Unverified Commit e178d670 authored by Nylon Chen's avatar Nylon Chen Committed by Palmer Dabbelt
Browse files

riscv/kasan: add KASAN_VMALLOC support 



It references to x86/s390 architecture.

So, it doesn't map the early shadow page to cover VMALLOC space.

Prepopulate top level page table for the range that would otherwise be
empty.

lower levels are filled dynamically upon memory allocation while
booting.

Signed-off-by: default avatarNylon Chen <nylon7@andestech.com>
Signed-off-by: default avatarNick Hu <nickhu@andestech.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent aec33b54

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ config RISCV 
	select HAVE_ARCH_JUMP_LABEL

	select HAVE_ARCH_JUMP_LABEL_RELATIVE

	select HAVE_ARCH_KASAN if MMU && 64BIT

	select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT

	select HAVE_ARCH_KGDB

	select HAVE_ARCH_KGDB_QXFER_PKT

	select HAVE_ARCH_MMAP_RND_BITS if MMU

arch/riscv/mm/kasan_init.c

+56 −1
Original line number Diff line number Diff line
@@ -9,6 +9,19 @@ 
#include <linux/pgtable.h>

#include <asm/tlbflush.h>

#include <asm/fixmap.h>

#include <asm/pgalloc.h>



static __init void *early_alloc(size_t size, int node)

{

	void *ptr = memblock_alloc_try_nid(size, size,

		__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);



	if (!ptr)

		panic("%pS: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",

			__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));



	return ptr;

}



extern pgd_t early_pg_dir[PTRS_PER_PGD];

asmlinkage void __init kasan_early_init(void)
@@ -83,6 +96,40 @@ static void __init populate(void *start, void *end) 
	memset(start, 0, end - start);

}



void __init kasan_shallow_populate(void *start, void *end)

{

	unsigned long vaddr = (unsigned long)start & PAGE_MASK;

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

	unsigned long pfn;

	int index;

	void *p;

	pud_t *pud_dir, *pud_k;

	pgd_t *pgd_dir, *pgd_k;

	p4d_t *p4d_dir, *p4d_k;



	while (vaddr < vend) {

		index = pgd_index(vaddr);

		pfn = csr_read(CSR_SATP) & SATP_PPN;

		pgd_dir = (pgd_t *)pfn_to_virt(pfn) + index;

		pgd_k = init_mm.pgd + index;

		pgd_dir = pgd_offset_k(vaddr);

		set_pgd(pgd_dir, *pgd_k);



		p4d_dir = p4d_offset(pgd_dir, vaddr);

		p4d_k  = p4d_offset(pgd_k, vaddr);



		vaddr = (vaddr + PUD_SIZE) & PUD_MASK;

		pud_dir = pud_offset(p4d_dir, vaddr);

		pud_k = pud_offset(p4d_k, vaddr);



		if (pud_present(*pud_dir)) {

			p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);

			pud_populate(&init_mm, pud_dir, p);

		}

		vaddr += PAGE_SIZE;

	}

}



void __init kasan_init(void)

{

	phys_addr_t _start, _end;
@@ -90,7 +137,15 @@ void __init kasan_init(void) 


	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,

				    (void *)kasan_mem_to_shadow((void *)

								VMALLOC_END));

								VMEMMAP_END));

	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))

		kasan_shallow_populate(

			(void *)kasan_mem_to_shadow((void *)VMALLOC_START),

			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));

	else

		kasan_populate_early_shadow(

			(void *)kasan_mem_to_shadow((void *)VMALLOC_START),

			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));



	for_each_mem_range(i, &_start, &_end) {

		void *start = (void *)_start;