From a5edf9815dd739fce660b4c8658f61b7d2517042 Mon Sep 17 00:00:00 2001 From: Nicholas Miehlbradt Date: Mon, 26 Sep 2022 07:57:26 +0000 Subject: [PATCH] powerpc/64s: Enable KFENCE on book3s64 KFENCE support was added for ppc32 in commit 90cbac0e995d ("powerpc: Enable KFENCE for PPC32"). Enable KFENCE on ppc64 architecture with hash and radix MMUs. It uses the same mechanism as debug pagealloc to protect/unprotect pages. All KFENCE kunit tests pass on both MMUs. KFENCE memory is initially allocated using memblock but is later marked as SLAB allocated. This necessitates the change to __pud_free to ensure that the KFENCE pages are freed appropriately. Based on previous work by Christophe Leroy and Jordan Niethe. Signed-off-by: Nicholas Miehlbradt Reviewed-by: Russell Currey Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926075726.2846-4-nicholas@linux.ibm.com --- arch/powerpc/Kconfig | 2 +- arch/powerpc/include/asm/book3s/64/pgalloc.h | 6 ++++-- arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +- arch/powerpc/include/asm/kfence.h | 15 +++++++++++++++ arch/powerpc/mm/book3s64/hash_utils.c | 10 +++++----- arch/powerpc/mm/book3s64/radix_pgtable.c | 6 ++++-- 6 files changed, 30 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 237c0e0..81c9f89 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -195,7 +195,7 @@ config PPC select HAVE_ARCH_KASAN if PPC_RADIX_MMU select HAVE_ARCH_KASAN if PPC_BOOK3E_64 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN - select HAVE_ARCH_KFENCE if PPC_BOOK3S_32 || PPC_8xx || 40x + select HAVE_ARCH_KFENCE if ARCH_SUPPORTS_DEBUG_PAGEALLOC select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h index e1af0b3..dd2cff5 100644 --- a/arch/powerpc/include/asm/book3s/64/pgalloc.h +++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h @@ -113,9 +113,11 @@ static inline void __pud_free(pud_t *pud) /* * Early pud pages allocated via memblock allocator - * can't be directly freed to slab + * can't be directly freed to slab. KFENCE pages have + * both reserved and slab flags set so need to be freed + * kmem_cache_free. */ - if (PageReserved(page)) + if (PageReserved(page) && !PageSlab(page)) free_reserved_page(page); else kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), pud); diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index b5f8264..c436d84 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1106,7 +1106,7 @@ static inline void vmemmap_remove_mapping(unsigned long start, } #endif -#ifdef CONFIG_DEBUG_PAGEALLOC +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) static inline void __kernel_map_pages(struct page *page, int numpages, int enable) { if (radix_enabled()) diff --git a/arch/powerpc/include/asm/kfence.h b/arch/powerpc/include/asm/kfence.h index a9846b6..6fd2b4d 100644 --- a/arch/powerpc/include/asm/kfence.h +++ b/arch/powerpc/include/asm/kfence.h @@ -11,11 +11,25 @@ #include #include +#ifdef CONFIG_PPC64_ELF_ABI_V1 +#define ARCH_FUNC_PREFIX "." +#endif + static inline bool arch_kfence_init_pool(void) { return true; } +#ifdef CONFIG_PPC64 +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + struct page *page = virt_to_page(addr); + + __kernel_map_pages(page, 1, !protect); + + return true; +} +#else static inline bool kfence_protect_page(unsigned long addr, bool protect) { pte_t *kpte = virt_to_kpte(addr); @@ -29,5 +43,6 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) return true; } +#endif #endif /* __ASM_POWERPC_KFENCE_H */ diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 6d985ac..df008ed 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -424,7 +424,7 @@ repeat: break; cond_resched(); - if (debug_pagealloc_enabled() && + if (debug_pagealloc_enabled_or_kfence() && (paddr >> PAGE_SHIFT) < linear_map_hash_count) linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80; } @@ -773,7 +773,7 @@ static void __init htab_init_page_sizes(void) bool aligned = true; init_hpte_page_sizes(); - if (!debug_pagealloc_enabled()) { + if (!debug_pagealloc_enabled_or_kfence()) { /* * Pick a size for the linear mapping. Currently, we only * support 16M, 1M and 4K which is the default @@ -1061,7 +1061,7 @@ static void __init htab_initialize(void) prot = pgprot_val(PAGE_KERNEL); - if (debug_pagealloc_enabled()) { + if (debug_pagealloc_enabled_or_kfence()) { linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT; linear_map_hash_slots = memblock_alloc_try_nid( linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT, @@ -1980,7 +1980,7 @@ repeat: return slot; } -#ifdef CONFIG_DEBUG_PAGEALLOC +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) static DEFINE_SPINLOCK(linear_map_hash_lock); static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi) @@ -2053,7 +2053,7 @@ void hash__kernel_map_pages(struct page *page, int numpages, int enable) } local_irq_restore(flags); } -#endif /* CONFIG_DEBUG_PAGEALLOC */ +#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_KFENCE */ void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base, phys_addr_t first_memblock_size) diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 94a05c6..70f1580 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -34,6 +34,8 @@ #include +#include + unsigned int mmu_base_pid; unsigned long radix_mem_block_size __ro_after_init; @@ -276,7 +278,7 @@ static int __meminit create_physical_mapping(unsigned long start, int psize; unsigned long max_mapping_size = radix_mem_block_size; - if (debug_pagealloc_enabled()) + if (debug_pagealloc_enabled_or_kfence()) max_mapping_size = PAGE_SIZE; start = ALIGN(start, PAGE_SIZE); @@ -899,7 +901,7 @@ void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long #endif #endif -#ifdef CONFIG_DEBUG_PAGEALLOC +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) void radix__kernel_map_pages(struct page *page, int numpages, int enable) { unsigned long addr; -- 2.7.4