Please ignore this patch, will resend a Version 6. Thanks! > -----Original Message----- > From: Chen, Yu C > Sent: Thursday, October 15, 2015 3:00 AM > To: [email protected]; [email protected] > Cc: [email protected]; [email protected]; [email protected]; Brown, Len; > Zhang, Rui; [email protected]; [email protected]; linux- > [email protected]; Chen, Yu C > Subject: [PATCH][v5] PM / hibernate: Print the possible panic reason when > resuming with inconsistent e820 map > > On some platforms, there is occasional panic triggered when trying to > resume from hibernation, a typical panic looks like: > > "BUG: unable to handle kernel paging request at ffff880085894000 > IP: [<ffffffff810c5dc2>] load_image_lzo+0x8c2/0xe70" > > This is because e820 map has been changed by BIOS before/after > hibernation, and one of the page frames from first kernel is right located in > second kernel's unmapped region, so panic comes out when accessing > unmapped kernel address. > > In order to tell user why this happeneded, and for scalability, we introduce a > framework to compare the e820 maps before/after hibernation. If these two > e820 maps are not compatible with each other, we will print the first corrupt > e820 entry's information (there might be more than one broken e820 entries) > once system goes into panic, for example: > > BUG: unable to handle kernel paging request at ffff8800a9688000 > IP: [<ffffffff810c5dc2>] load_image_lzo+0x8c2/0xe70 > PM: Hibernation Caution! Oops might be due to inconsistent e820 table. > PM: mem [0xa963b000-0xa963d000][ACPI Table] is an invalid old e820 region. > PM: Inconsistent with current [mem 0xa963b000-0xa963e000][ACPI Table]. > PM: Please update your BIOS, or do not use hibernation on this machine. > > The following e820 entries will be regarded as invalid ones: > 1.E820_RAM: old region is not a subset of any current region. > 2.E820_ACPI: old region is not strictly the same as any current > region(example above). > > Signed-off-by: Chen Yu <[email protected]> > --- > v5: > - Rewrite this patch to just warn user of the broken BIOS > when panic. > v4: > - Add __attribute__ ((unused)) for swsusp_page_is_valid, > to eliminate the warnning of: > 'swsusp_page_is_valid' defined but not used > on non-x86 platforms. > > v3: > - Adjust the logic to exclude the end_pfn boundary in pfn_mapped > when invoking mark_valid_pages, because the end_pfn is not > a mapped page frame, we should not regard it as a valid page. > > Move the sanity check of valid pages to a early stage in resuming > process(moved to mark_unsafe_pages), in this way, we can avoid > unnecessarily accessing these invalid pages in later stage(yes, > move to the original position Joey once introduced in: > Commit 84c91b7ae07c ("PM / hibernate: avoid unsafe pages in e820 > reserved regions") > > With v3 patch applied, I did 30 cycles on my problematic platform, > no panic triggered anymore(50% reproducible before patched, by > plugging/unplugging memory peripheral during hibernation), and it > just warns of invalid pages. > > v2: > - According to Ingo's suggestion, rewrite this patch. > > New version just checks each page frame according to pfn_mapped array. > So that we do not need to touch existing code related to > E820_RESERVED_KERN. And this method can naturely guarantee > that the system before/after hibernation do not need to be of > the same memory size on x86_64. > --- > arch/x86/Kconfig | 4 + > arch/x86/include/asm/suspend.h | 3 + > arch/x86/power/Makefile | 2 +- > arch/x86/power/hibernate.c | 229 > +++++++++++++++++++++++++++++++++++++++++ > include/linux/suspend.h | 16 +++ > kernel/power/power.h | 8 ++ > kernel/power/snapshot.c | 8 ++ > 7 files changed, 269 insertions(+), 1 deletion(-) create mode 100644 > arch/x86/power/hibernate.c > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 96d058a..0b2f10c > 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -2132,6 +2132,10 @@ config ARCH_HIBERNATION_HEADER > def_bool y > depends on X86_64 && HIBERNATION > > +config ARCH_RESUME_IMAGE_CHECKER > + def_bool y > + depends on HIBERNATION > + > source "kernel/power/Kconfig" > > source "drivers/acpi/Kconfig" > diff --git a/arch/x86/include/asm/suspend.h > b/arch/x86/include/asm/suspend.h index 2fab6c2..63bc53e 100644 > --- a/arch/x86/include/asm/suspend.h > +++ b/arch/x86/include/asm/suspend.h > @@ -3,3 +3,6 @@ > #else > # include <asm/suspend_64.h> > #endif > + > +extern int arch_image_info_save(char *dst, char *src, unsigned int > +limit_len); extern bool arch_image_info_check(const char *new, const > +char *old); > diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile index > a6a198c..47596e2 100644 > --- a/arch/x86/power/Makefile > +++ b/arch/x86/power/Makefile > @@ -4,4 +4,4 @@ nostackp := $(call cc-option, -fno-stack-protector) > CFLAGS_cpu.o := $(nostackp) > > obj-$(CONFIG_PM_SLEEP) += cpu.o > -obj-$(CONFIG_HIBERNATION) += hibernate_$(BITS).o > hibernate_asm_$(BITS).o > +obj-$(CONFIG_HIBERNATION) += hibernate_$(BITS).o > hibernate_asm_$(BITS).o hibernate.o > diff --git a/arch/x86/power/hibernate.c b/arch/x86/power/hibernate.c new > file mode 100644 index 0000000..d90b7ed > --- /dev/null > +++ b/arch/x86/power/hibernate.c > @@ -0,0 +1,229 @@ > +/* > + * Hibernation common support for x86 > + * > + * Distribute under GPLv2 > + * > + * Copyright (c) 2015 Chen Yu <[email protected]> */ > + > +#include <linux/suspend.h> > +#include <linux/kdebug.h> > + > +#include <asm/init.h> > +#include <asm/suspend.h> > + > +/* > + * The following section is to check whether the old e820 map > + * (system before hibernation) is compatible with current > + * e820 map(system for resuming). > + * We check two types of regions: E820_RAM and E820_ACPI, > + * and to make sure the two kinds of regions will satisfy: > + * 1. E820_RAM: each old region is a subset of the current ones. > + * 2. E820_ACPI: each old region is strictly the same as the current ones. > + * > + * We save the old e820 map inside the swsusp_info page, > + * then pass it to the second system for resuming, by the > + * following format: > + * > + * > + * +--------+---------+------+------+------+ > + * | swsusp |e820entry|entry0|entry1|entry2| > + * | info | number | | | | > + * +--------+---------+------+------+------+ > + * ^ ^ > + * | | > + * +--------------struct swsusp_info(PAGE_SIZE)-------------+ > + */ > + > +/* > + * Record the first pair of conflicted new/old > + * e820 entries if there's any. > + */ > +static u32 bad_old_type; > +static u64 bad_old_start, bad_old_end; > + > +static u32 bad_new_type; > +static u64 bad_new_start, bad_new_end; > + > +/** > + * arch_image_info_save - save specified e820 data to > + * the hibernation image header > + * @dst: address to save the data to. > + * @src: source data need to be saved, > + * if NULL then save current system's e820 map. > + * @limit_len: max len in bytes to write. > + */ > +int arch_image_info_save(char *dst, char *src, unsigned int limit_len) > +{ > + unsigned int e820_nr_map; > + unsigned int size_to_copy; > + struct e820map *e820_map; > + > + /* > + * The final copied structure is illustrated below: > + * [number_of_e820entry][e820entry0)[e820entry1)... > + */ > + if (src) { > + e820_nr_map = *(unsigned int *)src; > + e820_map = (struct e820map *)(src + sizeof(unsigned int)); > + } else { > + e820_nr_map = e820_saved.nr_map; > + e820_map = &e820_saved; > + } > + > + size_to_copy = e820_nr_map * sizeof(struct e820entry); > + > + if ((size_to_copy + sizeof(unsigned int)) > limit_len) { > + pr_warn("PM: Hibernation can not save extra info due to too > many e820 entries\n"); > + return -ENOMEM; > + } > + *(unsigned int *)dst = e820_nr_map; > + dst += sizeof(unsigned int); > + memcpy(dst, (void *)&e820_map->map[0], size_to_copy); > + return 0; > +} > + > +/** > + * arch_image_info_check - check the relationship between > + * new and old e820 map, to make sure that, the E820_RAM > + * in old e820, is a subset of the new e820 map, and the > + * E820_ACPI regions in old e820 map, are strictly the > + * same as new e820 map. If it is, return true, otherwise return false. > + * > + * @new: New e820 map address, usually it is the > + * current system's e820_saved. > + * @old: Old e820 map address, it is usually the > + * e820 map before hibernation. > + */ > +bool arch_image_info_check(const char *new, const char *old) { > + struct e820map *e820_old, *e820_new; > + int i, j, e820_old_num, e820_new_num; > + > + e820_old = (struct e820map *)old; > + e820_old_num = *(unsigned int *)e820_old; > + > + if (new) > + e820_new = (struct e820map *)new; > + else > + e820_new = &e820_saved; > + > + e820_new_num = e820_new->nr_map; > + > + if ((e820_old_num == 0) || (e820_new_num == 0) || > + (e820_old_num > E820_X_MAX) || (e820_new_num > > E820_X_MAX)) > + return false; > + > + for (i = 0; i < e820_old_num; i++) { > + u64 old_start, old_end; > + struct e820entry *ei_old; > + bool valid_old_entry = false; > + > + ei_old = &e820_old->map[i]; > + > + /* > + * Only check RAM memory and ACPI table regions, > + * and we follow this policy: > + * 1.The old e820 RAM region must be new RAM's subset. > + * 2.The old e820 ACPI table region must be the same > + * as the new one. > + */ > + if (ei_old->type != E820_RAM && ei_old->type != E820_ACPI) > + continue; > + > + old_start = ei_old->addr; > + old_end = ei_old->addr + ei_old->size; > + > + for (j = 0; j < e820_new_num; j++) { > + u64 new_start, new_end; > + struct e820entry *ei_new; > + > + if (valid_old_entry) > + break; > + > + ei_new = &e820_new->map[i]; > + new_start = ei_new->addr; > + new_end = ei_new->addr + ei_new->size; > + > + /* > + * Check the relationship between these two regions. > + */ > + if (old_start >= new_start && old_start < new_end) { > + /* Must be of the same type. */ > + if ((ei_old->type != ei_new->type) || > + /* E820_RAM must be the subset */ > + ((ei_old->type == E820_RAM) && > + (old_end > new_end)) || > + /* E820_ACPI must remain unchanged. */ > + ((ei_old->type == E820_ACPI) && > + (old_start != new_start || > + old_end != new_end))) { > + bad_old_start = old_start; > + bad_old_end = old_end; > + bad_old_type = ei_old->type; > + bad_new_start = new_start; > + bad_new_end = new_end; > + bad_new_type = ei_new->type; > + > + return false; > + } > + /* OK, this one is a valid e820 region. */ > + valid_old_entry = true; > + } > + } > + /* If we did not find any overlapping between this old e820 > + * region and the new regions, return invalid. > + */ > + if (!valid_old_entry) { > + bad_old_start = old_start; > + bad_old_end = old_end; > + return false; > + } > + } > + /* All the old e820 entries are valid */ > + return true; > +} > + > +/* > + * This hook is invoked when kernel dies, and will print the broken > +e820 map > + * if it is caused by BIOS memory bug. > + */ > +static int arch_hibernation_die_check(struct notifier_block *nb, > + unsigned long action, > + void *data) > +{ > + if (!bad_old_start || !bad_old_end) > + return 0; > + > + pr_err("PM: Hibernation Caution! Oops might be due to inconsistent > e820 table.\n"); > + pr_err("PM: [mem %#010llx-%#010llx][%s] is an invalid old e820 > region.\n", > + bad_old_start, bad_old_end, > + (bad_old_type == E820_RAM) ? "RAM" : "ACPI > Table"); > + if (bad_new_start && bad_new_end) > + pr_err("PM: Inconsistent with current [mem %#010llx- > %#010llx][%s]\n", > + bad_new_start, bad_new_end, > + (bad_new_type == E820_RAM) ? "RAM" : "ACPI > Table"); > + pr_err("PM: Please update your BIOS, or do not use hibernation on > this > +machine.\n"); > + > + /* Avoid nested die print*/ > + bad_old_start = bad_old_end = 0; > + > + return 0; > +} > + > +static struct notifier_block hibernation_notifier = { > + .notifier_call = arch_hibernation_die_check, }; > + > +static int __init arch_init_hibernation(void) { > + int retval; > + > + retval = register_die_notifier(&hibernation_notifier); > + if (retval) > + return retval; > + > + return 0; > +} > + > +late_initcall(arch_init_hibernation); > diff --git a/include/linux/suspend.h b/include/linux/suspend.h index > 5efe743..729fa2a 100644 > --- a/include/linux/suspend.h > +++ b/include/linux/suspend.h > @@ -8,6 +8,7 @@ > #include <linux/mm.h> > #include <linux/freezer.h> > #include <asm/errno.h> > +#include <asm/suspend.h> > > #ifdef CONFIG_VT > extern void pm_set_vt_switch(int); > @@ -361,6 +362,21 @@ static inline bool system_entering_hibernation(void) > { return false; } static inline bool hibernation_available(void) { return > false; } > #endif /* CONFIG_HIBERNATION */ > > +#ifndef CONFIG_ARCH_RESUME_IMAGE_CHECKER static inline bool > +arch_image_info_check(const char *new, > + const char *old) > +{ > + return true; > +} > + > +static inline int arch_image_info_save(char *dst, > + char *src, > + unsigned int limit_len) > +{ > + return 0; > +} > +#endif > + > /* Hibernation and suspend events */ > #define PM_HIBERNATION_PREPARE 0x0001 /* Going to hibernate */ > #define PM_POST_HIBERNATION 0x0002 /* Hibernation finished */ > diff --git a/kernel/power/power.h b/kernel/power/power.h index > caadb56..d279907 100644 > --- a/kernel/power/power.h > +++ b/kernel/power/power.h > @@ -14,6 +14,14 @@ struct swsusp_info { > unsigned long size; > } __aligned(PAGE_SIZE); > > +/* > + * Since struct swsusp_info will take one page size, > + * some platforms save the extra data right after the > + * last structure element. > + */ > +#define SWSUSP_INFO_ACTUAL_SIZE \ > + (offsetof(struct swsusp_info, size) + sizeof(unsigned long)) > + > #ifdef CONFIG_HIBERNATION > /* kernel/power/snapshot.c */ > extern void __init hibernate_reserved_size_init(void); > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index > 5235dd4..394d20d 100644 > --- a/kernel/power/snapshot.c > +++ b/kernel/power/snapshot.c > @@ -1970,6 +1970,11 @@ int snapshot_read_next(struct snapshot_handle > *handle) > error = init_header((struct swsusp_info *)buffer); > if (error) > return error; > + > + arch_image_info_save((char *)buffer + > SWSUSP_INFO_ACTUAL_SIZE, > + NULL, > + PAGE_SIZE-SWSUSP_INFO_ACTUAL_SIZE); > + > handle->buffer = buffer; > memory_bm_position_reset(&orig_bm); > memory_bm_position_reset(©_bm); > @@ -2491,6 +2496,9 @@ int snapshot_write_next(struct snapshot_handle > *handle) > if (error) > return error; > > + arch_image_info_check(NULL, > + (char *)buffer + > SWSUSP_INFO_ACTUAL_SIZE); > + > error = memory_bm_create(©_bm, GFP_ATOMIC, > PG_ANY); > if (error) > return error; > -- > 1.8.4.2
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