From 51b646b2d9f84d6ff6300e3c1d09f2be4329a424 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 9 Oct 2020 11:09:27 +0200 Subject: perf,mm: Handle non-page-table-aligned hugetlbfs A limited nunmber of architectures support hugetlbfs sizes that do not align with the page-tables (ARM64, Power, Sparc64). Add support for this to the generic perf_get_page_size() implementation, and also allow an architecture to override this implementation. This latter is only needed when it uses non-page-table aligned huge pages in its kernel map. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/perf_event.h | 4 ++++ kernel/events/core.c | 39 +++++++++++++++++++++++++++++++++------ 2 files changed, 37 insertions(+), 6 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index e533b03af053..0defb526cd0c 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1590,4 +1590,8 @@ extern void __weak arch_perf_update_userpage(struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now); +#ifdef CONFIG_MMU +extern __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr); +#endif + #endif /* _LINUX_PERF_EVENT_H */ diff --git a/kernel/events/core.c b/kernel/events/core.c index 7f655d19b8c4..b458ed3dc81b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7011,10 +7011,18 @@ static u64 perf_virt_to_phys(u64 virt) #ifdef CONFIG_MMU /* - * Return the MMU page size of a given virtual address + * Return the MMU page size of a given virtual address. + * + * This generic implementation handles page-table aligned huge pages, as well + * as non-page-table aligned hugetlbfs compound pages. + * + * If an architecture supports and uses non-page-table aligned pages in their + * kernel mapping it will need to provide it's own implementation of this + * function. */ -static u64 __perf_get_page_size(struct mm_struct *mm, unsigned long addr) +__weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr) { + struct page *page; pgd_t *pgd; p4d_t *p4d; pud_t *pud; @@ -7036,15 +7044,27 @@ static u64 __perf_get_page_size(struct mm_struct *mm, unsigned long addr) if (!pud_present(*pud)) return 0; - if (pud_leaf(*pud)) + if (pud_leaf(*pud)) { +#ifdef pud_page + page = pud_page(*pud); + if (PageHuge(page)) + return page_size(compound_head(page)); +#endif return 1ULL << PUD_SHIFT; + } pmd = pmd_offset(pud, addr); if (!pmd_present(*pmd)) return 0; - if (pmd_leaf(*pmd)) + if (pmd_leaf(*pmd)) { +#ifdef pmd_page + page = pmd_page(*pmd); + if (PageHuge(page)) + return page_size(compound_head(page)); +#endif return 1ULL << PMD_SHIFT; + } pte = pte_offset_map(pmd, addr); if (!pte_present(*pte)) { @@ -7052,13 +7072,20 @@ static u64 __perf_get_page_size(struct mm_struct *mm, unsigned long addr) return 0; } + page = pte_page(*pte); + if (PageHuge(page)) { + u64 size = page_size(compound_head(page)); + pte_unmap(pte); + return size; + } + pte_unmap(pte); return PAGE_SIZE; } #else -static u64 __perf_get_page_size(struct mm_struct *mm, unsigned long addr) +static u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr) { return 0; } @@ -7089,7 +7116,7 @@ static u64 perf_get_page_size(unsigned long addr) mm = &init_mm; } - size = __perf_get_page_size(mm, addr); + size = arch_perf_get_page_size(mm, addr); local_irq_restore(flags); -- cgit v1.2.3