From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
John Hubbard <jhubbard@nvidia.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Yang Shi <shy828301@gmail.com>, Vlastimil Babka <vbabka@suse.cz>,
Nadav Amit <namit@vmware.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Peter Xu <peterx@redhat.com>,
linux-mm@kvack.org, x86@kernel.org, linux-alpha@vger.kernel.org,
linux-snps-arc@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org,
loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org,
linux-mips@vger.kernel.org, openrisc@lists.librecores.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org,
David Hildenbrand <david@redhat.com>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Helge Deller <deller@gmx.de>
Subject: [PATCH mm-unstable v1 16/26] parisc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Date: Fri, 13 Jan 2023 18:10:16 +0100 [thread overview]
Message-ID: <20230113171026.582290-17-david@redhat.com> (raw)
In-Reply-To: <20230113171026.582290-1-david@redhat.com>
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using the yet-unused
_PAGE_ACCESSED location in the swap PTE. Looking at pte_present()
and pte_none() checks, there seems to be no actual reason why we cannot
use it: we only have to make sure we're not using _PAGE_PRESENT.
Reusing this bit avoids having to steal one bit from the swap offset.
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/parisc/include/asm/pgtable.h | 41 ++++++++++++++++++++++++++++---
1 file changed, 38 insertions(+), 3 deletions(-)
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index ea357430aafe..3033bb88df34 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -218,6 +218,9 @@ extern void __update_cache(pte_t pte);
#define _PAGE_KERNEL_RWX (_PAGE_KERNEL_EXEC | _PAGE_WRITE)
#define _PAGE_KERNEL (_PAGE_KERNEL_RO | _PAGE_WRITE)
+/* We borrow bit 23 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE _PAGE_ACCESSED
+
/* The pgd/pmd contains a ptr (in phys addr space); since all pgds/pmds
* are page-aligned, we don't care about the PAGE_OFFSET bits, except
* for a few meta-information bits, so we shift the address to be
@@ -394,17 +397,49 @@ extern void paging_init (void);
#define update_mmu_cache(vms,addr,ptep) __update_cache(*ptep)
-/* Encode and de-code a swap entry */
-
+/*
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
+ *
+ * Format of swap PTEs (32bit):
+ *
+ * 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 -----------------> P E <ofs> < type ->
+ *
+ * E is the exclusive marker that is not stored in swap entries.
+ * _PAGE_PRESENT (P) must be 0.
+ *
+ * For the 64bit version, the offset is extended by 32bit.
+ */
#define __swp_type(x) ((x).val & 0x1f)
#define __swp_offset(x) ( (((x).val >> 6) & 0x7) | \
(((x).val >> 8) & ~0x7) )
-#define __swp_entry(type, offset) ((swp_entry_t) { (type) | \
+#define __swp_entry(type, offset) ((swp_entry_t) { \
+ ((type) & 0x1f) | \
((offset & 0x7) << 6) | \
((offset & ~0x7) << 8) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
+#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;
+}
+
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
{
pte_t pte;
--
2.39.0
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next prev parent reply other threads:[~2023-01-13 17:22 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 17:10 [PATCH mm-unstable v1 00/26] mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 01/26] mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks David Hildenbrand
2023-01-14 16:09 ` David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 02/26] alpha/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 03/26] arc/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 04/26] arm/mm: " David Hildenbrand
2023-01-13 17:38 ` Russell King (Oracle)
2023-02-07 0:32 ` Mark Brown
2023-02-08 14:12 ` David Hildenbrand
2023-02-08 16:39 ` Mark Brown
2023-01-13 17:10 ` [PATCH mm-unstable v1 05/26] csky/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 06/26] hexagon/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 07/26] ia64/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 08/26] loongarch/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 09/26] m68k/mm: remove dummy __swp definitions for nommu David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 10/26] m68k/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 11/26] microblaze/mm: " David Hildenbrand
2023-02-26 20:13 ` Geert Uytterhoeven
2023-02-27 13:31 ` David Hildenbrand
2023-02-27 14:43 ` Geert Uytterhoeven
2023-02-27 17:01 ` David Hildenbrand
2023-02-27 19:46 ` Geert Uytterhoeven
2023-02-28 15:55 ` David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 12/26] mips/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 13/26] nios2/mm: refactor swap PTE layout David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 14/26] nios2/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 15/26] openrisc/mm: " David Hildenbrand
2023-01-13 17:10 ` David Hildenbrand [this message]
2023-01-13 17:10 ` [PATCH mm-unstable v1 17/26] powerpc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit book3s David Hildenbrand
2023-02-10 5:08 ` Michael Ellerman
2023-01-13 17:10 ` [PATCH mm-unstable v1 18/26] powerpc/nohash/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 19/26] riscv/mm: " David Hildenbrand
2023-02-28 15:50 ` Palmer Dabbelt
2023-02-28 15:56 ` David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 20/26] sh/mm: " David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 21/26] sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 22/26] sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 23/26] um/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 24/26] x86/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also on 32bit David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 25/26] xtensa/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-01-13 17:10 ` [PATCH mm-unstable v1 26/26] mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE David Hildenbrand
2023-02-28 21:11 ` [PATCH mm-unstable v1 00/26] mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs patchwork-bot+linux-riscv
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