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Patch "x86/mm: Fix {pmd,pud}_{set,clear}_flags()" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Mar 7, 2018

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This is a note to let you know that I've just added the patch titled

    x86/mm: Fix {pmd,pud}_{set,clear}_flags()

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     x86-mm-fix-pmd-pud-_-set-clear-_flags.patch

and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 842cef9113c2120f74f645111ded1e020193d84c Mon Sep 17 00:00:00 2001

From: Jan Beulich <[email protected]>
Date: Mon, 19 Feb 2018 07:48:11 -0700
Subject: x86/mm: Fix {pmd,pud}_{set,clear}_flags()

From: Jan Beulich <[email protected]>

commit 842cef9113c2120f74f645111ded1e020193d84c upstream.

Just like pte_{set,clear}_flags() their PMD and PUD counterparts should not do any address translation. This was outright wrong under Xen (causing a dead boot with no useful output on "suitable" systems), and produced needlessly more complicated code (even if just slightly) when paravirt was enabled.

---
 arch/x86/include/asm/pgtable.h       |    8 ++++----
 arch/x86/include/asm/pgtable_types.h |   10 ++++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)
arch/x86/include/asm/pgtable.h +4 -4
@@ -350,14 +350,14 @@ static inline pmd_t pmd_set_flags(pmd_t
 {
 	pmdval_t v = native_pmd_val(pmd);
 
-	return __pmd(v | set);
+	return native_make_pmd(v | set);
 }
 
 static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear)
 {
 	pmdval_t v = native_pmd_val(pmd);
 
-	return __pmd(v & ~clear);
+	return native_make_pmd(v & ~clear);
 }
 
 static inline pmd_t pmd_mkold(pmd_t pmd)
@@ -409,14 +409,14 @@ static inline pud_t pud_set_flags(pud_t
 {
 	pudval_t v = native_pud_val(pud);
 
-	return __pud(v | set);
+	return native_make_pud(v | set);
 }
 
 static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear)
 {
 	pudval_t v = native_pud_val(pud);
 
-	return __pud(v & ~clear);
+	return native_make_pud(v & ~clear);
 }
 
 static inline pud_t pud_mkold(pud_t pud)
arch/x86/include/asm/pgtable_types.h +10 -0
@@ -323,6 +323,11 @@ static inline pudval_t native_pud_val(pu
 #else
 #include <asm-generic/pgtable-nopud.h>
 
+static inline pud_t native_make_pud(pudval_t val)
+{
+	return (pud_t) { .p4d.pgd = native_make_pgd(val) };
+}
+
 static inline pudval_t native_pud_val(pud_t pud)
 {
 	return native_pgd_val(pud.p4d.pgd);
@@ -344,6 +349,11 @@ static inline pmdval_t native_pmd_val(pm
 #else
 #include <asm-generic/pgtable-nopmd.h>
 
+static inline pmd_t native_make_pmd(pmdval_t val)
+{
+	return (pmd_t) { .pud.p4d.pgd = native_make_pgd(val) };
+}
+
 static inline pmdval_t native_pmd_val(pmd_t pmd)
 {
 	return native_pgd_val(pmd.pud.p4d.pgd);

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/x86-mm-fix-pmd-pud-_-set-clear-_flags.patch