The patch titled
Subject: csky/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
has been added to the -mm mm-unstable branch. Its filename is
csky-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/csky-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: csky/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Date: Fri, 13 Jan 2023 18:10:05 +0100
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by stealing one bit from the
offset. This reduces the maximum swap space per file to 16 GiB (was 32
GiB).
We might actually be able to reuse one of the other software bits
(_PAGE_READ / PAGE_WRITE) instead, because we only have to keep
pte_present(), pte_none() and HW happy. For now, let's keep it simple
because there might be something non-obvious.
Link: https://lkml.kernel.org/r/20230113171026.582290-6-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/arch/csky/abiv1/inc/abi/pgtable-bits.h~csky-mm-support-__have_arch_pte_swp_exclusive
+++ a/arch/csky/abiv1/inc/abi/pgtable-bits.h
@@ -10,6 +10,9 @@
#define _PAGE_ACCESSED (1<<3)
#define _PAGE_MODIFIED (1<<4)
+/* We borrow bit 9 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE (1<<9)
+
/* implemented in hardware */
#define _PAGE_GLOBAL (1<<6)
#define _PAGE_VALID (1<<7)
@@ -26,7 +29,8 @@
#define _PAGE_PROT_NONE _PAGE_READ
/*
- * Encode and decode a swap entry
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
*
* Format of swap PTE:
* bit 0: _PAGE_PRESENT (zero)
@@ -35,15 +39,16 @@
* bit 6: _PAGE_GLOBAL (zero)
* bit 7: _PAGE_VALID (zero)
* bit 8: swap type[4]
- * bit 9 - 31: swap offset
+ * bit 9: exclusive marker
+ * bit 10 - 31: swap offset
*/
#define __swp_type(x) ((((x).val >> 2) & 0xf) | \
(((x).val >> 4) & 0x10))
-#define __swp_offset(x) ((x).val >> 9)
+#define __swp_offset(x) ((x).val >> 10)
#define __swp_entry(type, offset) ((swp_entry_t) { \
((type & 0xf) << 2) | \
((type & 0x10) << 4) | \
- ((offset) << 9)})
+ ((offset) << 10)})
#define HAVE_ARCH_UNMAPPED_AREA
--- a/arch/csky/abiv2/inc/abi/pgtable-bits.h~csky-mm-support-__have_arch_pte_swp_exclusive
+++ a/arch/csky/abiv2/inc/abi/pgtable-bits.h
@@ -10,6 +10,9 @@
#define _PAGE_PRESENT (1<<10)
#define _PAGE_MODIFIED (1<<11)
+/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE (1<<7)
+
/* implemented in hardware */
#define _PAGE_GLOBAL (1<<0)
#define _PAGE_VALID (1<<1)
@@ -26,23 +29,25 @@
#define _PAGE_PROT_NONE _PAGE_WRITE
/*
- * Encode and decode a swap entry
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
*
* Format of swap PTE:
* bit 0: _PAGE_GLOBAL (zero)
* bit 1: _PAGE_VALID (zero)
* bit 2 - 6: swap type
- * bit 7 - 8: swap offset[0 - 1]
+ * bit 7: exclusive marker
+ * bit 8: swap offset[0]
* bit 9: _PAGE_WRITE (zero)
* bit 10: _PAGE_PRESENT (zero)
- * bit 11 - 31: swap offset[2 - 22]
+ * bit 11 - 31: swap offset[1 - 21]
*/
#define __swp_type(x) (((x).val >> 2) & 0x1f)
-#define __swp_offset(x) ((((x).val >> 7) & 0x3) | \
- (((x).val >> 9) & 0x7ffffc))
+#define __swp_offset(x) ((((x).val >> 8) & 0x1) | \
+ (((x).val >> 10) & 0x3ffffe))
#define __swp_entry(type, offset) ((swp_entry_t) { \
((type & 0x1f) << 2) | \
- ((offset & 0x3) << 7) | \
- ((offset & 0x7ffffc) << 9)})
+ ((offset & 0x1) << 8) | \
+ ((offset & 0x3ffffe) << 10)})
#endif /* __ASM_CSKY_PGTABLE_BITS_H */
--- a/arch/csky/include/asm/pgtable.h~csky-mm-support-__have_arch_pte_swp_exclusive
+++ a/arch/csky/include/asm/pgtable.h
@@ -200,6 +200,24 @@ static inline pte_t pte_mkyoung(pte_t pt
return pte;
}
+#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;
+}
+
#define __HAVE_PHYS_MEM_ACCESS_PROT
struct file;
extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
_
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
