[PATCH 6.1 129/131] powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE

Greg Kroah-Hartman
2023-10-16T09:05:21Z

From: Christophe Leroy <christophe.leroy@csgroup.eu>

[ 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@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/57bcfbe578e43123f9ed73e040229b80f1ad56ec.1695659959.git.christophe.leroy@csgroup.eu
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/include/asm/nohash/32/pte-8xx.h | 7 +++++++
arch/powerpc/include/asm/nohash/pgtable.h | 2 ++
2 files changed, 9 insertions(+)

diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index 1a89ebdc3acc9..0238e6bd0d6c1 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -94,6 +94,13 @@ 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 d9067dfc531cc..3d7dce90863c2 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -25,7 +25,9 @@ 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; }
--
2.40.1