Commit 4a446b3d authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

arc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE 

Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE by using bit 5, which is yet
unused.  The only important parts seems to be to not use _PAGE_PRESENT
(bit 9).

Link: https://lkml.kernel.org/r/20230113171026.582290-4-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a172d512

arch/arc/include/asm/pgtable-bits-arcv2.h

+24 −3
Original line number Diff line number Diff line
@@ -26,6 +26,9 @@ 
#define _PAGE_GLOBAL		(1 << 8)  /* ASID agnostic (H) */

#define _PAGE_PRESENT		(1 << 9)  /* PTE/TLB Valid (H) */



/* We borrow bit 5 to store the exclusive marker in swap PTEs. */

#define _PAGE_SWP_EXCLUSIVE	_PAGE_DIRTY



#ifdef CONFIG_ARC_MMU_V4

#define _PAGE_HW_SZ		(1 << 10)  /* Normal/super (H) */

#else
@@ -106,9 +109,18 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, 
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,

		      pte_t *ptep);



/* Encode swap {type,off} tuple into PTE

 * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that

 * PAGE_PRESENT is zero in a PTE holding swap "identifier"

/*

 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that

 * are !pte_none() && !pte_present().

 *

 * Format of swap PTEs:

 *

 *   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

 *   <-------------- offset -------------> <--- zero --> E < type ->

 *

 *   E is the exclusive marker that is not stored in swap entries.

 *   The zero'ed bits include _PAGE_PRESENT.

 */

#define __swp_entry(type, off)		((swp_entry_t) \

					{ ((type) & 0x1f) | ((off) << 13) })
@@ -120,6 +132,15 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, 
#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;

}



PTE_BIT_FUNC(swp_mkexclusive, |= (_PAGE_SWP_EXCLUSIVE));

PTE_BIT_FUNC(swp_clear_exclusive, &= ~(_PAGE_SWP_EXCLUSIVE));



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#include <asm/hugepage.h>

#endif