As BPF trampoline of different archs moves from bpf_jit_[alloc|free]_exec()
to bpf_prog_pack_[alloc|free](), we need to use different _alloc, _free for
different archs during the transition. Add the following helpers for this
transition:
void *arch_alloc_bpf_trampoline(unsigned int size);
void arch_free_bpf_trampoline(void *image, unsigned int size);
void arch_protect_bpf_trampoline(void *image, unsigned int size);
void arch_unprotect_bpf_trampoline(void *image, unsigned int size);
The fallback version of these helpers require size <= PAGE_SIZE, but they
are only called with size == PAGE_SIZE. They will be called with size <
PAGE_SIZE when arch_bpf_trampoline_size() helper is introduced later.
Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> # on s390x
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20231206224054.492250-4-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
const struct btf_func_model *m, u32 flags,
struct bpf_tramp_links *tlinks,
void *func_addr);
+void *arch_alloc_bpf_trampoline(unsigned int size);
+void arch_free_bpf_trampoline(void *image, unsigned int size);
+void arch_protect_bpf_trampoline(void *image, unsigned int size);
+void arch_unprotect_bpf_trampoline(void *image, unsigned int size);
+
u64 notrace __bpf_prog_enter_sleepable_recur(struct bpf_prog *prog,
struct bpf_tramp_run_ctx *run_ctx);
void notrace __bpf_prog_exit_sleepable_recur(struct bpf_prog *prog, u64 start,
if (err)
goto reset_unlock;
}
- set_memory_rox((long)st_map->image, 1);
+ arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE);
/* Let bpf_link handle registration & unregistration.
*
* Pair with smp_load_acquire() during lookup_elem().
goto unlock;
}
- set_memory_rox((long)st_map->image, 1);
+ arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE);
err = st_ops->reg(kdata);
if (likely(!err)) {
/* This refcnt increment on the map here after
* there was a race in registering the struct_ops (under the same name) to
* a sub-system through different struct_ops's maps.
*/
- set_memory_nx((long)st_map->image, 1);
- set_memory_rw((long)st_map->image, 1);
+ arch_unprotect_bpf_trampoline(st_map->image, PAGE_SIZE);
reset_unlock:
bpf_struct_ops_map_put_progs(st_map);
bpf_struct_ops_map_put_progs(st_map);
bpf_map_area_free(st_map->links);
if (st_map->image) {
- bpf_jit_free_exec(st_map->image);
+ arch_free_bpf_trampoline(st_map->image, PAGE_SIZE);
bpf_jit_uncharge_modmem(PAGE_SIZE);
}
bpf_map_area_free(st_map->uvalue);
return ERR_PTR(ret);
}
- st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
+ st_map->image = arch_alloc_bpf_trampoline(PAGE_SIZE);
if (!st_map->image) {
/* __bpf_struct_ops_map_free() uses st_map->image as flag
* for "charged or not". In this case, we need to unchange
}
mutex_init(&st_map->lock);
- set_vm_flush_reset_perms(st_map->image);
bpf_map_init_from_attr(map, attr);
return map;
static void bpf_tramp_image_free(struct bpf_tramp_image *im)
{
bpf_image_ksym_del(&im->ksym);
- bpf_jit_free_exec(im->image);
+ arch_free_bpf_trampoline(im->image, PAGE_SIZE);
bpf_jit_uncharge_modmem(PAGE_SIZE);
percpu_ref_exit(&im->pcref);
kfree_rcu(im, rcu);
goto out_free_im;
err = -ENOMEM;
- im->image = image = bpf_jit_alloc_exec(PAGE_SIZE);
+ im->image = image = arch_alloc_bpf_trampoline(PAGE_SIZE);
if (!image)
goto out_uncharge;
- set_vm_flush_reset_perms(image);
err = percpu_ref_init(&im->pcref, __bpf_tramp_image_release, 0, GFP_KERNEL);
if (err)
return im;
out_free_image:
- bpf_jit_free_exec(im->image);
+ arch_free_bpf_trampoline(im->image, PAGE_SIZE);
out_uncharge:
bpf_jit_uncharge_modmem(PAGE_SIZE);
out_free_im:
if (err < 0)
goto out_free;
- set_memory_rox((long)im->image, 1);
+ arch_protect_bpf_trampoline(im->image, PAGE_SIZE);
WARN_ON(tr->cur_image && total == 0);
if (tr->cur_image)
tr->fops->trampoline = 0;
/* reset im->image memory attr for arch_prepare_bpf_trampoline */
- set_memory_nx((long)im->image, 1);
- set_memory_rw((long)im->image, 1);
+ arch_unprotect_bpf_trampoline(im->image, PAGE_SIZE);
goto again;
}
#endif
return -ENOTSUPP;
}
+void * __weak arch_alloc_bpf_trampoline(unsigned int size)
+{
+ void *image;
+
+ if (WARN_ON_ONCE(size > PAGE_SIZE))
+ return NULL;
+ image = bpf_jit_alloc_exec(PAGE_SIZE);
+ if (image)
+ set_vm_flush_reset_perms(image);
+ return image;
+}
+
+void __weak arch_free_bpf_trampoline(void *image, unsigned int size)
+{
+ WARN_ON_ONCE(size > PAGE_SIZE);
+ /* bpf_jit_free_exec doesn't need "size", but
+ * bpf_prog_pack_free() needs it.
+ */
+ bpf_jit_free_exec(image);
+}
+
+void __weak arch_protect_bpf_trampoline(void *image, unsigned int size)
+{
+ WARN_ON_ONCE(size > PAGE_SIZE);
+ set_memory_rox((long)image, 1);
+}
+
+void __weak arch_unprotect_bpf_trampoline(void *image, unsigned int size)
+{
+ WARN_ON_ONCE(size > PAGE_SIZE);
+ set_memory_nx((long)image, 1);
+ set_memory_rw((long)image, 1);
+}
+
static int __init init_trampolines(void)
{
int i;
goto out;
}
- image = bpf_jit_alloc_exec(PAGE_SIZE);
+ image = arch_alloc_bpf_trampoline(PAGE_SIZE);
if (!image) {
err = -ENOMEM;
goto out;
}
- set_vm_flush_reset_perms(image);
link = kzalloc(sizeof(*link), GFP_USER);
if (!link) {
if (err < 0)
goto out;
- set_memory_rox((long)image, 1);
+ arch_protect_bpf_trampoline(image, PAGE_SIZE);
prog_ret = dummy_ops_call_op(image, args);
err = dummy_ops_copy_args(args);
err = -EFAULT;
out:
kfree(args);
- bpf_jit_free_exec(image);
+ arch_free_bpf_trampoline(image, PAGE_SIZE);
if (link)
bpf_link_put(&link->link);
kfree(tlinks);