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Commit c9a7afa3 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/bpf,jit: add pkt_type support 



s390 version of 3b58908a "x86: bpf_jit_comp: add pkt_type support".

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent aa2d2c73

arch/s390/net/bpf_jit_comp.c

+42 −0
Original line number Diff line number Diff line
@@ -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 @@ load_abs: if ((int) K < 0) 
			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)> */