The patch titled
Subject: microblaze/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
has been added to the -mm mm-unstable branch. Its filename is
microblaze-mm-support-__have_arch_pte_swp_exclusive.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/microblaze-mm-support-__have_arch_pte_swp_exclusive.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: microblaze/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Date: Fri, 13 Jan 2023 18:10:11 +0100
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
type. Generic MM currently only uses 5 bits for the type
(MAX_SWAPFILES_SHIFT), so the stolen bit is effectively unused.
The shift by 2 when converting between PTE and arch-specific swap entry
makes the swap PTE layout a little bit harder to decipher.
While at it, drop the comment from paulus---copy-and-paste leftover from
powerpc where we actually have _PAGE_HASHPTE---and mask the type in
__swp_entry_to_pte() as well.
Link: https://lkml.kernel.org/r/20230113171026.582290-12-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/arch/m68k/include/asm/mcf_pgtable.h~microblaze-mm-support-__have_arch_pte_swp_exclusive
+++ a/arch/m68k/include/asm/mcf_pgtable.h
@@ -46,8 +46,8 @@
#define _CACHEMASK040 (~0x060)
#define _PAGE_GLOBAL040 0x400 /* 68040 global bit, used for kva descs */
-/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
-#define _PAGE_SWP_EXCLUSIVE 0x080
+/* We borrow bit 24 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE CF_PAGE_NOCACHE
/*
* Externally used page protection values.
--- a/arch/microblaze/include/asm/pgtable.h~microblaze-mm-support-__have_arch_pte_swp_exclusive
+++ a/arch/microblaze/include/asm/pgtable.h
@@ -131,10 +131,10 @@ extern pte_t *va_to_pte(unsigned long ad
* of the 16 available. Bit 24-26 of the TLB are cleared in the TLB
* miss handler. Bit 27 is PAGE_USER, thus selecting the correct
* zone.
- * - PRESENT *must* be in the bottom two bits because swap cache
- * entries use the top 30 bits. Because 4xx doesn't support SMP
- * anyway, M is irrelevant so we borrow it for PAGE_PRESENT. Bit 30
- * is cleared in the TLB miss handler before the TLB entry is loaded.
+ * - PRESENT *must* be in the bottom two bits because swap PTEs use the top
+ * 30 bits. Because 4xx doesn't support SMP anyway, M is irrelevant so we
+ * borrow it for PAGE_PRESENT. Bit 30 is cleared in the TLB miss handler
+ * before the TLB entry is loaded.
* - All other bits of the PTE are loaded into TLBLO without
* * modification, leaving us only the bits 20, 21, 24, 25, 26, 30 for
* software PTE bits. We actually use bits 21, 24, 25, and
@@ -155,6 +155,9 @@ extern pte_t *va_to_pte(unsigned long ad
#define _PAGE_ACCESSED 0x400 /* software: R: page referenced */
#define _PMD_PRESENT PAGE_MASK
+/* We borrow bit 24 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE _PAGE_DIRTY
+
/*
* Some bits are unused...
*/
@@ -393,18 +396,40 @@ static inline unsigned long pmd_page_vad
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
/*
- * Encode and decode a swap entry.
- * Note that the bits we use in a PTE for representing a swap entry
- * must not include the _PAGE_PRESENT bit, or the _PAGE_HASHPTE bit
- * (if used). -- paulus
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
+ *
+ * 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * <------------------ offset -------------------> E < type -> 0 0
+ *
+ * E is the exclusive marker that is not stored in swap entries.
*/
-#define __swp_type(entry) ((entry).val & 0x3f)
+#define __swp_type(entry) ((entry).val & 0x1f)
#define __swp_offset(entry) ((entry).val >> 6)
#define __swp_entry(type, offset) \
- ((swp_entry_t) { (type) | ((offset) << 6) })
+ ((swp_entry_t) { ((type) & 0x1f) | ((offset) << 6) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) >> 2 })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val << 2 })
+#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
+static inline int pte_swp_exclusive(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
+}
+
+static inline pte_t pte_swp_mkexclusive(pte_t pte)
+{
+ pte_val(pte) |= _PAGE_SWP_EXCLUSIVE;
+ return pte;
+}
+
+static inline pte_t pte_swp_clear_exclusive(pte_t pte)
+{
+ pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE;
+ return pte;
+}
+
extern unsigned long iopa(unsigned long addr);
/* Values for nocacheflag and cmode */
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-userfaultfd-rely-on-vma-vm_page_prot-in-uffd_wp_range.patch
mm-userfaultfd-rely-on-vma-vm_page_prot-in-uffd_wp_range-fix.patch
mm-mprotect-drop-pgprot_t-parameter-from-change_protection.patch
mm-mprotect-drop-pgprot_t-parameter-from-change_protection-fix.patch
selftests-vm-cow-add-cow-tests-for-collapsing-of-pte-mapped-anon-thp.patch
mm-nommu-factor-out-check-for-nommu-shared-mappings-into-is_nommu_shared_mapping.patch
mm-nommu-dont-use-vm_mayshare-for-map_private-mappings.patch
drivers-misc-open-dice-dont-touch-vm_mayshare.patch
selftests-mm-define-madv_pageout-to-fix-compilation-issues.patch
mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks.patch
alpha-mm-support-__have_arch_pte_swp_exclusive.patch
arc-mm-support-__have_arch_pte_swp_exclusive.patch
arm-mm-support-__have_arch_pte_swp_exclusive.patch
csky-mm-support-__have_arch_pte_swp_exclusive.patch
hexagon-mm-support-__have_arch_pte_swp_exclusive.patch
ia64-mm-support-__have_arch_pte_swp_exclusive.patch
loongarch-mm-support-__have_arch_pte_swp_exclusive.patch
m68k-mm-remove-dummy-__swp-definitions-for-nommu.patch
m68k-mm-support-__have_arch_pte_swp_exclusive.patch
microblaze-mm-support-__have_arch_pte_swp_exclusive.patch
mips-mm-support-__have_arch_pte_swp_exclusive.patch
nios2-mm-refactor-swap-pte-layout.patch
nios2-mm-support-__have_arch_pte_swp_exclusive.patch
openrisc-mm-support-__have_arch_pte_swp_exclusive.patch
parisc-mm-support-__have_arch_pte_swp_exclusive.patch
powerpc-mm-support-__have_arch_pte_swp_exclusive-on-32bit-book3s.patch
powerpc-nohash-mm-support-__have_arch_pte_swp_exclusive.patch
riscv-mm-support-__have_arch_pte_swp_exclusive.patch
sh-mm-support-__have_arch_pte_swp_exclusive.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-32bit.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-64bit.patch
um-mm-support-__have_arch_pte_swp_exclusive.patch
x86-mm-support-__have_arch_pte_swp_exclusive-also-on-32bit.patch
xtensa-mm-support-__have_arch_pte_swp_exclusive.patch
mm-remove-__have_arch_pte_swp_exclusive.patch
