linux/kernel/bpf
Paul Chaignon d71962f3e6 bpf: allow map helpers access to map values directly
Helpers that expect ARG_PTR_TO_MAP_KEY and ARG_PTR_TO_MAP_VALUE can only
access stack and packet memory.  Allow these helpers to directly access
map values by passing registers of type PTR_TO_MAP_VALUE.

This change removes the need for an extra copy to the stack when using a
map value to perform a second map lookup, as in the following:

struct bpf_map_def SEC("maps") infobyreq = {
    .type = BPF_MAP_TYPE_HASHMAP,
    .key_size = sizeof(struct request *),
    .value_size = sizeof(struct info_t),
    .max_entries = 1024,
};
struct bpf_map_def SEC("maps") counts = {
    .type = BPF_MAP_TYPE_HASHMAP,
    .key_size = sizeof(struct info_t),
    .value_size = sizeof(u64),
    .max_entries = 1024,
};
SEC("kprobe/blk_account_io_start")
int bpf_blk_account_io_start(struct pt_regs *ctx)
{
    struct info_t *info = bpf_map_lookup_elem(&infobyreq, &ctx->di);
    u64 *count = bpf_map_lookup_elem(&counts, info);
    (*count)++;
}

Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-04-24 22:39:13 +02:00
..
arraymap.c bpf: btf: Add pretty print support to the basic arraymap 2018-04-19 21:46:25 +02:00
bpf_lru_list.c bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
bpf_lru_list.h bpf: Only set node->ref = 1 if it has not been set 2017-09-01 09:57:39 -07:00
btf.c bpf: btf: Clean up btf.h in uapi 2018-04-23 11:32:01 +02:00
cgroup.c bpf: Hooks for sys_bind 2018-03-31 02:15:18 +02:00
core.c bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query 2018-02-14 08:59:37 -08:00
cpumap.c xdp: transition into using xdp_frame for return API 2018-04-17 10:50:29 -04:00
devmap.c bpf: add helper for copying attrs to struct bpf_map 2018-01-14 23:36:29 +01:00
disasm.c bpf: Remove struct bpf_verifier_env argument from print_bpf_insn 2018-03-23 17:38:57 +01:00
disasm.h bpf: Remove struct bpf_verifier_env argument from print_bpf_insn 2018-03-23 17:38:57 +01:00
hashtab.c bpf: add helper for copying attrs to struct bpf_map 2018-01-14 23:36:29 +01:00
helpers.c bpf: rename ARG_PTR_TO_STACK 2017-01-09 16:56:27 -05:00
inode.c bpf: btf: Add pretty print support to the basic arraymap 2018-04-19 21:46:25 +02:00
lpm_trie.c bpf: fix rcu lockdep warning for lpm_trie map_free callback 2018-02-22 21:29:12 +01:00
Makefile bpf: btf: Introduce BPF Type Format (BTF) 2018-04-19 21:46:24 +02:00
map_in_map.c bpf: Add syscall lookup support for fd array and htab 2017-06-29 13:13:25 -04:00
map_in_map.h bpf: Add syscall lookup support for fd array and htab 2017-06-29 13:13:25 -04:00
offload.c bpf: offload: report device information about offloaded maps 2018-01-18 22:54:25 +01:00
percpu_freelist.c bpf: fix lockdep splat 2017-11-15 19:46:32 +09:00
percpu_freelist.h bpf: introduce percpu_freelist 2016-03-08 15:28:31 -05:00
sockmap.c bpf: sockmap, duplicates release calls may NULL sk_prot 2018-04-04 11:04:31 +02:00
stackmap.c bpf: extend stackmap to save binary_build_id+offset instead of address 2018-03-15 01:09:28 +01:00
syscall.c bpf: btf: Add pretty print support to the basic arraymap 2018-04-19 21:46:25 +02:00
tnum.c bpf/verifier: track signed and unsigned min/max values 2017-08-08 17:51:34 -07:00
verifier.c bpf: allow map helpers access to map values directly 2018-04-24 22:39:13 +02:00