Merge "arm64: Memory hotplug support for arm64 platform" (8ca1290a) · Commits · e / devices / android_kernel_oneplus_sm7250

arch/arm64/Kconfig

+1 −3

Original line number	Diff line number	Diff line
		@@ -732,9 +732,7 @@ config HOTPLUG_CPU
		can be controlled through /sys/devices/system/cpu.

		config ARCH_ENABLE_MEMORY_HOTPLUG
		def_bool y

		config ARCH_ENABLE_MEMORY_HOTREMOVE
		depends on !NUMA
		def_bool y

		# The GPIO number here must be sorted by descending number. In case of

arch/arm64/include/asm/mmu.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -94,6 +94,9 @@ extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
		pgprot_t prot, bool page_mappings_only);
		extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
		extern void mark_linear_text_alias_ro(void);
		#ifdef CONFIG_MEMORY_HOTPLUG
		extern void hotplug_paging(phys_addr_t start, phys_addr_t size);
		#endif

		#endif /* !__ASSEMBLY__ */
		#endif

arch/arm64/mm/init.c

+60 −17

Original line number	Diff line number	Diff line
		@@ -698,35 +698,78 @@ int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
		pg_data_t *pgdat;
		unsigned long start_pfn = start >> PAGE_SHIFT;
		unsigned long nr_pages = size >> PAGE_SHIFT;
		unsigned long end_pfn = start_pfn + nr_pages;
		unsigned long max_sparsemem_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
		unsigned long pfn;
		int ret;

		if (end_pfn > max_sparsemem_pfn) {
		pr_err("end_pfn too big");
		return -1;
		}
		hotplug_paging(start, size);

		/*
		* Mark the first page in the range as unusable. This is needed
		* because __add_section (within __add_pages) wants pfn_valid
		* of it to be false, and in arm64 pfn falid is implemented by
		* just checking at the nomap flag for existing blocks.
		*
		* A small trick here is that __add_section() requires only
		* phys_start_pfn (that is the first pfn of a section) to be
		* invalid. Regardless of whether it was assumed (by the function
		* author) that all pfns within a section are either all valid
		* or all invalid, it allows to avoid looping twice (once here,
		* second when memblock_clear_nomap() is called) through all
		* pfns of the section and modify only one pfn. Thanks to that,
		* further, in __add_zone() only this very first pfn is skipped
		* and corresponding page is not flagged reserved. Therefore it
		* is enough to correct this setup only for it.
		*
		* When arch_add_memory() returns the walk_memory_range() function
		* is called and passed with online_memory_block() callback,
		* which execution finally reaches the memory_block_action()
		* function, where also only the first pfn of a memory block is
		* checked to be reserved. Above, it was first pfn of a section,
		* here it is a block but
		* (drivers/base/memory.c):
		* sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
		* (include/linux/memory.h):
		* #define MIN_MEMORY_BLOCK_SIZE (1UL << SECTION_SIZE_BITS)
		* so we can consider block and section equivalently
		*/
		memblock_mark_nomap(start, 1<<PAGE_SHIFT);

		pgdat = NODE_DATA(nid);

		ret = __add_pages(nid, start_pfn, nr_pages, want_memblock);

		if (ret)
		pr_warn("%s: Problem encountered in __add_pages() ret=%d\n",
		__func__, ret);

		return ret;
		}
		/*
		* Make the pages usable after they have been added.
		* This will make pfn_valid return true
		*/
		memblock_clear_nomap(start, 1<<PAGE_SHIFT);

		#ifdef CONFIG_MEMORY_HOTREMOVE
		int arch_remove_memory(u64 start, u64 size)
		{
		unsigned long start_pfn = start >> PAGE_SHIFT;
		unsigned long nr_pages = size >> PAGE_SHIFT;
		struct zone *zone;
		int ret;
		/*
		* This is a hack to avoid having to mix arch specific code
		* into arch independent code. SetPageReserved is supposed
		* to be called by __add_zone (within __add_section, within
		* __add_pages). However, when it is called there, it assumes that
		* pfn_valid returns true. For the way pfn_valid is implemented
		* in arm64 (a check on the nomap flag), the only way to make
		* this evaluate true inside __add_zone is to clear the nomap
		* flags of blocks in architecture independent code.
		*
		* To avoid this, we set the Reserved flag here after we cleared
		* the nomap flag in the line above.
		*/
		SetPageReserved(pfn_to_page(start_pfn));

		zone = page_zone(pfn_to_page(start_pfn));
		ret = __remove_pages(zone, start_pfn, nr_pages);
		if (ret)
		pr_warn("%s: Problem encountered in __remove_pages() ret=%d\n",
		pr_warn("%s: Problem encountered in __add_pages() ret=%d\n",
		__func__, ret);

		return ret;
		}
		#endif
		#endif

arch/arm64/mm/mmu.c

+31 −0

Original line number	Diff line number	Diff line
		#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
		/*
		* Based on arch/arm/mm/mmu.c
		*
		@@ -697,6 +698,36 @@ void __init paging_init(void)
		- PAGE_SIZE);
		}

		#ifdef CONFIG_MEMORY_HOTPLUG
		/*
		* hotplug_paging() is used by memory hotplug to build new page tables
		* for hot added memory.
		*/
		void hotplug_paging(phys_addr_t start, phys_addr_t size)
		{

		struct page *pg;
		phys_addr_t pgd_phys = pgd_pgtable_alloc();
		pgd_t *pgd = pgd_set_fixmap(pgd_phys);

		memcpy(pgd, swapper_pg_dir, PAGE_SIZE);

		__create_pgd_mapping(pgd, start, __phys_to_virt(start), size,
		PAGE_KERNEL, pgd_pgtable_alloc, !debug_pagealloc_enabled());

		cpu_replace_ttbr1(__va(pgd_phys));
		memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
		cpu_replace_ttbr1(swapper_pg_dir);

		pgd_clear_fixmap();

		pg = phys_to_page(pgd_phys);
		pgtable_page_dtor(pg);
		__free_pages(pg, 0);
		}

		#endif

		/*
		* Check whether a kernel address is valid (derived from arch/x86/).
		*/