From 83863f25e4b8214e994ef8b5647aad614d74b45d Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Fri, 5 Feb 2016 16:24:47 -0800 Subject: [PATCH] arm64: Add support for ARCH_SUPPORTS_DEBUG_PAGEALLOC ARCH_SUPPORTS_DEBUG_PAGEALLOC provides a hook to map and unmap pages for debugging purposes. This requires memory be mapped with PAGE_SIZE mappings since breaking down larger mappings at runtime will lead to TLB conflicts. Check if debug_pagealloc is enabled at runtime and if so, map everyting with PAGE_SIZE pages. Implement the functions to actually map/unmap the pages at runtime. Reviewed-by: Ard Biesheuvel Reviewed-by: Mark Rutland Tested-by: Mark Rutland Signed-off-by: Laura Abbott [catalin.marinas@arm.com: static annotation block_mappings_allowed() and #ifdef] Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 3 +++ arch/arm64/mm/mmu.c | 26 +++++++++++++++++++++-- arch/arm64/mm/pageattr.c | 46 +++++++++++++++++++++++++++++++--------- 3 files changed, 63 insertions(+), 12 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 53e48a617fef..5a1f2e47d153 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -537,6 +537,9 @@ config HOTPLUG_CPU source kernel/Kconfig.preempt source kernel/Kconfig.hz +config ARCH_SUPPORTS_DEBUG_PAGEALLOC + def_bool y + config ARCH_HAS_HOLES_MEMORYMODEL def_bool y if SPARSEMEM diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ef0d66cf5535..a6f28e5b9585 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -149,6 +149,26 @@ static void split_pud(pud_t *old_pud, pmd_t *pmd) } while (pmd++, i++, i < PTRS_PER_PMD); } +#ifdef CONFIG_DEBUG_PAGEALLOC +static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void)) +{ + + /* + * If debug_page_alloc is enabled we must map the linear map + * using pages. However, other mappings created by + * create_mapping_noalloc must use sections in some cases. Allow + * sections to be used in those cases, where no pgtable_alloc + * function is provided. + */ + return !pgtable_alloc || !debug_pagealloc_enabled(); +} +#else +static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void)) +{ + return true; +} +#endif + static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end, phys_addr_t phys, pgprot_t prot, phys_addr_t (*pgtable_alloc)(void)) @@ -181,7 +201,8 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end, do { next = pmd_addr_end(addr, end); /* try section mapping first */ - if (((addr | next | phys) & ~SECTION_MASK) == 0) { + if (((addr | next | phys) & ~SECTION_MASK) == 0 && + block_mappings_allowed(pgtable_alloc)) { pmd_t old_pmd =*pmd; set_pmd(pmd, __pmd(phys | pgprot_val(mk_sect_prot(prot)))); @@ -241,7 +262,8 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end, /* * For 4K granule only, attempt to put down a 1GB block */ - if (use_1G_block(addr, next, phys)) { + if (use_1G_block(addr, next, phys) && + block_mappings_allowed(pgtable_alloc)) { pud_t old_pud = *pud; set_pud(pud, __pud(phys | pgprot_val(mk_sect_prot(prot)))); diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 0795c3a36d8f..ca6d268e3313 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -37,14 +37,31 @@ static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr, return 0; } +/* + * This function assumes that the range is mapped with PAGE_SIZE pages. + */ +static int __change_memory_common(unsigned long start, unsigned long size, + pgprot_t set_mask, pgprot_t clear_mask) +{ + struct page_change_data data; + int ret; + + data.set_mask = set_mask; + data.clear_mask = clear_mask; + + ret = apply_to_page_range(&init_mm, start, size, change_page_range, + &data); + + flush_tlb_kernel_range(start, start + size); + return ret; +} + static int change_memory_common(unsigned long addr, int numpages, pgprot_t set_mask, pgprot_t clear_mask) { unsigned long start = addr; unsigned long size = PAGE_SIZE*numpages; unsigned long end = start + size; - int ret; - struct page_change_data data; struct vm_struct *area; if (!PAGE_ALIGNED(addr)) { @@ -75,14 +92,7 @@ static int change_memory_common(unsigned long addr, int numpages, if (!numpages) return 0; - data.set_mask = set_mask; - data.clear_mask = clear_mask; - - ret = apply_to_page_range(&init_mm, start, size, change_page_range, - &data); - - flush_tlb_kernel_range(start, end); - return ret; + return __change_memory_common(start, size, set_mask, clear_mask); } int set_memory_ro(unsigned long addr, int numpages) @@ -114,3 +124,19 @@ int set_memory_x(unsigned long addr, int numpages) __pgprot(PTE_PXN)); } EXPORT_SYMBOL_GPL(set_memory_x); + +#ifdef CONFIG_DEBUG_PAGEALLOC +void __kernel_map_pages(struct page *page, int numpages, int enable) +{ + unsigned long addr = (unsigned long) page_address(page); + + if (enable) + __change_memory_common(addr, PAGE_SIZE * numpages, + __pgprot(PTE_VALID), + __pgprot(0)); + else + __change_memory_common(addr, PAGE_SIZE * numpages, + __pgprot(0), + __pgprot(PTE_VALID)); +} +#endif