Hi Igor, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.16-rc7 next-20180327] [cannot apply to mmotm/master] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Igor-Stoppa/mm-security-ro-protection-for-dynamic-data/20180328-041541 config: i386-randconfig-x073-201812 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 All warnings (new ones prefixed by >>): In file included from include/asm-generic/bug.h:18:0, from arch/x86/include/asm/bug.h:83, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/mm.h:9, from mm/pmalloc.c:11: mm/pmalloc.c: In function 'grow': include/linux/kernel.h:809:16: warning: comparison of distinct pointer types lacks a cast (void) (&max1 == &max2); \ ^ include/linux/kernel.h:818:2: note: in expansion of macro '__max' __max(typeof(x), typeof(y), \ ^~~~~ >> mm/pmalloc.c:155:17: note: in expansion of macro 'max' addr = vmalloc(max(size, pool->refill)); ^~~ vim +/max +155 mm/pmalloc.c > 11 #include <linux/mm.h> 12 #include <linux/vmalloc.h> 13 #include <linux/kernel.h> 14 #include <linux/log2.h> 15 #include <linux/slab.h> 16 #include <linux/set_memory.h> 17 #include <linux/bug.h> 18 #include <linux/mutex.h> 19 #include <linux/llist.h> 20 #include <asm/cacheflush.h> 21 #include <asm/page.h> 22 23 #include <linux/pmalloc.h> 24 25 #define MAX_ALIGN_ORDER (ilog2(sizeof(void *))) 26 struct pmalloc_pool { 27 struct mutex mutex; 28 struct list_head pool_node; 29 struct llist_head vm_areas; 30 unsigned long refill; 31 unsigned long offset; 32 unsigned long align; 33 }; 34 35 static LIST_HEAD(pools_list); 36 static DEFINE_MUTEX(pools_mutex); 37 38 static inline void tag_area(struct vmap_area *area) 39 { 40 area->vm->flags |= VM_PMALLOC; 41 } 42 43 static inline void untag_area(struct vmap_area *area) 44 { 45 area->vm->flags &= ~VM_PMALLOC; 46 } 47 48 static inline struct vmap_area *current_area(struct pmalloc_pool *pool) 49 { 50 return llist_entry(pool->vm_areas.first, struct vmap_area, 51 area_list); 52 } 53 54 static inline bool is_area_protected(struct vmap_area *area) 55 { 56 return area->vm->flags & VM_PMALLOC_PROTECTED; 57 } 58 59 static inline bool protect_area(struct vmap_area *area) 60 { 61 if (unlikely(is_area_protected(area))) 62 return false; 63 set_memory_ro(area->va_start, area->vm->nr_pages); 64 area->vm->flags |= VM_PMALLOC_PROTECTED; 65 return true; 66 } 67 68 static inline void destroy_area(struct vmap_area *area) 69 { 70 WARN(!is_area_protected(area), "Destroying unprotected area."); 71 set_memory_rw(area->va_start, area->vm->nr_pages); 72 vfree((void *)area->va_start); 73 } 74 75 static inline bool empty(struct pmalloc_pool *pool) 76 { 77 return unlikely(llist_empty(&pool->vm_areas)); 78 } 79 80 static inline bool protected(struct pmalloc_pool *pool) 81 { 82 return is_area_protected(current_area(pool)); 83 } 84 85 static inline unsigned long get_align(struct pmalloc_pool *pool, 86 short int align_order) 87 { 88 if (likely(align_order < 0)) 89 return pool->align; 90 return 1UL << align_order; 91 } 92 93 static inline bool exhausted(struct pmalloc_pool *pool, size_t size, 94 short int align_order) 95 { 96 unsigned long align = get_align(pool, align_order); 97 unsigned long space_before = round_down(pool->offset, align); 98 unsigned long space_after = pool->offset - space_before; 99 100 return unlikely(space_after < size && space_before < size); 101 } 102 103 static inline bool space_needed(struct pmalloc_pool *pool, size_t size, 104 short int align_order) 105 { 106 return empty(pool) || protected(pool) || 107 exhausted(pool, size, align_order); 108 } 109 110 #define DEFAULT_REFILL_SIZE PAGE_SIZE 111 /** 112 * pmalloc_create_custom_pool() - create a new protectable memory pool 113 * @refill: the minimum size to allocate when in need of more memory. 114 * It will be rounded up to a multiple of PAGE_SIZE 115 * The value of 0 gives the default amount of PAGE_SIZE. 116 * @align_order: log2 of the alignment to use when allocating memory 117 * Negative values give log2(sizeof(size_t)). 118 * 119 * Creates a new (empty) memory pool for allocation of protectable 120 * memory. Memory will be allocated upon request (through pmalloc). 121 * 122 * Return: 123 * * pointer to the new pool - success 124 * * NULL - error 125 */ 126 struct pmalloc_pool *pmalloc_create_custom_pool(unsigned long refill, 127 short int align_order) 128 { 129 struct pmalloc_pool *pool; 130 131 pool = kzalloc(sizeof(struct pmalloc_pool), GFP_KERNEL); 132 if (WARN(!pool, "Could not allocate pool meta data.")) 133 return NULL; 134 135 pool->refill = refill ? PAGE_ALIGN(refill) : DEFAULT_REFILL_SIZE; 136 if (align_order < 0) 137 pool->align = sizeof(size_t); 138 else 139 pool->align = 1UL << align_order; 140 mutex_init(&pool->mutex); 141 142 mutex_lock(&pools_mutex); 143 list_add(&pool->pool_node, &pools_list); 144 mutex_unlock(&pools_mutex); 145 return pool; 146 } 147 148 149 static int grow(struct pmalloc_pool *pool, size_t size, 150 short int align_order) 151 { 152 void *addr; 153 struct vmap_area *area; 154 > 155 addr = vmalloc(max(size, pool->refill)); 156 if (WARN(!addr, "Failed to allocate %zd bytes", PAGE_ALIGN(size))) 157 return -ENOMEM; 158 159 area = find_vmap_area((unsigned long)addr); 160 tag_area(area); 161 pool->offset = area->vm->nr_pages * PAGE_SIZE; 162 llist_add(&area->area_list, &pool->vm_areas); 163 return 0; 164 } 165 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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