CONFIG_STRICT_KERNEL_RWX is no longer selectable on most architectures.
Update this info to the documentation.
Signed-off-by: Li Qiang <[email protected]>
---
Documentation/DocBook/kgdb.tmpl | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
index 856ac20..ef0b67b 100644
--- a/Documentation/DocBook/kgdb.tmpl
+++ b/Documentation/DocBook/kgdb.tmpl
@@ -121,7 +121,9 @@
If kgdb supports it for the architecture you are using, you can
use hardware breakpoints if you desire to run with the
CONFIG_STRICT_KERNEL_RWX option turned on, else you need to turn off
- this option.
+ this option. In most architectures, this option is not selectable.
+ For this situation, it can be turned off by adding a runtime parameter
+ 'rodata=off'.
</para>
<para>
Next you should choose one of more I/O drivers to interconnect
--
2.7.4
On 19/04/17 02:58, Li Qiang wrote:
> CONFIG_STRICT_KERNEL_RWX is no longer selectable on most architectures.
> Update this info to thedocumentation.
"git grep STRICT_KERNEL_RWX" comes up with nothing.
It is selectable on any architecture? If not we should remove it entirely!
Daniel.
>
> Signed-off-by: Li Qiang <[email protected]>
> ---
> Documentation/DocBook/kgdb.tmpl | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
> index 856ac20..ef0b67b 100644
> --- a/Documentation/DocBook/kgdb.tmpl
> +++ b/Documentation/DocBook/kgdb.tmpl
> @@ -121,7 +121,9 @@
> If kgdb supports it for the architecture you are using, you can
> use hardware breakpoints if you desire to run with the
> CONFIG_STRICT_KERNEL_RWX option turned on, else you need to turn off
> - this option.
> + this option. In most architectures, this option is not selectable.
> + For this situation, it can be turned off by adding a runtime parameter
> + 'rodata=off'.
> </para>
> <para>
> Next you should choose one of more I/O drivers to interconnect
>
On Tue, 18 Apr 2017 18:58:45 -0700
Li Qiang <[email protected]> wrote:
> CONFIG_STRICT_KERNEL_RWX is no longer selectable on most architectures.
> Update this info to the documentation.
>
> Signed-off-by: Li Qiang <[email protected]>
> ---
> Documentation/DocBook/kgdb.tmpl | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
> index 856ac20..ef0b67b 100644
> --- a/Documentation/DocBook/kgdb.tmpl
> +++ b/Documentation/DocBook/kgdb.tmpl
> @@ -121,7 +121,9 @@
> If kgdb supports it for the architecture you are using, you can
> use hardware breakpoints if you desire to run with the
> CONFIG_STRICT_KERNEL_RWX option turned on, else you need to turn off
> - this option.
> + this option. In most architectures, this option is not selectable.
> + For this situation, it can be turned off by adding a runtime parameter
> + 'rodata=off'.
So this is an improvement, I guess, though the paragraph remains kind of
confusing. Is there any chance we could actually just say which
architectures can use hardware breakpoints, and which should boot with
rodata=off?
Thanks,
jon
On 21/04/17 03:26, Li Qiang wrote:
>
> @Daniel
>
> 2017-04-20 23:28 GMT+08:00 Daniel Thompson <[email protected]
> <mailto:[email protected]>>:
>
> On 19/04/17 02:58, Li Qiang wrote:
>
> CONFIG_STRICT_KERNEL_RWX is no longer selectable on most
> architectures.
> Update this info to thedocumentation.
>
>
> "git grep STRICT_KERNEL_RWX" comes up with nothing.
>
>
> It was introduced in commit 0f5bf6d0afe4be6e1391908ff2d6dc9730e91550.
Oops. I did the grep on the wrong machine :-( and therefore on an older
kernel than I thought...
> It is selectable on any architecture? If not we should remove it
> entirely!
>
> The 'STRICT_KERNEL_RWX' is renamed from 'CONFIG_DEBUG_RODATA
> '. The original option is selectable.
>
> I'm not sure is this selectable on any architecture.
So... having found the right kernel, it looks to me like only arm,
arm64, parisc, s390 and x86 define ARCH_HAS_STRICT_KERNEL_RWX. Of these
five, only arm defines ARCH_OPTIONAL_KERNEL_RWX and makes it user
selectable.
>
> @Jonathan
>
> On Tue, 18 Apr 2017 18:58:45 -0700
> Li Qiang <[email protected] <mailto:[email protected]>> wrote:
>
> > CONFIG_STRICT_KERNEL_RWX is no longer selectable on most architectures.
> > Update this info to the documentation.
> >
> > Signed-off-by: Li Qiang <[email protected] <mailto:[email protected]>>
> > ---
> > Documentation/DocBook/kgdb.tmpl | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
> > index 856ac20..ef0b67b 100644
> > --- a/Documentation/DocBook/kgdb.tmpl
> > +++ b/Documentation/DocBook/kgdb.tmpl
> > @@ -121,7 +121,9 @@
> > If kgdb supports it for the architecture you are using, you can
> > use hardware breakpoints if you desire to run with the
> > CONFIG_STRICT_KERNEL_RWX option turned on, else you need to turn off
> > - this option.
> > + this option. In most architectures, this option is not selectable.
> > + For this situation, it can be turned off by adding a runtime parameter
> > + 'rodata=off'.
>
> So this is an improvement, I guess, though the paragraph remains kind of
> confusing. Is there any chance we could actually just say which
> architectures can use hardware breakpoints, and which should boot with
> rodata=off?
>
>
> I think this is unnecessary as it is not common to change the
> default CONFIG_STRICT_KERNEL_RWX /add rodata=off.
> We here give this hint because CONFIG_STRICT_KERNEL_RWX is renamed
> from CONFIG_DEBUG_RODATA.
> And the latter is selectable, this can help the peoples who
> think CONFIG_STRICT_KERNEL_RWX is also selectable.
Having looked at the earlier part of the paragraph I think the info
about rodata actually needs to be introduced slightly earlier (and
rodata should be presented as the primary way to do it because 4 of the
5 architectures don't make STRICT_KERNEL_RWX optional).
Something like:
If the architecture that you are using supports making the text
section read-only (CONFIG_STRICT_KERNEL_RWX), you should consider
turning it off by adding 'rodata=off' to the kernel commandline or,
if your architecture makes CONFIG_STRICT_KERNEL_RWX optional, by
disabling this config option. Alternatively, if your architecture
supports hardware breakpoints, these can be used to provide limited
breakpoint support if you desire to run with a read-only text section.
Daniel.