diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/core.c | 9 | ||||
| -rw-r--r-- | kernel/bpf/dispatcher.c | 27 |
2 files changed, 28 insertions, 8 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d1be78c28619..711fd293b6de 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -825,6 +825,11 @@ struct bpf_prog_pack { unsigned long bitmap[]; }; +void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) +{ + memset(area, 0, size); +} + #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) static DEFINE_MUTEX(pack_mutex); @@ -864,7 +869,7 @@ static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_ins return pack; } -static void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) +void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) { unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); struct bpf_prog_pack *pack; @@ -905,7 +910,7 @@ out: return ptr; } -static void bpf_prog_pack_free(struct bpf_binary_header *hdr) +void bpf_prog_pack_free(struct bpf_binary_header *hdr) { struct bpf_prog_pack *pack = NULL, *tmp; unsigned int nbits; diff --git a/kernel/bpf/dispatcher.c b/kernel/bpf/dispatcher.c index 2444bd15cc2d..fa64b80b8bca 100644 --- a/kernel/bpf/dispatcher.c +++ b/kernel/bpf/dispatcher.c @@ -85,12 +85,12 @@ static bool bpf_dispatcher_remove_prog(struct bpf_dispatcher *d, return false; } -int __weak arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs) +int __weak arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs) { return -ENOTSUPP; } -static int bpf_dispatcher_prepare(struct bpf_dispatcher *d, void *image) +static int bpf_dispatcher_prepare(struct bpf_dispatcher *d, void *image, void *buf) { s64 ips[BPF_DISPATCHER_MAX] = {}, *ipsp = &ips[0]; int i; @@ -99,12 +99,12 @@ static int bpf_dispatcher_prepare(struct bpf_dispatcher *d, void *image) if (d->progs[i].prog) *ipsp++ = (s64)(uintptr_t)d->progs[i].prog->bpf_func; } - return arch_prepare_bpf_dispatcher(image, &ips[0], d->num_progs); + return arch_prepare_bpf_dispatcher(image, buf, &ips[0], d->num_progs); } static void bpf_dispatcher_update(struct bpf_dispatcher *d, int prev_num_progs) { - void *old, *new; + void *old, *new, *tmp; u32 noff; int err; @@ -117,8 +117,14 @@ static void bpf_dispatcher_update(struct bpf_dispatcher *d, int prev_num_progs) } new = d->num_progs ? d->image + noff : NULL; + tmp = d->num_progs ? d->rw_image + noff : NULL; if (new) { - if (bpf_dispatcher_prepare(d, new)) + /* Prepare the dispatcher in d->rw_image. Then use + * bpf_arch_text_copy to update d->image, which is RO+X. + */ + if (bpf_dispatcher_prepare(d, new, tmp)) + return; + if (IS_ERR(bpf_arch_text_copy(new, tmp, PAGE_SIZE / 2))) return; } @@ -140,9 +146,18 @@ void bpf_dispatcher_change_prog(struct bpf_dispatcher *d, struct bpf_prog *from, mutex_lock(&d->mutex); if (!d->image) { - d->image = bpf_jit_alloc_exec_page(); + d->image = bpf_prog_pack_alloc(PAGE_SIZE, bpf_jit_fill_hole_with_zero); if (!d->image) goto out; + d->rw_image = bpf_jit_alloc_exec(PAGE_SIZE); + if (!d->rw_image) { + u32 size = PAGE_SIZE; + + bpf_arch_text_copy(d->image, &size, sizeof(size)); + bpf_prog_pack_free((struct bpf_binary_header *)d->image); + d->image = NULL; + goto out; + } bpf_image_ksym_add(d->image, &d->ksym); } |