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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-03-14 02:27:17 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-15 21:57:25 -0400 |
| commit | c04167ce2ca0ecaeaafef006cb0d65cf01b68e42 (patch) | |
| tree | ef0c4dc4642696d84bd56c4f409dd32507981bb0 /kernel/bpf | |
| parent | 03e69b508b6f7c51743055c9f61d1dfeadf4b635 (diff) | |
| download | linux-stable-c04167ce2ca0ecaeaafef006cb0d65cf01b68e42.tar.gz linux-stable-c04167ce2ca0ecaeaafef006cb0d65cf01b68e42.tar.bz2 linux-stable-c04167ce2ca0ecaeaafef006cb0d65cf01b68e42.zip | |
ebpf: add helper for obtaining current processor id
This patch adds the possibility to obtain raw_smp_processor_id() in
eBPF. Currently, this is only possible in classic BPF where commit
da2033c28226 ("filter: add SKF_AD_RXHASH and SKF_AD_CPU") has added
facilities for this.
Perhaps most importantly, this would also allow us to track per CPU
statistics with eBPF maps, or to implement a poor-man's per CPU data
structure through eBPF maps.
Example function proto-type looks like:
u32 (*smp_processor_id)(void) = (void *)BPF_FUNC_get_smp_processor_id;
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/core.c | 1 | ||||
| -rw-r--r-- | kernel/bpf/helpers.c | 12 |
2 files changed, 13 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c1dbbb5d289b..4139a0f8b558 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -662,6 +662,7 @@ const struct bpf_func_proto bpf_map_update_elem_proto __weak; const struct bpf_func_proto bpf_map_delete_elem_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; +const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; /* 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. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 95eb59a045ea..bd7f5988ed9c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -12,6 +12,7 @@ #include <linux/bpf.h> #include <linux/rcupdate.h> #include <linux/random.h> +#include <linux/smp.h> /* If kernel subsystem is allowing eBPF programs to call this function, * inside its own verifier_ops->get_func_proto() callback it should return @@ -99,3 +100,14 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = { .gpl_only = false, .ret_type = RET_INTEGER, }; + +static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + return raw_smp_processor_id(); +} + +const struct bpf_func_proto bpf_get_smp_processor_id_proto = { + .func = bpf_get_smp_processor_id, + .gpl_only = false, + .ret_type = RET_INTEGER, +}; |