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Subject[PATCH 30/39] x86/mm/pti: Clone entry-text again in pti_finalize()
Date
From: Joerg Roedel <jroedel@suse.de>

The mapping for entry-text might have changed in the kernel
after it was cloned to the user page-table. Clone again
to update the user page-table to bring the mapping in sync
with the kernel again.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/mm/pti.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 1825f30..b879ccd 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -404,7 +404,7 @@ static void __init pti_setup_espfix64(void)
/*
* Clone the populated PMDs of the entry and irqentry text and force it RO.
*/
-static void __init pti_clone_entry_text(void)
+static void pti_clone_entry_text(void)
{
pti_clone_pmds((unsigned long) __entry_text_start,
(unsigned long) __irqentry_text_end,
@@ -528,13 +528,18 @@ void __init pti_init(void)
}

/*
- * Finalize the kernel mappings in the userspace page-table.
+ * Finalize the kernel mappings in the userspace page-table. Some of the
+ * mappings for the kernel image might have changed since pti_init()
+ * cloned them. This is because parts of the kernel image have been
+ * mapped RO and/or NX. These changes need to be cloned again to the
+ * userspace page-table.
*/
void pti_finalize(void)
{
/*
- * Do this after all of the manipulation of the
- * kernel text page tables are complete.
+ * We need to clone everything (again) that maps parts of the
+ * kernel image.
*/
+ pti_clone_entry_text();
pti_clone_kernel_text();
}
--
2.7.4
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