From: Wei Liu <wl@xen.org>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Wei Liu" <wl@xen.org>, "Jan Beulich" <jbeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH] x86: refine link time stub area related assertion
Date: Wed, 15 Jan 2020 16:08:22 +0000 [thread overview]
Message-ID: <20200115160822.qpvsjp7vti75eno2@debian> (raw)
In-Reply-To: <b68451ec-6594-d4a4-1227-fa3026608122@citrix.com>
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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next prev parent reply other threads:[~2020-01-15 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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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