Commit 83863f25 authored by Laura Abbott's avatar Laura Abbott Committed by Catalin Marinas
Browse files

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: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarLaura Abbott <labbott@fedoraproject.org>
[catalin.marinas@arm.com: static annotation block_mappings_allowed() and #ifdef]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 132233a7

arch/arm64/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/mm/mmu.c

+24 −2
Original line number Diff line number Diff line
@@ -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))));

arch/arm64/mm/pageattr.c

+36 −10
Original line number Diff line number Diff line
@@ -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

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