Commit adf8e329 authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

sparc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 64bit 

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: default avatarDavid Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e6b37d7f

arch/sparc/include/asm/pgtable_64.h

+35 −3
Original line number Diff line number Diff line
@@ -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);



/*