On 30/01/2019 16:55, Andrew Cooper wrote:
> Xen will warn when an unknown parameter is found in the command line. e.g.
>
> (d8) [ 1556.334664] (XEN) parameter "pv-shim" unknown!
>
> One case where this goes wrong is a workaround for an old grub bug, which
> resulted in "placeholder" being prepended to the command line.
>
> Another case is when booting a CONFIG_PV_SHIM_EXCLUSIVE build, in which the
> parsing for the "pv-shim" parameter is discarded.
>
> Introduce ignore_param() and OPT_IGNORE to cope with known cases, where
> warning the user is the wrong course of action to take.
>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
> ---
> CC: Jan Beulich <jbeul...@suse.com>
> CC: Wei Liu <wei.l...@citrix.com>
> CC: Roger Pau Monné <roger....@citrix.com>
> CC: Juergen Gross <jgr...@suse.com>
>
> v2:
> * Rewrite from scratch, following Juergen's suggestion
>
> An implementation detail of ignore_param() is that it can only be used once
> per translation unit, which is fine for now. Two options to fix this are to
> tokenise __LINE__ in (requires some extreme preprocessor magic to make work,
> as ## inhibits expansion, and may cause livepatching issues), or to retain the
> _val parameter and require callers to just pass in a unique string.
Or make the unique string an optional parameter via:
#define ignore_param(_name, uniq...) \
__setup_str __setup_str_ign ## uniq[] = _name; \
__kparam __setup_ign ## uniq = \
{ .name = __setup_str_ign ## uniq, \
.type = OPT_IGNORE }
With or without that change:
Reviewed-by: Juergen Gross <jgr...@suse.com>
Release-acked-by: Juergen Gross <jgr...@suse.com>
Juergen
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