ebpf: misc core cleanup
Besides others, move bpf_tail_call_proto to the remaining definitions
of other protos, improve comments a bit (i.e. remove some obvious ones,
where the code is already self-documenting, add objectives for others),
simplify bpf_prog_array_compatible() a bit.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 4548422..1e00aa3 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -26,9 +26,10 @@
#include <linux/vmalloc.h>
#include <linux/random.h>
#include <linux/moduleloader.h>
-#include <asm/unaligned.h>
#include <linux/bpf.h>
+#include <asm/unaligned.h>
+
/* Registers */
#define BPF_R0 regs[BPF_REG_0]
#define BPF_R1 regs[BPF_REG_1]
@@ -62,6 +63,7 @@
ptr = skb_network_header(skb) + k - SKF_NET_OFF;
else if (k >= SKF_LL_OFF)
ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
+
if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
return ptr;
@@ -176,15 +178,6 @@
return 0;
}
-const struct bpf_func_proto bpf_tail_call_proto = {
- .func = NULL,
- .gpl_only = false,
- .ret_type = RET_VOID,
- .arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_CONST_MAP_PTR,
- .arg3_type = ARG_ANYTHING,
-};
-
/**
* __bpf_prog_run - run eBPF program on a given context
* @ctx: is the data we are operating on
@@ -650,36 +643,35 @@
return 0;
}
-void __weak bpf_int_jit_compile(struct bpf_prog *prog)
+bool bpf_prog_array_compatible(struct bpf_array *array,
+ const struct bpf_prog *fp)
{
-}
-
-bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp)
-{
- if (array->owner_prog_type) {
- if (array->owner_prog_type != fp->type)
- return false;
- if (array->owner_jited != fp->jited)
- return false;
- } else {
+ if (!array->owner_prog_type) {
+ /* There's no owner yet where we could check for
+ * compatibility.
+ */
array->owner_prog_type = fp->type;
array->owner_jited = fp->jited;
+
+ return true;
}
- return true;
+
+ return array->owner_prog_type == fp->type &&
+ array->owner_jited == fp->jited;
}
-static int check_tail_call(const struct bpf_prog *fp)
+static int bpf_check_tail_call(const struct bpf_prog *fp)
{
struct bpf_prog_aux *aux = fp->aux;
int i;
for (i = 0; i < aux->used_map_cnt; i++) {
+ struct bpf_map *map = aux->used_maps[i];
struct bpf_array *array;
- struct bpf_map *map;
- map = aux->used_maps[i];
if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
continue;
+
array = container_of(map, struct bpf_array, map);
if (!bpf_prog_array_compatible(array, fp))
return -EINVAL;
@@ -689,22 +681,25 @@
}
/**
- * bpf_prog_select_runtime - select execution runtime for BPF program
+ * bpf_prog_select_runtime - select exec runtime for BPF program
* @fp: bpf_prog populated with internal BPF program
*
- * try to JIT internal BPF program, if JIT is not available select interpreter
- * BPF program will be executed via BPF_PROG_RUN() macro
+ * Try to JIT eBPF program, if JIT is not available, use interpreter.
+ * The BPF program will be executed via BPF_PROG_RUN() macro.
*/
int bpf_prog_select_runtime(struct bpf_prog *fp)
{
fp->bpf_func = (void *) __bpf_prog_run;
- /* Probe if internal BPF can be JITed */
bpf_int_jit_compile(fp);
- /* Lock whole bpf_prog as read-only */
bpf_prog_lock_ro(fp);
- return check_tail_call(fp);
+ /* The tail call compatibility check can only be done at
+ * this late stage as we need to determine, if we deal
+ * with JITed or non JITed program concatenations and not
+ * all eBPF JITs might immediately support all features.
+ */
+ return bpf_check_tail_call(fp);
}
EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
@@ -736,6 +731,21 @@
const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
+/* Always built-in helper functions. */
+const struct bpf_func_proto bpf_tail_call_proto = {
+ .func = NULL,
+ .gpl_only = false,
+ .ret_type = RET_VOID,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_CONST_MAP_PTR,
+ .arg3_type = ARG_ANYTHING,
+};
+
+/* For classic BPF JITs that don't implement bpf_int_jit_compile(). */
+void __weak bpf_int_jit_compile(struct bpf_prog *prog)
+{
+}
+
/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
* skb_copy_bits(), so provide a weak definition of it for NET-less config.
*/
