cregit-Linux how code gets into the kernel

Release 4.14 arch/powerpc/mm/hugetlbpage.c

Directory: arch/powerpc/mm
/*
 * PPC Huge TLB Page Support for Kernel.
 *
 * Copyright (C) 2003 David Gibson, IBM Corporation.
 * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
 *
 * Based on the IA-32 version:
 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
 */

#include <linux/mm.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <linux/export.h>
#include <linux/of_fdt.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>
#include <linux/moduleparam.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/hugetlb.h>
#include <asm/pte-walk.h>


#ifdef CONFIG_HUGETLB_PAGE


#define PAGE_SHIFT_64K	16

#define PAGE_SHIFT_512K	19

#define PAGE_SHIFT_8M	23

#define PAGE_SHIFT_16M	24

#define PAGE_SHIFT_16G	34


unsigned int HPAGE_SHIFT;

EXPORT_SYMBOL(HPAGE_SHIFT);


#define hugepd_none(hpd)	(hpd_val(hpd) == 0)


pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz) { /* * Only called for hugetlbfs pages, hence can ignore THP and the * irq disabled walk. */ return __find_linux_pte(mm->pgd, addr, NULL, NULL); }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V2882.35%350.00%
Punit Agrawal411.76%116.67%
David Gibson25.88%233.33%
Total34100.00%6100.00%


static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, unsigned long address, unsigned pdshift, unsigned pshift) { struct kmem_cache *cachep; pte_t *new; int i; int num_hugepd; if (pshift >= pdshift) { cachep = hugepte_cache; num_hugepd = 1 << (pshift - pdshift); } else { cachep = PGT_CACHE(pdshift - pshift); num_hugepd = 1; } new = kmem_cache_zalloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL)); BUG_ON(pshift > HUGEPD_SHIFT_MASK); BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK); if (! new) return -ENOMEM; /* * Make sure other cpus find the hugepd set only after a * properly initialized page table is visible to them. * For more details look for comment in __pte_alloc(). */ smp_wmb(); spin_lock(&mm->page_table_lock); /* * We have multiple higher-level entries that point to the same * actual pte location. Fill in each as we go and backtrack on error. * We need all of these so the DTLB pgtable walk code can find the * right higher-level entry without knowing if it's a hugepage or not. */ for (i = 0; i < num_hugepd; i++, hpdp++) { if (unlikely(!hugepd_none(*hpdp))) break; else { #ifdef CONFIG_PPC_BOOK3S_64 *hpdp = __hugepd(__pa(new) | (shift_to_mmu_psize(pshift) << 2)); #elif defined(CONFIG_PPC_8xx) *hpdp = __hugepd(__pa(new) | (pshift == PAGE_SHIFT_8M ? _PMD_PAGE_8M : _PMD_PAGE_512K) | _PMD_PRESENT); #else /* We use the old format for PPC_FSL_BOOK3E */ *hpdp = __hugepd(((unsigned long)new & ~PD_HUGE) | pshift); #endif } } /* If we bailed from the for loop early, an error occurred, clean up */ if (i < num_hugepd) { for (i = i - 1 ; i >= 0; i--, hpdp--) *hpdp = __hugepd(0); kmem_cache_free(cachep, new); } spin_unlock(&mm->page_table_lock); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V17960.68%327.27%
Christophe Leroy7023.73%218.18%
David Gibson3511.86%327.27%
Balbir Singh51.69%19.09%
Sukadev Bhattiprolu41.36%19.09%
Jon Tollefson20.68%19.09%
Total295100.00%11100.00%

/* * These macros define how to determine which level of the page table holds * the hpdp. */ #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx) #define HUGEPD_PGD_SHIFT PGDIR_SHIFT #define HUGEPD_PUD_SHIFT PUD_SHIFT #else #define HUGEPD_PGD_SHIFT PUD_SHIFT #define HUGEPD_PUD_SHIFT PMD_SHIFT #endif /* * At this point we do the placement change only for BOOK3S 64. This would * possibly work on other subarchs. */
pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) { pgd_t *pg; pud_t *pu; pmd_t *pm; hugepd_t *hpdp = NULL; unsigned pshift = __ffs(sz); unsigned pdshift = PGDIR_SHIFT; addr &= ~(sz-1); pg = pgd_offset(mm, addr); #ifdef CONFIG_PPC_BOOK3S_64 if (pshift == PGDIR_SHIFT) /* 16GB huge page */ return (pte_t *) pg; else if (pshift > PUD_SHIFT) /* * We need to use hugepd table */ hpdp = (hugepd_t *)pg; else { pdshift = PUD_SHIFT; pu = pud_alloc(mm, pg, addr); if (pshift == PUD_SHIFT) return (pte_t *)pu; else if (pshift > PMD_SHIFT) hpdp = (hugepd_t *)pu; else { pdshift = PMD_SHIFT; pm = pmd_alloc(mm, pu, addr); if (pshift == PMD_SHIFT) /* 16MB hugepage */ return (pte_t *)pm; else hpdp = (hugepd_t *)pm; } } #else if (pshift >= HUGEPD_PGD_SHIFT) { hpdp = (hugepd_t *)pg; } else { pdshift = PUD_SHIFT; pu = pud_alloc(mm, pg, addr); if (pshift >= HUGEPD_PUD_SHIFT) { hpdp = (hugepd_t *)pu; } else { pdshift = PMD_SHIFT; pm = pmd_alloc(mm, pu, addr); hpdp = (hugepd_t *)pm; } } #endif if (!hpdp) return NULL; BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp)); if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift)) return NULL; return hugepte_offset(*hpdp, addr, pdshift); }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson14243.29%428.57%
Aneesh Kumar K.V13842.07%321.43%
Becky Bruce267.93%321.43%
Jon Tollefson175.18%321.43%
Christophe Leroy51.52%17.14%
Total328100.00%14100.00%

#ifdef CONFIG_PPC_BOOK3S_64 /* * Tracks gpages after the device tree is scanned and before the * huge_boot_pages list is ready on pseries. */ #define MAX_NUMBER_GPAGES 1024 __initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES]; __initdata static unsigned nr_gpages; /* * Build list of addresses of gigantic pages. This function is used in early * boot before the buddy allocator is setup. */
void __init pseries_add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages) { if (!addr) return; while (number_of_pages > 0) { gpage_freearray[nr_gpages] = addr; nr_gpages++; number_of_pages--; addr += page_size; } }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson2451.06%125.00%
Aneesh Kumar K.V1429.79%125.00%
Kenneth W. Chen714.89%125.00%
Becky Bruce24.26%125.00%
Total47100.00%4100.00%


int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate) { struct huge_bootmem_page *m; if (nr_gpages == 0) return 0; m = phys_to_virt(gpage_freearray[--nr_gpages]); gpage_freearray[nr_gpages] = 0; list_add(&m->list, &huge_boot_pages); m->hstate = hstate; return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Becky Bruce5282.54%125.00%
Aneesh Kumar K.V69.52%125.00%
David Gibson57.94%250.00%
Total63100.00%4100.00%

#endif
int __init alloc_bootmem_huge_page(struct hstate *h) { #ifdef CONFIG_PPC_BOOK3S_64 if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled()) return pseries_alloc_bootmem_huge_page(h); #endif return __alloc_bootmem_huge_page(h); }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V2153.85%150.00%
Becky Bruce1846.15%150.00%
Total39100.00%2100.00%

#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx) #define HUGEPD_FREELIST_SIZE \ ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t)) struct hugepd_freelist { struct rcu_head rcu; unsigned int index; void *ptes[0]; }; static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
static void hugepd_free_rcu_callback(struct rcu_head *head) { struct hugepd_freelist *batch = container_of(head, struct hugepd_freelist, rcu); unsigned int i; for (i = 0; i < batch->index; i++) kmem_cache_free(hugepte_cache, batch->ptes[i]); free_page((unsigned long)batch); }

Contributors

PersonTokensPropCommitsCommitProp
Becky Bruce66100.00%1100.00%
Total66100.00%1100.00%


static void hugepd_free(struct mmu_gather *tlb, void *hugepte) { struct hugepd_freelist **batchp; batchp = &get_cpu_var(hugepd_freelist_cur); if (atomic_read(&tlb->mm->mm_users) < 2 || mm_is_thread_local(tlb->mm)) { kmem_cache_free(hugepte_cache, hugepte); put_cpu_var(hugepd_freelist_cur); return; } if (*batchp == NULL) { *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC); (*batchp)->index = 0; } (*batchp)->ptes[(*batchp)->index++] = hugepte; if ((*batchp)->index == HUGEPD_FREELIST_SIZE) { call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback); *batchp = NULL; } put_cpu_var(hugepd_freelist_cur); }

Contributors

PersonTokensPropCommitsCommitProp
Becky Bruce10972.67%116.67%
David Gibson2718.00%116.67%
Tiejun Chen106.67%116.67%
Sebastian Andrzej Siewior21.33%116.67%
Christoph Lameter10.67%116.67%
Benjamin Herrenschmidt10.67%116.67%
Total150100.00%6100.00%

#else
static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}

Contributors

PersonTokensPropCommitsCommitProp
Christophe Leroy15100.00%1100.00%
Total15100.00%1100.00%

#endif
static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift, unsigned long start, unsigned long end, unsigned long floor, unsigned long ceiling) { pte_t *hugepte = hugepd_page(*hpdp); int i; unsigned long pdmask = ~((1UL << pdshift) - 1); unsigned int num_hugepd = 1; unsigned int shift = hugepd_shift(*hpdp); /* Note: On fsl the hpdp may be the first of several */ if (shift > pdshift) num_hugepd = 1 << (shift - pdshift); start &= pdmask; if (start < floor) return; if (ceiling) { ceiling &= pdmask; if (! ceiling) return; } if (end - 1 > ceiling - 1) return; for (i = 0; i < num_hugepd; i++, hpdp++) *hpdp = __hugepd(0); if (shift >= pdshift) hugepd_free(tlb, hugepte); else pgtable_free_tlb(tlb, hugepte, pdshift - shift); }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson10658.24%228.57%
Becky Bruce4625.27%228.57%
Christophe Leroy2413.19%114.29%
Aneesh Kumar K.V42.20%114.29%
Jon Tollefson21.10%114.29%
Total182100.00%7100.00%


static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling) { pmd_t *pmd; unsigned long next; unsigned long start; start = addr; do { unsigned long more; pmd = pmd_offset(pud, addr); next = pmd_addr_end(addr, end); if (!is_hugepd(__hugepd(pmd_val(*pmd)))) { /* * if it is not hugepd pointer, we should already find * it cleared. */ WARN_ON(!pmd_none_or_clear_bad(pmd)); continue; } /* * Increment next by the size of the huge mapping since * there may be more than one entry at this level for a * single hugepage, but all of them point to * the same kmem cache that holds the hugepte. */ more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd)); if (more > next) next = more; free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT, addr, next, floor, ceiling); } while (addr = next, addr != end); start &= PUD_MASK; if (start < floor) return; if (ceiling) { ceiling &= PUD_MASK; if (!ceiling) return; } if (end - 1 > ceiling - 1) return; pmd = pmd_offset(pud, start); pud_clear(pud); pmd_free_tlb(tlb, pmd, start); mm_dec_nr_pmds(tlb->mm); }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson16371.18%222.22%
Aneesh Kumar K.V219.17%222.22%
Becky Bruce208.73%111.11%
Christophe Leroy156.55%111.11%
Scott Wood73.06%111.11%
Benjamin Herrenschmidt20.87%111.11%
Jon Tollefson10.44%111.11%
Total229100.00%9100.00%


static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling) { pud_t *pud; unsigned long next; unsigned long start; start = addr; do { pud = pud_offset(pgd, addr); next = pud_addr_end(addr, end); if (!is_hugepd(__hugepd(pud_val(*pud)))) { if (pud_none_or_clear_bad(pud)) continue; hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling); } else { unsigned long more; /* * Increment next by the size of the huge mapping since * there may be more than one entry at this level for a * single hugepage, but all of them point to * the same kmem cache that holds the hugepte. */ more = addr + (1 << hugepd_shift(*(hugepd_t *)pud)); if (more > next) next = more; free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT, addr, next, floor, ceiling); } } while (addr = next, addr != end); start &= PGDIR_MASK; if (start < floor) return; if (ceiling) { ceiling &= PGDIR_MASK; if (!ceiling) return; } if (end - 1 > ceiling - 1) return; pud = pud_offset(pgd, start); pgd_clear(pgd); pud_free_tlb(tlb, pud, start); }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson16368.78%225.00%
Jon Tollefson3012.66%225.00%
Becky Bruce208.44%112.50%
Christophe Leroy156.33%112.50%
Aneesh Kumar K.V72.95%112.50%
Benjamin Herrenschmidt20.84%112.50%
Total237100.00%8100.00%

/* * This function frees user-level page tables of a process. */
void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling) { pgd_t *pgd; unsigned long next; /* * Because there are a number of different possible pagetable * layouts for hugepage ranges, we limit knowledge of how * things should be laid out to the allocation path * (huge_pte_alloc(), above). Everything else works out the * structure as it goes from information in the hugepd * pointers. That means that we can't here use the * optimization used in the normal page free_pgd_range(), of * checking whether we're actually covering a large enough * range to have to do anything at the top level of the walk * instead of at the bottom. * * To make sense of this, you should probably go read the big * block comment at the top of the normal free_pgd_range(), * too. */ do { next = pgd_addr_end(addr, end); pgd = pgd_offset(tlb->mm, addr); if (!is_hugepd(__hugepd(pgd_val(*pgd)))) { if (pgd_none_or_clear_bad(pgd)) continue; hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling); } else { unsigned long more; /* * Increment next by the size of the huge mapping since * there may be more than one entry at the pgd level * for a single hugepage, but all of them point to the * same kmem cache that holds the hugepte. */ more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd)); if (more > next) next = more; free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT, addr, next, floor, ceiling); } } while (addr = next, addr != end); }

Contributors

PersonTokensPropCommitsCommitProp
David Gibson9959.64%545.45%
Becky Bruce2917.47%218.18%
Christophe Leroy159.04%19.09%
Anton Blanchard127.23%19.09%
Aneesh Kumar K.V74.22%19.09%
Benjamin Herrenschmidt42.41%19.09%
Total166100.00%11100.00%


struct page *follow_huge_pd(struct vm_area_struct *vma, unsigned long address, hugepd_t hpd, int flags, int pdshift) { pte_t *ptep; spinlock_t *ptl; struct page *page = NULL; unsigned long mask; int shift = hugepd_shift(hpd); struct mm_struct *mm = vma->vm_mm; retry: ptl = &mm->page_table_lock; spin_lock(ptl); ptep = hugepte_offset(hpd, address, pdshift); if (pte_present(*ptep)) { mask = (1UL << shift) - 1; page = pte_page(*ptep); page += ((address & mask) >> PAGE_SHIFT); if (flags & FOLL_GET) get_page(page); } else { if (is_hugetlb_entry_migration(*ptep)) { spin_unlock(ptl); __migration_entry_wait(mm, ptep, ptl); goto retry; } } spin_unlock(ptl); return page; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V175100.00%1100.00%
Total175100.00%1100.00%


static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, unsigned long sz) { unsigned long __boundary = (addr + sz) & ~(sz-1); return (__boundary - 1 < end - 1) ? __boundary : end; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V4690.20%150.00%
David Gibson59.80%150.00%
Total51100.00%2100.00%


int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift, unsigned long end, int write, struct page **pages, int *nr) { pte_t *ptep; unsigned long sz = 1UL << hugepd_shift(hugepd); unsigned long next; ptep = hugepte_offset(hugepd, addr, pdshift); do { next = hugepte_addr_end(addr, end, sz); if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr)) return 0; } while (ptep++, addr = next, addr != end); return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V6455.17%240.00%
David Gibson4942.24%120.00%
Andi Kleen21.72%120.00%
Andrea Arcangeli10.86%120.00%
Total116100.00%5100.00%

#ifdef CONFIG_PPC_MM_SLICES
unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct hstate *hstate = hstate_file(file); int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate)); if (radix_enabled()) return radix__hugetlb_get_unmapped_area(file, addr, len, pgoff, flags); return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1); }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V5466.67%250.00%
David Gibson2733.33%250.00%
Total81100.00%4100.00%

#endif
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) { #ifdef CONFIG_PPC_MM_SLICES unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start); /* With radix we don't use slice, so derive it from vma*/ if (!radix_enabled()) return 1UL << mmu_psize_to_shift(psize); #endif if (!is_vm_hugetlb_page(vma)) return PAGE_SIZE; return huge_page_size(hstate_vma(vma)); }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V3857.58%233.33%
David Gibson2537.88%350.00%
Andrew Morton34.55%116.67%
Total66100.00%6100.00%


static inline bool is_power_of_4(unsigned long x) { if (is_power_of_2(x)) return (__ilog2(x) % 2) ? false : true; return false; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V1954.29%114.29%
David Gibson411.43%228.57%
Benjamin Herrenschmidt411.43%114.29%
Andrea Arcangeli38.57%114.29%
Andrew Morton38.57%114.29%
Jon Tollefson25.71%114.29%
Total35100.00%7100.00%


static int __init add_huge_page_size(unsigned long long size) { int shift = __ffs(size); int mmu_psize; /* Check that it is a page size supported by the hardware and * that it fits within pagetable and slice limits. */ if (size <= PAGE_SIZE) return -EINVAL; #if defined(CONFIG_PPC_FSL_BOOK3E) if (!is_power_of_4(size)) return -EINVAL; #elif !defined(CONFIG_PPC_8xx) if (!is_power_of_2(size) || (shift > SLICE_HIGH_SHIFT)) return -EINVAL; #endif if ((mmu_psize = shift_to_mmu_psize(shift)) < 0) return -EINVAL; #ifdef CONFIG_PPC_BOOK3S_64 /* * We need to make sure that for different page sizes reported by * firmware we only add hugetlb support for page sizes that can be * supported by linux page table layout. * For now we have * Radix: 2M * Hash: 16M and 16G */ if (radix_enabled()) { if (mmu_psize != MMU_PAGE_2M) { if (cpu_has_feature(CPU_FTR_POWER9_DD1) || (mmu_psize != MMU_PAGE_1G)) return -EINVAL; } } else { if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G) return -EINVAL; } #endif BUG_ON(mmu_psize_defs[mmu_psize].shift != shift); /* Return if huge page size has already been setup */ if (size_to_hstate(size)) return 0; hugetlb_add_hstate(shift - PAGE_SHIFT); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V13070.65%337.50%
Christophe Leroy2211.96%225.00%
Mel Gorman126.52%112.50%
David Gibson105.43%112.50%
Becky Bruce105.43%112.50%
Total184100.00%8100.00%


static int __init hugepage_setup_sz(char *str) { unsigned long long size; size = memparse(str, &str); if (add_huge_page_size(size) != 0) { hugetlb_bad_size(); pr_err("Invalid huge page size specified(%llu)\n", size); } return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Aneesh Kumar K.V3876.00%120.00%
Vaishali Thakkar612.00%120.00%
David Gibson48.00%240.00%
Becky Bruce24.00%120.00%
Total50100.00%5100.00%

__setup("hugepagesz=", hugepage_setup_sz); struct kmem_cache *hugepte_cache;
static int __init hugetlbpage_init(void) { int psize; #if !defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_PPC_8xx) if (!radix_enabled() && !mmu_has_feature(MMU_FTR_16M_PAGE)) return -ENODEV; #endif for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { unsigned shift; unsigned pdshift; if (!mmu_psize_defs[psize].