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Revision 7f453c24b95a085fc7bd35d53b33abc4dc5a048b authored by Peter Zijlstra on 21 July 2009, 11:19:40 UTC, committed by Peter Zijlstra on 22 July 2009, 16:05:56 UTC 
perf_counter: PERF_SAMPLE_ID and inherited counters
 
Anton noted that for inherited counters the counter-id as provided by
PERF_SAMPLE_ID isn't mappable to the id found through PERF_RECORD_ID
because each inherited counter gets its own id.

His suggestion was to always return the parent counter id, since that
is the primary counter id as exposed. However, these inherited
counters have a unique identifier so that events like
PERF_EVENT_PERIOD and PERF_EVENT_THROTTLE can be specific about which
counter gets modified, which is important when trying to normalize the
sample streams.

This patch removes PERF_EVENT_PERIOD in favour of PERF_SAMPLE_PERIOD,
which is more useful anyway, since changing periods became a lot more
common than initially thought -- rendering PERF_EVENT_PERIOD the less
useful solution (also, PERF_SAMPLE_PERIOD reports the more accurate
value, since it reports the value used to trigger the overflow,
whereas PERF_EVENT_PERIOD simply reports the requested period changed,
which might only take effect on the next cycle).

This still leaves us PERF_EVENT_THROTTLE to consider, but since that
_should_ be a rare occurrence, and linking it to a primary id is the
most useful bit to diagnose the problem, we introduce a
PERF_SAMPLE_STREAM_ID, for those few cases where the full
reconstruction is important.

[Does change the ABI a little, but I see no other way out]

Suggested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1248095846.15751.8781.camel@twins>
1 parent 573402d
Raw File
aes_cmac.c 
/*
 * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
 * Copyright 2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>

#include <net/mac80211.h>
#include "key.h"
#include "aes_cmac.h"

#define AES_BLOCK_SIZE 16
#define AES_CMAC_KEY_LEN 16
#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
#define AAD_LEN 20


static void gf_mulx(u8 *pad)
{
	int i, carry;

	carry = pad[0] & 0x80;
	for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
		pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
	pad[AES_BLOCK_SIZE - 1] <<= 1;
	if (carry)
		pad[AES_BLOCK_SIZE - 1] ^= 0x87;
}


static void aes_128_cmac_vector(struct crypto_cipher *tfm, u8 *scratch,
				size_t num_elem,
				const u8 *addr[], const size_t *len, u8 *mac)
{
	u8 *cbc, *pad;
	const u8 *pos, *end;
	size_t i, e, left, total_len;

	cbc = scratch;
	pad = scratch + AES_BLOCK_SIZE;

	memset(cbc, 0, AES_BLOCK_SIZE);

	total_len = 0;
	for (e = 0; e < num_elem; e++)
		total_len += len[e];
	left = total_len;

	e = 0;
	pos = addr[0];
	end = pos + len[0];

	while (left >= AES_BLOCK_SIZE) {
		for (i = 0; i < AES_BLOCK_SIZE; i++) {
			cbc[i] ^= *pos++;
			if (pos >= end) {
				e++;
				pos = addr[e];
				end = pos + len[e];
			}
		}
		if (left > AES_BLOCK_SIZE)
			crypto_cipher_encrypt_one(tfm, cbc, cbc);
		left -= AES_BLOCK_SIZE;
	}

	memset(pad, 0, AES_BLOCK_SIZE);
	crypto_cipher_encrypt_one(tfm, pad, pad);
	gf_mulx(pad);

	if (left || total_len == 0) {
		for (i = 0; i < left; i++) {
			cbc[i] ^= *pos++;
			if (pos >= end) {
				e++;
				pos = addr[e];
				end = pos + len[e];
			}
		}
		cbc[left] ^= 0x80;
		gf_mulx(pad);
	}

	for (i = 0; i < AES_BLOCK_SIZE; i++)
		pad[i] ^= cbc[i];
	crypto_cipher_encrypt_one(tfm, pad, pad);
	memcpy(mac, pad, CMAC_TLEN);
}


void ieee80211_aes_cmac(struct crypto_cipher *tfm, u8 *scratch, const u8 *aad,
			const u8 *data, size_t data_len, u8 *mic)
{
	const u8 *addr[3];
	size_t len[3];
	u8 zero[CMAC_TLEN];

	memset(zero, 0, CMAC_TLEN);
	addr[0] = aad;
	len[0] = AAD_LEN;
	addr[1] = data;
	len[1] = data_len - CMAC_TLEN;
	addr[2] = zero;
	len[2] = CMAC_TLEN;

	aes_128_cmac_vector(tfm, scratch, 3, addr, len, mic);
}


struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[])
{
	struct crypto_cipher *tfm;

	tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(tfm))
		return NULL;

	crypto_cipher_setkey(tfm, key, AES_CMAC_KEY_LEN);

	return tfm;
}


void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm)
{
	if (tfm)
		crypto_free_cipher(tfm);
}
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