From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>, <kernel-team@fb.com>,
<netdev@vger.kernel.org>
Subject: [PATCH v3 bpf-next 1/3] bpf: Add BPF_FUNC_jiffies64
Date: Wed, 22 Jan 2020 15:36:46 -0800 [thread overview]
Message-ID: <20200122233646.903260-1-kafai@fb.com> (raw)
In-Reply-To: <20200122233639.903041-1-kafai@fb.com>
This patch adds a helper to read the 64bit jiffies. It will be used
in a later patch to implement the bpf_cubic.c.
The helper is inlined for jit_requested and 64 BITS_PER_LONG
as the map_gen_lookup(). Other cases could be considered together
with map_gen_lookup() if needed.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 9 ++++++++-
kernel/bpf/core.c | 1 +
kernel/bpf/helpers.c | 12 ++++++++++++
kernel/bpf/verifier.c | 24 ++++++++++++++++++++++++
net/core/filter.c | 2 ++
6 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 05d16615054c..a9687861fd7e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1414,6 +1414,7 @@ extern const struct bpf_func_proto bpf_get_local_storage_proto;
extern const struct bpf_func_proto bpf_strtol_proto;
extern const struct bpf_func_proto bpf_strtoul_proto;
extern const struct bpf_func_proto bpf_tcp_sock_proto;
+extern const struct bpf_func_proto bpf_jiffies64_proto;
/* Shared helpers among cBPF and eBPF. */
void bpf_user_rnd_init_once(void);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e81628eb059c..f1d74a2bd234 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2886,6 +2886,12 @@ union bpf_attr {
* **-EPERM** if no permission to send the *sig*.
*
* **-EAGAIN** if bpf program can try again.
+ *
+ * u64 bpf_jiffies64(void)
+ * Description
+ * Obtain the 64bit jiffies
+ * Return
+ * The 64 bit jiffies
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3005,7 +3011,8 @@ union bpf_attr {
FN(probe_read_user_str), \
FN(probe_read_kernel_str), \
FN(tcp_send_ack), \
- FN(send_signal_thread),
+ FN(send_signal_thread), \
+ FN(jiffies64),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 29d47aae0dd1..973a20d49749 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2137,6 +2137,7 @@ const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
const struct bpf_func_proto bpf_spin_lock_proto __weak;
const struct bpf_func_proto bpf_spin_unlock_proto __weak;
+const struct bpf_func_proto bpf_jiffies64_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;
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index cada974c9f4e..d8b7b110a1c5 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -11,6 +11,7 @@
#include <linux/uidgid.h>
#include <linux/filter.h>
#include <linux/ctype.h>
+#include <linux/jiffies.h>
#include "../../lib/kstrtox.h"
@@ -312,6 +313,17 @@ void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
preempt_enable();
}
+BPF_CALL_0(bpf_jiffies64)
+{
+ return get_jiffies_64();
+}
+
+const struct bpf_func_proto bpf_jiffies64_proto = {
+ .func = bpf_jiffies64,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+};
+
#ifdef CONFIG_CGROUPS
BPF_CALL_0(bpf_get_current_cgroup_id)
{
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9fe94f64f0ec..734abaa02123 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9445,6 +9445,30 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
goto patch_call_imm;
}
+ if (prog->jit_requested && BITS_PER_LONG == 64 &&
+ insn->imm == BPF_FUNC_jiffies64) {
+ struct bpf_insn ld_jiffies_addr[2] = {
+ BPF_LD_IMM64(BPF_REG_0,
+ (unsigned long)&jiffies),
+ };
+
+ insn_buf[0] = ld_jiffies_addr[0];
+ insn_buf[1] = ld_jiffies_addr[1];
+ insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
+ BPF_REG_0, 0);
+ cnt = 3;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
+ cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
patch_call_imm:
fn = env->ops->get_func_proto(insn->imm, env->prog);
/* all functions that have prototype and verifier allowed
diff --git a/net/core/filter.c b/net/core/filter.c
index 17de6747d9e3..4bf3e4aa8a7a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5923,6 +5923,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
return &bpf_spin_unlock_proto;
case BPF_FUNC_trace_printk:
return bpf_get_trace_printk_proto();
+ case BPF_FUNC_jiffies64:
+ return &bpf_jiffies64_proto;
default:
return NULL;
}
--
2.17.1
next prev parent reply other threads:[~2020-01-22 23:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 23:36 [PATCH v3 bpf-next 0/3] bpf: tcp: Add bpf_cubic example Martin KaFai Lau
2020-01-22 23:36 ` Martin KaFai Lau [this message]
2020-01-22 23:36 ` [PATCH v3 bpf-next 2/3] bpf: Sync uapi bpf.h to tools/ Martin KaFai Lau
2020-01-22 23:36 ` [PATCH v3 bpf-next 3/3] bpf: tcp: Add bpf_cubic example Martin KaFai Lau
2020-01-23 0:40 ` [PATCH v3 bpf-next 0/3] " Alexei Starovoitov
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