From: Zhenzhong Duan <zhenzhong.duan@oracle.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
konrad.wilk@oracle.com, x86@kernel.org, dwmw@amazon.co.uk,
tglx@linutronix.de,
Srinivas REDDY Eeda <srinivas.eeda@oracle.com>,
bp@suse.de, hpa@zytor.com, dhaval.giani@oracle.com
Subject: Re: [PATCH] x86/speculation: Use AMD specific retpoline for inline asm on AMD
Date: Tue, 18 Sep 2018 20:04:44 +0800 [thread overview]
Message-ID: <1c6ca05f-094e-03e9-b21a-866aaf80cebb@oracle.com> (raw)
In-Reply-To: <20180918105939.GK24106@hirez.programming.kicks-ass.net>
On 2018/9/18 18:59, Peter Zijlstra wrote:
> On Tue, Sep 18, 2018 at 06:31:07PM +0800, Zhenzhong Duan wrote:
>> On 2018/9/18 17:50, Peter Zijlstra wrote:
>>> On Mon, Sep 17, 2018 at 10:17:30PM -0700, Zhenzhong Duan wrote:
>>>> -#elif defined(CONFIG_X86_32) && defined(CONFIG_RETPOLINE)
>>>> +#elif defined(CONFIG_RETPOLINE)
>>>
>>> This doesn't make any sense..
>> This change is used for x86_64 to have minimal Retpoline support when
>> CONFIG_RETPOLINE is defined but RETPOLINE isn't defined, or I missed
>> something?
>
> No it doesn't.
>
> #if defined(X86_64) && defined(RETPOLINE)
>
> /* x86_64 retpoline goes here */
>
> #elif defined(RETPOLINE)
>
> /* !x86_64 retpoline goes here */
>
> #else
>
> /* !retpoline goes here
>
> #endif
Sorry, but I am confused.
So where is 'if defined(x86_64) && !defined(RETPOLINE) &&
defined(CONFIG_RETPOLINE)' go?
In original code, it will go to "call *%[thunk_target]\n" while
we have set SPECTRE_V2_RETPOLINE_MINIMAL or
SPECTRE_V2_RETPOLINE_MINIMAL_AMD. Is this expected?
Thanks
Zhenzhong
next prev parent reply other threads:[~2018-09-18 12:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 5:17 [PATCH] x86/speculation: Use AMD specific retpoline for inline asm on AMD Zhenzhong Duan
2018-09-18 9:50 ` Peter Zijlstra
2018-09-18 10:31 ` Zhenzhong Duan
2018-09-18 10:59 ` Peter Zijlstra
2018-09-18 12:04 ` Zhenzhong Duan [this message]
2018-09-18 13:00 ` Peter Zijlstra
2018-09-18 13:03 ` Peter Zijlstra
2018-09-18 13:32 ` David Woodhouse
2018-09-18 14:41 ` Zhenzhong Duan
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