From 1e03c7e2ea83b0acac7934e55943d1d4354baa43 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 29 Nov 2018 14:07:07 +0000 Subject: [PATCH] powerpc/mm: fix a warning when a cache is common to PGD and hugepages While implementing TLB miss HW assistance on the 8xx, the following warning was encountered: [ 423.732965] WARNING: CPU: 0 PID: 345 at mm/slub.c:2412 ___slab_alloc.constprop.30+0x26c/0x46c [ 423.733033] CPU: 0 PID: 345 Comm: mmap Not tainted 4.18.0-rc8-00664-g2dfff9121c55 #671 [ 423.733075] NIP: c0108f90 LR: c0109ad0 CTR: 00000004 [ 423.733121] REGS: c455bba0 TRAP: 0700 Not tainted (4.18.0-rc8-00664-g2dfff9121c55) [ 423.733147] MSR: 00021032 CR: 24224848 XER: 20000000 [ 423.733319] [ 423.733319] GPR00: c0109ad0 c455bc50 c4521910 c60053c0 007080c0 c0011b34 c7fa41e0 c455be30 [ 423.733319] GPR08: 00000001 c00103a0 c7fa41e0 c49afcc4 24282842 10018840 c079b37c 00000040 [ 423.733319] GPR16: 73f00000 00210d00 00000000 00000001 c455a000 00000100 00000200 c455a000 [ 423.733319] GPR24: c60053c0 c0011b34 007080c0 c455a000 c455a000 c7fa41e0 00000000 00009032 [ 423.734190] NIP [c0108f90] ___slab_alloc.constprop.30+0x26c/0x46c [ 423.734257] LR [c0109ad0] kmem_cache_alloc+0x210/0x23c [ 423.734283] Call Trace: [ 423.734326] [c455bc50] [00000100] 0x100 (unreliable) [ 423.734430] [c455bcc0] [c0109ad0] kmem_cache_alloc+0x210/0x23c [ 423.734543] [c455bcf0] [c0011b34] huge_pte_alloc+0xc0/0x1dc [ 423.734633] [c455bd20] [c01044dc] hugetlb_fault+0x408/0x48c [ 423.734720] [c455bdb0] [c0104b20] follow_hugetlb_page+0x14c/0x44c [ 423.734826] [c455be10] [c00e8e54] __get_user_pages+0x1c4/0x3dc [ 423.734919] [c455be80] [c00e9924] __mm_populate+0xac/0x140 [ 423.735020] [c455bec0] [c00db14c] vm_mmap_pgoff+0xb4/0xb8 [ 423.735127] [c455bf00] [c00f27c0] ksys_mmap_pgoff+0xcc/0x1fc [ 423.735222] [c455bf40] [c000e0f8] ret_from_syscall+0x0/0x38 [ 423.735271] Instruction dump: [ 423.735321] 7cbf482e 38fd0008 7fa6eb78 7fc4f378 4bfff5dd 7fe3fb78 4bfffe24 81370010 [ 423.735536] 71280004 41a2ff88 4840c571 4bffff80 <0fe00000> 4bfffeb8 81340010 712a0004 [ 423.735757] ---[ end trace e9b222919a470790 ]--- This warning occurs when calling kmem_cache_zalloc() on a cache having a constructor. In this case it happens because PGD cache and 512k hugepte cache are the same size (4k). While a cache with constructor is created for the PGD, hugepages create cache without constructor and uses kmem_cache_zalloc(). As both expect a cache with the same size, the hugepages reuse the cache created for PGD, hence the conflict. In order to avoid this conflict, this patch: - modifies pgtable_cache_add() so that a zeroising constructor is added for any cache size. - replaces calls to kmem_cache_zalloc() by kmem_cache_alloc() Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/pgtable.h | 2 +- arch/powerpc/mm/hugetlbpage.c | 6 ++-- arch/powerpc/mm/init-common.c | 46 +++++++++++++++++++++--------- 3 files changed, 36 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index 56ef5437eb2f..f2bfaf674674 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -101,7 +101,7 @@ extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, /* can we use this in kvm */ unsigned long vmalloc_to_phys(void *vmalloc_addr); -void pgtable_cache_add(unsigned shift, void (*ctor)(void *)); +void pgtable_cache_add(unsigned int shift); void pgtable_cache_init(void); #if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_PPC32) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index c4f1263228b8..bc97874d7c74 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -70,7 +70,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, num_hugepd = 1; } - new = kmem_cache_zalloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL)); + new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL)); BUG_ON(pshift > HUGEPD_SHIFT_MASK); BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK); @@ -701,10 +701,10 @@ static int __init hugetlbpage_init(void) * use pgt cache for hugepd. */ if (pdshift > shift) - pgtable_cache_add(pdshift - shift, NULL); + pgtable_cache_add(pdshift - shift); #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx) else - pgtable_cache_add(PTE_T_ORDER, NULL); + pgtable_cache_add(PTE_T_ORDER); #endif } diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c index 41190f2b60c2..b7ca03643d0b 100644 --- a/arch/powerpc/mm/init-common.c +++ b/arch/powerpc/mm/init-common.c @@ -25,19 +25,37 @@ #include #include -static void pgd_ctor(void *addr) -{ - memset(addr, 0, PGD_TABLE_SIZE); +#define CTOR(shift) static void ctor_##shift(void *addr) \ +{ \ + memset(addr, 0, sizeof(void *) << (shift)); \ } -static void pud_ctor(void *addr) -{ - memset(addr, 0, PUD_TABLE_SIZE); -} +CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7); +CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15); -static void pmd_ctor(void *addr) +static inline void (*ctor(int shift))(void *) { - memset(addr, 0, PMD_TABLE_SIZE); + BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15); + + switch (shift) { + case 0: return ctor_0; + case 1: return ctor_1; + case 2: return ctor_2; + case 3: return ctor_3; + case 4: return ctor_4; + case 5: return ctor_5; + case 6: return ctor_6; + case 7: return ctor_7; + case 8: return ctor_8; + case 9: return ctor_9; + case 10: return ctor_10; + case 11: return ctor_11; + case 12: return ctor_12; + case 13: return ctor_13; + case 14: return ctor_14; + case 15: return ctor_15; + } + return NULL; } struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1]; @@ -50,7 +68,7 @@ EXPORT_SYMBOL_GPL(pgtable_cache); /* used by kvm_hv module */ * everything else. Caches created by this function are used for all * the higher level pagetables, and for hugepage pagetables. */ -void pgtable_cache_add(unsigned shift, void (*ctor)(void *)) +void pgtable_cache_add(unsigned int shift) { char *name; unsigned long table_size = sizeof(void *) << shift; @@ -78,7 +96,7 @@ void pgtable_cache_add(unsigned shift, void (*ctor)(void *)) align = max_t(unsigned long, align, minalign); name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift); - new = kmem_cache_create(name, table_size, align, 0, ctor); + new = kmem_cache_create(name, table_size, align, 0, ctor(shift)); if (!new) panic("Could not allocate pgtable cache for order %d", shift); @@ -91,15 +109,15 @@ EXPORT_SYMBOL_GPL(pgtable_cache_add); /* used by kvm_hv module */ void pgtable_cache_init(void) { - pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor); + pgtable_cache_add(PGD_INDEX_SIZE); if (PMD_CACHE_INDEX && !PGT_CACHE(PMD_CACHE_INDEX)) - pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor); + pgtable_cache_add(PMD_CACHE_INDEX); /* * In all current configs, when the PUD index exists it's the * same size as either the pgd or pmd index except with THP enabled * on book3s 64 */ if (PUD_CACHE_INDEX && !PGT_CACHE(PUD_CACHE_INDEX)) - pgtable_cache_add(PUD_CACHE_INDEX, pud_ctor); + pgtable_cache_add(PUD_CACHE_INDEX); } -- 2.30.2