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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Andrew Morton <akpm@linux-foundation.org>,
	Jason Gunthorpe <jgg@nvidia.com>, Peter Xu <peterx@redhat.com>,
	Oscar Salvador <osalvador@suse.de>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH v2 16/20] powerpc/e500: Encode hugepage size in PTE bits
Date: Fri, 17 May 2024 21:00:10 +0200	[thread overview]
Message-ID: <f4f76cf605b84ff60cd8cb347775a8ff2338ce18.1715971869.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1715971869.git.christophe.leroy@csgroup.eu>

Use U0-U3 bits to encode hugepage size, more exactly page shift.

As we start using hugepages at shift 21 (2Mbytes), substract 20
so that it fits into 4 bits. That may change in the future if
we want to use smaller hugepages.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/nohash/hugetlb-e500.h | 6 ++++++
 arch/powerpc/include/asm/nohash/pte-e500.h     | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/arch/powerpc/include/asm/nohash/hugetlb-e500.h b/arch/powerpc/include/asm/nohash/hugetlb-e500.h
index 8f04ad20e040..d8e51a3f8557 100644
--- a/arch/powerpc/include/asm/nohash/hugetlb-e500.h
+++ b/arch/powerpc/include/asm/nohash/hugetlb-e500.h
@@ -42,4 +42,10 @@ static inline int check_and_get_huge_psize(int shift)
 	return shift_to_mmu_psize(shift);
 }
 
+static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
+{
+	return __pte(pte_val(entry) | (_PAGE_U3 * (shift - 20)));
+}
+#define arch_make_huge_pte arch_make_huge_pte
+
 #endif /* _ASM_POWERPC_NOHASH_HUGETLB_E500_H */
diff --git a/arch/powerpc/include/asm/nohash/pte-e500.h b/arch/powerpc/include/asm/nohash/pte-e500.h
index 975facc7e38e..091e4bff1fba 100644
--- a/arch/powerpc/include/asm/nohash/pte-e500.h
+++ b/arch/powerpc/include/asm/nohash/pte-e500.h
@@ -46,6 +46,9 @@
 #define _PAGE_NO_CACHE	0x400000 /* I: cache inhibit */
 #define _PAGE_WRITETHRU	0x800000 /* W: cache write-through */
 
+#define _PAGE_HSIZE_MSK (_PAGE_U0 | _PAGE_U1 | _PAGE_U2 | _PAGE_U3)
+#define _PAGE_HSIZE_SHIFT	14
+
 /* "Higher level" linux bit combinations */
 #define _PAGE_EXEC		(_PAGE_BAP_SX | _PAGE_BAP_UX) /* .. and was cache cleaned */
 #define _PAGE_READ		(_PAGE_BAP_SR | _PAGE_BAP_UR) /* User read permission */
-- 
2.44.0


  parent reply	other threads:[~2024-05-17 19:04 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-17 18:59 [RFC PATCH v2 00/20] Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64) Christophe Leroy
2024-05-17 18:59 ` [RFC PATCH v2 01/20] mm: Provide pagesize to pmd_populate() Christophe Leroy
2024-05-20  9:01   ` Oscar Salvador
2024-05-20 16:24     ` Christophe Leroy
2024-05-21 11:57       ` Oscar Salvador
2024-05-22  8:37         ` Christophe Leroy
2024-05-17 18:59 ` [RFC PATCH v2 02/20] mm: Provide page size to pte_alloc_huge() Christophe Leroy
2024-05-17 18:59 ` [RFC PATCH v2 03/20] mm: Provide pmd to pte_leaf_size() Christophe Leroy
2024-05-21  9:39   ` Oscar Salvador
2024-05-22 10:22     ` Christophe Leroy
2024-05-17 18:59 ` [RFC PATCH v2 04/20] mm: Provide mm_struct and address to huge_ptep_get() Christophe Leroy
2024-05-17 18:59 ` [RFC PATCH v2 05/20] powerpc/mm: Allow hugepages without hugepd Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 06/20] powerpc/8xx: Fix size given to set_huge_pte_at() Christophe Leroy
2024-05-20  9:14   ` Oscar Salvador
2024-05-20 16:31     ` Christophe Leroy
2024-05-20 17:42       ` Oscar Salvador
2024-05-22  8:45         ` Christophe Leroy
2024-05-21  0:48       ` Michael Ellerman
2024-05-21  9:26         ` Oscar Salvador
2024-05-22  8:32           ` Christophe Leroy
2024-05-22 12:18             ` Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 07/20] powerpc/8xx: Rework support for 8M pages using contiguous PTE entries Christophe Leroy
2024-05-24 10:02   ` Oscar Salvador
2024-05-24 11:47     ` Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 08/20] powerpc/8xx: Simplify struct mmu_psize_def Christophe Leroy
2024-05-25  3:36   ` Oscar Salvador
2024-05-17 19:00 ` [RFC PATCH v2 09/20] powerpc/mm: Remove _PAGE_PSIZE Christophe Leroy
2024-05-25  3:40   ` Oscar Salvador
2024-05-17 19:00 ` [RFC PATCH v2 10/20] powerpc/mm: Fix __find_linux_pte() on 32 bits with PMD leaf entries Christophe Leroy
2024-05-25  4:12   ` Oscar Salvador
2024-05-25  6:41     ` Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 11/20] powerpc/mm: Complement huge_pte_alloc() for all non HUGEPD setups Christophe Leroy
2024-05-25  4:29   ` Oscar Salvador
2024-05-25  6:44     ` Christophe Leroy
2024-05-25 10:33       ` Oscar Salvador
2024-05-17 19:00 ` [RFC PATCH v2 12/20] powerpc/64e: Remove unneeded #ifdef CONFIG_PPC_E500 Christophe Leroy
2024-05-24  7:31   ` Michael Ellerman
2024-05-24  8:45     ` Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 13/20] powerpc/64e: Clean up impossible setups Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 14/20] powerpc/e500: Remove enc field from struct mmu_psize_def Christophe Leroy
2024-05-25  4:35   ` Oscar Salvador
2024-05-17 19:00 ` [RFC PATCH v2 15/20] powerpc/85xx: Switch to 64 bits PGD Christophe Leroy
2024-05-25  4:54   ` Oscar Salvador
2024-05-25  9:02     ` Christophe Leroy
2024-05-17 19:00 ` Christophe Leroy [this message]
2024-05-17 19:00 ` [RFC PATCH v2 17/20] powerpc/e500: Use contiguous PMD instead of hugepd Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 18/20] powerpc/64s: Use contiguous PMD/PUD instead of HUGEPD Christophe Leroy
2024-05-20 12:54   ` Nicholas Piggin
2024-05-20 16:43     ` Christophe Leroy
2024-05-22  1:13       ` Nicholas Piggin
2024-05-22  9:32         ` Christophe Leroy
2024-05-22 12:23         ` Jason Gunthorpe
2024-05-17 19:00 ` [RFC PATCH v2 19/20] powerpc/mm: Remove hugepd leftovers Christophe Leroy
2024-05-17 19:00 ` [RFC PATCH v2 20/20] mm: Remove CONFIG_ARCH_HAS_HUGEPD Christophe Leroy
2024-05-17 19:06 ` [RFC PATCH v2 00/20] Reimplement huge pages without hugepd on powerpc (8xx, e500, book3s/64) Jason Gunthorpe
2024-05-18  6:28   ` Christophe Leroy
2024-05-23 19:40 ` Peter Xu
2024-05-24  4:46   ` Michael Ellerman
2024-05-27 14:14     ` Peter Xu
2024-05-24  6:31   ` Oscar Salvador

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