From: Jan Beulich <jbeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Juergen Gross" <jgross@suse.com>, "Wei Liu" <wl@xen.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Ross Lagerwall" <ross.lagerwall@citrix.com>,
"Norbert Manthey" <nmanthey@amazon.de>,
Xen-devel <xen-devel@lists.xenproject.org>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v3 5/7] x86/livepatch: Fail the build if duplicate symbols exist
Date: Wed, 30 Oct 2019 09:41:57 +0100 [thread overview]
Message-ID: <ffa68df2-0f4c-da6c-cd57-29746ae5f889@suse.com> (raw)
In-Reply-To: <1f0bd38c-d1c4-fa45-d13e-55615be4188e@citrix.com>
On 29.10.2019 18:06, Andrew Cooper wrote:
> On 24/10/2019 13:03, Jan Beulich wrote:
>> On 23.10.2019 15:58, Andrew Cooper wrote:
>>> --- a/xen/common/Kconfig
>>> +++ b/xen/common/Kconfig
>>> @@ -361,9 +361,23 @@ config FAST_SYMBOL_LOOKUP
>>>
>>> If unsure, say Y.
>>>
>>> +config ENFORCE_UNIQUE_SYMBOLS
>>> + bool "Enforce unique symbols" if LIVEPATCH
>>> + default y if LIVEPATCH
>> Instead of two identical "if", why not "depends on LIVEPATCH"?
>>
>>> + ---help---
>>> + Multiple symbols with the same name aren't generally a problem
>>> + unless Live patching is to be used.
>>> +
>>> + Livepatch loading involves resolving relocations against symbol
>>> + names, and attempting to a duplicate symbol in a livepatch will
>>> + result in incorrect livepatch application.
>>> +
>>> + This option should be used to ensure that a build of Xen can have a
>>> + livepatch build and apply correctly.
>>> +
>>> config SUPPRESS_DUPLICATE_SYMBOL_WARNINGS
>>> - bool "Suppress duplicate symbol warnings" if !LIVEPATCH
>>> - default y if !LIVEPATCH
>>> + bool "Suppress duplicate symbol warnings" if !ENFORCE_UNIQUE_SYMBOLS
>>> + default y if !ENFORCE_UNIQUE_SYMBOLS
>> Similarly here then. With this changed, or with a proper reason
>> supplied
>> Reviewed-by: Jan Beulich <jbeulich@suse.com>
>
> That's a question for the author of c/s 064a2652233 to answer... I'm
> merely following the prevailing style.
"Prevailing style" seems a little bold considering that according to
my grep-ing there's exactly on other such instance (VGA). I.e. you'd
grow the "badness" by 50% when you could equally well shrink it by
this same percentage.
Jan
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next prev parent reply other threads:[~2019-10-30 8:42 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 13:58 [Xen-devel] [PATCH for-4.13 v3 0/7] Unbreak evaluate_nospec() and livepatching Andrew Cooper
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 1/7] x86/nospec: Two trivial fixes Andrew Cooper
2019-10-23 14:03 ` Jan Beulich
2019-10-23 14:43 ` Jürgen Groß
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 2/7] xen/nospec: Use always_inline to fix code gen for evaluate_nospec Andrew Cooper
2019-10-23 14:44 ` Jürgen Groß
2019-10-25 12:03 ` Jan Beulich
2019-10-25 12:10 ` Andrew Cooper
2019-10-25 12:34 ` Jan Beulich
2019-10-25 15:27 ` Andrew Cooper
2019-10-25 15:40 ` Jan Beulich
2019-10-25 21:56 ` Norbert Manthey
2019-10-28 17:05 ` Andrew Cooper
2019-10-29 8:25 ` Norbert Manthey
2019-10-29 13:46 ` Andrew Cooper
2019-10-29 14:03 ` Jan Beulich
2019-10-29 14:16 ` Andrew Cooper
2019-10-29 14:33 ` Norbert Manthey
2019-10-29 16:53 ` Andrew Cooper
2019-10-30 8:33 ` Jan Beulich
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 3/7] xen/nospec: Introduce CONFIG_SPECULATIVE_HARDEN_BRANCH Andrew Cooper
2019-10-23 14:45 ` Jürgen Groß
2019-10-25 12:04 ` Jan Beulich
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 4/7] x86/nospec: Rename and rework l1tf-barrier as branch-harden Andrew Cooper
2019-10-23 14:43 ` Jürgen Groß
2019-10-25 12:09 ` Jan Beulich
2019-10-29 17:00 ` Andrew Cooper
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 5/7] x86/livepatch: Fail the build if duplicate symbols exist Andrew Cooper
2019-10-23 14:46 ` Jürgen Groß
2019-10-23 16:14 ` Konrad Rzeszutek Wilk
2019-10-23 16:37 ` Ross Lagerwall
2019-10-24 12:03 ` Jan Beulich
2019-10-29 17:06 ` Andrew Cooper
2019-10-30 8:41 ` Jan Beulich [this message]
2019-10-30 10:37 ` Andrew Cooper
2019-10-30 11:21 ` Jan Beulich
2019-10-23 13:58 ` [Xen-devel] [PATCH for-next v3 6/7] x86/nospec: Move array_index_mask_nospec() into nospec.h Andrew Cooper
2019-10-25 12:10 ` Jan Beulich
2019-10-23 13:58 ` [Xen-devel] [PATCH v3 7/7] x86/nospec: Optimise array_index_mask_nospec() for power-of-2 arrays Andrew Cooper
2019-10-25 12:24 ` Jan Beulich
2019-10-25 12:58 ` Andrew Cooper
2019-10-25 13:25 ` Jan Beulich
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