[PATCH v2 30/37] powerpc/e500: Introduce _PAGE_READ and remove _PAGE_USER
From: Christophe Leroy
Date: Mon Sep 25 2023 - 14:35:07 EST
e500 MMU has 6 page protection bits:
- R, W, X for supervisor
- R, W, X for user
It means that it can support X without R.
To do that, _PAGE_READ flag is needed.
With 32 bits PTE there is no bit available for it in PTE. On the
other hand the only real use of _PAGE_USER is to implement PAGE_NONE
by clearing _PAGE_USER. As _PAGE_NONE can also be implemented by
clearing _PAGE_READ, remove _PAGE_USER and add _PAGE_READ. Move
_PAGE_PRESENT into bit 30 so that _PAGE_READ can match SR bit.
With 64 bits PTE _PAGE_USER is already the combination of SR and UR
so all we need to do is to rename it _PAGE_READ.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/nohash/32/pte-85xx.h | 22 ++++---------------
arch/powerpc/include/asm/nohash/pte-e500.h | 20 ++++++++---------
arch/powerpc/kernel/head_85xx.S | 10 ++++-----
3 files changed, 18 insertions(+), 34 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/pte-85xx.h b/arch/powerpc/include/asm/nohash/32/pte-85xx.h
index 462acf69e302..653a342d3b25 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-85xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-85xx.h
@@ -17,9 +17,9 @@
*/
/* Definitions for FSL Book-E Cores */
-#define _PAGE_PRESENT 0x00001 /* S: PTE contains a translation */
-#define _PAGE_USER 0x00002 /* S: User page (maps to UR) */
-#define _PAGE_RW 0x00004 /* S: Write permission (SW) */
+#define _PAGE_READ 0x00001 /* H: Read permission (SR) */
+#define _PAGE_PRESENT 0x00002 /* S: PTE contains a translation */
+#define _PAGE_WRITE 0x00004 /* S: Write permission (SW) */
#define _PAGE_DIRTY 0x00008 /* S: Page dirty */
#define _PAGE_EXEC 0x00010 /* H: SX permission */
#define _PAGE_ACCESSED 0x00020 /* S: Page referenced */
@@ -31,13 +31,6 @@
#define _PAGE_WRITETHRU 0x00400 /* H: W bit */
#define _PAGE_SPECIAL 0x00800 /* S: Special page */
-#define _PAGE_WRITE _PAGE_RW
-
-#define _PAGE_KERNEL_RO 0
-#define _PAGE_KERNEL_ROX _PAGE_EXEC
-#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW)
-#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC)
-
/* No page size encoding in the linux PTE */
#define _PAGE_PSIZE 0
@@ -63,14 +56,7 @@
#define _PAGE_BASE (_PAGE_BASE_NC)
#endif
-/* Permission masks used to generate the __P and __S table */
-#define PAGE_NONE __pgprot(_PAGE_BASE)
-#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
-#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
-#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
-#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
+#include <asm/pgtable-masks.h>
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_NOHASH_32_PTE_FSL_85xx_H */
diff --git a/arch/powerpc/include/asm/nohash/pte-e500.h b/arch/powerpc/include/asm/nohash/pte-e500.h
index b775c7d465a4..31d2c3ea7df8 100644
--- a/arch/powerpc/include/asm/nohash/pte-e500.h
+++ b/arch/powerpc/include/asm/nohash/pte-e500.h
@@ -48,14 +48,19 @@
/* "Higher level" linux bit combinations */
#define _PAGE_EXEC (_PAGE_BAP_SX | _PAGE_BAP_UX) /* .. and was cache cleaned */
-#define _PAGE_RW (_PAGE_BAP_SW | _PAGE_BAP_UW) /* User write permission */
+#define _PAGE_READ (_PAGE_BAP_SR | _PAGE_BAP_UR) /* User read permission */
+#define _PAGE_WRITE (_PAGE_BAP_SW | _PAGE_BAP_UW) /* User write permission */
+
#define _PAGE_KERNEL_RW (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY)
#define _PAGE_KERNEL_RO (_PAGE_BAP_SR)
#define _PAGE_KERNEL_RWX (_PAGE_BAP_SW | _PAGE_BAP_SR | _PAGE_DIRTY | _PAGE_BAP_SX)
#define _PAGE_KERNEL_ROX (_PAGE_BAP_SR | _PAGE_BAP_SX)
-#define _PAGE_USER (_PAGE_BAP_UR | _PAGE_BAP_SR) /* Can be read */
-#define _PAGE_WRITE _PAGE_RW
+#define _PAGE_NA 0
+#define _PAGE_RO _PAGE_READ
+#define _PAGE_ROX (_PAGE_READ | _PAGE_BAP_UX)
+#define _PAGE_RW (_PAGE_READ | _PAGE_WRITE)
+#define _PAGE_RWX (_PAGE_READ | _PAGE_WRITE | _PAGE_BAP_UX)
#define _PAGE_SPECIAL _PAGE_SW0
@@ -90,14 +95,7 @@
#define _PAGE_BASE (_PAGE_BASE_NC)
#endif
-/* Permission masks used to generate the __P and __S table */
-#define PAGE_NONE __pgprot(_PAGE_BASE)
-#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
-#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_BAP_UX)
-#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_BAP_UX)
-#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_BAP_UX)
+#include <asm/pgtable-masks.h>
#ifndef __ASSEMBLY__
static inline pte_t pte_mkexec(pte_t pte)
diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S
index 594756a62c8e..3739d5a281a7 100644
--- a/arch/powerpc/kernel/head_85xx.S
+++ b/arch/powerpc/kernel/head_85xx.S
@@ -485,10 +485,10 @@ END_BTB_FLUSH_SECTION
*/
mfspr r12,SPRN_ESR
#ifdef CONFIG_PTE_64BIT
- li r13,_PAGE_PRESENT
+ li r13,_PAGE_PRESENT|_PAGE_BAP_SR
oris r13,r13,_PAGE_ACCESSED@h
#else
- li r13,_PAGE_PRESENT|_PAGE_ACCESSED
+ li r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED
#endif
rlwimi r13,r12,11,29,29
@@ -783,15 +783,15 @@ BEGIN_MMU_FTR_SECTION
mtspr SPRN_MAS7, r10
END_MMU_FTR_SECTION_IFSET(MMU_FTR_BIG_PHYS)
#else
- li r10, (_PAGE_EXEC | _PAGE_PRESENT)
+ li r10, (_PAGE_EXEC | _PAGE_READ)
mr r13, r11
rlwimi r10, r11, 31, 29, 29 /* extract _PAGE_DIRTY into SW */
and r12, r11, r10
- andi. r10, r11, _PAGE_USER /* Test for _PAGE_USER */
+ mcrf cr0, cr5 /* Test for user page */
slwi r10, r12, 1
or r10, r10, r12
rlwinm r10, r10, 0, ~_PAGE_EXEC /* Clear SX on user pages */
- iseleq r12, r12, r10
+ isellt r12, r10, r12
rlwimi r13, r12, 0, 20, 31 /* Get RPN from PTE, merge w/ perms */
mtspr SPRN_MAS3, r13
#endif
--
2.41.0