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ebpf: misc core cleanup

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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>
This commit is contained in:
Daniel Borkmann 2015-05-29 23:23:07 +02:00 committed by David S. Miller
parent 17ca8cbf49
commit 3324b584b6
2 changed files with 58 additions and 48 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

72
kernel/bpf/core.c
View file

@ -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 @@ void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, uns
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 @@ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
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;
}
static int check_tail_call(const struct bpf_prog *fp)
return array->owner_prog_type == fp->type &&
array->owner_jited == fp->jited;
}
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 @@ static int check_tail_call(const struct bpf_prog *fp)
}
/**
* 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_prandom_u32_proto __weak;
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.
*/