linux-kernel - [PATCH bpf-next 4/4] bpf: export bpf_jit

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Date:   Fri, 24 Sep 2021 10:55:42 +0100
From:   Lorenz Bauer <lmb@...udflare.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     kernel-team@...udflare.com, Lorenz Bauer <lmb@...udflare.com>,
        netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next 4/4] bpf: export bpf_jit_current

Expose bpf_jit_current as a read only value via sysctl.

Signed-off-by: Lorenz Bauer <lmb@...udflare.com>
---
 include/linux/filter.h     | 1 +
 kernel/bpf/core.c          | 3 +--
 net/core/sysctl_net_core.c | 7 +++++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index ef03ff34234d..b2143ad5ce00 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1052,6 +1052,7 @@ extern int bpf_jit_harden;
 extern int bpf_jit_kallsyms;
 extern long bpf_jit_limit;
 extern long bpf_jit_limit_max;
+extern atomic_long_t bpf_jit_current;
 
 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index e844a2a4c99a..93f95e9ee8be 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -525,6 +525,7 @@ int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
 int bpf_jit_harden   __read_mostly;
 long bpf_jit_limit   __read_mostly;
 long bpf_jit_limit_max __read_mostly;
+atomic_long_t bpf_jit_current __read_mostly;
 
 static void
 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
@@ -800,8 +801,6 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
 	return slot;
 }
 
-static atomic_long_t bpf_jit_current;
-
 /* Can be overridden by an arch's JIT compiler if it has a custom,
  * dedicated BPF backend memory area, or if neither of the two
  * below apply.
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 5f88526ad61c..674aac163b84 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -421,6 +421,13 @@ static struct ctl_table net_core_table[] = {
 		.extra1		= &long_one,
 		.extra2		= &bpf_jit_limit_max,
 	},
+	{
+		.procname	= "bpf_jit_current",
+		.data		= &bpf_jit_current,
+		.maxlen		= sizeof(long),
+		.mode		= 0400,
+		.proc_handler	= proc_dolongvec_minmax_bpf_restricted,
+	},
 #endif
 	{
 		.procname	= "netdev_tstamp_prequeue",
-- 
2.30.2