kernel.git/arch/powerpc/mm/pgtable.c, branch linux-rolling-stable

mm: introduce memdesc_flags_t

2025-09-13T23:55:07Z

Patch series "Add and use memdesc_flags_t". At some point struct page will be separated from struct slab and struct folio. This is a step towards that by introducing a type for the 'flags' word of all three structures. This gives us a certain amount of type safety by establishing that some of these unsigned longs are different from other unsigned longs in that they contain things like node ID, section number and zone number in the upper bits. That lets us have functions that can be easily called by anyone who has a slab, folio or page (but not easily by anyone else) to get the node or zone. There's going to be some unusual merge problems with this as some odd bits of the kernel decide they want to print out the flags value or something similar by writing page->flags and now they'll need to write page->flags.f instead. That's most of the churn here. Maybe we should be removing these things from the debug output? This patch (of 11): Wrap the unsigned long flags in a typedef. In upcoming patches, this will provide a strong hint that you can't just pass a random unsigned long to functions which take this as an argument. [willy@infradead.org: s/flags/flags.f/ in several architectures] Link: https://lkml.kernel.org/r/aKMgPRLD-WnkPxYm@casper.infradead.org [nicola.vetrini@gmail.com: mips: fix compilation error] Link: https://lore.kernel.org/lkml/CA+G9fYvkpmqGr6wjBNHY=dRp71PLCoi2341JxOudi60yqaeUdg@mail.gmail.com/ Link: https://lkml.kernel.org/r/20250825214245.1838158-1-nicola.vetrini@gmail.com Link: https://lkml.kernel.org/r/20250805172307.1302730-1-willy@infradead.org Link: https://lkml.kernel.org/r/20250805172307.1302730-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Zi Yan Cc: Shakeel Butt Signed-off-by: Andrew Morton

powerpc: remove checks for devmap pages and PMDs/PUDs

2025-07-10T05:42:17Z

PFN_DEV no longer exists. This means no devmap PMDs or PUDs will be created, so checking for them is redundant. Instead mappings of pages that would have previously returned true for pXd_devmap() will return true for pXd_trans_huge() Link: https://lkml.kernel.org/r/31f63cc8dd518f9e2ec300681fe302eb4adf49b4.1750323463.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Jason Gunthorpe Acked-by: David Hildenbrand Cc: Balbir Singh Cc: Björn Töpel Cc: Björn Töpel Cc: Christoph Hellwig Cc: Chunyan Zhang Cc: Dan Williams Cc: Deepak Gupta Cc: Gerald Schaefer Cc: Inki Dae Cc: John Groves Cc: John Hubbard Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Will Deacon Signed-off-by: Andrew Morton

powerpc: assert_pte_locked() use pte_offset_map_ro_nolock()

2024-11-06T00:56:26Z

In assert_pte_locked(), we just get the ptl and assert if it was already held, so convert it to using pte_offset_map_ro_nolock(). Link: https://lkml.kernel.org/r/42559e042eb6fc3129a40f710d671712030646b4.1727332572.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Acked-by: David Hildenbrand Reviewed-by: Muchun Song Cc: Hugh Dickins Cc: Matthew Wilcox Cc: Mike Rapoport (Microsoft) Cc: Peter Xu Cc: Ryan Roberts Cc: Vishal Moola (Oracle) Signed-off-by: Andrew Morton

powerpc/8xx: document and enforce that split PT locks are not used

2024-09-02T03:25:52Z

Right now, we cannot have split PT locks because 8xx does not support SMP. But for the sake of documentation *why* 8xx is fine regarding what we documented in huge_pte_lockptr(), let's just add code to enforce it at the same time as documenting it. This should also make everybody who wants to copy from the 8xx approach of supporting such unusual ways of mapping hugetlb folios aware that it gets tricky once multiple page tables are involved. Link: https://lkml.kernel.org/r/20240726150728.3159964-4-david@redhat.com Signed-off-by: David Hildenbrand Cc: Alexander Viro Cc: Borislav Petkov Cc: Boris Ostrovsky Cc: Christian Brauner Cc: Christophe Leroy Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Juergen Gross Cc: Michael Ellerman Cc: Mike Rapoport (Microsoft) Cc: Muchun Song Cc: "Naveen N. Rao" Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Cc: Russell King Cc: Thomas Gleixner Signed-off-by: Andrew Morton

powerpc/mm: remove hugepd leftovers

2024-07-12T22:52:19Z

All targets have now opted out of CONFIG_ARCH_HAS_HUGEPD so remove left over code. Link: https://lkml.kernel.org/r/39c0d0adee6790fc42cee9f458e05fb95136c3dd.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Acked-by: Oscar Salvador Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc/64s: use contiguous PMD/PUD instead of HUGEPD

2024-07-12T22:52:19Z

On book3s/64, the only user of hugepd is hash in 4k mode. All other setups (hash-64, radix-4, radix-64) use leaf PMD/PUD. Rework hash-4k to use contiguous PMD and PUD instead. In that setup there are only two huge page sizes: 16M and 16G. 16M sits at PMD level and 16G at PUD level. pte_update doesn't know page size, lets use the same trick as hpte_need_flush() to get page size from segment properties. That's not the most efficient way but let's do that until callers of pte_update() provide page size instead of just a huge flag. Link: https://lkml.kernel.org/r/7448f60a9b3efd396595f4f735d1e0babc5ae379.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman (powerpc) Cc: Jason Gunthorpe Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc/e500: use contiguous PMD instead of hugepd

2024-07-12T22:52:18Z

e500 supports many page sizes among which the following size are implemented in the kernel at the time being: 4M, 16M, 64M, 256M, 1G. On e500, TLB miss for hugepages is exclusively handled by SW even on e6500 which has HW assistance for 4k pages, so there are no constraints like on the 8xx. On e500/32, all are at PGD/PMD level and can be handled as cont-PMD. On e500/64, smaller ones are on PMD while bigger ones are on PUD. Again, they can easily be handled as cont-PMD and cont-PUD instead of hugepd. On e500/32, use the pagesize bits in PTE to know if it is a PMD or a leaf entry. This works because the pagesize bits are in the last 12 bits and page tables are 4k aligned. On e500/64, use highest bit which is always 1 on PxD (Because PxD contains virtual address of a kernel memory) and always 0 on PTEs because not all bits of RPN are used/possible. Link: https://lkml.kernel.org/r/dd085987816ed2a0c70adb7e34966cb833fc03e1.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oscar Salvador Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc/8xx: rework support for 8M pages using contiguous PTE entries

2024-07-12T22:52:17Z

In order to fit better with standard Linux page tables layout, add support for 8M pages using contiguous PTE entries in a standard page table. Page tables will then be populated with 1024 similar entries and two PMD entries will point to that page table. The PMD entries also get a flag to tell it is addressing an 8M page, this is required for the HW tablewalk assistance. Link: https://lkml.kernel.org/r/8693d9a0408371043ca63bf9e4a9c140667af63e.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Reviewed-by: Oscar Salvador Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc/mm: allow hugepages without hugepd

2024-07-12T22:52:16Z

In preparation of implementing huge pages on powerpc 8xx without hugepd, enclose hugepd related code inside an ifdef CONFIG_ARCH_HAS_HUGEPD This also allows removing some stubs. Link: https://lkml.kernel.org/r/ada097ca8a4fa85a77f51719516ef2478800d77a.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Reviewed-by: Oscar Salvador Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Xu Signed-off-by: Andrew Morton

powerpc/mm: fix __find_linux_pte() on 32 bits with PMD leaf entries

2024-07-12T22:52:16Z

Building on 32 bits with pmd_leaf() not returning always false leads to the following error: CC arch/powerpc/mm/pgtable.o arch/powerpc/mm/pgtable.c: In function '__find_linux_pte': arch/powerpc/mm/pgtable.c:506:1: error: function may return address of local variable [-Werror=return-local-addr] 506 | } | ^ arch/powerpc/mm/pgtable.c:394:15: note: declared here 394 | pud_t pud, *pudp; | ^~~ arch/powerpc/mm/pgtable.c:394:15: note: declared here This is due to pmd_offset() being a no-op in that case. So rework it for powerpc/32 so that pXd_offset() are used on real pointers and not on on-stack copies. Behind fixing the problem, it also has the advantage of simplifying __find_linux_pte() including the removal of stack frame: After this patch: 00000018 <__find_linux_pte>: 18: 2c 06 00 00 cmpwi r6,0 1c: 41 82 00 0c beq 28 <__find_linux_pte+0x10> 20: 39 20 00 00 li r9,0 24: 91 26 00 00 stw r9,0(r6) 28: 2f 85 00 00 cmpwi cr7,r5,0 2c: 41 9e 00 0c beq cr7,38 <__find_linux_pte+0x20> 30: 39 20 00 00 li r9,0 34: 99 25 00 00 stb r9,0(r5) 38: 54 89 65 3a rlwinm r9,r4,12,20,29 3c: 7c 63 48 2e lwzx r3,r3,r9 40: 2f 83 00 00 cmpwi cr7,r3,0 44: 41 9e 00 30 beq cr7,74 <__find_linux_pte+0x5c> 48: 54 69 07 3a rlwinm r9,r3,0,28,29 4c: 2f 89 00 0c cmpwi cr7,r9,12 50: 54 63 00 26 clrrwi r3,r3,12 54: 54 84 b5 36 rlwinm r4,r4,22,20,27 58: 3c 63 c0 00 addis r3,r3,-16384 5c: 7c 63 22 14 add r3,r3,r4 60: 4c be 00 20 bnelr+ cr7 64: 4d 82 00 20 beqlr 68: 39 20 00 17 li r9,23 6c: 91 26 00 00 stw r9,0(r6) 70: 4e 80 00 20 blr 74: 38 60 00 00 li r3,0 78: 4e 80 00 20 blr Before this patch: 00000018 <__find_linux_pte>: 18: 2c 06 00 00 cmpwi r6,0 1c: 94 21 ff e0 stwu r1,-32(r1) 20: 41 82 00 0c beq 2c <__find_linux_pte+0x14> 24: 39 20 00 00 li r9,0 28: 91 26 00 00 stw r9,0(r6) 2c: 2f 85 00 00 cmpwi cr7,r5,0 30: 41 9e 00 0c beq cr7,3c <__find_linux_pte+0x24> 34: 39 20 00 00 li r9,0 38: 99 25 00 00 stb r9,0(r5) 3c: 54 89 65 3a rlwinm r9,r4,12,20,29 40: 7c 63 48 2e lwzx r3,r3,r9 44: 54 69 07 3a rlwinm r9,r3,0,28,29 48: 2f 89 00 0c cmpwi cr7,r9,12 4c: 90 61 00 0c stw r3,12(r1) 50: 41 9e 00 4c beq cr7,9c <__find_linux_pte+0x84> 54: 80 61 00 0c lwz r3,12(r1) 58: 54 69 07 3a rlwinm r9,r3,0,28,29 5c: 2f 89 00 0c cmpwi cr7,r9,12 60: 90 61 00 08 stw r3,8(r1) 64: 41 9e 00 38 beq cr7,9c <__find_linux_pte+0x84> 68: 80 61 00 08 lwz r3,8(r1) 6c: 2f 83 00 00 cmpwi cr7,r3,0 70: 41 9e 00 54 beq cr7,c4 <__find_linux_pte+0xac> 74: 54 69 07 3a rlwinm r9,r3,0,28,29 78: 2f 89 00 0c cmpwi cr7,r9,12 7c: 54 69 00 26 clrrwi r9,r3,12 80: 54 8a b5 36 rlwinm r10,r4,22,20,27 84: 3c 69 c0 00 addis r3,r9,-16384 88: 7c 63 52 14 add r3,r3,r10 8c: 54 84 93 be srwi r4,r4,14 90: 41 9e 00 14 beq cr7,a4 <__find_linux_pte+0x8c> 94: 38 21 00 20 addi r1,r1,32 98: 4e 80 00 20 blr 9c: 54 69 00 26 clrrwi r9,r3,12 a0: 54 84 93 be srwi r4,r4,14 a4: 3c 69 c0 00 addis r3,r9,-16384 a8: 54 84 25 36 rlwinm r4,r4,4,20,27 ac: 7c 63 22 14 add r3,r3,r4 b0: 41 a2 ff e4 beq 94 <__find_linux_pte+0x7c> b4: 39 20 00 17 li r9,23 b8: 91 26 00 00 stw r9,0(r6) bc: 38 21 00 20 addi r1,r1,32 c0: 4e 80 00 20 blr c4: 38 60 00 00 li r3,0 c8: 38 21 00 20 addi r1,r1,32 cc: 4e 80 00 20 blr Link: https://lkml.kernel.org/r/50a3cfbab5b11890a0da027de5cb011a9d47ba89.1719928057.git.christophe.leroy@csgroup.eu Signed-off-by: Christophe Leroy Reviewed-by: Oscar Salvador Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Peter Xu Signed-off-by: Andrew Morton