From: Joerg Roedel <jroedel@xxxxxxx>
The function sets the global-bit on cloned PMD entries,
which only makes sense when the permissions are identical
between the user and the kernel page-table.
Further, only write-permissions are cleared for entry-text
and kernel-text sections, which are not writeable anyway.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/mm/pti.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 113ba14..5164c98 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -291,7 +291,7 @@ static void __init pti_setup_vsyscall(void) { }
#endif
static void
-pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear)
+pti_clone_pmds(unsigned long start, unsigned long end)
{
unsigned long addr;
@@ -352,7 +352,7 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear)
* tables will share the last-level page tables of this
* address range
*/
- *target_pmd = pmd_clear_flags(*pmd, clear);
+ *target_pmd = *pmd;
}
}
@@ -398,7 +398,7 @@ static void __init pti_clone_user_shared(void)
start = CPU_ENTRY_AREA_BASE;
end = start + (PAGE_SIZE * CPU_ENTRY_AREA_PAGES);
- pti_clone_pmds(start, end, 0);
+ pti_clone_pmds(start, end);
}
#endif /* CONFIG_X86_64 */
@@ -418,8 +418,7 @@ static void __init pti_setup_espfix64(void)
static void pti_clone_entry_text(void)
{
pti_clone_pmds((unsigned long) __entry_text_start,
- (unsigned long) __irqentry_text_end,
- _PAGE_RW);
+ (unsigned long) __irqentry_text_end);
}
/*
@@ -501,7 +500,7 @@ static void pti_clone_kernel_text(void)
* pti_set_kernel_image_nonglobal() did to clear the
* global bit.
*/
- pti_clone_pmds(start, end_clone, _PAGE_RW);
+ pti_clone_pmds(start, end_clone);
/*
* pti_clone_pmds() will set the global bit in any PMDs
--
2.7.4
