linux-kernel - Re: [PATCH 1/2] x86 boot: add E820_RESVD

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 27 Jun 2008 11:03:04 +0800
From:	"Huang, Ying" <ying.huang@...el.com>
To:	Yinghai Lu <yhlu.kernel@...il.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>, andi@...stfloor.org,
	mingo@...hat.com, tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] x86 boot: add E820_RESVD_KERN

On Thu, 2008-06-26 at 19:52 -0700, Yinghai Lu wrote:
> On Thu, Jun 26, 2008 at 7:48 PM, Huang, Ying <ying.huang@...el.com> wrote:
> > On Thu, 2008-06-26 at 19:22 -0700, Yinghai Lu wrote:
> >> On Thu, Jun 26, 2008 at 2:47 AM, Yinghai Lu <yhlu.kernel@...il.com> wrote:
> >> > On Thu, Jun 26, 2008 at 12:48 AM, Huang, Ying <ying.huang@...el.com> wrote:
> >> >> On Thu, 2008-06-26 at 00:25 -0700, Yinghai Lu wrote:
> >> >> [...]
> >> >>> >                if (pfn >= limit_pfn)
> >> >>> > @@ -977,7 +978,7 @@ u64 __init early_reserve_e820(u64 startt
> >> >>> >                return 0;
> >> >>> >
> >> >>> >        addr = round_down(start + size - sizet, align);
> >> >>> > -       e820_update_range(addr, sizet, E820_RAM, E820_RESERVED);
> >> >>> > +       e820_update_range(addr, sizet, E820_RAM, E820_RESVD_KERN);
> >> >>>
> >> >>> this line is not needed.
> >> >>
> >> >> Why? Memory reserved by early_rserved_e820 should not be saved during
> >> >> hibernation? shoudl not be saved by kdump?
> >> >>
> >
> > Can you tell me why this line is not needed?
> 
> that function only have one user. the mpc reserve_new, so we want it
> to be E820_RESERVED, and kexec  tools could have that range reserved,
> the next kernel will not overwrite the updated mptable.

This is OK for kexec. Does it need to be saved by kdump? Does it need to
be saved by hibernation (suspend to disk)?

> >
> > [...]
> >> some like the attach patch...
> >>
> >> you still can merge parse_setup_data parse_e820_ext
> >> also entries in parse_e820_ext is not initialized..., __copy_e820_map
> >> will do nothing.
> >
> > OK. Because some E820 entries are available after parse_setup_data(),
> > it is better to call reserve_setup_data() after calling
> > parse_setup_data() if update_e820_range() is used instead of
> > reserve_early().
> 
> can you double check parse_e820_ext()?
> it seems entries is not initialized properly,
> 
> void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
> {
>         u32 map_len;
>         int entries;
>         struct e820entry *extmap;
> 
>         entries = sdata->len / sizeof(struct e820entry);
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
          here entries are initialized to be the number of entries in
          extended E820 table.
>         map_len = sdata->len + sizeof(struct setup_data);
>         if (map_len > PAGE_SIZE)
>                 sdata = early_ioremap(pa_data, map_len);
>         extmap = (struct e820entry *)(sdata->data);
>         __copy_e820_map(extmap, entries);===========> what is value for entries?
>         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
>         if (map_len > PAGE_SIZE)
>                 early_iounmap(sdata, map_len);
>         printk(KERN_INFO "extended physical RAM map:\n");
>         e820_print_map("extended");
> }

Best Regards,
Huang Ying

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/