Re: [PATCH v21 08/26] x86/mm: Introduce _PAGE_COW

[Yu, Yu-cheng]

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