Re: [PATCH v21 08/26] x86/mm: Introduce _PAGE_COW
From: Yu, Yu-cheng
Date: Wed Mar 03 2021 - 06:02:21 EST
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