mirror of
https://github.com/torvalds/linux.git
synced 2024-12-04 18:13:04 +00:00
93c0eac40d
Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE just like we already do on x86-64. After deciphering the PTE layout it becomes clear that there are still unused bits for 2-level and 3-level page tables that we should be able to use. Reusing a bit avoids stealing one bit from the swap offset. While at it, mask the type in __swp_entry(); use some helper definitions to make the macros easier to grasp. Link: https://lkml.kernel.org/r/20230113171026.582290-25-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_X86_PGTABLE_2LEVEL_H
|
|
#define _ASM_X86_PGTABLE_2LEVEL_H
|
|
|
|
#define pte_ERROR(e) \
|
|
pr_err("%s:%d: bad pte %08lx\n", __FILE__, __LINE__, (e).pte_low)
|
|
#define pgd_ERROR(e) \
|
|
pr_err("%s:%d: bad pgd %08lx\n", __FILE__, __LINE__, pgd_val(e))
|
|
|
|
/*
|
|
* Certain architectures need to do special things when PTEs
|
|
* within a page table are directly modified. Thus, the following
|
|
* hook is made available.
|
|
*/
|
|
static inline void native_set_pte(pte_t *ptep , pte_t pte)
|
|
{
|
|
*ptep = pte;
|
|
}
|
|
|
|
static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
|
|
{
|
|
*pmdp = pmd;
|
|
}
|
|
|
|
static inline void native_set_pud(pud_t *pudp, pud_t pud)
|
|
{
|
|
}
|
|
|
|
static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
|
|
{
|
|
native_set_pte(ptep, pte);
|
|
}
|
|
|
|
static inline void native_pmd_clear(pmd_t *pmdp)
|
|
{
|
|
native_set_pmd(pmdp, __pmd(0));
|
|
}
|
|
|
|
static inline void native_pud_clear(pud_t *pudp)
|
|
{
|
|
}
|
|
|
|
static inline void native_pte_clear(struct mm_struct *mm,
|
|
unsigned long addr, pte_t *xp)
|
|
{
|
|
*xp = native_make_pte(0);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
static inline pte_t native_ptep_get_and_clear(pte_t *xp)
|
|
{
|
|
return __pte(xchg(&xp->pte_low, 0));
|
|
}
|
|
#else
|
|
#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
|
|
{
|
|
return __pmd(xchg((pmdval_t *)xp, 0));
|
|
}
|
|
#else
|
|
#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
static inline pud_t native_pudp_get_and_clear(pud_t *xp)
|
|
{
|
|
return __pud(xchg((pudval_t *)xp, 0));
|
|
}
|
|
#else
|
|
#define native_pudp_get_and_clear(xp) native_local_pudp_get_and_clear(xp)
|
|
#endif
|
|
|
|
/* Bit manipulation helper on pte/pgoff entry */
|
|
static inline unsigned long pte_bitop(unsigned long value, unsigned int rightshift,
|
|
unsigned long mask, unsigned int leftshift)
|
|
{
|
|
return ((value >> rightshift) & mask) << leftshift;
|
|
}
|
|
|
|
/*
|
|
* 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 ------------------> 0 E <- type --> 0
|
|
*
|
|
* E is the exclusive marker that is not stored in swap entries.
|
|
*/
|
|
#define SWP_TYPE_BITS 5
|
|
#define _SWP_TYPE_MASK ((1U << SWP_TYPE_BITS) - 1)
|
|
#define _SWP_TYPE_SHIFT (_PAGE_BIT_PRESENT + 1)
|
|
#define SWP_OFFSET_SHIFT (_PAGE_BIT_PROTNONE + 1)
|
|
|
|
#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > 5)
|
|
|
|
#define __swp_type(x) (((x).val >> _SWP_TYPE_SHIFT) \
|
|
& _SWP_TYPE_MASK)
|
|
#define __swp_offset(x) ((x).val >> SWP_OFFSET_SHIFT)
|
|
#define __swp_entry(type, offset) ((swp_entry_t) { \
|
|
(((type) & _SWP_TYPE_MASK) << _SWP_TYPE_SHIFT) \
|
|
| ((offset) << SWP_OFFSET_SHIFT) })
|
|
#define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_low })
|
|
#define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val })
|
|
|
|
/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
|
|
#define _PAGE_SWP_EXCLUSIVE _PAGE_PSE
|
|
|
|
/* No inverted PFNs on 2 level page tables */
|
|
|
|
static inline u64 protnone_mask(u64 val)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask)
|
|
{
|
|
return val;
|
|
}
|
|
|
|
static inline bool __pte_needs_invert(u64 val)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#endif /* _ASM_X86_PGTABLE_2LEVEL_H */
|