From: "Jan Beulich" <JBeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xen.org>,
"Wei Liu" <wei.liu2@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 1/7] x86/alt: Drop unused alternative infrastructure
Date: Wed, 14 Feb 2018 03:02:49 -0700 [thread overview]
Message-ID: <5A84175902000078001A7ACE@prv-mh.provo.novell.com> (raw)
In-Reply-To: <02038159-a76f-5fd2-3a74-5facad5c3d40@citrix.com>
>>> On 13.02.18 at 15:41, <andrew.cooper3@citrix.com> wrote:
> On 13/02/18 14:22, Jan Beulich wrote:
>>>>> On 12.02.18 at 12:23, <andrew.cooper3@citrix.com> wrote:
>>> --- a/xen/include/asm-x86/alternative.h
>>> +++ b/xen/include/asm-x86/alternative.h
>>> @@ -65,11 +65,6 @@ extern void alternative_instructions(void);
>>> ALTERNATIVE(oldinstr, newinstr1, feature1) \
>>> ALTERNATIVE_N(newinstr2, feature2, 2)
>>>
>>> -#define ALTERNATIVE_3(oldinstr, newinstr1, feature1, newinstr2, feature2, \
>>> - newinstr3, feature3) \
>>> - ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
>>> - ALTERNATIVE_N(newinstr3, feature3, 3)
>>> -
>>> /*
>>> * Alternative instructions for different CPU types or capabilities.
>>> *
>> While this one is fine, ...
>>
>>> @@ -118,26 +113,6 @@ extern void alternative_instructions(void);
>>> newinstr2, feature2) \
>>> : output : input)
>>>
>>> -/*
>>> - * This is similar to alternative_io. But it has three features and
>>> - * respective instructions.
>>> - *
>>> - * If CPU has feature3, newinstr3 is used.
>>> - * Otherwise, if CPU has feature2, newinstr2 is used.
>>> - * Otherwise, if CPU has feature1, newinstr1 is used.
>>> - * Otherwise, oldinstr is used.
>>> - */
>>> -#define alternative_io_3(oldinstr, newinstr1, feature1, newinstr2, \
>>> - feature2, newinstr3, feature3, output, \
>>> - input...) \
>>> - asm volatile(ALTERNATIVE_3(oldinstr, newinstr1, feature1, \
>>> - newinstr2, feature2, newinstr3, \
>>> - feature3) \
>>> - : output : input)
>>> -
>>> -/* Use this macro(s) if you need more than one output parameter. */
>>> -#define ASM_OUTPUT2(a...) a
>> ... I'm having patches to post which use both of these, so I'd
>> very much prefer them to not go away. It is simply a lack of time
>> which resulted in me not having posted that series already.
>
> In which case I'll need to review that patch before commenting on this
> one (i.e. whether it actually needs to be an alternative_3, or whether
> there is a shorter way to do it).
>
> The problem is that the gas_max() expression expands its parameters 5
> times, and ISTR a report on LKML saying that older version of GAS
> couldn't cope with the eventual expansion of the 3-replacement version.
As per my earlier reply, with ASM_OUTPUT2() retained
Reviewed-by: Jan Beulich <jbeulich@suse.com>
provided all of this (minus patch 7) goes in together (at which
point I'll have quite some re-basing fun).
Jan
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next prev parent reply other threads:[~2018-02-14 10:02 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 11:23 [PATCH 0/7] x86/alternatives: Support for automatic padding calculations Andrew Cooper
2018-02-12 11:23 ` [PATCH 1/7] x86/alt: Drop unused alternative infrastructure Andrew Cooper
2018-02-12 12:30 ` Wei Liu
2018-02-12 15:56 ` Roger Pau Monné
2018-02-12 15:58 ` Andrew Cooper
2018-02-13 14:22 ` Jan Beulich
2018-02-13 14:41 ` Andrew Cooper
2018-02-13 15:33 ` Jan Beulich
2018-02-14 10:02 ` Jan Beulich [this message]
2018-02-12 11:23 ` [PATCH 2/7] x86/alt: Clean up struct alt_instr and its users Andrew Cooper
2018-02-12 12:30 ` Wei Liu
2018-02-12 16:52 ` Roger Pau Monné
2018-02-12 17:18 ` Wei Liu
2018-02-12 17:53 ` Andrew Cooper
2018-02-13 14:26 ` Jan Beulich
2018-02-21 21:22 ` Konrad Rzeszutek Wilk
2018-02-12 11:23 ` [PATCH 3/7] x86/alt: Clean up the assembly used to generate alternatives Andrew Cooper
2018-02-12 12:30 ` Wei Liu
2018-02-12 17:26 ` Roger Pau Monné
2018-02-12 17:54 ` Andrew Cooper
2018-02-13 14:37 ` Jan Beulich
2018-02-23 14:03 ` Andrew Cooper
2018-02-23 15:12 ` Jan Beulich
2018-02-23 16:24 ` Andrew Cooper
2018-02-23 17:28 ` Jan Beulich
2018-02-12 11:23 ` [PATCH 4/7] x86/asm: Remove opencoded uses of altinstruction_entry Andrew Cooper
2018-02-12 12:30 ` Wei Liu
2018-02-12 12:34 ` Andrew Cooper
2018-02-13 9:56 ` Jan Beulich
2018-02-13 10:07 ` Andrew Cooper
2018-02-13 11:10 ` Jan Beulich
2018-02-12 12:52 ` Wei Liu
2018-02-12 17:46 ` Roger Pau Monné
2018-02-12 17:59 ` Andrew Cooper
2018-02-14 9:53 ` Jan Beulich
2018-02-12 11:23 ` [PATCH 5/7] x86/alt: Support for automatic padding calculations Andrew Cooper
2018-02-12 14:39 ` Wei Liu
2018-02-12 15:04 ` Andrew Cooper
2018-02-12 18:41 ` Roger Pau Monné
2018-02-12 18:45 ` Andrew Cooper
2018-02-12 18:09 ` Roger Pau Monné
2018-02-13 9:45 ` Roger Pau Monné
2018-02-13 10:09 ` Andrew Cooper
2018-02-13 10:26 ` Roger Pau Monné
2018-02-14 9:46 ` Jan Beulich
2018-02-12 11:23 ` [PATCH 6/7] x86/alt: Drop explicit padding of origin sites Andrew Cooper
2018-02-12 14:39 ` Wei Liu
2018-02-12 18:12 ` Roger Pau Monné
2018-02-14 9:53 ` Jan Beulich
2018-02-12 11:23 ` [PATCH 7/7] x86/build: Use new .nop directive when available Andrew Cooper
2018-02-12 14:40 ` Wei Liu
2018-02-13 11:08 ` Roger Pau Monné
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