Merge "arm: mm: consider only lowmem regions while remap" (3d75a97e) · Commits · e / devices / android_kernel_xiaomi_sm6125

arch/arm/Kconfig.debug

+11 −0

Original line number	Diff line number	Diff line
		@@ -63,6 +63,17 @@ config DEBUG_USER
		8 - SIGSEGV faults
		16 - SIGBUS faults

		config FORCE_PAGES
		bool "Force lowmem to be mapped with 4K pages"
		help
		There are some advanced debug features that can only be done when
		memory is mapped with pages instead of sections. Enable this option
		to always map lowmem pages with pages. This may have a performance
		cost due to increased TLB pressure.

		If unsure say N.


		# These options are only for real kernel hackers who want to get their hands dirty.
		config DEBUG_LL
		bool "Kernel low-level debugging functions (read help!)"

arch/arm/mm/mmu.c

+114 −0

Original line number	Diff line number	Diff line
		@@ -1586,6 +1586,119 @@ static void __init early_paging_init(const struct machine_desc *mdesc)

		#endif

		#ifdef CONFIG_FORCE_PAGES
		/*
		* remap a PMD into pages
		* We split a single pmd here none of this two pmd nonsense
		*/
		static noinline void __init split_pmd(pmd_t *pmd, unsigned long addr,
		unsigned long end, unsigned long pfn,
		const struct mem_type *type)
		{
		pte_t pte, start_pte;
		pmd_t *base_pmd;

		base_pmd = pmd_offset(
		pud_offset(pgd_offset(&init_mm, addr), addr), addr);

		if (pmd_none(base_pmd) \|\| pmd_bad(base_pmd)) {
		start_pte = early_alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
		#ifndef CONFIG_ARM_LPAE
		/*
		* Following is needed when new pte is allocated for pmd[1]
		* cases, which may happen when base (start) address falls
		* under pmd[1].
		*/
		if (addr & SECTION_SIZE)
		start_pte += pte_index(addr);
		#endif
		} else {
		start_pte = pte_offset_kernel(base_pmd, addr);
		}

		pte = start_pte;

		do {
		set_pte_ext(pte, pfn_pte(pfn, type->prot_pte), 0);
		pfn++;
		} while (pte++, addr += PAGE_SIZE, addr != end);

		*pmd = __pmd((__pa(start_pte) + PTE_HWTABLE_OFF) \| type->prot_l1);
		mb(); /* let pmd be programmed */
		flush_pmd_entry(pmd);
		flush_tlb_all();
		}

		/*
		* It's significantly easier to remap as pages later after all memory is
		* mapped. Everything is sections so all we have to do is split
		*/
		static void __init remap_pages(void)
		{
		struct memblock_region *reg;

		for_each_memblock(memory, reg) {
		phys_addr_t phys_start = reg->base;
		phys_addr_t phys_end = reg->base + reg->size;
		unsigned long addr = (unsigned long)__va(phys_start);
		unsigned long end = (unsigned long)__va(phys_end);
		pmd_t *pmd = NULL;
		unsigned long next;
		unsigned long pfn = __phys_to_pfn(phys_start);
		bool fixup = false;
		unsigned long saved_start = addr;

		if (phys_start > arm_lowmem_limit)
		break;
		if (phys_end > arm_lowmem_limit)
		end = (unsigned long)__va(arm_lowmem_limit);
		if (phys_start >= phys_end)
		break;

		pmd = pmd_offset(
		pud_offset(pgd_offset(&init_mm, addr), addr), addr);

		#ifndef CONFIG_ARM_LPAE
		if (addr & SECTION_SIZE) {
		fixup = true;
		pmd_empty_section_gap((addr - SECTION_SIZE) & PMD_MASK);
		pmd++;
		}

		if (end & SECTION_SIZE)
		pmd_empty_section_gap(end);
		#endif

		do {
		next = addr + SECTION_SIZE;

		if (pmd_none(pmd) \|\| pmd_bad(pmd))
		split_pmd(pmd, addr, next, pfn,
		&mem_types[MT_MEMORY_RWX]);
		pmd++;
		pfn += SECTION_SIZE >> PAGE_SHIFT;

		} while (addr = next, addr < end);

		if (fixup) {
		/*
		* Put a faulting page table here to avoid detecting no
		* pmd when accessing an odd section boundary. This
		* needs to be faulting to help catch errors and avoid
		* speculation
		*/
		pmd = pmd_off_k(saved_start);
		pmd[0] = pmd[1] & ~1;
		}
		}
		}
		#else
		static void __init remap_pages(void)
		{

		}
		#endif

		static void __init early_fixmap_shutdown(void)
		{
		int i;
		@@ -1628,6 +1741,7 @@ void __init paging_init(const struct machine_desc *mdesc)
		memblock_set_current_limit(arm_lowmem_limit);
		dma_contiguous_remap();
		early_fixmap_shutdown();
		remap_pages();
		devicemaps_init(mdesc);
		kmap_init();
		tcm_init();

arch/arm/mm/pageattr.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -56,7 +56,8 @@ static int change_memory_common(unsigned long addr, int numpages,
		if (!size)
		return 0;

		if (!in_range(start, size, MODULES_VADDR, MODULES_END) &&
		if (!IS_ENABLED(CONFIG_FORCE_PAGES) &&
		!in_range(start, size, MODULES_VADDR, MODULES_END) &&
		!in_range(start, size, VMALLOC_START, VMALLOC_END))
		return -EINVAL;