* [PATCH] Increase kernel text size for x86_64
@ 2009-08-12 7:41 Hannes Reinecke
2009-08-13 0:40 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Hannes Reinecke @ 2009-08-12 7:41 UTC (permalink / raw)
To: Simon Horman; +Cc: kexec mailing list
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Hi all,
I cannot load a x86_64 kernel with kexec on 2.6.31; the error message is:
Can't find kernel text map area from kcore
Cannot load /boot/vmlinuz
Digging through the source I found a mismatch between the assumed
kernel text size; kexec has:
#define KERNEL_TEXT_SIZE (40UL*1024*1024)
but on the kernel side we have:
include/asm/page_64_types.h:
#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
And, indeed, changing the definition in kexec-tools to the kernel one
fixed the problem.
Not sure if this has been reported before, if so please ignore
the noise.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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diff --git a/kexec/arch/x86_64/crashdump-x86_64.h b/kexec/arch/x86_64/crashdump-x86_64.h
index 9f4dee9..0e83527 100644
--- a/kexec/arch/x86_64/crashdump-x86_64.h
+++ b/kexec/arch/x86_64/crashdump-x86_64.h
@@ -11,7 +11,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
#define MAXMEM 0x3fffffffffffUL
/* Kernel text size */
-#define KERNEL_TEXT_SIZE (40UL*1024*1024)
+#define KERNEL_TEXT_SIZE (512UL*1024*1024)
#define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1)
#define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2)
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Increase kernel text size for x86_64
2009-08-12 7:41 [PATCH] Increase kernel text size for x86_64 Hannes Reinecke
@ 2009-08-13 0:40 ` Simon Horman
2009-08-13 8:12 ` Hannes Reinecke
0 siblings, 1 reply; 4+ messages in thread
From: Simon Horman @ 2009-08-13 0:40 UTC (permalink / raw)
To: Hannes Reinecke; +Cc: kexec mailing list
On Wed, Aug 12, 2009 at 09:41:23AM +0200, Hannes Reinecke wrote:
> Hi all,
>
> I cannot load a x86_64 kernel with kexec on 2.6.31; the error message is:
>
> Can't find kernel text map area from kcore
> Cannot load /boot/vmlinuz
>
> Digging through the source I found a mismatch between the assumed
> kernel text size; kexec has:
>
> #define KERNEL_TEXT_SIZE (40UL*1024*1024)
>
> but on the kernel side we have:
>
> include/asm/page_64_types.h:
> #define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
>
> And, indeed, changing the definition in kexec-tools to the kernel one
> fixed the problem.
>
> Not sure if this has been reported before, if so please ignore
> the noise.
Hi,
I'm wondering what effect this would have when using
kexec-tools with older kernels, which presumably have
a smaller value for KERNEL_IMAGE_SIZE.
> diff --git a/kexec/arch/x86_64/crashdump-x86_64.h b/kexec/arch/x86_64/crashdump-x86_64.h
> index 9f4dee9..0e83527 100644
> --- a/kexec/arch/x86_64/crashdump-x86_64.h
> +++ b/kexec/arch/x86_64/crashdump-x86_64.h
> @@ -11,7 +11,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
> #define MAXMEM 0x3fffffffffffUL
>
> /* Kernel text size */
> -#define KERNEL_TEXT_SIZE (40UL*1024*1024)
> +#define KERNEL_TEXT_SIZE (512UL*1024*1024)
>
> #define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1)
> #define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2)
_______________________________________________
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kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Increase kernel text size for x86_64
2009-08-13 0:40 ` Simon Horman
@ 2009-08-13 8:12 ` Hannes Reinecke
2009-08-13 8:21 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Hannes Reinecke @ 2009-08-13 8:12 UTC (permalink / raw)
To: Simon Horman; +Cc: kexec mailing list
Simon Horman wrote:
> On Wed, Aug 12, 2009 at 09:41:23AM +0200, Hannes Reinecke wrote:
>> Hi all,
>>
>> I cannot load a x86_64 kernel with kexec on 2.6.31; the error message is:
>>
>> Can't find kernel text map area from kcore
>> Cannot load /boot/vmlinuz
>>
>> Digging through the source I found a mismatch between the assumed
>> kernel text size; kexec has:
>>
>> #define KERNEL_TEXT_SIZE (40UL*1024*1024)
>>
>> but on the kernel side we have:
>>
>> include/asm/page_64_types.h:
>> #define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
>>
>> And, indeed, changing the definition in kexec-tools to the kernel one
>> fixed the problem.
>>
>> Not sure if this has been reported before, if so please ignore
>> the noise.
>
> Hi,
>
> I'm wondering what effect this would have when using
> kexec-tools with older kernels, which presumably have
> a smaller value for KERNEL_IMAGE_SIZE.
>
>> diff --git a/kexec/arch/x86_64/crashdump-x86_64.h b/kexec/arch/x86_64/crashdump-x86_64.h
>> index 9f4dee9..0e83527 100644
>> --- a/kexec/arch/x86_64/crashdump-x86_64.h
>> +++ b/kexec/arch/x86_64/crashdump-x86_64.h
>> @@ -11,7 +11,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
>> #define MAXMEM 0x3fffffffffffUL
>>
>> /* Kernel text size */
>> -#define KERNEL_TEXT_SIZE (40UL*1024*1024)
>> +#define KERNEL_TEXT_SIZE (512UL*1024*1024)
>>
>> #define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1)
>> #define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2)
>
Well, the actual point of failure is in kexec/arch/x86_64/crashdump-x86_64.c:125
/* Look for kernel text mapping header. */
if ((saddr >= __START_KERNEL_map) &&
(eaddr <= __START_KERNEL_map + KERNEL_TEXT_SIZE)) {
saddr = (saddr) & (~(KERN_VADDR_ALIGN - 1));
info->kern_vaddr_start = saddr;
size = eaddr - saddr;
which basically should look for a ELF header into which the kernel fits. As we're
effectively just moving the upper limit I fail to see any harm to older kernels.
Hmm. Haven't checked for other occurrences of KERNEL_TEXT_SIZE, though.
Would be nice we could be getting these values off somewhere; rely on
some kernel defines is going to break now and then.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Increase kernel text size for x86_64
2009-08-13 8:12 ` Hannes Reinecke
@ 2009-08-13 8:21 ` Simon Horman
0 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2009-08-13 8:21 UTC (permalink / raw)
To: Hannes Reinecke; +Cc: kexec mailing list
On Thu, Aug 13, 2009 at 10:12:37AM +0200, Hannes Reinecke wrote:
> Simon Horman wrote:
> > On Wed, Aug 12, 2009 at 09:41:23AM +0200, Hannes Reinecke wrote:
> >> Hi all,
> >>
> >> I cannot load a x86_64 kernel with kexec on 2.6.31; the error message is:
> >>
> >> Can't find kernel text map area from kcore
> >> Cannot load /boot/vmlinuz
> >>
> >> Digging through the source I found a mismatch between the assumed
> >> kernel text size; kexec has:
> >>
> >> #define KERNEL_TEXT_SIZE (40UL*1024*1024)
> >>
> >> but on the kernel side we have:
> >>
> >> include/asm/page_64_types.h:
> >> #define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
> >>
> >> And, indeed, changing the definition in kexec-tools to the kernel one
> >> fixed the problem.
> >>
> >> Not sure if this has been reported before, if so please ignore
> >> the noise.
> >
> > Hi,
> >
> > I'm wondering what effect this would have when using
> > kexec-tools with older kernels, which presumably have
> > a smaller value for KERNEL_IMAGE_SIZE.
> >
> >> diff --git a/kexec/arch/x86_64/crashdump-x86_64.h b/kexec/arch/x86_64/crashdump-x86_64.h
> >> index 9f4dee9..0e83527 100644
> >> --- a/kexec/arch/x86_64/crashdump-x86_64.h
> >> +++ b/kexec/arch/x86_64/crashdump-x86_64.h
> >> @@ -11,7 +11,7 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline,
> >> #define MAXMEM 0x3fffffffffffUL
> >>
> >> /* Kernel text size */
> >> -#define KERNEL_TEXT_SIZE (40UL*1024*1024)
> >> +#define KERNEL_TEXT_SIZE (512UL*1024*1024)
> >>
> >> #define CRASH_MAX_MEMMAP_NR (KEXEC_MAX_SEGMENTS + 1)
> >> #define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2)
> >
> Well, the actual point of failure is in kexec/arch/x86_64/crashdump-x86_64.c:125
>
> /* Look for kernel text mapping header. */
> if ((saddr >= __START_KERNEL_map) &&
> (eaddr <= __START_KERNEL_map + KERNEL_TEXT_SIZE)) {
> saddr = (saddr) & (~(KERN_VADDR_ALIGN - 1));
> info->kern_vaddr_start = saddr;
> size = eaddr - saddr;
>
> which basically should look for a ELF header into which the kernel fits. As we're
> effectively just moving the upper limit I fail to see any harm to older kernels.
>
> Hmm. Haven't checked for other occurrences of KERNEL_TEXT_SIZE, though.
>
> Would be nice we could be getting these values off somewhere; rely on
> some kernel defines is going to break now and then.
Agreed, but I think that your patch is worth having in the mean time.
I will apply it.
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread
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2009-08-12 7:41 [PATCH] Increase kernel text size for x86_64 Hannes Reinecke
2009-08-13 0:40 ` Simon Horman
2009-08-13 8:12 ` Hannes Reinecke
2009-08-13 8:21 ` Simon Horman
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