[PATCH mm-unstable v1 22/26] sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit
From: David Hildenbrand <hidden>
Date: 2023-01-13 17:21:06
Also in:
linux-alpha, linux-arm-kernel, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
Subsystem:
sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
"David S. Miller", Andreas Larsson, Linus Torvalds
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 was effectively unused. While at it, mask the type in __swp_entry(). Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: David Hildenbrand <redacted> --- arch/sparc/include/asm/pgtable_64.h | 38 ++++++++++++++++++++++++++--- 1 file changed, 35 insertions(+), 3 deletions(-)
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 3bc9736bddb1..a1658eebd036 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h@@ -187,6 +187,9 @@ bool kern_addr_valid(unsigned long addr); #define _PAGE_SZHUGE_4U _PAGE_SZ4MB_4U #define _PAGE_SZHUGE_4V _PAGE_SZ4MB_4V +/* We borrow bit 20 to store the exclusive marker in swap PTEs. */ +#define _PAGE_SWP_EXCLUSIVE _AC(0x0000000000100000, UL) + #ifndef __ASSEMBLY__ pte_t mk_pte_io(unsigned long, pgprot_t, int, unsigned long);
@@ -961,18 +964,47 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); #endif -/* Encode and de-code a swap entry */ -#define __swp_type(entry) (((entry).val >> PAGE_SHIFT) & 0xffUL) +/* + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that + * are !pte_none() && !pte_present(). + * + * Format of swap PTEs: + * + * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 + * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 + * <--------------------------- offset --------------------------- + * + * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 + * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 + * --------------------> E <-- type ---> <------- zeroes --------> + */ +#define __swp_type(entry) (((entry).val >> PAGE_SHIFT) & 0x7fUL) #define __swp_offset(entry) ((entry).val >> (PAGE_SHIFT + 8UL)) #define __swp_entry(type, offset) \ ( (swp_entry_t) \ { \ - (((long)(type) << PAGE_SHIFT) | \ + ((((long)(type) & 0x7fUL) << PAGE_SHIFT) | \ ((long)(offset) << (PAGE_SHIFT + 8UL))) \ } ) #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) +{ + return __pte(pte_val(pte) | _PAGE_SWP_EXCLUSIVE); +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + return __pte(pte_val(pte) & ~_PAGE_SWP_EXCLUSIVE); +} + int page_in_phys_avail(unsigned long paddr); /*
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2.39.0