Unverified Commit cd0334e1 authored by Alexandre Ghiti's avatar Alexandre Ghiti Committed by Palmer Dabbelt
Browse files

riscv: Split early and final KASAN population functions 



This is a preliminary work that allows to make the code more
understandable.

Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230203075232.274282-2-alexghiti@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 6d796c50

arch/riscv/mm/kasan_init.c

+116 −69
Original line number Diff line number Diff line
@@ -95,23 +95,13 @@ static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned 
}



static void __init kasan_populate_pud(pgd_t *pgd,

				      unsigned long vaddr, unsigned long end,

				      bool early)

				      unsigned long vaddr, unsigned long end)

{

	phys_addr_t phys_addr;

	pud_t *pudp, *base_pud;

	unsigned long next;



	if (early) {

		/*

		 * We can't use pgd_page_vaddr here as it would return a linear

		 * mapping address but it is not mapped yet, but when populating

		 * early_pg_dir, we need the physical address and when populating

		 * swapper_pg_dir, we need the kernel virtual address so use

		 * pt_ops facility.

		 */

		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));

	} else if (pgd_none(*pgd)) {

	if (pgd_none(*pgd)) {

		base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);

		memcpy(base_pud, (void *)kasan_early_shadow_pud,

			sizeof(pud_t) * PTRS_PER_PUD);
@@ -130,18 +120,12 @@ static void __init kasan_populate_pud(pgd_t *pgd, 
		next = pud_addr_end(vaddr, end);



		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {

			if (early) {

				phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd));

				set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));

				continue;

			} else {

			phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);

			if (phys_addr) {

				set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));

				continue;

			}

		}

		}



		kasan_populate_pmd(pudp, vaddr, next);

	} while (pudp++, vaddr = next, vaddr != end);
@@ -152,35 +136,22 @@ static void __init kasan_populate_pud(pgd_t *pgd, 
	 * it entirely, memblock could allocate a page at a physical address

	 * where KASAN is not populated yet and then we'd get a page fault.

	 */

	if (!early)

	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));

}



static void __init kasan_populate_p4d(pgd_t *pgd,

				      unsigned long vaddr, unsigned long end,

				      bool early)

				      unsigned long vaddr, unsigned long end)

{

	phys_addr_t phys_addr;

	p4d_t *p4dp, *base_p4d;

	unsigned long next;



	if (early) {

		/*

		 * We can't use pgd_page_vaddr here as it would return a linear

		 * mapping address but it is not mapped yet, but when populating

		 * early_pg_dir, we need the physical address and when populating

		 * swapper_pg_dir, we need the kernel virtual address so use

		 * pt_ops facility.

		 */

		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd)));

	} else {

	base_p4d = (p4d_t *)pgd_page_vaddr(*pgd);

	if (base_p4d == lm_alias(kasan_early_shadow_p4d)) {

		base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE);

		memcpy(base_p4d, (void *)kasan_early_shadow_p4d,

		       sizeof(p4d_t) * PTRS_PER_P4D);

	}

	}



	p4dp = base_p4d + p4d_index(vaddr);
@@ -188,20 +159,14 @@ static void __init kasan_populate_p4d(pgd_t *pgd, 
		next = p4d_addr_end(vaddr, end);



		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) {

			if (early) {

				phys_addr = __pa(((uintptr_t)kasan_early_shadow_pud));

				set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));

				continue;

			} else {

			phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);

			if (phys_addr) {

				set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));

				continue;

			}

		}

		}



		kasan_populate_pud((pgd_t *)p4dp, vaddr, next, early);

		kasan_populate_pud((pgd_t *)p4dp, vaddr, next);

	} while (p4dp++, vaddr = next, vaddr != end);



	/*
@@ -210,7 +175,6 @@ static void __init kasan_populate_p4d(pgd_t *pgd, 
	 * it entirely, memblock could allocate a page at a physical address

	 * where KASAN is not populated yet and then we'd get a page fault.

	 */

	if (!early)

	set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE));

}
@@ -219,16 +183,15 @@ static void __init kasan_populate_p4d(pgd_t *pgd, 
							(pgtable_l4_enabled ?	\

				(uintptr_t)kasan_early_shadow_pud :		\

				(uintptr_t)kasan_early_shadow_pmd))

#define kasan_populate_pgd_next(pgdp, vaddr, next, early)			\

#define kasan_populate_pgd_next(pgdp, vaddr, next)				\

		(pgtable_l5_enabled ?						\

		kasan_populate_p4d(pgdp, vaddr, next, early) :			\

		kasan_populate_p4d(pgdp, vaddr, next) :				\

		(pgtable_l4_enabled ?						\

			kasan_populate_pud(pgdp, vaddr, next, early) :		\

			kasan_populate_pud(pgdp, vaddr, next) :			\

			kasan_populate_pmd((pud_t *)pgdp, vaddr, next)))



static void __init kasan_populate_pgd(pgd_t *pgdp,

				      unsigned long vaddr, unsigned long end,

				      bool early)

				      unsigned long vaddr, unsigned long end)

{

	phys_addr_t phys_addr;

	unsigned long next;
@@ -237,11 +200,7 @@ static void __init kasan_populate_pgd(pgd_t *pgdp, 
		next = pgd_addr_end(vaddr, end);



		if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) {

			if (early) {

				phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next);

				set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));

				continue;

			} else if (pgd_page_vaddr(*pgdp) ==

			if (pgd_page_vaddr(*pgdp) ==

				   (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) {

				/*

				 * pgdp can't be none since kasan_early_init
@@ -258,7 +217,95 @@ static void __init kasan_populate_pgd(pgd_t *pgdp, 
			}

		}



		kasan_populate_pgd_next(pgdp, vaddr, next, early);

		kasan_populate_pgd_next(pgdp, vaddr, next);

	} while (pgdp++, vaddr = next, vaddr != end);

}



static void __init kasan_early_populate_pud(p4d_t *p4dp,

					    unsigned long vaddr,

					    unsigned long end)

{

	pud_t *pudp, *base_pud;

	phys_addr_t phys_addr;

	unsigned long next;



	if (!pgtable_l4_enabled) {

		pudp = (pud_t *)p4dp;

	} else {

		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));

		pudp = base_pud + pud_index(vaddr);

	}



	do {

		next = pud_addr_end(vaddr, end);



		if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) &&

		    (next - vaddr) >= PUD_SIZE) {

			phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);

			set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));

			continue;

		}



		BUG();

	} while (pudp++, vaddr = next, vaddr != end);

}



static void __init kasan_early_populate_p4d(pgd_t *pgdp,

					    unsigned long vaddr,

					    unsigned long end)

{

	p4d_t *p4dp, *base_p4d;

	phys_addr_t phys_addr;

	unsigned long next;



	/*

	 * We can't use pgd_page_vaddr here as it would return a linear

	 * mapping address but it is not mapped yet, but when populating

	 * early_pg_dir, we need the physical address and when populating

	 * swapper_pg_dir, we need the kernel virtual address so use

	 * pt_ops facility.

	 * Note that this test is then completely equivalent to

	 * p4dp = p4d_offset(pgdp, vaddr)

	 */

	if (!pgtable_l5_enabled) {

		p4dp = (p4d_t *)pgdp;

	} else {

		base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));

		p4dp = base_p4d + p4d_index(vaddr);

	}



	do {

		next = p4d_addr_end(vaddr, end);



		if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) &&

		    (next - vaddr) >= P4D_SIZE) {

			phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);

			set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));

			continue;

		}



		kasan_early_populate_pud(p4dp, vaddr, next);

	} while (p4dp++, vaddr = next, vaddr != end);

}



static void __init kasan_early_populate_pgd(pgd_t *pgdp,

					    unsigned long vaddr,

					    unsigned long end)

{

	phys_addr_t phys_addr;

	unsigned long next;



	do {

		next = pgd_addr_end(vaddr, end);



		if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&

		    (next - vaddr) >= PGDIR_SIZE) {

			phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);

			set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));

			continue;

		}



		kasan_early_populate_p4d(pgdp, vaddr, next);

	} while (pgdp++, vaddr = next, vaddr != end);

}
@@ -295,16 +342,16 @@ asmlinkage void __init kasan_early_init(void) 
					PAGE_TABLE));

	}



	kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),

			   KASAN_SHADOW_START, KASAN_SHADOW_END, true);

	kasan_early_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),

				 KASAN_SHADOW_START, KASAN_SHADOW_END);



	local_flush_tlb_all();

}



void __init kasan_swapper_init(void)

{

	kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),

			   KASAN_SHADOW_START, KASAN_SHADOW_END, true);

	kasan_early_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),

				 KASAN_SHADOW_START, KASAN_SHADOW_END);



	local_flush_tlb_all();

}
@@ -314,7 +361,7 @@ static void __init kasan_populate(void *start, void *end) 
	unsigned long vaddr = (unsigned long)start & PAGE_MASK;

	unsigned long vend = PAGE_ALIGN((unsigned long)end);



	kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false);

	kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);



	local_flush_tlb_all();

	memset(start, KASAN_SHADOW_INIT, end - start);