s390/bpf,jit: add pkt_type support
s390 version of 3b58908a "x86: bpf_jit_comp: add pkt_type support".
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 788e223..d5f10a4 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -10,6 +10,7 @@
#include <linux/if_vlan.h>
#include <linux/filter.h>
#include <linux/random.h>
+#include <linux/init.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/facility.h>
@@ -222,6 +223,37 @@
EMIT2(0x07fe);
}
+/* Helper to find the offset of pkt_type in sk_buff
+ * Make sure its still a 3bit field starting at the MSBs within a byte.
+ */
+#define PKT_TYPE_MAX 0xe0
+static int pkt_type_offset;
+
+static int __init bpf_pkt_type_offset_init(void)
+{
+ struct sk_buff skb_probe = {
+ .pkt_type = ~0,
+ };
+ char *ct = (char *)&skb_probe;
+ int off;
+
+ pkt_type_offset = -1;
+ for (off = 0; off < sizeof(struct sk_buff); off++) {
+ if (!ct[off])
+ continue;
+ if (ct[off] == PKT_TYPE_MAX)
+ pkt_type_offset = off;
+ else {
+ /* Found non matching bit pattern, fix needed. */
+ WARN_ON_ONCE(1);
+ pkt_type_offset = -1;
+ return -1;
+ }
+ }
+ return 0;
+}
+device_initcall(bpf_pkt_type_offset_init);
+
/*
* make sure we dont leak kernel information to user
*/
@@ -721,6 +753,16 @@
EMIT4_DISP(0x88500000, 12);
}
break;
+ case BPF_S_ANC_PKTTYPE:
+ if (pkt_type_offset < 0)
+ goto out;
+ /* lhi %r5,0 */
+ EMIT4(0xa7580000);
+ /* ic %r5,<d(pkt_type_offset)>(%r2) */
+ EMIT4_DISP(0x43502000, pkt_type_offset);
+ /* srl %r5,5 */
+ EMIT4_DISP(0x88500000, 5);
+ break;
case BPF_S_ANC_CPU: /* A = smp_processor_id() */
#ifdef CONFIG_SMP
/* l %r5,<d(cpu_nr)> */