From ea00f4f4f00cc2bc3b63ad512a4e6df3b20832b9 Mon Sep 17 00:00:00 2001 From: Lianwei Wang Date: Sun, 19 Jun 2016 23:52:27 -0700 Subject: PM / sleep: make PM notifiers called symmetrically This makes pm notifier PREPARE/POST symmetrical: if PREPARE fails, we will only undo what ever happened on PREPARE. It fixes the unbalanced CPU hotplug enable in CPU PM notifier. Signed-off-by: Lianwei Wang Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'kernel/power/hibernate.c') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index fca9254280ee..126e24caa82e 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -647,7 +647,7 @@ static void power_down(void) */ int hibernate(void) { - int error; + int error, nr_calls = 0; if (!hibernation_available()) { pr_debug("PM: Hibernation not available.\n"); @@ -662,9 +662,11 @@ int hibernate(void) } pm_prepare_console(); - error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE); - if (error) + error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); + if (error) { + nr_calls--; goto Exit; + } printk(KERN_INFO "PM: Syncing filesystems ... "); sys_sync(); @@ -714,7 +716,7 @@ int hibernate(void) /* Don't bother checking whether freezer_test_done is true */ freezer_test_done = false; Exit: - pm_notifier_call_chain(PM_POST_HIBERNATION); + __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL); pm_restore_console(); atomic_inc(&snapshot_device_available); Unlock: @@ -740,7 +742,7 @@ int hibernate(void) */ static int software_resume(void) { - int error; + int error, nr_calls = 0; unsigned int flags; /* @@ -827,9 +829,11 @@ static int software_resume(void) } pm_prepare_console(); - error = pm_notifier_call_chain(PM_RESTORE_PREPARE); - if (error) + error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); + if (error) { + nr_calls--; goto Close_Finish; + } pr_debug("PM: Preparing processes for restore.\n"); error = freeze_processes(); @@ -855,7 +859,7 @@ static int software_resume(void) unlock_device_hotplug(); thaw_processes(); Finish: - pm_notifier_call_chain(PM_POST_RESTORE); + __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); pm_restore_console(); atomic_inc(&snapshot_device_available); /* For success case, the suspend path will release the lock */ -- cgit v1.2.3 From 2f88e41a22ccfa95291c4df573f8ed4c6a71f29b Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 6 Jul 2016 02:40:56 +0200 Subject: PM / hibernate: Add missing braces in hibernate_setup() Make hibernate_setup() follow the coding style more closely by adding some missing braces to the if () statement in it. Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/power/hibernate.c') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 126e24caa82e..b00f270d328e 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -1119,11 +1119,11 @@ static int __init resume_offset_setup(char *str) static int __init hibernate_setup(char *str) { - if (!strncmp(str, "noresume", 8)) + if (!strncmp(str, "noresume", 8)) { noresume = 1; - else if (!strncmp(str, "nocompress", 10)) + } else if (!strncmp(str, "nocompress", 10)) { nocompress = 1; - else if (!strncmp(str, "no", 2)) { + } else if (!strncmp(str, "no", 2)) { noresume = 1; nohibernate = 1; } -- cgit v1.2.3 From 4c0b6c10fbaf0c82efe2a7ba6c236c633d4f2ed7 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 10 Jul 2016 02:12:10 +0200 Subject: PM / hibernate: Image data protection during restoration Make it possible to protect all pages holding image data during hibernate image restoration by setting them read-only (so as to catch attempts to write to those pages after image data have been stored in them). This adds overhead to image restoration code (it may cause large page mappings to be split as a result of page flags changes) and the errors it protects against should never happen in theory, so the feature is only active after passing hibernate=protect_image to the command line of the restore kernel. Also it only is built if CONFIG_DEBUG_RODATA is set. Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/power/hibernate.c') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index b00f270d328e..51441d87f0b6 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -1126,6 +1126,9 @@ static int __init hibernate_setup(char *str) } else if (!strncmp(str, "no", 2)) { noresume = 1; nohibernate = 1; + } else if (IS_ENABLED(CONFIG_DEBUG_RODATA) + && !strncmp(str, "protect_image", 13)) { + enable_restore_image_protection(); } return 1; } -- cgit v1.2.3 From 406f992e4a372dafbe3c2cff7efbb2002a5c8ebd Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 14 Jul 2016 03:55:23 +0200 Subject: x86 / hibernate: Use hlt_play_dead() when resuming from hibernation On Intel hardware, native_play_dead() uses mwait_play_dead() by default and only falls back to the other methods if that fails. That also happens during resume from hibernation, when the restore (boot) kernel runs disable_nonboot_cpus() to take all of the CPUs except for the boot one offline. However, that is problematic, because the address passed to __monitor() in mwait_play_dead() is likely to be written to in the last phase of hibernate image restoration and that causes the "dead" CPU to start executing instructions again. Unfortunately, the page containing the address in that CPU's instruction pointer may not be valid any more at that point. First, that page may have been overwritten with image kernel memory contents already, so the instructions the CPU attempts to execute may simply be invalid. Second, the page tables previously used by that CPU may have been overwritten by image kernel memory contents, so the address in its instruction pointer is impossible to resolve then. A report from Varun Koyyalagunta and investigation carried out by Chen Yu show that the latter sometimes happens in practice. To prevent it from happening, temporarily change the smp_ops.play_dead pointer during resume from hibernation so that it points to a special "play dead" routine which uses hlt_play_dead() and avoids the inadvertent "revivals" of "dead" CPUs this way. A slightly unpleasant consequence of this change is that if the system is hibernated with one or more CPUs offline, it will generally draw more power after resume than it did before hibernation, because the physical state entered by CPUs via hlt_play_dead() is higher-power than the mwait_play_dead() one in the majority of cases. It is possible to work around this, but it is unclear how much of a problem that's going to be in practice, so the workaround will be implemented later if it turns out to be necessary. Link: https://bugzilla.kernel.org/show_bug.cgi?id=106371 Reported-by: Varun Koyyalagunta Original-by: Chen Yu Tested-by: Chen Yu Signed-off-by: Rafael J. Wysocki Acked-by: Ingo Molnar --- kernel/power/hibernate.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel/power/hibernate.c') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 51441d87f0b6..5f3523e18e46 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -409,6 +409,11 @@ int hibernation_snapshot(int platform_mode) goto Close; } +int __weak hibernate_resume_nonboot_cpu_disable(void) +{ + return disable_nonboot_cpus(); +} + /** * resume_target_kernel - Restore system state from a hibernation image. * @platform_mode: Whether or not to use the platform driver. @@ -433,7 +438,7 @@ static int resume_target_kernel(bool platform_mode) if (error) goto Cleanup; - error = disable_nonboot_cpus(); + error = hibernate_resume_nonboot_cpu_disable(); if (error) goto Enable_cpus; -- cgit v1.2.3 From fe12c00d21bb4985fa8da282942250be21e7dd59 Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Fri, 22 Jul 2016 10:30:47 +0800 Subject: PM / hibernate: Introduce test_resume mode for hibernation test_resume mode is to verify if the snapshot data written to swap device can be successfully restored to memory. It is useful to ease the debugging process on hibernation, since this mode can not only bypass the BIOSes/bootloader, but also the system re-initialization. To avoid the risk to break the filesystm on persistent storage, this patch resumes the image with tasks frozen. For example: echo test_resume > /sys/power/disk echo disk > /sys/power/state [ 187.306470] PM: Image saving progress: 70% [ 187.395298] PM: Image saving progress: 80% [ 187.476697] PM: Image saving progress: 90% [ 187.554641] PM: Image saving done. [ 187.558896] PM: Wrote 594600 kbytes in 0.90 seconds (660.66 MB/s) [ 187.566000] PM: S| [ 187.589742] PM: Basic memory bitmaps freed [ 187.594694] PM: Checking hibernation image [ 187.599865] PM: Image signature found, resuming [ 187.605209] PM: Loading hibernation image. [ 187.665753] PM: Basic memory bitmaps created [ 187.691397] PM: Using 3 thread(s) for decompression. [ 187.691397] PM: Loading and decompressing image data (148650 pages)... [ 187.889719] PM: Image loading progress: 0% [ 188.100452] PM: Image loading progress: 10% [ 188.244781] PM: Image loading progress: 20% [ 189.057305] PM: Image loading done. [ 189.068793] PM: Image successfully loaded Suggested-by: Rafael J. Wysocki Signed-off-by: Chen Yu Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 65 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 44 insertions(+), 21 deletions(-) (limited to 'kernel/power/hibernate.c') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 5f3523e18e46..0ee1df0a0bd6 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -52,6 +52,7 @@ enum { #ifdef CONFIG_SUSPEND HIBERNATION_SUSPEND, #endif + HIBERNATION_TEST_RESUME, /* keep last */ __HIBERNATION_AFTER_LAST }; @@ -647,12 +648,39 @@ static void power_down(void) cpu_relax(); } +static int load_image_and_restore(void) +{ + int error; + unsigned int flags; + + pr_debug("PM: Loading hibernation image.\n"); + + lock_device_hotplug(); + error = create_basic_memory_bitmaps(); + if (error) + goto Unlock; + + error = swsusp_read(&flags); + swsusp_close(FMODE_READ); + if (!error) + hibernation_restore(flags & SF_PLATFORM_MODE); + + printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n"); + swsusp_free(); + free_basic_memory_bitmaps(); + Unlock: + unlock_device_hotplug(); + + return error; +} + /** * hibernate - Carry out system hibernation, including saving the image. */ int hibernate(void) { int error, nr_calls = 0; + bool snapshot_test = false; if (!hibernation_available()) { pr_debug("PM: Hibernation not available.\n"); @@ -704,8 +732,12 @@ int hibernate(void) pr_debug("PM: writing image.\n"); error = swsusp_write(flags); swsusp_free(); - if (!error) - power_down(); + if (!error) { + if (hibernation_mode == HIBERNATION_TEST_RESUME) + snapshot_test = true; + else + power_down(); + } in_suspend = 0; pm_restore_gfp_mask(); } else { @@ -716,6 +748,12 @@ int hibernate(void) free_basic_memory_bitmaps(); Thaw: unlock_device_hotplug(); + if (snapshot_test) { + pr_debug("PM: Checking hibernation image\n"); + error = swsusp_check(); + if (!error) + error = load_image_and_restore(); + } thaw_processes(); /* Don't bother checking whether freezer_test_done is true */ @@ -748,7 +786,6 @@ int hibernate(void) static int software_resume(void) { int error, nr_calls = 0; - unsigned int flags; /* * If the user said "noresume".. bail out early. @@ -844,24 +881,7 @@ static int software_resume(void) error = freeze_processes(); if (error) goto Close_Finish; - - pr_debug("PM: Loading hibernation image.\n"); - - lock_device_hotplug(); - error = create_basic_memory_bitmaps(); - if (error) - goto Thaw; - - error = swsusp_read(&flags); - swsusp_close(FMODE_READ); - if (!error) - hibernation_restore(flags & SF_PLATFORM_MODE); - - printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n"); - swsusp_free(); - free_basic_memory_bitmaps(); - Thaw: - unlock_device_hotplug(); + error = load_image_and_restore(); thaw_processes(); Finish: __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); @@ -887,6 +907,7 @@ static const char * const hibernation_modes[] = { #ifdef CONFIG_SUSPEND [HIBERNATION_SUSPEND] = "suspend", #endif + [HIBERNATION_TEST_RESUME] = "test_resume", }; /* @@ -933,6 +954,7 @@ static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr, #ifdef CONFIG_SUSPEND case HIBERNATION_SUSPEND: #endif + case HIBERNATION_TEST_RESUME: break; case HIBERNATION_PLATFORM: if (hibernation_ops) @@ -979,6 +1001,7 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr, #ifdef CONFIG_SUSPEND case HIBERNATION_SUSPEND: #endif + case HIBERNATION_TEST_RESUME: hibernation_mode = mode; break; case HIBERNATION_PLATFORM: -- cgit v1.2.3