* Copyright (C) 2024 Mike Rapoport IBM.
*/
+#define pr_fmt(fmt) "execmem: " fmt
+
#include <linux/mm.h>
+#include <linux/mutex.h>
#include <linux/vmalloc.h>
#include <linux/execmem.h>
+#include <linux/maple_tree.h>
+#include <linux/set_memory.h>
#include <linux/moduleloader.h>
#include <linux/text-patching.h>
+#include <asm/tlbflush.h>
+
+#include "internal.h"
+
static struct execmem_info *execmem_info __ro_after_init;
static struct execmem_info default_execmem_info __ro_after_init;
-static void *__execmem_alloc(struct execmem_range *range, size_t size)
+#ifdef CONFIG_MMU
+static void *execmem_vmalloc(struct execmem_range *range, size_t size,
+ pgprot_t pgprot, unsigned long vm_flags)
{
bool kasan = range->flags & EXECMEM_KASAN_SHADOW;
- unsigned long vm_flags = VM_FLUSH_RESET_PERMS;
gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
+ unsigned int align = range->alignment;
unsigned long start = range->start;
unsigned long end = range->end;
- unsigned int align = range->alignment;
- pgprot_t pgprot = range->pgprot;
void *p;
if (kasan)
vm_flags |= VM_DEFER_KMEMLEAK;
+ if (vm_flags & VM_ALLOW_HUGE_VMAP)
+ align = PMD_SIZE;
+
p = __vmalloc_node_range(size, align, start, end, gfp_flags,
pgprot, vm_flags, NUMA_NO_NODE,
__builtin_return_address(0));
}
if (!p) {
- pr_warn_ratelimited("execmem: unable to allocate memory\n");
+ pr_warn_ratelimited("unable to allocate memory\n");
return NULL;
}
return NULL;
}
- return kasan_reset_tag(p);
+ return p;
}
+#else
+static void *execmem_vmalloc(struct execmem_range *range, size_t size,
+ pgprot_t pgprot, unsigned long vm_flags)
+{
+ return vmalloc(size);
+}
+#endif /* CONFIG_MMU */
+
+#ifdef CONFIG_ARCH_HAS_EXECMEM_ROX
+struct execmem_cache {
+ struct mutex mutex;
+ struct maple_tree busy_areas;
+ struct maple_tree free_areas;
+};
+
+static struct execmem_cache execmem_cache = {
+ .mutex = __MUTEX_INITIALIZER(execmem_cache.mutex),
+ .busy_areas = MTREE_INIT_EXT(busy_areas, MT_FLAGS_LOCK_EXTERN,
+ execmem_cache.mutex),
+ .free_areas = MTREE_INIT_EXT(free_areas, MT_FLAGS_LOCK_EXTERN,
+ execmem_cache.mutex),
+};
+
+static inline unsigned long mas_range_len(struct ma_state *mas)
+{
+ return mas->last - mas->index + 1;
+}
+
+static int execmem_set_direct_map_valid(struct vm_struct *vm, bool valid)
+{
+ unsigned int nr = (1 << get_vm_area_page_order(vm));
+ unsigned int updated = 0;
+ int err = 0;
+
+ for (int i = 0; i < vm->nr_pages; i += nr) {
+ err = set_direct_map_valid_noflush(vm->pages[i], nr, valid);
+ if (err)
+ goto err_restore;
+ updated += nr;
+ }
+
+ return 0;
+
+err_restore:
+ for (int i = 0; i < updated; i += nr)
+ set_direct_map_valid_noflush(vm->pages[i], nr, !valid);
+
+ return err;
+}
+
+static void execmem_cache_clean(struct work_struct *work)
+{
+ struct maple_tree *free_areas = &execmem_cache.free_areas;
+ struct mutex *mutex = &execmem_cache.mutex;
+ MA_STATE(mas, free_areas, 0, ULONG_MAX);
+ void *area;
+
+ mutex_lock(mutex);
+ mas_for_each(&mas, area, ULONG_MAX) {
+ size_t size = mas_range_len(&mas);
+
+ if (IS_ALIGNED(size, PMD_SIZE) &&
+ IS_ALIGNED(mas.index, PMD_SIZE)) {
+ struct vm_struct *vm = find_vm_area(area);
+
+ execmem_set_direct_map_valid(vm, true);
+ mas_store_gfp(&mas, NULL, GFP_KERNEL);
+ vfree(area);
+ }
+ }
+ mutex_unlock(mutex);
+}
+
+static DECLARE_WORK(execmem_cache_clean_work, execmem_cache_clean);
+
+static int execmem_cache_add(void *ptr, size_t size)
+{
+ struct maple_tree *free_areas = &execmem_cache.free_areas;
+ struct mutex *mutex = &execmem_cache.mutex;
+ unsigned long addr = (unsigned long)ptr;
+ MA_STATE(mas, free_areas, addr - 1, addr + 1);
+ unsigned long lower, upper;
+ void *area = NULL;
+ int err;
+
+ lower = addr;
+ upper = addr + size - 1;
+
+ mutex_lock(mutex);
+ area = mas_walk(&mas);
+ if (area && mas.last == addr - 1)
+ lower = mas.index;
+
+ area = mas_next(&mas, ULONG_MAX);
+ if (area && mas.index == addr + size)
+ upper = mas.last;
+
+ mas_set_range(&mas, lower, upper);
+ err = mas_store_gfp(&mas, (void *)lower, GFP_KERNEL);
+ mutex_unlock(mutex);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static bool within_range(struct execmem_range *range, struct ma_state *mas,
+ size_t size)
+{
+ unsigned long addr = mas->index;
+
+ if (addr >= range->start && addr + size < range->end)
+ return true;
+
+ if (range->fallback_start &&
+ addr >= range->fallback_start && addr + size < range->fallback_end)
+ return true;
+
+ return false;
+}
+
+static void *__execmem_cache_alloc(struct execmem_range *range, size_t size)
+{
+ struct maple_tree *free_areas = &execmem_cache.free_areas;
+ struct maple_tree *busy_areas = &execmem_cache.busy_areas;
+ MA_STATE(mas_free, free_areas, 0, ULONG_MAX);
+ MA_STATE(mas_busy, busy_areas, 0, ULONG_MAX);
+ struct mutex *mutex = &execmem_cache.mutex;
+ unsigned long addr, last, area_size = 0;
+ void *area, *ptr = NULL;
+ int err;
+
+ mutex_lock(mutex);
+ mas_for_each(&mas_free, area, ULONG_MAX) {
+ area_size = mas_range_len(&mas_free);
+
+ if (area_size >= size && within_range(range, &mas_free, size))
+ break;
+ }
+
+ if (area_size < size)
+ goto out_unlock;
+
+ addr = mas_free.index;
+ last = mas_free.last;
+
+ /* insert allocated size to busy_areas at range [addr, addr + size) */
+ mas_set_range(&mas_busy, addr, addr + size - 1);
+ err = mas_store_gfp(&mas_busy, (void *)addr, GFP_KERNEL);
+ if (err)
+ goto out_unlock;
+
+ mas_store_gfp(&mas_free, NULL, GFP_KERNEL);
+ if (area_size > size) {
+ void *ptr = (void *)(addr + size);
+
+ /*
+ * re-insert remaining free size to free_areas at range
+ * [addr + size, last]
+ */
+ mas_set_range(&mas_free, addr + size, last);
+ err = mas_store_gfp(&mas_free, ptr, GFP_KERNEL);
+ if (err) {
+ mas_store_gfp(&mas_busy, NULL, GFP_KERNEL);
+ goto out_unlock;
+ }
+ }
+ ptr = (void *)addr;
+
+out_unlock:
+ mutex_unlock(mutex);
+ return ptr;
+}
+
+static int execmem_cache_populate(struct execmem_range *range, size_t size)
+{
+ unsigned long vm_flags = VM_ALLOW_HUGE_VMAP;
+ unsigned long start, end;
+ struct vm_struct *vm;
+ size_t alloc_size;
+ int err = -ENOMEM;
+ void *p;
+
+ alloc_size = round_up(size, PMD_SIZE);
+ p = execmem_vmalloc(range, alloc_size, PAGE_KERNEL, vm_flags);
+ if (!p)
+ return err;
+
+ vm = find_vm_area(p);
+ if (!vm)
+ goto err_free_mem;
+
+ /* fill memory with instructions that will trap */
+ execmem_fill_trapping_insns(p, alloc_size, /* writable = */ true);
+
+ start = (unsigned long)p;
+ end = start + alloc_size;
+
+ vunmap_range(start, end);
+
+ err = execmem_set_direct_map_valid(vm, false);
+ if (err)
+ goto err_free_mem;
+
+ err = vmap_pages_range_noflush(start, end, range->pgprot, vm->pages,
+ PMD_SHIFT);
+ if (err)
+ goto err_free_mem;
+
+ err = execmem_cache_add(p, alloc_size);
+ if (err)
+ goto err_free_mem;
+
+ return 0;
+
+err_free_mem:
+ vfree(p);
+ return err;
+}
+
+static void *execmem_cache_alloc(struct execmem_range *range, size_t size)
+{
+ void *p;
+ int err;
+
+ p = __execmem_cache_alloc(range, size);
+ if (p)
+ return p;
+
+ err = execmem_cache_populate(range, size);
+ if (err)
+ return NULL;
+
+ return __execmem_cache_alloc(range, size);
+}
+
+static bool execmem_cache_free(void *ptr)
+{
+ struct maple_tree *busy_areas = &execmem_cache.busy_areas;
+ struct mutex *mutex = &execmem_cache.mutex;
+ unsigned long addr = (unsigned long)ptr;
+ MA_STATE(mas, busy_areas, addr, addr);
+ size_t size;
+ void *area;
+
+ mutex_lock(mutex);
+ area = mas_walk(&mas);
+ if (!area) {
+ mutex_unlock(mutex);
+ return false;
+ }
+ size = mas_range_len(&mas);
+
+ mas_store_gfp(&mas, NULL, GFP_KERNEL);
+ mutex_unlock(mutex);
+
+ execmem_fill_trapping_insns(ptr, size, /* writable = */ false);
+
+ execmem_cache_add(ptr, size);
+
+ schedule_work(&execmem_cache_clean_work);
+
+ return true;
+}
+#else /* CONFIG_ARCH_HAS_EXECMEM_ROX */
+static void *execmem_cache_alloc(struct execmem_range *range, size_t size)
+{
+ return NULL;
+}
+
+static bool execmem_cache_free(void *ptr)
+{
+ return false;
+}
+#endif /* CONFIG_ARCH_HAS_EXECMEM_ROX */
void *execmem_alloc(enum execmem_type type, size_t size)
{
struct execmem_range *range = &execmem_info->ranges[type];
+ bool use_cache = range->flags & EXECMEM_ROX_CACHE;
+ unsigned long vm_flags = VM_FLUSH_RESET_PERMS;
+ pgprot_t pgprot = range->pgprot;
+ void *p;
- return __execmem_alloc(range, size);
+ if (use_cache)
+ p = execmem_cache_alloc(range, size);
+ else
+ p = execmem_vmalloc(range, size, pgprot, vm_flags);
+
+ return kasan_reset_tag(p);
}
void execmem_free(void *ptr)
* supported by vmalloc.
*/
WARN_ON(in_interrupt());
- vfree(ptr);
+
+ if (!execmem_cache_free(ptr))
+ vfree(ptr);
}
void *execmem_update_copy(void *dst, const void *src, size_t size)
return false;
}
+ if (!IS_ENABLED(CONFIG_ARCH_HAS_EXECMEM_ROX)) {
+ for (int i = EXECMEM_DEFAULT; i < EXECMEM_TYPE_MAX; i++) {
+ r = &info->ranges[i];
+
+ if (r->flags & EXECMEM_ROX_CACHE) {
+ pr_warn_once("ROX cache is not supported\n");
+ r->flags &= ~EXECMEM_ROX_CACHE;
+ }
+ }
+ }
+
return true;
}
projects / users / jedix / linux-maple.git / commitdiff