iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert

Browse Source 
commit 0768f91530ff46683e0b372df14fd79fe8d156e5 upstream

Some cases in THP like:
  - MADV_FREE
  - mprotect
  - split

mark the PMD non present for temporarily to prevent races. The window for
an L1TF attack in these contexts is very small, but it wants to be fixed
for correctness sake.

Use the proper low level functions for pmd/pud_mknotpresent() to address
this.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andi Kleen 2018-08-07 15:09:37 -07:00 committed by Greg Kroah-Hartman
parent 4656dfb6b5
commit 5ebf3f8d5b
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/x86/include/asm/pgtable.h
View File

@ -350,11 +350,6 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd)
return pmd_set_flags(pmd, _PAGE_RW);
}
static inline pmd_t pmd_mknotpresent(pmd_t pmd)
{
return pmd_clear_flags(pmd, _PAGE_PRESENT | _PAGE_PROTNONE);
}
#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
static inline int pte_soft_dirty(pte_t pte)
{
@ -418,6 +413,12 @@ static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
return __pmd(pfn | massage_pgprot(pgprot));
}
static inline pmd_t pmd_mknotpresent(pmd_t pmd)
{
return pfn_pmd(pmd_pfn(pmd),
__pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE)));
}
static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)