Commit 7974c473 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32s: Implement dedicated kasan_init_region() 



Implement a kasan_init_region() dedicated to book3s/32 that
allocates KASAN regions using BATs.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/709e821602b48a1d7c211a9b156da26db98c3e9d.1589866984.git.christophe.leroy@csgroup.eu
parent 2b279c03

arch/powerpc/include/asm/kasan.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ static inline void kasan_init(void) { } 
static inline void kasan_late_init(void) { }

#endif



void kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte);

int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end);

int kasan_init_region(void *start, size_t size);

arch/powerpc/mm/kasan/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -4,3 +4,4 @@ KASAN_SANITIZE := n 


obj-$(CONFIG_PPC32)           += kasan_init_32.o

obj-$(CONFIG_PPC_8xx)		+= 8xx.o

obj-$(CONFIG_PPC_BOOK3S_32)	+= book3s_32.o

arch/powerpc/mm/kasan/book3s_32.c

0 → 100644
+57 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#define DISABLE_BRANCH_PROFILING



#include <linux/kasan.h>

#include <linux/memblock.h>

#include <asm/pgalloc.h>

#include <mm/mmu_decl.h>



int __init kasan_init_region(void *start, size_t size)

{

	unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);

	unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);

	unsigned long k_cur = k_start;

	int k_size = k_end - k_start;

	int k_size_base = 1 << (ffs(k_size) - 1);

	int ret;

	void *block;



	block = memblock_alloc(k_size, k_size_base);



	if (block && k_size_base >= SZ_128K && k_start == ALIGN(k_start, k_size_base)) {

		int k_size_more = 1 << (ffs(k_size - k_size_base) - 1);



		setbat(-1, k_start, __pa(block), k_size_base, PAGE_KERNEL);

		if (k_size_more >= SZ_128K)

			setbat(-1, k_start + k_size_base, __pa(block) + k_size_base,

			       k_size_more, PAGE_KERNEL);

		if (v_block_mapped(k_start))

			k_cur = k_start + k_size_base;

		if (v_block_mapped(k_start + k_size_base))

			k_cur = k_start + k_size_base + k_size_more;



		update_bats();

	}



	if (!block)

		block = memblock_alloc(k_size, PAGE_SIZE);

	if (!block)

		return -ENOMEM;



	ret = kasan_init_shadow_page_tables(k_start, k_end);

	if (ret)

		return ret;



	kasan_update_early_region(k_start, k_cur, __pte(0));



	for (; k_cur < k_end; k_cur += PAGE_SIZE) {

		pmd_t *pmd = pmd_ptr_k(k_cur);

		void *va = block + k_cur - k_start;

		pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);



		__set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);

	}

	flush_tlb_kernel_range(k_start, k_end);

	return 0;

}

arch/powerpc/mm/kasan/kasan_init_32.c

+1 −1
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ int __init __weak kasan_init_region(void *start, size_t size) 
	return 0;

}



static void __init

void __init

kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte)

{

	unsigned long k_cur;