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BACKPORT: bpf: add bpf_ktime_get_boot_ns()
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On a device like a cellphone which is constantly suspending
and resuming CLOCK_MONOTONIC is not particularly useful for
keeping track of or reacting to external network events.
Instead you want to use CLOCK_BOOTTIME.

Hence add bpf_ktime_get_boot_ns() as a mirror of bpf_ktime_get_ns()
based around CLOCK_BOOTTIME instead of CLOCK_MONOTONIC.

Signed-off-by: Maciej Żenczykowski <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
(cherry picked from commit 71d19214776e61b33da48f7c1b46e522c7f78221)
Change-Id: Ifd62c410dcc5112fd1a473a7e1f70231ca514bc0
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zenczykowski committed Feb 12, 2021
1 parent cbb4c73 commit 34073d7
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Showing 7 changed files with 162 additions and 0 deletions.
1 change: 1 addition & 0 deletions include/linux/bpf.h
Original file line number Diff line number Diff line change
Expand Up @@ -497,6 +497,7 @@ extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
extern const struct bpf_func_proto bpf_get_numa_node_id_proto;
extern const struct bpf_func_proto bpf_tail_call_proto;
extern const struct bpf_func_proto bpf_ktime_get_ns_proto;
extern const struct bpf_func_proto bpf_ktime_get_boot_ns_proto;
extern const struct bpf_func_proto bpf_get_current_pid_tgid_proto;
extern const struct bpf_func_proto bpf_get_current_uid_gid_proto;
extern const struct bpf_func_proto bpf_get_current_comm_proto;
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72 changes: 72 additions & 0 deletions include/uapi/linux/bpf.h
Original file line number Diff line number Diff line change
Expand Up @@ -681,6 +681,78 @@ union bpf_attr {
FN(redirect_map), \
FN(sk_redirect_map), \
FN(sock_map_update), \
FN(xdp_adjust_meta), \
FN(perf_event_read_value), \
FN(perf_prog_read_value), \
FN(getsockopt), \
FN(override_return), \
FN(sock_ops_cb_flags_set), \
FN(msg_redirect_map), \
FN(msg_apply_bytes), \
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
FN(xdp_adjust_tail), \
FN(skb_get_xfrm_state), \
FN(get_stack), \
FN(skb_load_bytes_relative), \
FN(fib_lookup), \
FN(sock_hash_update), \
FN(msg_redirect_hash), \
FN(sk_redirect_hash), \
FN(lwt_push_encap), \
FN(lwt_seg6_store_bytes), \
FN(lwt_seg6_adjust_srh), \
FN(lwt_seg6_action), \
FN(rc_repeat), \
FN(rc_keydown), \
FN(skb_cgroup_id), \
FN(get_current_cgroup_id), \
FN(get_local_storage), \
FN(sk_select_reuseport), \
FN(skb_ancestor_cgroup_id), \
FN(sk_lookup_tcp), \
FN(sk_lookup_udp), \
FN(sk_release), \
FN(map_push_elem), \
FN(map_pop_elem), \
FN(map_peek_elem), \
FN(msg_push_data), \
FN(msg_pop_data), \
FN(rc_pointer_rel), \
FN(spin_lock), \
FN(spin_unlock), \
FN(sk_fullsock), \
FN(tcp_sock), \
FN(skb_ecn_set_ce), \
FN(get_listener_sock), \
FN(skc_lookup_tcp), \
FN(tcp_check_syncookie), \
FN(sysctl_get_name), \
FN(sysctl_get_current_value), \
FN(sysctl_get_new_value), \
FN(sysctl_set_new_value), \
FN(strtol), \
FN(strtoul), \
FN(sk_storage_get), \
FN(sk_storage_delete), \
FN(send_signal), \
FN(tcp_gen_syncookie), \
FN(skb_output), \
FN(probe_read_user), \
FN(probe_read_kernel), \
FN(probe_read_user_str), \
FN(probe_read_kernel_str), \
FN(tcp_send_ack), \
FN(send_signal_thread), \
FN(jiffies64), \
FN(read_branch_records), \
FN(get_ns_current_pid_tgid), \
FN(xdp_output), \
FN(get_netns_cookie), \
FN(get_current_ancestor_cgroup_id), \
FN(sk_assign), \
FN(ktime_get_boot_ns),

/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
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1 change: 1 addition & 0 deletions kernel/bpf/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -1646,6 +1646,7 @@ 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_get_numa_node_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;

const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
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12 changes: 12 additions & 0 deletions kernel/bpf/helpers.c
Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,18 @@ const struct bpf_func_proto bpf_ktime_get_ns_proto = {
.ret_type = RET_INTEGER,
};

BPF_CALL_0(bpf_ktime_get_boot_ns)
{
/* NMI safe access to clock boottime */
return ktime_get_boot_fast_ns();
}

const struct bpf_func_proto bpf_ktime_get_boot_ns_proto = {
.func = bpf_ktime_get_boot_ns,
.gpl_only = false,
.ret_type = RET_INTEGER,
};

BPF_CALL_0(bpf_get_current_pid_tgid)
{
struct task_struct *task = current;
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2 changes: 2 additions & 0 deletions kernel/trace/bpf_trace.c
Original file line number Diff line number Diff line change
Expand Up @@ -481,6 +481,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
return &bpf_probe_read_proto;
case BPF_FUNC_ktime_get_ns:
return &bpf_ktime_get_ns_proto;
case BPF_FUNC_ktime_get_boot_ns:
return &bpf_ktime_get_boot_ns_proto;
case BPF_FUNC_tail_call:
return &bpf_tail_call_proto;
case BPF_FUNC_get_current_pid_tgid:
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2 changes: 2 additions & 0 deletions net/core/filter.c
Original file line number Diff line number Diff line change
Expand Up @@ -3191,6 +3191,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
return &bpf_tail_call_proto;
case BPF_FUNC_ktime_get_ns:
return &bpf_ktime_get_ns_proto;
case BPF_FUNC_ktime_get_boot_ns:
return &bpf_ktime_get_boot_ns_proto;
case BPF_FUNC_trace_printk:
if (capable(CAP_SYS_ADMIN))
return bpf_get_trace_printk_proto();
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72 changes: 72 additions & 0 deletions tools/include/uapi/linux/bpf.h
Original file line number Diff line number Diff line change
Expand Up @@ -639,6 +639,78 @@ union bpf_attr {
FN(redirect_map), \
FN(sk_redirect_map), \
FN(sock_map_update), \
FN(xdp_adjust_meta), \
FN(perf_event_read_value), \
FN(perf_prog_read_value), \
FN(getsockopt), \
FN(override_return), \
FN(sock_ops_cb_flags_set), \
FN(msg_redirect_map), \
FN(msg_apply_bytes), \
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
FN(xdp_adjust_tail), \
FN(skb_get_xfrm_state), \
FN(get_stack), \
FN(skb_load_bytes_relative), \
FN(fib_lookup), \
FN(sock_hash_update), \
FN(msg_redirect_hash), \
FN(sk_redirect_hash), \
FN(lwt_push_encap), \
FN(lwt_seg6_store_bytes), \
FN(lwt_seg6_adjust_srh), \
FN(lwt_seg6_action), \
FN(rc_repeat), \
FN(rc_keydown), \
FN(skb_cgroup_id), \
FN(get_current_cgroup_id), \
FN(get_local_storage), \
FN(sk_select_reuseport), \
FN(skb_ancestor_cgroup_id), \
FN(sk_lookup_tcp), \
FN(sk_lookup_udp), \
FN(sk_release), \
FN(map_push_elem), \
FN(map_pop_elem), \
FN(map_peek_elem), \
FN(msg_push_data), \
FN(msg_pop_data), \
FN(rc_pointer_rel), \
FN(spin_lock), \
FN(spin_unlock), \
FN(sk_fullsock), \
FN(tcp_sock), \
FN(skb_ecn_set_ce), \
FN(get_listener_sock), \
FN(skc_lookup_tcp), \
FN(tcp_check_syncookie), \
FN(sysctl_get_name), \
FN(sysctl_get_current_value), \
FN(sysctl_get_new_value), \
FN(sysctl_set_new_value), \
FN(strtol), \
FN(strtoul), \
FN(sk_storage_get), \
FN(sk_storage_delete), \
FN(send_signal), \
FN(tcp_gen_syncookie), \
FN(skb_output), \
FN(probe_read_user), \
FN(probe_read_kernel), \
FN(probe_read_user_str), \
FN(probe_read_kernel_str), \
FN(tcp_send_ack), \
FN(send_signal_thread), \
FN(jiffies64), \
FN(read_branch_records), \
FN(get_ns_current_pid_tgid), \
FN(xdp_output), \
FN(get_netns_cookie), \
FN(get_current_ancestor_cgroup_id), \
FN(sk_assign), \
FN(ktime_get_boot_ns),

/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
Expand Down

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