From af3d0a68698c7e5df8b72267086b23422a3954bb Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 6 Mar 2020 16:49:49 +0000 Subject: powerpc/kasan: Fix shadow memory protection with CONFIG_KASAN_VMALLOC With CONFIG_KASAN_VMALLOC, new page tables are created at the time shadow memory for vmalloc area is unmapped. If some parts of the page table still have entries to the zero page shadow memory, the entries are wrongly marked RW. With CONFIG_KASAN_VMALLOC, almost the entire kernel address space is managed by KASAN. To make it simple, just create KASAN page tables for the entire kernel space at kasan_init(). That doesn't use much more space, and that's anyway already done for hash platforms. Fixes: 3d4247fcc938 ("powerpc/32: Add support of KASAN_VMALLOC") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/ef5248fc1f496c6b0dfdb59380f24968f25f75c5.1583513368.git.christophe.leroy@c-s.fr --- arch/powerpc/mm/kasan/kasan_init_32.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c index db5664dde5ff..d2bed3fcb719 100644 --- a/arch/powerpc/mm/kasan/kasan_init_32.c +++ b/arch/powerpc/mm/kasan/kasan_init_32.c @@ -120,12 +120,6 @@ static void __init kasan_unmap_early_shadow_vmalloc(void) unsigned long k_cur; phys_addr_t pa = __pa(kasan_early_shadow_page); - if (!early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) { - int ret = kasan_init_shadow_page_tables(k_start, k_end); - - if (ret) - panic("kasan: kasan_init_shadow_page_tables() failed"); - } for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur); pte_t *ptep = pte_offset_kernel(pmd, k_cur); @@ -143,7 +137,8 @@ void __init kasan_mmu_init(void) int ret; struct memblock_region *reg; - if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) { + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE) || + IS_ENABLED(CONFIG_KASAN_VMALLOC)) { ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END); if (ret) -- cgit