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sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit

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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().

Link: https://lkml.kernel.org/r/20230113171026.582290-23-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2023-01-13 18:10:22 +01:00 committed by Andrew Morton
parent e6b37d7f6f
commit adf8e329ff
1 changed files with 35 additions and 3 deletions
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38
arch/sparc/include/asm/pgtable_64.h
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@ -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);
/*