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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>
This commit is contained in:
Heiko Carstens 2013-07-17 14:26:50 +02:00 committed by Martin Schwidefsky
parent aa2d2c73c2
commit c9a7afa380
1 changed files with 42 additions and 0 deletions
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42
arch/s390/net/bpf_jit_comp.c
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@ -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 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
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 @@ call_fn: /* lg %r1,<d(function)>(%r13) */
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)> */