This is a note to let you know that I've just added the patch titled
powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE
to the 5.4-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:
powerpc-8xx-fix-pte_access_permitted-for-page_none.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2136b8f769090de5277132aa051b10e02a17e834
Author: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Date: Mon Sep 25 20:31:15 2023 +0200
powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE
[ Upstream commit 5d9cea8a552ee122e21fbd5a3c5d4eb85f648e06 ]
On 8xx, PAGE_NONE is handled by setting _PAGE_NA instead of clearing
_PAGE_USER.
But then pte_user() returns 1 also for PAGE_NONE.
As _PAGE_NA prevent reads, add a specific version of pte_read()
that returns 0 when _PAGE_NA is set instead of always returning 1.
Fixes: 351750331fc1 ("powerpc/mm: Introduce _PAGE_NA")
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/57bcfbe578e43123f9ed73e040229b80f1ad56ec.1695659959.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index c9e4b2d90f65c..93ecf4e80ca70 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -91,6 +91,13 @@ static inline pte_t pte_wrprotect(pte_t pte)
#define pte_wrprotect pte_wrprotect
+static inline int pte_read(pte_t pte)
+{
+ return (pte_val(pte) & _PAGE_RO) != _PAGE_NA;
+}
+
+#define pte_read pte_read
+
static inline int pte_write(pte_t pte)
{
return !(pte_val(pte) & _PAGE_RO);
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 3d2a78ab051a7..15dec9994c780 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -45,7 +45,9 @@ static inline int pte_write(pte_t pte)
return pte_val(pte) & _PAGE_RW;
}
#endif
+#ifndef pte_read
static inline int pte_read(pte_t pte) { return 1; }
+#endif
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; }
static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
