From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B47F1CF96 for ; Fri, 12 Jul 2024 22:54:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720824871; cv=none; b=IH83AdkJUYxQe+KXOIAPwxuIF3UgUGuOvE9v+I6ORUe522HBLJX8DoUo44WNZxSVrcKtgN73q8CG8Cv9sYBeEh1XStwYkBTV4H5zVnpUfRur/N4gwyYjOGVkgvzmewIeMnsASunWoEr0PU0Jky0UiEFxVQlMfzyHAQDtCCmChLg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720824871; c=relaxed/simple; bh=R7aW8s3aHYCq2PMaPxhMHKjxr1n/TuL5Nk/2wubSEnM=; h=Date:To:From:Subject:Message-Id; b=Ssj2IHp6q52Swc5QYUFaEeszgwBVJgI/BXZgRJJxHEz3Tquiq59aDNZ9hTF60j/EDG/NwDufYnPN8REtmOge5q64oyHIm63BTe/89GhcLn5xk9tq90pdTqBsCLkDXI2DQIxz4MStbBpMpD//+amHgUWUMxXjqHMbbaw5EZXOqR0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=zxpWygvg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="zxpWygvg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95531C32782; Fri, 12 Jul 2024 22:54:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1720824870; bh=R7aW8s3aHYCq2PMaPxhMHKjxr1n/TuL5Nk/2wubSEnM=; h=Date:To:From:Subject:From; b=zxpWygvgOSDVlQKYuThHIOknin5f60D+Bvh8AZf8XdEhw9U2f5aGTHotNy3MvVpj0 t/7H/06U3gnFrnj+FHff2XuBKq81EjX5SDKLAZr6LO8k85dFRM7f4y8gwEmTn+TDyR Zl7UFRoORaYVDDDtYUhZHikPsmcTJ98B5GPjAEsk= Date: Fri, 12 Jul 2024 15:54:30 -0700 To: mm-commits@vger.kernel.org,peterx@redhat.com,osalvador@suse.de,npiggin@gmail.com,mpe@ellerman.id.au,jgg@nvidia.com,christophe.leroy@csgroup.eu,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] powerpc-mm-fix-__find_linux_pte-on-32-bits-with-pmd-leaf-entries.patch removed from -mm tree Message-Id: <20240712225430.95531C32782@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: powerpc/mm: fix __find_linux_pte() on 32 bits with PMD leaf entries has been removed from the -mm tree. Its filename was powerpc-mm-fix-__find_linux_pte-on-32-bits-with-pmd-leaf-entries.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Christophe Leroy Subject: powerpc/mm: fix __find_linux_pte() on 32 bits with PMD leaf entries Date: Tue, 2 Jul 2024 15:51:22 +0200 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 --- arch/powerpc/mm/pgtable.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/arch/powerpc/mm/pgtable.c~powerpc-mm-fix-__find_linux_pte-on-32-bits-with-pmd-leaf-entries +++ a/arch/powerpc/mm/pgtable.c @@ -382,8 +382,10 @@ pte_t *__find_linux_pte(pgd_t *pgdir, un bool *is_thp, unsigned *hpage_shift) { pgd_t *pgdp; +#ifdef CONFIG_PPC64 p4d_t p4d, *p4dp; pud_t pud, *pudp; +#endif pmd_t pmd, *pmdp; pte_t *ret_pte; hugepd_t *hpdp = NULL; @@ -401,8 +403,12 @@ pte_t *__find_linux_pte(pgd_t *pgdir, un * page fault or a page unmap. The return pte_t * is still not * stable. So should be checked there for above conditions. * Top level is an exception because it is folded into p4d. + * + * On PPC32, P4D/PUD/PMD are folded into PGD so go straight to + * PMD level. */ pgdp = pgdir + pgd_index(ea); +#ifdef CONFIG_PPC64 p4dp = p4d_offset(pgdp, ea); p4d = READ_ONCE(*p4dp); pdshift = P4D_SHIFT; @@ -442,8 +448,11 @@ pte_t *__find_linux_pte(pgd_t *pgdir, un goto out_huge; } - pdshift = PMD_SHIFT; pmdp = pmd_offset(&pud, ea); +#else + pmdp = pmd_offset(pud_offset(p4d_offset(pgdp, ea), ea), ea); +#endif + pdshift = PMD_SHIFT; pmd = READ_ONCE(*pmdp); /* _ Patches currently in -mm which might be from christophe.leroy@csgroup.eu are