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Date:	Sat, 31 Jan 2015 00:28:14 +0800
From:	joeyli <jlee@...e.com>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	"Lee, Chun-Yi" <joeyli.kernel@...il.com>,
	Huang Ying <ying.huang@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Ingo Molnar <mingo@...nel.org>, Pavel Machek <pavel@....cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	the arch/x86 maintainers <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Len Brown <len.brown@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>, Takashi Iwai <tiwai@...e.de>
Subject: Re: [PATCH] x86/mm, hibernate: Fix misjudgment of register
 setup_data page to nosave region

On Fri, Jan 30, 2015 at 10:46:48PM +0800, joeyli wrote:
> On Fri, Jan 30, 2015 at 12:30:00AM -0800, Yinghai Lu wrote:
> > On Thu, Jan 29, 2015 at 7:58 PM, Lee, Chun-Yi <joeyli.kernel@...il.com> wrote:
> > > The reserve setup_data action break usable regions to not align to
> > > page size. As following case:
> > >
> > > BIOS-e820: [mem 0x0000000000088000-0x00000000000bffff] reserved
> > > BIOS-e820: [mem 0x0000000000100000-0x0000000094caffff] usable
> > > ...
> > > e820: update [mem 0x93c5f018-0x93c6f057] usable ==> usable      /* reserve setup_data */
> > > e820: update [mem 0x93c4f018-0x93c5e057] usable ==> usable      /* reserve setup_data */
> > > ...
> > > reserve setup_data: [mem0x0000000000088000-0x00000000000bffff] reserved
> > > reserve setup_data: [mem0x0000000000100000-0x0000000093c4f017] usable /* not align */
> > > reserve setup_data: [mem0x0000000093c4f018-0x0000000093c5e057] usable /* not align */
> > > reserve setup_data: [mem0x0000000093c5e058-0x0000000093c5f017] usable /* not align */
> > > reserve setup_data: [mem0x0000000093c5f018-0x0000000093c6f057] usable /* not align */
> > > reserve setup_data: [mem0x0000000093c6f058-0x0000000094caffff] usable
> > >
> > > The codes in e820_mark_nosave_regions() check pfn of each e820
> > > entry to find out the hole between two entries then register it to
> > > nosave region. This logic misjudges the non-align but continuous usable
> > > region, then register one page in usable region to nosave. As following:
> > >
> > > PM: Registered nosave memory: [mem 0x000c0000-0x000fffff]
> > > PM: Registered nosave memory: [mem 0x93c4f000-0x93c4ffff] /* misjudgment */
> > > PM: Registered nosave memory: [mem 0x93c5e000-0x93c5efff] /* misjudgment */
> > > PM: Registered nosave memory: [mem 0x93c5f000-0x93c5ffff] /* misjudgment */
> > > PM: Registered nosave memory: [mem 0x93c6f000-0x93c6ffff] /* misjudgment */
> > > PM: Registered nosave memory: [mem 0x94cb0000-0x960affff]
> > >
> > > The issue causes some usable pages didn't collect to hibernate snapshot image.
> > > And, it also misjudges a usable page in nosave regions then hibernate resuming
> > > process interrupted by the unsafe pages checking:
> > >         https://bugzilla.opensuse.org/show_bug.cgi?id=913885
> > >
> > > This patch changed the code in e820_mark_nosave_regions() to check the
> > > address instead of pfn to avoid above issue.
> > 
> > [+cc: Ying Huang]
> > 
> > would like to suggest use attached instead:
> > 
> > Subject: [RFC PATCH] x86: Kill E820_RESERVED_KERN
> > 
> > Now we are using memblock to do early resource allocation instead of using
> > e820 map directly, and setup_data is reserved in memblock early.
> > Also kexec pass setup_data pointer to second kernel, so second kernel
> > will reserve setup_data by their own.
> > 
> > So we can kill E820_RESERVED_KERN and not touch e820 map at all.
> > 
> > That will fix bug in mark_nonsave_region that can not handle that
> > case: E820_RAM and E820_RESERVED_KERN continuous and boundary is
> > not page aligned.
> > 
> > Not sure about why tboot need to use this...
> 
> Yes, that's good to totally remove the E820_RESERVED_KERN because we already
> use memblock to reserve setup_data ranges.
> 
> 
> Thanks
> Joey Lee

This patch works on my Gateway EG50_HW notebook to fix issue in nosave regions.

Tested-by: Lee, Chun-Yi <jlee@...e.com>


Thanks a lot!
Joey Lee

> 
> > Subject: [RFC PATCH] x86: Kill E820_RESERVED_KERN
> > 
> > Now we are using memblock to do early resource allocation instead of using
> > e820 map directly, and setup_data is reserved in memblock early.
> > Also kexec pass setup_data pointer to second kernel, so second kernel
> > will reserve setup_data by their own.
> > 
> > So we can kill E820_RESERVED_KERN and not touch e820 map at all.
> > 
> > That will fix bug in mark_nonsave_region that can not handle that
> > case: E820_RAM and E820_RESERVED_KERN continuous and boundary is
> > not page aligned.
> > 
> > Not sure about why tboot need to use this...
> > 
> > Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> > 
> > ---
> >  arch/x86/include/uapi/asm/e820.h |    9 ---------
> >  arch/x86/kernel/e820.c           |    6 ++----
> >  arch/x86/kernel/setup.c          |   26 --------------------------
> >  arch/x86/kernel/tboot.c          |    3 +--
> >  arch/x86/mm/init_64.c            |   11 ++++-------
> >  5 files changed, 7 insertions(+), 48 deletions(-)
> > 
> > Index: linux-2.6/arch/x86/include/uapi/asm/e820.h
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/include/uapi/asm/e820.h
> > +++ linux-2.6/arch/x86/include/uapi/asm/e820.h
> > @@ -33,15 +33,6 @@
> >  #define E820_NVS	4
> >  #define E820_UNUSABLE	5
> >  
> > -
> > -/*
> > - * reserved RAM used by kernel itself
> > - * if CONFIG_INTEL_TXT is enabled, memory of this type will be
> > - * included in the S3 integrity calculation and so should not include
> > - * any memory that BIOS might alter over the S3 transition
> > - */
> > -#define E820_RESERVED_KERN        128
> > -
> >  #ifndef __ASSEMBLY__
> >  #include <linux/types.h>
> >  struct e820entry {
> > Index: linux-2.6/arch/x86/kernel/e820.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/kernel/e820.c
> > +++ linux-2.6/arch/x86/kernel/e820.c
> > @@ -134,7 +134,6 @@ static void __init e820_print_type(u32 t
> >  {
> >  	switch (type) {
> >  	case E820_RAM:
> > -	case E820_RESERVED_KERN:
> >  		printk(KERN_CONT "usable");
> >  		break;
> >  	case E820_RESERVED:
> > @@ -688,7 +687,7 @@ void __init e820_mark_nosave_regions(uns
> >  			register_nosave_region(pfn, PFN_UP(ei->addr));
> >  
> >  		pfn = PFN_DOWN(ei->addr + ei->size);
> > -		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
> > +		if (ei->type != E820_RAM)
> >  			register_nosave_region(PFN_UP(ei->addr), pfn);
> >  
> >  		if (pfn >= limit_pfn)
> > @@ -902,7 +901,6 @@ void __init finish_e820_parsing(void)
> >  static inline const char *e820_type_to_string(int e820_type)
> >  {
> >  	switch (e820_type) {
> > -	case E820_RESERVED_KERN:
> >  	case E820_RAM:	return "System RAM";
> >  	case E820_ACPI:	return "ACPI Tables";
> >  	case E820_NVS:	return "ACPI Non-volatile Storage";
> > @@ -1077,7 +1075,7 @@ void __init memblock_x86_fill(void)
> >  		if (end != (resource_size_t)end)
> >  			continue;
> >  
> > -		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
> > +		if (ei->type != E820_RAM)
> >  			continue;
> >  
> >  		memblock_add(ei->addr, ei->size);
> > Index: linux-2.6/arch/x86/kernel/setup.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/kernel/setup.c
> > +++ linux-2.6/arch/x86/kernel/setup.c
> > @@ -456,30 +456,6 @@ static void __init parse_setup_data(void
> >  	}
> >  }
> >  
> > -static void __init e820_reserve_setup_data(void)
> > -{
> > -	struct setup_data *data;
> > -	u64 pa_data;
> > -	int found = 0;
> > -
> > -	pa_data = boot_params.hdr.setup_data;
> > -	while (pa_data) {
> > -		data = early_memremap(pa_data, sizeof(*data));
> > -		e820_update_range(pa_data, sizeof(*data)+data->len,
> > -			 E820_RAM, E820_RESERVED_KERN);
> > -		found = 1;
> > -		pa_data = data->next;
> > -		early_iounmap(data, sizeof(*data));
> > -	}
> > -	if (!found)
> > -		return;
> > -
> > -	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
> > -	memcpy(&e820_saved, &e820, sizeof(struct e820map));
> > -	printk(KERN_INFO "extended physical RAM map:\n");
> > -	e820_print_map("reserve setup_data");
> > -}
> > -
> >  static void __init memblock_x86_reserve_range_setup_data(void)
> >  {
> >  	struct setup_data *data;
> > @@ -1011,8 +987,6 @@ void __init setup_arch(char **cmdline_p)
> >  		early_dump_pci_devices();
> >  #endif
> >  
> > -	/* update the e820_saved too */
> > -	e820_reserve_setup_data();
> >  	finish_e820_parsing();
> >  
> >  	if (efi_enabled(EFI_BOOT))
> > Index: linux-2.6/arch/x86/kernel/tboot.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/kernel/tboot.c
> > +++ linux-2.6/arch/x86/kernel/tboot.c
> > @@ -195,8 +195,7 @@ static int tboot_setup_sleep(void)
> >  	tboot->num_mac_regions = 0;
> >  
> >  	for (i = 0; i < e820.nr_map; i++) {
> > -		if ((e820.map[i].type != E820_RAM)
> > -		 && (e820.map[i].type != E820_RESERVED_KERN))
> > +		if (e820.map[i].type != E820_RAM)
> >  			continue;
> >  
> >  		add_mac_region(e820.map[i].addr, e820.map[i].size);
> > Index: linux-2.6/arch/x86/mm/init_64.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/mm/init_64.c
> > +++ linux-2.6/arch/x86/mm/init_64.c
> > @@ -426,8 +426,7 @@ phys_pte_init(pte_t *pte_page, unsigned
> >  		next = (addr & PAGE_MASK) + PAGE_SIZE;
> >  		if (addr >= end) {
> >  			if (!after_bootmem &&
> > -			    !e820_any_mapped(addr & PAGE_MASK, next, E820_RAM) &&
> > -			    !e820_any_mapped(addr & PAGE_MASK, next, E820_RESERVED_KERN))
> > +			    !e820_any_mapped(addr & PAGE_MASK, next, E820_RAM))
> >  				set_pte(pte, __pte(0));
> >  			continue;
> >  		}
> > @@ -473,9 +472,8 @@ phys_pmd_init(pmd_t *pmd_page, unsigned
> >  
> >  		next = (address & PMD_MASK) + PMD_SIZE;
> >  		if (address >= end) {
> > -			if (!after_bootmem &&
> > -			    !e820_any_mapped(address & PMD_MASK, next, E820_RAM) &&
> > -			    !e820_any_mapped(address & PMD_MASK, next, E820_RESERVED_KERN))
> > +			if (!after_bootmem && !e820_any_mapped(
> > +					address & PMD_MASK, next, E820_RAM))
> >  				set_pmd(pmd, __pmd(0));
> >  			continue;
> >  		}
> > @@ -548,8 +546,7 @@ phys_pud_init(pud_t *pud_page, unsigned
> >  		next = (addr & PUD_MASK) + PUD_SIZE;
> >  		if (addr >= end) {
> >  			if (!after_bootmem &&
> > -			    !e820_any_mapped(addr & PUD_MASK, next, E820_RAM) &&
> > -			    !e820_any_mapped(addr & PUD_MASK, next, E820_RESERVED_KERN))
> > +			    !e820_any_mapped(addr & PUD_MASK, next, E820_RAM))
> >  				set_pud(pud, __pud(0));
> >  			continue;
> >  		}
> 
--
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