In article <5912ca9e-b4e7-423d-a45d-f4693d1c9...@zoulas.com>,
Christos Zoulas <chris...@zoulas.com> wrote:
>-=-=-=-=-=-
Here's the final changes
- Make ALIGNED_POINTER use __alignof(t) instead of sizeof(t). This is more
correct because it works with non-primitive types and provides the ABI
alignment for the type the compiler will use.
- Remove all the *_HDR_ALIGNMENT macros and asserts
- Replace POINTER_ALIGNED_P with ACCESSIBLE_POINTER which is identical to
ALIGNED_POINTER, but returns that the pointer is always aligned if the
CPU supports unaligned accesses.
Index: sys/mbuf.h
===================================================================
RCS file: /cvsroot/src/sys/sys/mbuf.h,v
retrieving revision 1.231
diff -u -u -r1.231 mbuf.h
--- sys/mbuf.h 17 Feb 2021 22:32:04 -0000 1.231
+++ sys/mbuf.h 17 Feb 2021 23:54:31 -0000
@@ -843,15 +843,21 @@
m->m_pkthdr.rcvif_index = n->m_pkthdr.rcvif_index;
}
+#define M_GET_ALIGNED_HDR(m, type, linkhdr) \
+ m_get_aligned_hdr((m), __alignof(type) - 1, sizeof(type), (linkhdr))
+
static __inline int
-m_get_aligned_hdr(struct mbuf **m, int align, size_t hlen, bool linkhdr)
+m_get_aligned_hdr(struct mbuf **m, int mask, size_t hlen, bool linkhdr)
{
- if (POINTER_ALIGNED_P(mtod(*m, void *), align) == 0) {
- --align; // Turn into mask
+#ifndef __NO_STRICT_ALIGNMENT
+ if (((uintptr_t)mtod(*m, void *) & mask) != 0)
*m = m_copyup(*m, hlen,
- linkhdr ? (max_linkhdr + align) & ~align : 0);
- } else if (__predict_false((size_t)(*m)->m_len < hlen))
+ linkhdr ? (max_linkhdr + mask) & ~mask : 0);
+ else
+#endif
+ if (__predict_false((size_t)(*m)->m_len < hlen))
*m = m_pullup(*m, hlen);
+
return *m == NULL;
}
Index: sys/param.h
===================================================================
RCS file: /cvsroot/src/sys/sys/param.h,v
retrieving revision 1.689
diff -u -u -r1.689 param.h
--- sys/param.h 17 Feb 2021 22:32:04 -0000 1.689
+++ sys/param.h 17 Feb 2021 23:54:31 -0000
@@ -281,16 +281,24 @@
#define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &
~ALIGNBYTES)
#endif
#ifndef ALIGNED_POINTER
-#define ALIGNED_POINTER(p,t) ((((uintptr_t)(p)) & (sizeof(t) - 1))
== 0)
+#define ALIGNED_POINTER(p,t) ((((uintptr_t)(p)) & (__alignof(t) -
1)) == 0)
#endif
#ifndef ALIGNED_POINTER_LOAD
#define ALIGNED_POINTER_LOAD(q,p,t) (*(q) = *((const t *)(p)))
#endif
+/*
+ * Return if the pointer p is accessible for type t. For primitive types
+ * this means that the pointer itself can be dereferenced; for structures
+ * and unions this means that any field can be dereferenced. On CPUs
+ * that allow unaligned pointer access, we always return that the pointer
+ * is accessible to prevent unnecessary copies, although this might not be
+ * necessarily faster.
+ */
#ifdef __NO_STRICT_ALIGNMENT
-#define POINTER_ALIGNED_P(p, a) 1
+#define ACCESSIBLE_POINTER(p, t) 1
#else
-#define POINTER_ALIGNED_P(p, a) (((uintptr_t)(p) & ((a) - 1))
== 0)
+#define ACCESSIBLE_POINTER(p, t) ALIGNED_POINTER(p, t)
#endif
/*
Index: net/if_arp.h
===================================================================
RCS file: /cvsroot/src/sys/net/if_arp.h,v
retrieving revision 1.42
diff -u -u -r1.42 if_arp.h
--- net/if_arp.h 17 Feb 2021 22:32:04 -0000 1.42
+++ net/if_arp.h 17 Feb 2021 23:54:31 -0000
@@ -72,8 +72,6 @@
uint8_t ar_tpa[]; /* target protocol address */
#endif
};
-#define ARP_HDR_ALIGNMENT __alignof(struct arphdr)
-__CTASSERT(ARP_HDR_ALIGNMENT == 2);
static __inline uint8_t *
ar_data(struct arphdr *ap)
Index: net/if_bridge.c
===================================================================
RCS file: /cvsroot/src/sys/net/if_bridge.c,v
retrieving revision 1.178
diff -u -u -r1.178 if_bridge.c
--- net/if_bridge.c 14 Feb 2021 20:58:34 -0000 1.178
+++ net/if_bridge.c 17 Feb 2021 23:54:31 -0000
@@ -2806,7 +2806,7 @@
if (*mp == NULL)
return -1;
- if (m_get_aligned_hdr(&m, IP_HDR_ALIGNMENT, sizeof(*ip), true) != 0) {
+ if (M_GET_ALIGNED_HDR(&m, struct ip, true) != 0) {
/* XXXJRT new stat, please */
ip_statinc(IP_STAT_TOOSMALL);
goto bad;
@@ -2900,7 +2900,7 @@
* it. Otherwise, if it is aligned, make sure the entire base
* IPv6 header is in the first mbuf of the chain.
*/
- if (m_get_aligned_hdr(&m, IP6_HDR_ALIGNMENT, sizeof(*ip6), true) != 0) {
+ if (M_GET_ALIGNED_HDR(&m, struct ip6_hdr, true) != 0) {
struct ifnet *inifp = m_get_rcvif_NOMPSAFE(m);
/* XXXJRT new stat, please */
ip6_statinc(IP6_STAT_TOOSMALL);
Index: netinet/if_arp.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/if_arp.c,v
retrieving revision 1.306
diff -u -u -r1.306 if_arp.c
--- netinet/if_arp.c 16 Feb 2021 10:22:52 -0000 1.306
+++ netinet/if_arp.c 17 Feb 2021 23:54:31 -0000
@@ -706,7 +706,7 @@
goto badlen;
}
ar = mtod(m, struct arphdr *);
- KASSERT(POINTER_ALIGNED_P(ar, ARP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(ar, struct arphdr));
rcvif = m_get_rcvif(m, &s);
if (__predict_false(rcvif == NULL)) {
@@ -735,7 +735,7 @@
if ((m = m_pullup(m, arplen)) == NULL)
goto badlen;
ar = mtod(m, struct arphdr *);
- KASSERT(POINTER_ALIGNED_P(ar, ARP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(ar, struct arphdr));
}
switch (ntohs(ar->ar_pro)) {
Index: netinet/in_l2tp.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/in_l2tp.c,v
retrieving revision 1.19
diff -u -u -r1.19 in_l2tp.c
--- netinet/in_l2tp.c 14 Feb 2021 20:58:35 -0000 1.19
+++ netinet/in_l2tp.c 17 Feb 2021 23:54:31 -0000
@@ -197,8 +197,7 @@
error = ENOBUFS;
goto out;
}
- if (m_get_aligned_hdr(&m, IP_HDR_ALIGNMENT, sizeof(iphdr), false) != 0)
- {
+ if (M_GET_ALIGNED_HDR(&m, struct ip, false) != 0) {
error = ENOBUFS;
goto out;
}
Index: netinet/ip_flow.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/ip_flow.c,v
retrieving revision 1.84
diff -u -u -r1.84 ip_flow.c
--- netinet/ip_flow.c 15 Feb 2021 03:41:01 -0000 1.84
+++ netinet/ip_flow.c 17 Feb 2021 23:54:31 -0000
@@ -231,7 +231,7 @@
* IP header with no option and valid version and length
*/
ip = mtod(m, struct ip *);
- if (!POINTER_ALIGNED_P(ip, IP_HDR_ALIGNMENT)) {
+ if (!ACCESSIBLE_POINTER(ip, struct ip)) {
memcpy(&ip_store, mtod(m, const void *), sizeof(ip_store));
ip = &ip_store;
}
@@ -313,7 +313,7 @@
*
* XXX Use m_copyback_cow(9) here? --dyoung
*/
- if (!POINTER_ALIGNED_P(mtod(m, void *), IP_HDR_ALIGNMENT))
+ if (!ACCESSIBLE_POINTER(mtod(m, void *), struct ip))
memcpy(mtod(m, void *), &ip_store, sizeof(ip_store));
/*
Index: netinet/ip_input.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/ip_input.c,v
retrieving revision 1.398
diff -u -u -r1.398 ip_input.c
--- netinet/ip_input.c 14 Feb 2021 20:58:35 -0000 1.398
+++ netinet/ip_input.c 17 Feb 2021 23:54:31 -0000
@@ -454,7 +454,7 @@
* it. Otherwise, if it is aligned, make sure the entire
* base IP header is in the first mbuf of the chain.
*/
- if (m_get_aligned_hdr(&m, IP_HDR_ALIGNMENT, sizeof(*ip), true) != 0) {
+ if (M_GET_ALIGNED_HDR(&m, struct ip, true) != 0) {
/* XXXJRT new stat, please */
IP_STATINC(IP_STAT_TOOSMALL);
goto out;
Index: netinet/ip_private.h
===================================================================
RCS file: /cvsroot/src/sys/netinet/ip_private.h,v
retrieving revision 1.5
diff -u -u -r1.5 ip_private.h
--- netinet/ip_private.h 17 Feb 2021 22:32:04 -0000 1.5
+++ netinet/ip_private.h 17 Feb 2021 23:54:31 -0000
@@ -43,8 +43,6 @@
#define IP_STATINC(x) _NET_STATINC(ipstat_percpu, x)
#define IP_STATDEC(x) _NET_STATDEC(ipstat_percpu, x)
-#define IP_HDR_ALIGNMENT __alignof(struct ip)
-__CTASSERT(IP_HDR_ALIGNMENT == 4);
#endif /* _KERNEL */
#endif /* !_NETINET_IP_PRIVATE_H_ */
Index: netinet/tcp_input.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/tcp_input.c,v
retrieving revision 1.425
diff -u -u -r1.425 tcp_input.c
--- netinet/tcp_input.c 14 Feb 2021 20:58:35 -0000 1.425
+++ netinet/tcp_input.c 17 Feb 2021 23:54:31 -0000
@@ -1274,7 +1274,7 @@
* Enforce alignment requirements that are violated in
* some cases, see kern/50766 for details.
*/
- if (POINTER_ALIGNED_P(th, TCP_HDR_ALIGNMENT) == 0) {
+ if (ACCESSIBLE_POINTER(th, struct tcp_hdr) == 0) {
m = m_copyup(m, off + sizeof(struct tcphdr), 0);
if (m == NULL) {
TCP_STATINC(TCP_STAT_RCVSHORT);
@@ -1282,7 +1282,7 @@
}
th = (struct tcphdr *)(mtod(m, char *) + off);
}
- KASSERT(POINTER_ALIGNED_P(th, TCP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(th, struct tcp_hdr));
/*
* Get IP and TCP header.
@@ -1362,7 +1362,7 @@
TCP_STATINC(TCP_STAT_RCVSHORT);
return;
}
- KASSERT(POINTER_ALIGNED_P(th, TCP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(th, struct tcp_hdr));
optlen = thlen - sizeof(struct tcphdr);
optp = ((u_int8_t *)th) + sizeof(struct tcphdr);
Index: netinet/tcp_private.h
===================================================================
RCS file: /cvsroot/src/sys/netinet/tcp_private.h,v
retrieving revision 1.5
diff -u -u -r1.5 tcp_private.h
--- netinet/tcp_private.h 17 Feb 2021 22:32:04 -0000 1.5
+++ netinet/tcp_private.h 17 Feb 2021 23:54:31 -0000
@@ -43,8 +43,6 @@
#define TCP_STATINC(x) _NET_STATINC(tcpstat_percpu, x)
#define TCP_STATADD(x, v) _NET_STATADD(tcpstat_percpu, x, v)
-#define TCP_HDR_ALIGNMENT __alignof(struct tcphdr)
-__CTASSERT(TCP_HDR_ALIGNMENT == 4);
#endif /* _KERNEL */
#endif /* !_NETINET_TCP_PRIVATE_H_ */
Index: netinet/udp_private.h
===================================================================
RCS file: /cvsroot/src/sys/netinet/udp_private.h,v
retrieving revision 1.5
diff -u -u -r1.5 udp_private.h
--- netinet/udp_private.h 17 Feb 2021 22:32:04 -0000 1.5
+++ netinet/udp_private.h 17 Feb 2021 23:54:31 -0000
@@ -39,8 +39,6 @@
#define UDP_STATINC(x) _NET_STATINC(udpstat_percpu, x)
-#define UDP_HDR_ALIGNMENT __alignof(struct udphdr)
-__CTASSERT(UDP_HDR_ALIGNMENT == 2);
#endif /* _KERNEL */
#endif /* !_NETINET_UDP_PRIVATE_H_ */
Index: netinet/udp_usrreq.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/udp_usrreq.c,v
retrieving revision 1.260
diff -u -u -r1.260 udp_usrreq.c
--- netinet/udp_usrreq.c 14 Feb 2021 20:58:35 -0000 1.260
+++ netinet/udp_usrreq.c 17 Feb 2021 23:54:31 -0000
@@ -335,7 +335,7 @@
* Enforce alignment requirements that are violated in
* some cases, see kern/50766 for details.
*/
- if (POINTER_ALIGNED_P(uh, UDP_HDR_ALIGNMENT) == 0) {
+ if (ACCESSIBLE_POINTER(uh, struct udphdr) == 0) {
m = m_copyup(m, iphlen + sizeof(struct udphdr), 0);
if (m == NULL) {
UDP_STATINC(UDP_STAT_HDROPS);
@@ -344,7 +344,7 @@
ip = mtod(m, struct ip *);
uh = (struct udphdr *)(mtod(m, char *) + iphlen);
}
- KASSERT(POINTER_ALIGNED_P(uh, UDP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(uh, struct udphdr));
/* destination port of 0 is illegal, based on RFC768. */
if (uh->uh_dport == 0)
Index: netinet6/icmp6.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/icmp6.c,v
retrieving revision 1.249
diff -u -u -r1.249 icmp6.c
--- netinet6/icmp6.c 15 Feb 2021 10:13:45 -0000 1.249
+++ netinet6/icmp6.c 17 Feb 2021 23:54:31 -0000
@@ -538,7 +538,7 @@
* Enforce alignment requirements that are violated in
* some cases, see kern/50766 for details.
*/
- if (POINTER_ALIGNED_P(icmp6, IP6_HDR_ALIGNMENT) == 0) {
+ if (ACCESSIBLE_POINTER(icmp6, struct ip6_hdr) == 0) {
m = m_copyup(m, off + sizeof(struct icmp6_hdr), 0);
if (m == NULL) {
ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
@@ -548,7 +548,7 @@
ip6 = mtod(m, struct ip6_hdr *);
icmp6 = (struct icmp6_hdr *)(mtod(m, char *) + off);
}
- KASSERT(POINTER_ALIGNED_P(icmp6, IP6_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(icmp6, struct ip6_hdr));
/*
* calculate the checksum
Index: netinet6/in6_l2tp.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/in6_l2tp.c,v
retrieving revision 1.20
diff -u -u -r1.20 in6_l2tp.c
--- netinet6/in6_l2tp.c 14 Feb 2021 20:58:35 -0000 1.20
+++ netinet6/in6_l2tp.c 17 Feb 2021 23:54:31 -0000
@@ -193,8 +193,7 @@
M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
if (m == NULL)
return ENOBUFS;
- if (m_get_aligned_hdr(&m, IP6_HDR_ALIGNMENT, sizeof(ip6hdr),
- false) != 0)
+ if (M_GET_ALIGNED_HDR(&m, struct ip6_hdr, false) != 0)
return ENOBUFS;
memcpy(mtod(m, struct ip6_hdr *), &ip6hdr, sizeof(struct ip6_hdr));
Index: netinet6/ip6_flow.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/ip6_flow.c,v
retrieving revision 1.41
diff -u -u -r1.41 ip6_flow.c
--- netinet6/ip6_flow.c 14 Feb 2021 20:58:35 -0000 1.41
+++ netinet6/ip6_flow.c 17 Feb 2021 23:54:31 -0000
@@ -283,7 +283,7 @@
if ((m->m_flags & (M_BCAST|M_MCAST)) != 0)
goto out;
- if (POINTER_ALIGNED_P(mtod(m, const void *), IP6_HDR_ALIGNMENT) == 0) {
+ if (ACCESSIBLE_POINTER(mtod(m, const void *), struct ip6_hdr) == 0) {
if ((m = m_copyup(m, sizeof(struct ip6_hdr),
(max_linkhdr + 3) & ~3)) == NULL) {
ret = 1;
Index: netinet6/ip6_input.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/ip6_input.c,v
retrieving revision 1.223
diff -u -u -r1.223 ip6_input.c
--- netinet6/ip6_input.c 14 Feb 2021 20:58:35 -0000 1.223
+++ netinet6/ip6_input.c 17 Feb 2021 23:54:31 -0000
@@ -301,7 +301,7 @@
* it. Otherwise, if it is aligned, make sure the entire base
* IPv6 header is in the first mbuf of the chain.
*/
- if (m_get_aligned_hdr(&m, IP6_HDR_ALIGNMENT, sizeof(*ip6), true) != 0) {
+ if (M_GET_ALIGNED_HDR(&m, struct ip6_hdr, true) != 0) {
/* XXXJRT new stat, please */
IP6_STATINC(IP6_STAT_TOOSMALL);
in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
@@ -602,7 +602,7 @@
rtcache_percpu_putref(ip6_forward_rt_percpu);
return;
}
- KASSERT(POINTER_ALIGNED_P(hbh, IP6_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(hbh, struct ip6_hdr));
nxt = hbh->ip6h_nxt;
/*
@@ -875,7 +875,7 @@
IP6_STATINC(IP6_STAT_TOOSHORT);
return -1;
}
- KASSERT(POINTER_ALIGNED_P(hbh, IP6_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(hbh, struct ip6_hdr));
off += hbhlen;
hbhlen -= sizeof(struct ip6_hbh);
@@ -1215,7 +1215,7 @@
IP6_STATINC(IP6_STAT_TOOSHORT);
return;
}
- KASSERT(POINTER_ALIGNED_P(ip6e, IP6_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(ip6e, struct ip6_hdr));
switch (nxt) {
case IPPROTO_DSTOPTS:
Index: netinet6/ip6_private.h
===================================================================
RCS file: /cvsroot/src/sys/netinet6/ip6_private.h,v
retrieving revision 1.5
diff -u -u -r1.5 ip6_private.h
--- netinet6/ip6_private.h 17 Feb 2021 22:32:04 -0000 1.5
+++ netinet6/ip6_private.h 17 Feb 2021 23:54:31 -0000
@@ -43,8 +43,6 @@
#define IP6_STATINC(x) _NET_STATINC(ip6stat_percpu, x)
#define IP6_STATDEC(x) _NET_STATDEC(ip6stat_percpu, x)
-#define IP6_HDR_ALIGNMENT __alignof(struct ip6_hdr)
-__CTASSERT(IP6_HDR_ALIGNMENT == 4);
#endif /* _KERNEL */
#endif /* !_NETINET_IP6_PRIVATE_H_ */
Index: netinet6/udp6_usrreq.c
===================================================================
RCS file: /cvsroot/src/sys/netinet6/udp6_usrreq.c,v
retrieving revision 1.149
diff -u -u -r1.149 udp6_usrreq.c
--- netinet6/udp6_usrreq.c 14 Feb 2021 20:58:35 -0000 1.149
+++ netinet6/udp6_usrreq.c 17 Feb 2021 23:54:31 -0000
@@ -665,7 +665,7 @@
* Enforce alignment requirements that are violated in
* some cases, see kern/50766 for details.
*/
- if (POINTER_ALIGNED_P(uh, UDP_HDR_ALIGNMENT) == 0) {
+ if (ACCESSIBLE_POINTER(uh, struct udphdr) == 0) {
m = m_copyup(m, off + sizeof(struct udphdr), 0);
if (m == NULL) {
IP6_STATINC(IP6_STAT_TOOSHORT);
@@ -674,7 +674,7 @@
ip6 = mtod(m, struct ip6_hdr *);
uh = (struct udphdr *)(mtod(m, char *) + off);
}
- KASSERT(POINTER_ALIGNED_P(uh, UDP_HDR_ALIGNMENT));
+ KASSERT(ACCESSIBLE_POINTER(uh, struct udphdr));
ulen = ntohs((u_short)uh->uh_ulen);
/*
