On 9/24/21 11:55 AM, Lorenz Bauer wrote:
Expose bpf_jit_current as a read only value via sysctl.
Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
---
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,
Overall series looks good to me. The only nit I would have is that the above could (in theory)
be subject to atomic_long_t vs long type confusion. I would rather prefer to have a small handler
which properly reads out the atomic_long_t and then passes it onwards as a temporary/plain long
to user space.
Thanks,
Daniel
+ },
#endif
{
.procname = "netdev_tstamp_prequeue",
