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authorAlexei Starovoitov <ast@plumgrid.com>2014-05-14 06:50:47 +0400
committerDavid S. Miller <davem@davemloft.net>2014-05-16 00:31:30 +0400
commit8f577cadf7181243d336be9aba40c1bcc02c4c54 (patch)
tree67daf2164c9c5b633160489d637b8ecc84b62881
parent622582786c9e041d0bd52bde201787adeab249f8 (diff)
downloadlinux-8f577cadf7181243d336be9aba40c1bcc02c4c54.tar.xz
seccomp: JIT compile seccomp filter
Take advantage of internal BPF JIT 05-sim-long_jumps.c of libseccomp was used as micro-benchmark: seccomp_rule_add_exact(ctx,... seccomp_rule_add_exact(ctx,... rc = seccomp_load(ctx); for (i = 0; i < 10000000; i++) syscall(...); $ sudo sysctl net.core.bpf_jit_enable=1 $ time ./bench real 0m2.769s user 0m1.136s sys 0m1.624s $ sudo sysctl net.core.bpf_jit_enable=0 $ time ./bench real 0m5.825s user 0m1.268s sys 0m4.548s Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--kernel/seccomp.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index b35c21503a36..7e02d624cc50 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -54,8 +54,7 @@
struct seccomp_filter {
atomic_t usage;
struct seccomp_filter *prev;
- unsigned short len; /* Instruction count */
- struct sock_filter_int insnsi[];
+ struct sk_filter *prog;
};
/* Limit any path through the tree to 256KB worth of instructions. */
@@ -189,7 +188,8 @@ static u32 seccomp_run_filters(int syscall)
* value always takes priority (ignoring the DATA).
*/
for (f = current->seccomp.filter; f; f = f->prev) {
- u32 cur_ret = sk_run_filter_int_seccomp(&sd, f->insnsi);
+ u32 cur_ret = SK_RUN_FILTER(f->prog, (void *)&sd);
+
if ((cur_ret & SECCOMP_RET_ACTION) < (ret & SECCOMP_RET_ACTION))
ret = cur_ret;
}
@@ -215,7 +215,7 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
return -EINVAL;
for (filter = current->seccomp.filter; filter; filter = filter->prev)
- total_insns += filter->len + 4; /* include a 4 instr penalty */
+ total_insns += filter->prog->len + 4; /* include a 4 instr penalty */
if (total_insns > MAX_INSNS_PER_PATH)
return -ENOMEM;
@@ -256,19 +256,27 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
/* Allocate a new seccomp_filter */
ret = -ENOMEM;
- filter = kzalloc(sizeof(struct seccomp_filter) +
- sizeof(struct sock_filter_int) * new_len,
+ filter = kzalloc(sizeof(struct seccomp_filter),
GFP_KERNEL|__GFP_NOWARN);
if (!filter)
goto free_prog;
- ret = sk_convert_filter(fp, fprog->len, filter->insnsi, &new_len);
- if (ret)
+ filter->prog = kzalloc(sk_filter_size(new_len),
+ GFP_KERNEL|__GFP_NOWARN);
+ if (!filter->prog)
goto free_filter;
+
+ ret = sk_convert_filter(fp, fprog->len, filter->prog->insnsi, &new_len);
+ if (ret)
+ goto free_filter_prog;
kfree(fp);
atomic_set(&filter->usage, 1);
- filter->len = new_len;
+ filter->prog->len = new_len;
+ filter->prog->bpf_func = (void *)sk_run_filter_int_seccomp;
+
+ /* JIT internal BPF into native HW instructions */
+ bpf_int_jit_compile(filter->prog);
/*
* If there is an existing filter, make it the prev and don't drop its
@@ -278,6 +286,8 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
current->seccomp.filter = filter;
return 0;
+free_filter_prog:
+ kfree(filter->prog);
free_filter:
kfree(filter);
free_prog:
@@ -330,6 +340,7 @@ void put_seccomp_filter(struct task_struct *tsk)
while (orig && atomic_dec_and_test(&orig->usage)) {
struct seccomp_filter *freeme = orig;
orig = orig->prev;
+ bpf_jit_free(freeme->prog);
kfree(freeme);
}
}