On 8xx, the number of entries occupied by a PTE in the page tables
depends on the size of the page. At the time being, this calculation
is done in two places: in pte_update() and in set_huge_pte_at()
Refactor this calculation into a helper called
number_of_cells_per_pte(). For the time being, the val param is
unused. It will be used by following patch.
Instead of opencoding is_hugepd(), use hugepd_ok() with a forward
declaration.
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/include/asm/nohash/32/pgtable.h | 18 ++++++++++++------
arch/powerpc/mm/pgtable.c | 6 ++++--
2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index b9e134d0f03a..80bbc21b87f0 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -227,6 +227,17 @@ static inline void pmd_clear(pmd_t *pmdp)
*/
#ifdef CONFIG_PPC_8xx
static pmd_t *pmd_off(struct mm_struct *mm, unsigned long addr);
+static int hugepd_ok(hugepd_t hpd);
+
+static int number_of_cells_per_pte(pmd_t *pmd, pte_basic_t val, int huge)
+{
+ if (!huge)
+ return PAGE_SIZE / SZ_4K;
+ else if (hugepd_ok(*((hugepd_t *)pmd)))
+ return 1;
+ else
+ return SZ_512K / SZ_4K;
+}
static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, pte_t *p,
unsigned long clr, unsigned long set, int huge)
@@ -237,12 +248,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
int num, i;
pmd_t *pmd = pmd_off(mm, addr);
- if (!huge)
- num = PAGE_SIZE / SZ_4K;
- else if ((pmd_val(*pmd) & _PMD_PAGE_MASK) != _PMD_PAGE_8M)
- num = SZ_512K / SZ_4K;
- else
- num = 1;
+ num = number_of_cells_per_pte(pmd, new, huge);
for (i = 0; i < num; i++, entry++, new += SZ_4K)
*entry = new;
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 9c0547d77af3..2dcad640b869 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -266,8 +266,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_
pmd_t *pmd = pmd_off(mm, addr);
pte_basic_t val;
pte_basic_t *entry = &ptep->pte;
- int num = is_hugepd(*((hugepd_t *)pmd)) ? 1 : SZ_512K / SZ_4K;
- int i;
+ int num, i;
/*
* Make sure hardware valid bit is not set. We don't do
@@ -280,6 +279,9 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_
pte = set_pte_filter(pte);
val = pte_val(pte);
+
+ num = number_of_cells_per_pte(pmd, val, 1);
+
for (i = 0; i < num; i++, entry++, val += SZ_4K)
*entry = val;
}
--
2.25.0
The 8xx has 4 page sizes: 4k, 16k, 512k and 8M
4k and 16k can be selected at build time as standard page sizes,
and 512k and 8M are hugepages.
When 4k standard pages are selected, 16k pages are not available.
Allow 16k pages as hugepages when 4k pages are used.
To allow that, implement arch_make_huge_pte() which receives
the necessary arguments to allow setting the PTE in accordance
with the page size:
- 512 k pages must have _PAGE_HUGE and _PAGE_SPS. They are set
by pte_mkhuge(). arch_make_huge_pte() does nothing.
- 16 k pages must have only _PAGE_SPS. arch_make_huge_pte() clears
_PAGE_HUGE.
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 14 ++++++++++++++
arch/powerpc/include/asm/nohash/32/pgtable.h | 2 ++
arch/powerpc/mm/hugetlbpage.c | 2 +-
arch/powerpc/mm/nohash/tlb.c | 4 ----
arch/powerpc/mm/ptdump/8xx.c | 5 +++++
include/uapi/asm-generic/hugetlb_encode.h | 1 +
include/uapi/linux/mman.h | 1 +
7 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
index e752a5807a59..39be9aea86db 100644
--- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
@@ -65,4 +65,18 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
pte_update(mm, addr, ptep, clr, set, 1);
}
+#ifdef CONFIG_PPC_4K_PAGES
+static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
+ struct page *page, int writable)
+{
+ size_t size = huge_page_size(hstate_vma(vma));
+
+ if (size == SZ_16K)
+ return __pte(pte_val(entry) & ~_PAGE_HUGE);
+ else
+ return entry;
+}
+#define arch_make_huge_pte arch_make_huge_pte
+#endif
+
#endif /* _ASM_POWERPC_NOHASH_32_HUGETLB_8XX_H */
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 80bbc21b87f0..ee2243ba96cf 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -235,6 +235,8 @@ static int number_of_cells_per_pte(pmd_t *pmd, pte_basic_t val, int huge)
return PAGE_SIZE / SZ_4K;
else if (hugepd_ok(*((hugepd_t *)pmd)))
return 1;
+ else if (IS_ENABLED(CONFIG_PPC_4K_PAGES) && !(val & _PAGE_HUGE))
+ return SZ_16K / SZ_4K;
else
return SZ_512K / SZ_4K;
}
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index e7ae2a2c4545..36c3800769fb 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -180,7 +180,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
if (!hpdp)
return NULL;
- if (IS_ENABLED(CONFIG_PPC_8xx) && sz == SZ_512K)
+ if (IS_ENABLED(CONFIG_PPC_8xx) && pshift < PMD_SHIFT)
return pte_alloc_map(mm, (pmd_t *)hpdp, addr);
BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index 14514585db98..5872f69141d5 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -83,16 +83,12 @@ struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
};
#elif defined(CONFIG_PPC_8xx)
struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT] = {
- /* we only manage 4k and 16k pages as normal pages */
-#ifdef CONFIG_PPC_4K_PAGES
[MMU_PAGE_4K] = {
.shift = 12,
},
-#else
[MMU_PAGE_16K] = {
.shift = 14,
},
-#endif
[MMU_PAGE_512K] = {
.shift = 19,
},
diff --git a/arch/powerpc/mm/ptdump/8xx.c b/arch/powerpc/mm/ptdump/8xx.c
index 8a797dcbf475..86da2a669680 100644
--- a/arch/powerpc/mm/ptdump/8xx.c
+++ b/arch/powerpc/mm/ptdump/8xx.c
@@ -11,8 +11,13 @@
static const struct flag_info flag_array[] = {
{
+#ifdef CONFIG_PPC_16K_PAGES
.mask = _PAGE_HUGE,
.val = _PAGE_HUGE,
+#else
+ .mask = _PAGE_SPS,
+ .val = _PAGE_SPS,
+#endif
.set = "huge",
.clear = " ",
}, {
diff --git a/include/uapi/asm-generic/hugetlb_encode.h b/include/uapi/asm-generic/hugetlb_encode.h
index b0f8e87235bd..4f3d5aaa11f5 100644
--- a/include/uapi/asm-generic/hugetlb_encode.h
+++ b/include/uapi/asm-generic/hugetlb_encode.h
@@ -20,6 +20,7 @@
#define HUGETLB_FLAG_ENCODE_SHIFT 26
#define HUGETLB_FLAG_ENCODE_MASK 0x3f
+#define HUGETLB_FLAG_ENCODE_16KB (14 << HUGETLB_FLAG_ENCODE_SHIFT)
#define HUGETLB_FLAG_ENCODE_64KB (16 << HUGETLB_FLAG_ENCODE_SHIFT)
#define HUGETLB_FLAG_ENCODE_512KB (19 << HUGETLB_FLAG_ENCODE_SHIFT)
#define HUGETLB_FLAG_ENCODE_1MB (20 << HUGETLB_FLAG_ENCODE_SHIFT)
diff --git a/include/uapi/linux/mman.h b/include/uapi/linux/mman.h
index 923cc162609c..f55bc680b5b0 100644
--- a/include/uapi/linux/mman.h
+++ b/include/uapi/linux/mman.h
@@ -27,6 +27,7 @@
#define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
#define MAP_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK
+#define MAP_HUGE_16KB HUGETLB_FLAG_ENCODE_16KB
#define MAP_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB
#define MAP_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB
#define MAP_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB
--
2.25.0
On Mon, 31 Aug 2020 08:30:43 +0000 (UTC), Christophe Leroy wrote:
> On 8xx, the number of entries occupied by a PTE in the page tables
> depends on the size of the page. At the time being, this calculation
> is done in two places: in pte_update() and in set_huge_pte_at()
>
> Refactor this calculation into a helper called
> number_of_cells_per_pte(). For the time being, the val param is
> unused. It will be used by following patch.
>
> [...]
Applied to powerpc/next.
[1/2] powerpc/8xx: Refactor calculation of number of entries per PTE in page tables
https://git.kernel.org/powerpc/c/175a99991511fed16108dcb823f0af8e72325a1f
[2/2] powerpc/8xx: Support 16k hugepages with 4k pages
https://git.kernel.org/powerpc/c/e47168f3d1b14af5281cf50c59561d59d28201f9
cheers