On suspend no additional memory is required but on resume the > + * keys need to be memorized until the page data has been restored. > + * Only then can the storage keys be set to their old state. > + */ > +unsigned long page_key_additional_pages(unsigned long pages) > +{ > + return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE); > +} > + > +/* > + * Free page_key_data list of arrays. > + */ > +void page_key_free(void) > +{ > + struct page_key_data *pkd; > + > + while (page_key_data) { > + pkd = page_key_data; > + page_key_data = pkd->next; > + free_page((unsigned long) pkd); > + } > +} > + > +/* > + * Allocate page_key_data list of arrays with enough room to store > + * one byte for each page in the hibernation image. > + */ > +int page_key_alloc(unsigned long pages) > +{ > + struct page_key_data *pk; > + unsigned long size; > + > + size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE); > + while (size--) { > + pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL); > + if (!pk) { > + page_key_free(); > + return -ENOMEM; > + } > + pk->next = page_key_data; > + page_key_data = pk; > + } > + page_key_rp = page_key_wp = page_key_data; > + page_key_rx = page_key_wx = 0; > + return 0; > +} > + > +/* > + * Save the storage key into the upper 8 bits of the page frame number. > + */ > +void page_key_read(unsigned long *pfn) > +{ > + unsigned long addr; > + > + addr = (unsigned long) page_address(pfn_to_page(*pfn)); > + *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr); > +} > + > +/* > + * Extract the storage key from the upper 8 bits of the page frame number > + * and store it in the page_key_data list of arrays. > + */ > +void page_key_memorize(unsigned long *pfn) > +{ > + page_key_wp->data[page_key_wx] = *(unsigned char *) pfn; > + *(unsigned char *) pfn = 0; > + if (++page_key_wx < PAGE_KEY_DATA_SIZE) > + return; > + page_key_wp = page_key_wp->next; > + page_key_wx = 0; > +} > + > +/* > + * Get the next key from the page_key_data list of arrays and set the > + * storage key of the page referred by @address. If @address refers to > + * a "safe" page the swsusp_arch_resume code will transfer the storage > + * key from the buffer page to the original page. > + */ > +void page_key_write(void *address) > +{ > + page_set_storage_key((unsigned long) address, > + page_key_rp->data[page_key_rx], 0); > + if (++page_key_rx >= PAGE_KEY_DATA_SIZE) > + return; > + page_key_rp = page_key_rp->next; > + page_key_rx = 0; > +} > + > int pfn_is_nosave(unsigned long pfn) > { > unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin)); > Index: hibernate-2.6/arch/s390/kernel/swsusp_asm64.S > =================================================================== > --- hibernate-2.6.orig/arch/s390/kernel/swsusp_asm64.S 2011-08-09 17:40:09.228010544 +0200 > +++ hibernate-2.6/arch/s390/kernel/swsusp_asm64.S 2011-08-16 16:06:09.845540931 +0200 > @@ -136,11 +136,14 @@ > 0: > lg %r2,8(%r1) > lg %r4,0(%r1) > + iske %r0,%r4 > lghi %r3,PAGE_SIZE > lghi %r5,PAGE_SIZE > 1: > mvcle %r2,%r4,0 > jo 1b > + lg %r2,8(%r1) > + sske %r0,%r2 > lg %r1,16(%r1) > ltgr %r1,%r1 > jnz 0b > Index: hibernate-2.6/include/linux/suspend.h > =================================================================== > --- hibernate-2.6.orig/include/linux/suspend.h 2011-08-09 17:40:10.164030551 +0200 > +++ hibernate-2.6/include/linux/suspend.h 2011-08-16 16:06:09.845540931 +0200 > @@ -334,4 +334,38 @@ > } > #endif > > +#ifdef CONFIG_ARCH_SAVE_PAGE_KEYS > +/* > + * The ARCH_SAVE_PAGE_KEYS functions can be used by an architecture > + * to save/restore additional information to/from the array of page > + * frame numbers in the hibernation image. For s390 this is used to > + * save and restore the storage key for each page that is included > + * in the hibernation image. > + */ > +unsigned long page_key_additional_pages(unsigned long pages); > +int page_key_alloc(unsigned long pages); > +void page_key_free(void); > +void page_key_read(unsigned long *pfn); > +void page_key_memorize(unsigned long *pfn); > +void page_key_write(void *address); > + > +#else /* !CONFIG_ARCH_SAVE_PAGE_KEYS */ > + > +static inline unsigned long page_key_additional_pages(unsigned long pages) > +{ > + return 0; > +} > + > +static inline int page_key_alloc(unsigned long pages) > +{ > + return 0; > +} > + > +static inline void page_key_free(void) {} > +static inline void page_key_read(unsigned long *pfn) {} > +static inline void page_key_memorize(unsigned long *pfn) {} > +static inline void page_key_write(void *address) {} > + > +#endif /* !CONFIG_ARCH_SAVE_PAGE_KEYS */ > + > #endif /* _LINUX_SUSPEND_H */ > Index: hibernate-2.6/kernel/power/Kconfig > =================================================================== > --- hibernate-2.6.orig/kernel/power/Kconfig 2011-08-09 17:40:10.192031153 +0200 > +++ hibernate-2.6/kernel/power/Kconfig 2011-08-16 16:06:09.845540931 +0200 > @@ -65,6 +65,9 @@ > > For more information take a look at . > > +config ARCH_SAVE_PAGE_KEYS > + bool > + > config PM_STD_PARTITION > string "Default resume partition" > depends on HIBERNATION > Index: hibernate-2.6/kernel/power/snapshot.c > =================================================================== > --- hibernate-2.6.orig/kernel/power/snapshot.c 2011-07-08 11:25:06.293203483 +0200 > +++ hibernate-2.6/kernel/power/snapshot.c 2011-08-16 16:06:09.845540931 +0200 > @@ -1339,6 +1339,9 @@ > count += highmem; > count -= totalreserve_pages; > > + /* Add number of pages required for page keys (s390 only). */ > + size += page_key_additional_pages(saveable); > + > /* Compute the maximum number of saveable pages to leave in memory. */ > max_size = (count - (size + PAGES_FOR_IO)) / 2 > - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE); > @@ -1662,6 +1665,8 @@ > buf[j] = memory_bm_next_pfn(bm); > if (unlikely(buf[j] == BM_END_OF_MAP)) > break; > + /* Save page key for data page (s390 only). */ > + page_key_read(buf + j); > } > } > > @@ -1821,6 +1826,9 @@ > if (unlikely(buf[j] == BM_END_OF_MAP)) > break; > > + /* Extract and buffer page key for data page (s390 only). */ > + page_key_memorize(buf + j); > + > if (memory_bm_pfn_present(bm, buf[j])) > memory_bm_set_bit(bm, buf[j]); > else > @@ -2223,6 +2231,11 @@ > if (error) > return error; > > + /* Allocate buffer for page keys. */ > + error = page_key_alloc(nr_copy_pages); > + if (error) > + return error; > + > } else if (handle->cur <= nr_meta_pages + 1) { > error = unpack_orig_pfns(buffer, ©_bm); > if (error) > @@ -2243,6 +2256,8 @@ > } > } else { > copy_last_highmem_page(); > + /* Restore page key for data page (s390 only). */ > + page_key_write(handle->buffer); > handle->buffer = get_buffer(&orig_bm, &ca); > if (IS_ERR(handle->buffer)) > return PTR_ERR(handle->buffer); > @@ -2264,6 +2279,9 @@ > void snapshot_write_finalize(struct snapshot_handle *handle) > { > copy_last_highmem_page(); > + /* Restore page key for data page (s390 only). */ > + page_key_write(handle->buffer); > + page_key_free(); > /* Free only if we have loaded the image entirely */ > if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) { > memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR); > > >