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powerpc: Free up four 64K PTE bits in 64K backed HPTE pages

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Rearrange 64K PTE bits to free up bits 3, 4, 5 and 6
in the 64K backed HPTE pages. This along with the earlier
patch will entirely free up the four bits from 64K PTE.
The bit numbers are big-endian as defined in the ISA3.0

This patch does the following change to 64K PTE backed
by 64K HPTE.

H_PAGE_F_SECOND (S) which occupied bit 4 moves to the
	second part of the pte to bit 60.
H_PAGE_F_GIX (G,I,X) which occupied bit 5, 6 and 7 also
	moves to the second part of the pte to bit 61,
 	62, 63, 64 respectively

since bit 7 is now freed up, we move H_PAGE_BUSY (B) from
bit 9 to bit 7.

The second part of the PTE will hold
(H_PAGE_F_SECOND|H_PAGE_F_GIX) at bit 60,61,62,63.
NOTE: None of the bits in the secondary PTE were not used
by 64k-HPTE backed PTE.

Before the patch, the 64K HPTE backed 64k PTE format was
as follows

 0 1 2 3 4  5  6  7  8 9 10...........................63
 : : : : :  :  :  :  : : :                            :
 v v v v v  v  v  v  v v v                            v

,-,-,-,-,--,--,--,--,-,-,-,-,-,------------------,-,-,-,
|x|x|x| |S |G |I |X |x|B| |x|x|................|x|x|x|x| <- primary pte
'_'_'_'_'__'__'__'__'_'_'_'_'_'________________'_'_'_'_'
| | | | |  |  |  |  | | | | |..................| | | | | <- secondary pte
'_'_'_'_'__'__'__'__'_'_'_'_'__________________'_'_'_'_'

After the patch, the 64k HPTE backed 64k PTE format is
as follows

 0 1 2 3 4  5  6  7  8 9 10...........................63
 : : : : :  :  :  :  : : :                            :
 v v v v v  v  v  v  v v v                            v

,-,-,-,-,--,--,--,--,-,-,-,-,-,------------------,-,-,-,
|x|x|x| |  |  |  |B |x| | |x|x|................|.|.|.|.| <- primary pte
'_'_'_'_'__'__'__'__'_'_'_'_'_'________________'_'_'_'_'
| | | | |  |  |  |  | | | | |..................|S|G|I|X| <- secondary pte
'_'_'_'_'__'__'__'__'_'_'_'_'__________________'_'_'_'_'

The above PTE changes is applicable to hugetlbpages aswell.

The patch does the following code changes:

a) moves the H_PAGE_F_SECOND and H_PAGE_F_GIX to 4k PTE
	header since it is no more needed b the 64k PTEs.
b) abstracts out __real_pte() and __rpte_to_hidx() so the
	caller need not know the bit location of the slot.
c) moves the slot bits to the secondary pte.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Ram Pai 2017-11-06 00:50:48 -08:00 committed by Michael Ellerman
parent 9d2edb1848
commit bf9a95f9a6
5 changed files with 33 additions and 40 deletions
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3
arch/powerpc/include/asm/book3s/64/hash-4k.h
View file

@ -17,6 +17,9 @@
#define H_PUD_TABLE_SIZE (sizeof(pud_t) << H_PUD_INDEX_SIZE)
#define H_PGD_TABLE_SIZE (sizeof(pgd_t) << H_PGD_INDEX_SIZE)
#define H_PAGE_F_GIX_SHIFT 56
#define H_PAGE_F_SECOND _RPAGE_RSV2 /* HPTE is in 2ndary HPTEG */
#define H_PAGE_F_GIX (_RPAGE_RSV3 | _RPAGE_RSV4 | _RPAGE_RPN44)
#define H_PAGE_BUSY _RPAGE_RSV1 /* software: PTE & hash are busy */
/* PTE flags to conserve for HPTE identification */

30
arch/powerpc/include/asm/book3s/64/hash-64k.h
View file

@ -13,7 +13,7 @@
*/
#define H_PAGE_COMBO _RPAGE_RPN0 /* this is a combo 4k page */
#define H_PAGE_4K_PFN _RPAGE_RPN1 /* PFN is for a single 4k page */
#define H_PAGE_BUSY _RPAGE_RPN42 /* software: PTE & hash are busy */
#define H_PAGE_BUSY _RPAGE_RPN44 /* software: PTE & hash are busy */
/*
* We need to differentiate between explicit huge page and THP huge
@ -22,8 +22,7 @@
#define H_PAGE_THP_HUGE H_PAGE_4K_PFN
/* PTE flags to conserve for HPTE identification */
#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_F_SECOND | \
H_PAGE_F_GIX | H_PAGE_HASHPTE | H_PAGE_COMBO)
#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_HASHPTE | H_PAGE_COMBO)
/*
* we support 16 fragments per PTE page of 64K size.
*/
@ -51,27 +50,26 @@ static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep)
unsigned long *hidxp;
rpte.pte = pte;
rpte.hidx = 0;
if (pte_val(pte) & H_PAGE_COMBO) {
/*
* Make sure we order the hidx load against the H_PAGE_COMBO
* check. The store side ordering is done in __hash_page_4K
*/
smp_rmb();
hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
rpte.hidx = *hidxp;
}
/*
* Ensure that we do not read the hidx before we read the PTE. Because
* the writer side is expected to finish writing the hidx first followed
* by the PTE, by using smp_wmb(). pte_set_hash_slot() ensures that.
*/
smp_rmb();
hidxp = (unsigned long *)(ptep + PTRS_PER_PTE);
rpte.hidx = *hidxp;
return rpte;
}
#define HIDX_BITS(x, index) (x << (index << 2))
#define BITS_TO_HIDX(x, index) ((x >> (index << 2)) & 0xfUL)
#define INVALID_RPTE_HIDX ~(0x0UL)
static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index)
{
if ((pte_val(rpte.pte) & H_PAGE_COMBO))
return (rpte.hidx >> (index<<2)) & 0xf;
return (pte_val(rpte.pte) >> H_PAGE_F_GIX_SHIFT) & 0xf;
return BITS_TO_HIDX(rpte.hidx, index);
}
/*

3
arch/powerpc/include/asm/book3s/64/hash.h
View file

@ -9,9 +9,6 @@
*
*/
#define H_PTE_NONE_MASK _PAGE_HPTEFLAGS
#define H_PAGE_F_GIX_SHIFT 56
#define H_PAGE_F_SECOND _RPAGE_RSV2 /* HPTE is in 2ndary HPTEG */
#define H_PAGE_F_GIX (_RPAGE_RSV3 | _RPAGE_RSV4 | _RPAGE_RPN44)
#define H_PAGE_HASHPTE _RPAGE_RPN43 /* PTE has associated HPTE */
#ifdef CONFIG_PPC_64K_PAGES

21
arch/powerpc/mm/hash64_64k.c
View file

@ -103,8 +103,8 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* On hash insert failure we use old pte value and we don't
* want slot information there if we have a insert failure.
*/
old_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND);
new_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND);
old_pte &= ~H_PAGE_HASHPTE;
new_pte &= ~H_PAGE_HASHPTE;
goto htab_insert_hpte;
}
/*
@ -225,6 +225,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
unsigned long vsid, pte_t *ptep, unsigned long trap,
unsigned long flags, int ssize)
{
real_pte_t rpte;
unsigned long hpte_group;
unsigned long rflags, pa;
unsigned long old_pte, new_pte;
@ -261,6 +262,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
rflags = htab_convert_pte_flags(new_pte);
rpte = __real_pte(__pte(old_pte), ptep);
if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
@ -268,16 +270,13 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
vpn = hpt_vpn(ea, vsid, ssize);
if (unlikely(old_pte & H_PAGE_HASHPTE)) {
unsigned long gslot;
/*
* There MIGHT be an HPTE for this pte
*/
hash = hpt_hash(vpn, shift, ssize);
if (old_pte & H_PAGE_F_SECOND)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT;
if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_64K,
gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0);
if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_64K,
MMU_PAGE_64K, ssize,
flags) == -1)
old_pte &= ~_PAGE_HPTEFLAGS;
@ -326,9 +325,9 @@ repeat:
MMU_PAGE_64K, MMU_PAGE_64K, old_pte);
return -1;
}
new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE;
new_pte |= (slot << H_PAGE_F_GIX_SHIFT) &
(H_PAGE_F_SECOND | H_PAGE_F_GIX);
new_pte |= pte_set_hidx(ptep, rpte, 0, slot);
}
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;

16
arch/powerpc/mm/hugetlbpage-hash64.c
View file

@ -23,6 +23,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, unsigned long flags,
int ssize, unsigned int shift, unsigned int mmu_psize)
{
real_pte_t rpte;
unsigned long vpn;
unsigned long old_pte, new_pte;
unsigned long rflags, pa, sz;
@ -62,6 +63,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
} while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
rflags = htab_convert_pte_flags(new_pte);
rpte = __real_pte(__pte(old_pte), ptep);
sz = ((1UL) << shift);
if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
@ -72,15 +74,10 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
/* Check if pte already has an hpte (case 2) */
if (unlikely(old_pte & H_PAGE_HASHPTE)) {
/* There MIGHT be an HPTE for this pte */
unsigned long hash, slot;
unsigned long gslot;
hash = hpt_hash(vpn, shift, ssize);
if (old_pte & H_PAGE_F_SECOND)
hash = ~hash;
slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT;
if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, mmu_psize,
gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0);
if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize,
mmu_psize, ssize, flags) == -1)
old_pte &= ~_PAGE_HPTEFLAGS;
}
@ -107,8 +104,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
return -1;
}
new_pte |= (slot << H_PAGE_F_GIX_SHIFT) &
(H_PAGE_F_SECOND | H_PAGE_F_GIX);
new_pte |= pte_set_hidx(ptep, rpte, 0, slot);
}
/*