diff options
Diffstat (limited to 'kernel/bpf/arena.c')
| -rw-r--r-- | kernel/bpf/arena.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 86571e760dd6..343c3456c8dd 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -38,7 +38,7 @@ /* number of bytes addressable by LDX/STX insn with 16-bit 'off' field */ #define GUARD_SZ (1ull << sizeof(((struct bpf_insn *)0)->off) * 8) -#define KERN_VM_SZ ((1ull << 32) + GUARD_SZ) +#define KERN_VM_SZ (SZ_4G + GUARD_SZ) struct bpf_arena { struct bpf_map map; @@ -110,7 +110,7 @@ static struct bpf_map *arena_map_alloc(union bpf_attr *attr) return ERR_PTR(-EINVAL); vm_range = (u64)attr->max_entries * PAGE_SIZE; - if (vm_range > (1ull << 32)) + if (vm_range > SZ_4G) return ERR_PTR(-E2BIG); if ((attr->map_extra >> 32) != ((attr->map_extra + vm_range - 1) >> 32)) @@ -301,7 +301,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad if (pgoff) return -EINVAL; - if (len > (1ull << 32)) + if (len > SZ_4G) return -E2BIG; /* if user_vm_start was specified at arena creation time */ @@ -322,7 +322,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad if (WARN_ON_ONCE(arena->user_vm_start)) /* checks at map creation time should prevent this */ return -EFAULT; - return round_up(ret, 1ull << 32); + return round_up(ret, SZ_4G); } static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) @@ -346,7 +346,7 @@ static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) return -EBUSY; /* Earlier checks should prevent this */ - if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > (1ull << 32) || vma->vm_pgoff)) + if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > SZ_4G || vma->vm_pgoff)) return -EFAULT; if (remember_vma(arena, vma)) @@ -420,7 +420,7 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt if (uaddr & ~PAGE_MASK) return 0; pgoff = compute_pgoff(arena, uaddr); - if (pgoff + page_cnt > page_cnt_max) + if (pgoff > page_cnt_max - page_cnt) /* requested address will be outside of user VMA */ return 0; } @@ -447,7 +447,13 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt goto out; uaddr32 = (u32)(arena->user_vm_start + pgoff * PAGE_SIZE); - /* Earlier checks make sure that uaddr32 + page_cnt * PAGE_SIZE will not overflow 32-bit */ + /* Earlier checks made sure that uaddr32 + page_cnt * PAGE_SIZE - 1 + * will not overflow 32-bit. Lower 32-bit need to represent + * contiguous user address range. + * Map these pages at kern_vm_start base. + * kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE - 1 can overflow + * lower 32-bit and it's ok. + */ ret = vm_area_map_pages(arena->kern_vm, kern_vm_start + uaddr32, kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE, pages); if (ret) { @@ -510,6 +516,11 @@ static void arena_free_pages(struct bpf_arena *arena, long uaddr, long page_cnt) if (!page) continue; if (page_cnt == 1 && page_mapped(page)) /* mapped by some user process */ + /* Optimization for the common case of page_cnt==1: + * If page wasn't mapped into some user vma there + * is no need to call zap_pages which is slow. When + * page_cnt is big it's faster to do the batched zap. + */ zap_pages(arena, full_uaddr, 1); vm_area_unmap_pages(arena->kern_vm, kaddr, kaddr + PAGE_SIZE); __free_page(page); |