From: Catalin Marinas <catalin.marinas@arm.com>
Date: Wed, 28 Nov 2012 17:06:05 +0000 (+0000)
Subject: arm64: Make !dirty ptes read-only
X-Git-Tag: firefly_0821_release~3680^2~1500^2~16
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=33eaa58f854770dc9c98411a356c98e3a53edfda;p=firefly-linux-kernel-4.4.55.git

arm64: Make !dirty ptes read-only

The AArch64 Linux port relies on the mm code to wrprotect clean ptes.
This however is not the case with newly created ptes and
PAGE_SHARED(_EXEC) is writable but !dirty.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
---

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 8960239be722..937ae2064682 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -159,6 +159,8 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 {
 	if (pte_present_exec_user(pte))
 		__sync_icache_dcache(pte, addr);
+	if (!pte_dirty(pte))
+		pte = pte_wrprotect(pte);
 	set_pte(ptep, pte);
 }