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Date: Tue, 2 Mar 2021 15:46:31 -0800
From: "Yu, Yu-cheng" <yu-cheng.yu@...el.com>
To: Borislav Petkov <bp@...en8.de>
Cc: x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-mm@...ck.org,
linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
Arnd Bergmann <arnd@...db.de>,
Andy Lutomirski <luto@...nel.org>,
Balbir Singh <bsingharora@...il.com>,
Cyrill Gorcunov <gorcunov@...il.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Eugene Syromiatnikov <esyr@...hat.com>,
Florian Weimer <fweimer@...hat.com>,
"H.J. Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
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Mike Kravetz <mike.kravetz@...cle.com>,
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Peter Zijlstra <peterz@...radead.org>,
Randy Dunlap <rdunlap@...radead.org>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@...el.com>,
Dave Martin <Dave.Martin@....com>,
Weijiang Yang <weijiang.yang@...el.com>,
Pengfei Xu <pengfei.xu@...el.com>,
Haitao Huang <haitao.huang@...el.com>
Subject: Re: [PATCH v21 08/26] x86/mm: Introduce _PAGE_COW
On 3/1/2021 7:52 AM, Borislav Petkov wrote:
> On Wed, Feb 17, 2021 at 02:27:12PM -0800, Yu-cheng Yu wrote:
[...]
>> static inline pmd_t pmd_mkdirty(pmd_t pmd)
>> {
>> - return pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
>> + pmdval_t dirty = _PAGE_DIRTY;
>> +
>> + /* Avoid creating (HW)Dirty=1, Write=0 PMDs */
>> + if (cpu_feature_enabled(X86_FEATURE_SHSTK) && !(pmd_flags(pmd) & _PAGE_RW))
>
> !(pmd_write(pmd))
>
There is a problem of doing that: pmd_write() is defined after this
function. Maybe we can declare it first, or leave this as-is?
--
Yu-cheng
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