* [Xen-devel] [PATCH] x86: refine link time stub area related assertion
@ 2020-01-15 10:26 Jan Beulich
2020-01-15 14:36 ` Andrew Cooper
0 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2020-01-15 10:26 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Wei Liu, Roger Pau Monné
While it has been me to introduce this, the use of | there has become
(and perhaps was from the very beginning) misleading. Rather than
avoiding the right side of it when linking the xen.efi intermediate file
at a different base address, make the expression cope with that case,
thus verifying placement on every step.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -351,8 +351,8 @@ SECTIONS
.comment 0 : { *(.comment) }
}
-ASSERT(__image_base__ > XEN_VIRT_START |
- __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
+ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
+ NR_CPUS * PAGE_SIZE,
"Xen image overlaps stubs area")
#ifdef CONFIG_KEXEC
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
2020-01-15 10:26 [Xen-devel] [PATCH] x86: refine link time stub area related assertion Jan Beulich
@ 2020-01-15 14:36 ` Andrew Cooper
2020-01-15 16:08 ` Wei Liu
2020-01-15 16:27 ` Jan Beulich
0 siblings, 2 replies; 6+ messages in thread
From: Andrew Cooper @ 2020-01-15 14:36 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: Wei Liu, Roger Pau Monné
On 15/01/2020 10:26, Jan Beulich wrote:
> While it has been me to introduce this, the use of | there has become
> (and perhaps was from the very beginning) misleading. Rather than
> avoiding the right side of it when linking the xen.efi intermediate file
> at a different base address, make the expression cope with that case,
> thus verifying placement on every step.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> as this is simply a
rearranging, but...
>
> --- a/xen/arch/x86/xen.lds.S
> +++ b/xen/arch/x86/xen.lds.S
> @@ -351,8 +351,8 @@ SECTIONS
> .comment 0 : { *(.comment) }
> }
>
> -ASSERT(__image_base__ > XEN_VIRT_START |
> - __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
> +ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
> + NR_CPUS * PAGE_SIZE,
... doesn't this want a stubs_per_page term? We don't have 4k per cpu.
Wei: FYI, if you do introduce executable fixmap entries, this ASSERT()
wants adjusting by NR_X_FIXMAP * PAGE_SIZE as well.
~Andrew
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
2020-01-15 14:36 ` Andrew Cooper
@ 2020-01-15 16:08 ` Wei Liu
2020-01-15 16:27 ` Jan Beulich
1 sibling, 0 replies; 6+ messages in thread
From: Wei Liu @ 2020-01-15 16:08 UTC (permalink / raw)
To: Andrew Cooper; +Cc: xen-devel, Wei Liu, Jan Beulich, Roger Pau Monné
On Wed, Jan 15, 2020 at 02:36:24PM +0000, Andrew Cooper wrote:
> On 15/01/2020 10:26, Jan Beulich wrote:
> > While it has been me to introduce this, the use of | there has become
> > (and perhaps was from the very beginning) misleading. Rather than
> > avoiding the right side of it when linking the xen.efi intermediate file
> > at a different base address, make the expression cope with that case,
> > thus verifying placement on every step.
> >
> > Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> as this is simply a
> rearranging, but...
>
> >
> > --- a/xen/arch/x86/xen.lds.S
> > +++ b/xen/arch/x86/xen.lds.S
> > @@ -351,8 +351,8 @@ SECTIONS
> > .comment 0 : { *(.comment) }
> > }
> >
> > -ASSERT(__image_base__ > XEN_VIRT_START |
> > - __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
> > +ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
> > + NR_CPUS * PAGE_SIZE,
>
> ... doesn't this want a stubs_per_page term? We don't have 4k per cpu.
>
> Wei: FYI, if you do introduce executable fixmap entries, this ASSERT()
> wants adjusting by NR_X_FIXMAP * PAGE_SIZE as well.
It is a bit problematic to do that if NR_X_FIXMAP is calculated from the
last enum element (see FIXADDR_SIZE)
I can expose a constant for the largest possible numbers of executable
fixed mappings to put in the ASSERT.
Wei.
>
> ~Andrew
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
2020-01-15 14:36 ` Andrew Cooper
2020-01-15 16:08 ` Wei Liu
@ 2020-01-15 16:27 ` Jan Beulich
2020-01-15 16:29 ` Andrew Cooper
1 sibling, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2020-01-15 16:27 UTC (permalink / raw)
To: Andrew Cooper; +Cc: xen-devel, Wei Liu, Roger Pau Monné
On 15.01.2020 15:36, Andrew Cooper wrote:
> On 15/01/2020 10:26, Jan Beulich wrote:
>> While it has been me to introduce this, the use of | there has become
>> (and perhaps was from the very beginning) misleading. Rather than
>> avoiding the right side of it when linking the xen.efi intermediate file
>> at a different base address, make the expression cope with that case,
>> thus verifying placement on every step.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> as this is simply a
> rearranging, but...
>
>>
>> --- a/xen/arch/x86/xen.lds.S
>> +++ b/xen/arch/x86/xen.lds.S
>> @@ -351,8 +351,8 @@ SECTIONS
>> .comment 0 : { *(.comment) }
>> }
>>
>> -ASSERT(__image_base__ > XEN_VIRT_START |
>> - __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
>> +ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
>> + NR_CPUS * PAGE_SIZE,
>
> ... doesn't this want a stubs_per_page term? We don't have 4k per cpu.
Good point - let me see if I can fix this at this same occasion.
I guess when introducing these pages I had one per CPU initially,
and then forgot to update the assertion here (it being too strict
of course is better than it being too lax).
Jan
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
2020-01-15 16:27 ` Jan Beulich
@ 2020-01-15 16:29 ` Andrew Cooper
2020-01-15 16:31 ` Jan Beulich
0 siblings, 1 reply; 6+ messages in thread
From: Andrew Cooper @ 2020-01-15 16:29 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel, Wei Liu, Roger Pau Monné
On 15/01/2020 16:27, Jan Beulich wrote:
> On 15.01.2020 15:36, Andrew Cooper wrote:
>> On 15/01/2020 10:26, Jan Beulich wrote:
>>> While it has been me to introduce this, the use of | there has become
>>> (and perhaps was from the very beginning) misleading. Rather than
>>> avoiding the right side of it when linking the xen.efi intermediate file
>>> at a different base address, make the expression cope with that case,
>>> thus verifying placement on every step.
>>>
>>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> as this is simply a
>> rearranging, but...
>>
>>> --- a/xen/arch/x86/xen.lds.S
>>> +++ b/xen/arch/x86/xen.lds.S
>>> @@ -351,8 +351,8 @@ SECTIONS
>>> .comment 0 : { *(.comment) }
>>> }
>>>
>>> -ASSERT(__image_base__ > XEN_VIRT_START |
>>> - __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
>>> +ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
>>> + NR_CPUS * PAGE_SIZE,
>> ... doesn't this want a stubs_per_page term? We don't have 4k per cpu.
> Good point - let me see if I can fix this at this same occasion.
> I guess when introducing these pages I had one per CPU initially,
> and then forgot to update the assertion here (it being too strict
> of course is better than it being too lax).
With some suitable term, feel free to up my A-by to R-by.
~Andrew
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
2020-01-15 16:29 ` Andrew Cooper
@ 2020-01-15 16:31 ` Jan Beulich
0 siblings, 0 replies; 6+ messages in thread
From: Jan Beulich @ 2020-01-15 16:31 UTC (permalink / raw)
To: Andrew Cooper; +Cc: xen-devel, Wei Liu, Roger Pau Monné
On 15.01.2020 17:29, Andrew Cooper wrote:
> On 15/01/2020 16:27, Jan Beulich wrote:
>> On 15.01.2020 15:36, Andrew Cooper wrote:
>>> On 15/01/2020 10:26, Jan Beulich wrote:
>>>> While it has been me to introduce this, the use of | there has become
>>>> (and perhaps was from the very beginning) misleading. Rather than
>>>> avoiding the right side of it when linking the xen.efi intermediate file
>>>> at a different base address, make the expression cope with that case,
>>>> thus verifying placement on every step.
>>>>
>>>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> as this is simply a
>>> rearranging, but...
>>>
>>>> --- a/xen/arch/x86/xen.lds.S
>>>> +++ b/xen/arch/x86/xen.lds.S
>>>> @@ -351,8 +351,8 @@ SECTIONS
>>>> .comment 0 : { *(.comment) }
>>>> }
>>>>
>>>> -ASSERT(__image_base__ > XEN_VIRT_START |
>>>> - __2M_rwdata_end <= XEN_VIRT_END - NR_CPUS * PAGE_SIZE,
>>>> +ASSERT(__2M_rwdata_end <= XEN_VIRT_END - XEN_VIRT_START + __XEN_VIRT_START -
>>>> + NR_CPUS * PAGE_SIZE,
>>> ... doesn't this want a stubs_per_page term? We don't have 4k per cpu.
>> Good point - let me see if I can fix this at this same occasion.
>> I guess when introducing these pages I had one per CPU initially,
>> and then forgot to update the assertion here (it being too strict
>> of course is better than it being too lax).
>
> With some suitable term, feel free to up my A-by to R-by.
Let me rather post what I have, because there's going to be some
ugliness (and hence room for mistakes) because of the rounding
needed. But thanks for the offer.
Jan
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2020-01-15 10:26 [Xen-devel] [PATCH] x86: refine link time stub area related assertion Jan Beulich
2020-01-15 14:36 ` Andrew Cooper
2020-01-15 16:08 ` Wei Liu
2020-01-15 16:27 ` Jan Beulich
2020-01-15 16:29 ` Andrew Cooper
2020-01-15 16:31 ` Jan Beulich
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