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linux/drivers/net/tile/tilepro.c

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/*
* Copyright 2011 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/netdevice.h> /* struct device, and other headers */
#include <linux/etherdevice.h> /* eth_type_trans */
#include <linux/skbuff.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/hugetlb.h>
#include <linux/in6.h>
#include <linux/timer.h>
#include <linux/io.h>
#include <asm/checksum.h>
#include <asm/homecache.h>
#include <hv/drv_xgbe_intf.h>
#include <hv/drv_xgbe_impl.h>
#include <hv/hypervisor.h>
#include <hv/netio_intf.h>
/* For TSO */
#include <linux/ip.h>
#include <linux/tcp.h>
/*
* First, "tile_net_init_module()" initializes all four "devices" which
* can be used by linux.
*
* Then, "ifconfig DEVICE up" calls "tile_net_open()", which analyzes
* the network cpus, then uses "tile_net_open_aux()" to initialize
* LIPP/LEPP, and then uses "tile_net_open_inner()" to register all
* the tiles, provide buffers to LIPP, allow ingress to start, and
* turn on hypervisor interrupt handling (and NAPI) on all tiles.
*
* If registration fails due to the link being down, then "retry_work"
* is used to keep calling "tile_net_open_inner()" until it succeeds.
*
* If "ifconfig DEVICE down" is called, it uses "tile_net_stop()" to
* stop egress, drain the LIPP buffers, unregister all the tiles, stop
* LIPP/LEPP, and wipe the LEPP queue.
*
* We start out with the ingress interrupt enabled on each CPU. When
* this interrupt fires, we disable it, and call "napi_schedule()".
* This will cause "tile_net_poll()" to be called, which will pull
* packets from the netio queue, filtering them out, or passing them
* to "netif_receive_skb()". If our budget is exhausted, we will
* return, knowing we will be called again later. Otherwise, we
* reenable the ingress interrupt, and call "napi_complete()".
*
* HACK: Since disabling the ingress interrupt is not reliable, we
* ignore the interrupt if the global "active" flag is false.
*
*
* NOTE: The use of "native_driver" ensures that EPP exists, and that
* we are using "LIPP" and "LEPP".
*
* NOTE: Failing to free completions for an arbitrarily long time
* (which is defined to be illegal) does in fact cause bizarre
* problems. The "egress_timer" helps prevent this from happening.
*/
/* HACK: Allow use of "jumbo" packets. */
/* This should be 1500 if "jumbo" is not set in LIPP. */
/* This should be at most 10226 (10240 - 14) if "jumbo" is set in LIPP. */
/* ISSUE: This has not been thoroughly tested (except at 1500). */
#define TILE_NET_MTU 1500
/* HACK: Define to support GSO. */
/* ISSUE: This may actually hurt performance of the TCP blaster. */
/* #define TILE_NET_GSO */
/* Define this to collapse "duplicate" acks. */
/* #define IGNORE_DUP_ACKS */
/* HACK: Define this to verify incoming packets. */
/* #define TILE_NET_VERIFY_INGRESS */
/* Use 3000 to enable the Linux Traffic Control (QoS) layer, else 0. */
#define TILE_NET_TX_QUEUE_LEN 0
/* Define to dump packets (prints out the whole packet on tx and rx). */
/* #define TILE_NET_DUMP_PACKETS */
/* Define to enable debug spew (all PDEBUG's are enabled). */
/* #define TILE_NET_DEBUG */
/* Define to activate paranoia checks. */
/* #define TILE_NET_PARANOIA */
/* Default transmit lockup timeout period, in jiffies. */
#define TILE_NET_TIMEOUT (5 * HZ)
/* Default retry interval for bringing up the NetIO interface, in jiffies. */
#define TILE_NET_RETRY_INTERVAL (5 * HZ)
/* Number of ports (xgbe0, xgbe1, gbe0, gbe1). */
#define TILE_NET_DEVS 4
/* Paranoia. */
#if NET_IP_ALIGN != LIPP_PACKET_PADDING
#error "NET_IP_ALIGN must match LIPP_PACKET_PADDING."
#endif
/* Debug print. */
#ifdef TILE_NET_DEBUG
#define PDEBUG(fmt, args...) net_printk(fmt, ## args)
#else
#define PDEBUG(fmt, args...)
#endif
MODULE_AUTHOR("Tilera");
MODULE_LICENSE("GPL");
/*
* Queue of incoming packets for a specific cpu and device.
*
* Includes a pointer to the "system" data, and the actual "user" data.
*/
struct tile_netio_queue {
netio_queue_impl_t *__system_part;
netio_queue_user_impl_t __user_part;
};
/*
* Statistics counters for a specific cpu and device.
*/
struct tile_net_stats_t {
u32 rx_packets;
u32 rx_bytes;
u32 tx_packets;
u32 tx_bytes;
};
/*
* Info for a specific cpu and device.
*
* ISSUE: There is a "dev" pointer in "napi" as well.
*/
struct tile_net_cpu {
/* The NAPI struct. */
struct napi_struct napi;
/* Packet queue. */
struct tile_netio_queue queue;
/* Statistics. */
struct tile_net_stats_t stats;
/* True iff NAPI is enabled. */
bool napi_enabled;
/* True if this tile has succcessfully registered with the IPP. */
bool registered;
/* True if the link was down last time we tried to register. */
bool link_down;
/* True if "egress_timer" is scheduled. */
bool egress_timer_scheduled;
/* Number of small sk_buffs which must still be provided. */
unsigned int num_needed_small_buffers;
/* Number of large sk_buffs which must still be provided. */
unsigned int num_needed_large_buffers;
/* A timer for handling egress completions. */
struct timer_list egress_timer;
};
/*
* Info for a specific device.
*/
struct tile_net_priv {
/* Our network device. */
struct net_device *dev;
/* Pages making up the egress queue. */
struct page *eq_pages;
/* Address of the actual egress queue. */
lepp_queue_t *eq;
/* Protects "eq". */
spinlock_t eq_lock;
/* The hypervisor handle for this interface. */
int hv_devhdl;
/* The intr bit mask that IDs this device. */
u32 intr_id;
/* True iff "tile_net_open_aux()" has succeeded. */
bool partly_opened;
/* True iff the device is "active". */
bool active;
/* Effective network cpus. */
struct cpumask network_cpus_map;
/* Number of network cpus. */
int network_cpus_count;
/* Credits per network cpu. */
int network_cpus_credits;
/* Network stats. */
struct net_device_stats stats;
/* For NetIO bringup retries. */
struct delayed_work retry_work;
/* Quick access to per cpu data. */
struct tile_net_cpu *cpu[NR_CPUS];
};
/* Log2 of the number of small pages needed for the egress queue. */
#define EQ_ORDER get_order(sizeof(lepp_queue_t))
/* Size of the egress queue's pages. */
#define EQ_SIZE (1 << (PAGE_SHIFT + EQ_ORDER))
/*
* The actual devices (xgbe0, xgbe1, gbe0, gbe1).
*/
static struct net_device *tile_net_devs[TILE_NET_DEVS];
/*
* The "tile_net_cpu" structures for each device.
*/
static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe0);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_xgbe1);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe0);
static DEFINE_PER_CPU(struct tile_net_cpu, hv_gbe1);
/*
* True if "network_cpus" was specified.
*/
static bool network_cpus_used;
/*
* The actual cpus in "network_cpus".
*/
static struct cpumask network_cpus_map;
#ifdef TILE_NET_DEBUG
/*
* printk with extra stuff.
*
* We print the CPU we're running in brackets.
*/
static void net_printk(char *fmt, ...)
{
int i;
int len;
va_list args;
static char buf[256];
len = sprintf(buf, "tile_net[%2.2d]: ", smp_processor_id());
va_start(args, fmt);
i = vscnprintf(buf + len, sizeof(buf) - len - 1, fmt, args);
va_end(args);
buf[255] = '\0';
pr_notice(buf);
}
#endif
#ifdef TILE_NET_DUMP_PACKETS
/*
* Dump a packet.
*/
static void dump_packet(unsigned char *data, unsigned long length, char *s)
{
int my_cpu = smp_processor_id();
unsigned long i;
char buf[128];
static unsigned int count;
pr_info("dump_packet(data %p, length 0x%lx s %s count 0x%x)\n",
data, length, s, count++);
pr_info("\n");
for (i = 0; i < length; i++) {
if ((i & 0xf) == 0)
sprintf(buf, "[%02d] %8.8lx:", my_cpu, i);
sprintf(buf + strlen(buf), " %2.2x", data[i]);
if ((i & 0xf) == 0xf || i == length - 1) {
strcat(buf, "\n");
pr_info("%s", buf);
}
}
}
#endif
/*
* Provide support for the __netio_fastio1() swint
* (see <hv/drv_xgbe_intf.h> for how it is used).
*
* The fastio swint2 call may clobber all the caller-saved registers.
* It rarely clobbers memory, but we allow for the possibility in
* the signature just to be on the safe side.
*
* Also, gcc doesn't seem to allow an input operand to be
* clobbered, so we fake it with dummy outputs.
*
* This function can't be static because of the way it is declared
* in the netio header.
*/
inline int __netio_fastio1(u32 fastio_index, u32 arg0)
{
long result, clobber_r1, clobber_r10;
asm volatile("swint2"
: "=R00" (result),
"=R01" (clobber_r1), "=R10" (clobber_r10)
: "R10" (fastio_index), "R01" (arg0)
: "memory", "r2", "r3", "r4",
"r5", "r6", "r7", "r8", "r9",
"r11", "r12", "r13", "r14",
"r15", "r16", "r17", "r18", "r19",
"r20", "r21", "r22", "r23", "r24",
"r25", "r26", "r27", "r28", "r29");
return result;
}
/*
* Provide a linux buffer to LIPP.
*/
static void tile_net_provide_linux_buffer(struct tile_net_cpu *info,
void *va, bool small)
{
struct tile_netio_queue *queue = &info->queue;
/* Convert "va" and "small" to "linux_buffer_t". */
unsigned int buffer = ((unsigned int)(__pa(va) >> 7) << 1) + small;
__netio_fastio_free_buffer(queue->__user_part.__fastio_index, buffer);
}
/*
* Provide a linux buffer for LIPP.
*
* Note that the ACTUAL allocation for each buffer is a "struct sk_buff",
* plus a chunk of memory that includes not only the requested bytes, but
* also NET_SKB_PAD bytes of initial padding, and a "struct skb_shared_info".
*
* Note that "struct skb_shared_info" is 88 bytes with 64K pages and
* 268 bytes with 4K pages (since the frags[] array needs 18 entries).
*
* Without jumbo packets, the maximum packet size will be 1536 bytes,
* and we use 2 bytes (NET_IP_ALIGN) of padding. ISSUE: If we told
* the hardware to clip at 1518 bytes instead of 1536 bytes, then we
* could save an entire cache line, but in practice, we don't need it.
*
* Since CPAs are 38 bits, and we can only encode the high 31 bits in
* a "linux_buffer_t", the low 7 bits must be zero, and thus, we must
* align the actual "va" mod 128.
*
* We assume that the underlying "head" will be aligned mod 64. Note
* that in practice, we have seen "head" NOT aligned mod 128 even when
* using 2048 byte allocations, which is surprising.
*
* If "head" WAS always aligned mod 128, we could change LIPP to
* assume that the low SIX bits are zero, and the 7th bit is one, that
* is, align the actual "va" mod 128 plus 64, which would be "free".
*
* For now, the actual "head" pointer points at NET_SKB_PAD bytes of
* padding, plus 28 or 92 bytes of extra padding, plus the sk_buff
* pointer, plus the NET_IP_ALIGN padding, plus 126 or 1536 bytes for
* the actual packet, plus 62 bytes of empty padding, plus some
* padding and the "struct skb_shared_info".
*
* With 64K pages, a large buffer thus needs 32+92+4+2+1536+62+88
* bytes, or 1816 bytes, which fits comfortably into 2048 bytes.
*
* With 64K pages, a small buffer thus needs 32+92+4+2+126+88
* bytes, or 344 bytes, which means we are wasting 64+ bytes, and
* could presumably increase the size of small buffers.
*
* With 4K pages, a large buffer thus needs 32+92+4+2+1536+62+268
* bytes, or 1996 bytes, which fits comfortably into 2048 bytes.
*
* With 4K pages, a small buffer thus needs 32+92+4+2+126+268
* bytes, or 524 bytes, which is annoyingly wasteful.
*
* Maybe we should increase LIPP_SMALL_PACKET_SIZE to 192?
*
* ISSUE: Maybe we should increase "NET_SKB_PAD" to 64?
*/
static bool tile_net_provide_needed_buffer(struct tile_net_cpu *info,
bool small)
{
#if TILE_NET_MTU <= 1536
/* Without "jumbo", 2 + 1536 should be sufficient. */
unsigned int large_size = NET_IP_ALIGN + 1536;
#else
/* ISSUE: This has not been tested. */
unsigned int large_size = NET_IP_ALIGN + TILE_NET_MTU + 100;
#endif
/* Avoid "false sharing" with last cache line. */
/* ISSUE: This is already done by "dev_alloc_skb()". */
unsigned int len =
(((small ? LIPP_SMALL_PACKET_SIZE : large_size) +
CHIP_L2_LINE_SIZE() - 1) & -CHIP_L2_LINE_SIZE());
unsigned int padding = 128 - NET_SKB_PAD;
unsigned int align;
struct sk_buff *skb;
void *va;
struct sk_buff **skb_ptr;
/* Request 96 extra bytes for alignment purposes. */
skb = dev_alloc_skb(len + padding);
if (skb == NULL)
return false;
/* Skip 32 or 96 bytes to align "data" mod 128. */
align = -(long)skb->data & (128 - 1);
BUG_ON(align > padding);
skb_reserve(skb, align);
/* This address is given to IPP. */
va = skb->data;
/* Buffers must not span a huge page. */
BUG_ON(((((long)va & ~HPAGE_MASK) + len) & HPAGE_MASK) != 0);
#ifdef TILE_NET_PARANOIA
#if CHIP_HAS_CBOX_HOME_MAP()
if (hash_default) {
HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)va);
if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3)
panic("Non-HFH ingress buffer! VA=%p Mode=%d PTE=%llx",
va, hv_pte_get_mode(pte), hv_pte_val(pte));
}
#endif
#endif
/* Invalidate the packet buffer. */
if (!hash_default)
__inv_buffer(va, len);
/* Skip two bytes to satisfy LIPP assumptions. */
/* Note that this aligns IP on a 16 byte boundary. */
/* ISSUE: Do this when the packet arrives? */
skb_reserve(skb, NET_IP_ALIGN);
/* Save a back-pointer to 'skb'. */
skb_ptr = va - sizeof(*skb_ptr);
*skb_ptr = skb;
/* Make sure "skb_ptr" has been flushed. */
__insn_mf();
/* Provide the new buffer. */
tile_net_provide_linux_buffer(info, va, small);
return true;
}
/*
* Provide linux buffers for LIPP.
*/
static void tile_net_provide_needed_buffers(struct tile_net_cpu *info)
{
while (info->num_needed_small_buffers != 0) {
if (!tile_net_provide_needed_buffer(info, true))
goto oops;
info->num_needed_small_buffers--;
}
while (info->num_needed_large_buffers != 0) {
if (!tile_net_provide_needed_buffer(info, false))
goto oops;
info->num_needed_large_buffers--;
}
return;
oops:
/* Add a description to the page allocation failure dump. */
pr_notice("Could not provide a linux buffer to LIPP.\n");
}
/*
* Grab some LEPP completions, and store them in "comps", of size
* "comps_size", and return the number of completions which were
* stored, so the caller can free them.
*/
static unsigned int tile_net_lepp_grab_comps(lepp_queue_t *eq,
struct sk_buff *comps[],
unsigned int comps_size,
unsigned int min_size)
{
unsigned int n = 0;
unsigned int comp_head = eq->comp_head;
unsigned int comp_busy = eq->comp_busy;
while (comp_head != comp_busy && n < comps_size) {
comps[n++] = eq->comps[comp_head];
LEPP_QINC(comp_head);
}
if (n < min_size)
return 0;
eq->comp_head = comp_head;
return n;
}
/*
* Free some comps, and return true iff there are still some pending.
*/
static bool tile_net_lepp_free_comps(struct net_device *dev, bool all)
{
struct tile_net_priv *priv = netdev_priv(dev);
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[64];
unsigned int wanted = 64;
unsigned int i, n;
bool pending;
spin_lock(&priv->eq_lock);
if (all)
eq->comp_busy = eq->comp_tail;
n = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
pending = (eq->comp_head != eq->comp_tail);
spin_unlock(&priv->eq_lock);
for (i = 0; i < n; i++)
kfree_skb(olds[i]);
return pending;
}
/*
* Make sure the egress timer is scheduled.
*
* Note that we use "schedule if not scheduled" logic instead of the more
* obvious "reschedule" logic, because "reschedule" is fairly expensive.
*/
static void tile_net_schedule_egress_timer(struct tile_net_cpu *info)
{
if (!info->egress_timer_scheduled) {
mod_timer_pinned(&info->egress_timer, jiffies + 1);
info->egress_timer_scheduled = true;
}
}
/*
* The "function" for "info->egress_timer".
*
* This timer will reschedule itself as long as there are any pending
* completions expected (on behalf of any tile).
*
* ISSUE: Realistically, will the timer ever stop scheduling itself?
*
* ISSUE: This timer is almost never actually needed, so just use a global
* timer that can run on any tile.
*
* ISSUE: Maybe instead track number of expected completions, and free
* only that many, resetting to zero if "pending" is ever false.
*/
static void tile_net_handle_egress_timer(unsigned long arg)
{
struct tile_net_cpu *info = (struct tile_net_cpu *)arg;
struct net_device *dev = info->napi.dev;
/* The timer is no longer scheduled. */
info->egress_timer_scheduled = false;
/* Free comps, and reschedule timer if more are pending. */
if (tile_net_lepp_free_comps(dev, false))
tile_net_schedule_egress_timer(info);
}
#ifdef IGNORE_DUP_ACKS
/*
* Help detect "duplicate" ACKs. These are sequential packets (for a
* given flow) which are exactly 66 bytes long, sharing everything but
* ID=2@0x12, Hsum=2@0x18, Ack=4@0x2a, WinSize=2@0x30, Csum=2@0x32,
* Tstamps=10@0x38. The ID's are +1, the Hsum's are -1, the Ack's are
* +N, and the Tstamps are usually identical.
*
* NOTE: Apparently truly duplicate acks (with identical "ack" values),
* should not be collapsed, as they are used for some kind of flow control.
*/
static bool is_dup_ack(char *s1, char *s2, unsigned int len)
{
int i;
unsigned long long ignorable = 0;
/* Identification. */
ignorable |= (1ULL << 0x12);
ignorable |= (1ULL << 0x13);
/* Header checksum. */
ignorable |= (1ULL << 0x18);
ignorable |= (1ULL << 0x19);
/* ACK. */
ignorable |= (1ULL << 0x2a);
ignorable |= (1ULL << 0x2b);
ignorable |= (1ULL << 0x2c);
ignorable |= (1ULL << 0x2d);
/* WinSize. */
ignorable |= (1ULL << 0x30);
ignorable |= (1ULL << 0x31);
/* Checksum. */
ignorable |= (1ULL << 0x32);
ignorable |= (1ULL << 0x33);
for (i = 0; i < len; i++, ignorable >>= 1) {
if ((ignorable & 1) || (s1[i] == s2[i]))
continue;
#ifdef TILE_NET_DEBUG
/* HACK: Mention non-timestamp diffs. */
if (i < 0x38 && i != 0x2f &&
net_ratelimit())
pr_info("Diff at 0x%x\n", i);
#endif
return false;
}
#ifdef TILE_NET_NO_SUPPRESS_DUP_ACKS
/* HACK: Do not suppress truly duplicate ACKs. */
/* ISSUE: Is this actually necessary or helpful? */
if (s1[0x2a] == s2[0x2a] &&
s1[0x2b] == s2[0x2b] &&
s1[0x2c] == s2[0x2c] &&
s1[0x2d] == s2[0x2d]) {
return false;
}
#endif
return true;
}
#endif
static void tile_net_discard_aux(struct tile_net_cpu *info, int index)
{
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
int index2_aux = index + sizeof(netio_pkt_t);
int index2 =
((index2_aux ==
qsp->__packet_receive_queue.__last_packet_plus_one) ?
0 : index2_aux);
netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index);
/* Extract the "linux_buffer_t". */
unsigned int buffer = pkt->__packet.word;
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
kfree_skb(skb);
/* Consume this packet. */
qup->__packet_receive_read = index2;
}
/*
* Like "tile_net_poll()", but just discard packets.
*/
static void tile_net_discard_packets(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
while (qup->__packet_receive_read !=
qsp->__packet_receive_queue.__packet_write) {
int index = qup->__packet_receive_read;
tile_net_discard_aux(info, index);
}
}
/*
* Handle the next packet. Return true if "processed", false if "filtered".
*/
static bool tile_net_poll_aux(struct tile_net_cpu *info, int index)
{
struct net_device *dev = info->napi.dev;
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
struct tile_net_stats_t *stats = &info->stats;
int filter;
int index2_aux = index + sizeof(netio_pkt_t);
int index2 =
((index2_aux ==
qsp->__packet_receive_queue.__last_packet_plus_one) ?
0 : index2_aux);
netio_pkt_t *pkt = (netio_pkt_t *)((unsigned long) &qsp[1] + index);
netio_pkt_metadata_t *metadata = NETIO_PKT_METADATA(pkt);
/* Extract the packet size. FIXME: Shouldn't the second line */
/* get subtracted? Mostly moot, since it should be "zero". */
unsigned long len =
(NETIO_PKT_CUSTOM_LENGTH(pkt) +
NET_IP_ALIGN - NETIO_PACKET_PADDING);
/* Extract the "linux_buffer_t". */
unsigned int buffer = pkt->__packet.word;
/* Extract "small" (vs "large"). */
bool small = ((buffer & 1) != 0);
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Extract the packet data pointer. */
/* Compare to "NETIO_PKT_CUSTOM_DATA(pkt)". */
unsigned char *buf = va + NET_IP_ALIGN;
/* Invalidate the packet buffer. */
if (!hash_default)
__inv_buffer(buf, len);
/* ISSUE: Is this needed? */
dev->last_rx = jiffies;
#ifdef TILE_NET_DUMP_PACKETS
dump_packet(buf, len, "rx");
#endif /* TILE_NET_DUMP_PACKETS */
#ifdef TILE_NET_VERIFY_INGRESS
if (!NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt) &&
NETIO_PKT_L4_CSUM_CALCULATED_M(metadata, pkt)) {
/* Bug 6624: Includes UDP packets with a "zero" checksum. */
pr_warning("Bad L4 checksum on %d byte packet.\n", len);
}
if (!NETIO_PKT_L3_CSUM_CORRECT_M(metadata, pkt) &&
NETIO_PKT_L3_CSUM_CALCULATED_M(metadata, pkt)) {
dump_packet(buf, len, "rx");
panic("Bad L3 checksum.");
}
switch (NETIO_PKT_STATUS_M(metadata, pkt)) {
case NETIO_PKT_STATUS_OVERSIZE:
if (len >= 64) {
dump_packet(buf, len, "rx");
panic("Unexpected OVERSIZE.");
}
break;
case NETIO_PKT_STATUS_BAD:
pr_warning("Unexpected BAD %ld byte packet.\n", len);
}
#endif
filter = 0;
/* ISSUE: Filter TCP packets with "bad" checksums? */
if (!(dev->flags & IFF_UP)) {
/* Filter packets received before we're up. */
filter = 1;
} else if (NETIO_PKT_STATUS_M(metadata, pkt) == NETIO_PKT_STATUS_BAD) {
/* Filter "truncated" packets. */
filter = 1;
} else if (!(dev->flags & IFF_PROMISC)) {
/* FIXME: Implement HW multicast filter. */
if (!is_multicast_ether_addr(buf)) {
/* Filter packets not for our address. */
const u8 *mine = dev->dev_addr;
filter = compare_ether_addr(mine, buf);
}
}
if (filter) {
/* ISSUE: Update "drop" statistics? */
tile_net_provide_linux_buffer(info, va, small);
} else {
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
/* Paranoia. */
if (skb->data != buf)
panic("Corrupt linux buffer from LIPP! "
"VA=%p, skb=%p, skb->data=%p\n",
va, skb, skb->data);
/* Encode the actual packet length. */
skb_put(skb, len);
/* NOTE: This call also sets "skb->dev = dev". */
skb->protocol = eth_type_trans(skb, dev);
/* Avoid recomputing "good" TCP/UDP checksums. */
if (NETIO_PKT_L4_CSUM_CORRECT_M(metadata, pkt))
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_receive_skb(skb);
stats->rx_packets++;
stats->rx_bytes += len;
if (small)
info->num_needed_small_buffers++;
else
info->num_needed_large_buffers++;
}
/* Return four credits after every fourth packet. */
if (--qup->__receive_credit_remaining == 0) {
u32 interval = qup->__receive_credit_interval;
qup->__receive_credit_remaining = interval;
__netio_fastio_return_credits(qup->__fastio_index, interval);
}
/* Consume this packet. */
qup->__packet_receive_read = index2;
return !filter;
}
/*
* Handle some packets for the given device on the current CPU.
*
* If "tile_net_stop()" is called on some other tile while this
* function is running, we will return, hopefully before that
* other tile asks us to call "napi_disable()".
*
* The "rotting packet" race condition occurs if a packet arrives
* during the extremely narrow window between the queue appearing to
* be empty, and the ingress interrupt being re-enabled. This happens
* a LOT under heavy network load.
*/
static int tile_net_poll(struct napi_struct *napi, int budget)
{
struct net_device *dev = napi->dev;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_netio_queue *queue = &info->queue;
netio_queue_impl_t *qsp = queue->__system_part;
netio_queue_user_impl_t *qup = &queue->__user_part;
unsigned int work = 0;
while (priv->active) {
int index = qup->__packet_receive_read;
if (index == qsp->__packet_receive_queue.__packet_write)
break;
if (tile_net_poll_aux(info, index)) {
if (++work >= budget)
goto done;
}
}
napi_complete(&info->napi);
if (!priv->active)
goto done;
/* Re-enable the ingress interrupt. */
enable_percpu_irq(priv->intr_id);
/* HACK: Avoid the "rotting packet" problem (see above). */
if (qup->__packet_receive_read !=
qsp->__packet_receive_queue.__packet_write) {
/* ISSUE: Sometimes this returns zero, presumably */
/* because an interrupt was handled for this tile. */
(void)napi_reschedule(&info->napi);
}
done:
if (priv->active)
tile_net_provide_needed_buffers(info);
return work;
}
/*
* Handle an ingress interrupt for the given device on the current cpu.
*
* ISSUE: Sometimes this gets called after "disable_percpu_irq()" has
* been called! This is probably due to "pending hypervisor downcalls".
*
* ISSUE: Is there any race condition between the "napi_schedule()" here
* and the "napi_complete()" call above?
*/
static irqreturn_t tile_net_handle_ingress_interrupt(int irq, void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Ignore unwanted interrupts. */
if (!priv->active)
return IRQ_HANDLED;
/* ISSUE: Sometimes "info->napi_enabled" is false here. */
napi_schedule(&info->napi);
return IRQ_HANDLED;
}
/*
* One time initialization per interface.
*/
static int tile_net_open_aux(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int ret;
int dummy;
unsigned int epp_lotar;
/*
* Find out where EPP memory should be homed.
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&epp_lotar, sizeof(epp_lotar),
NETIO_EPP_SHM_OFF);
if (ret < 0) {
pr_err("could not read epp_shm_queue lotar.\n");
return -EIO;
}
/*
* Home the page on the EPP.
*/
{
int epp_home = hv_lotar_to_cpu(epp_lotar);
homecache_change_page_home(priv->eq_pages, EQ_ORDER, epp_home);
}
/*
* Register the EPP shared memory queue.
*/
{
netio_ipp_address_t ea = {
.va = 0,
.pa = __pa(priv->eq),
.pte = hv_pte(0),
.size = EQ_SIZE,
};
ea.pte = hv_pte_set_lotar(ea.pte, epp_lotar);
ea.pte = hv_pte_set_mode(ea.pte, HV_PTE_MODE_CACHE_TILE_L3);
ret = hv_dev_pwrite(priv->hv_devhdl, 0,
(HV_VirtAddr)&ea,
sizeof(ea),
NETIO_EPP_SHM_OFF);
if (ret < 0)
return -EIO;
}
/*
* Start LIPP/LEPP.
*/
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_START_SHIM_OFF) < 0) {
pr_warning("Failed to start LIPP/LEPP.\n");
return -EIO;
}
return 0;
}
/*
* Register with hypervisor on the current CPU.
*
* Strangely, this function does important things even if it "fails",
* which is especially common if the link is not up yet. Hopefully
* these things are all "harmless" if done twice!
*/
static void tile_net_register(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info;
struct tile_netio_queue *queue;
/* Only network cpus can receive packets. */
int queue_id =
cpumask_test_cpu(my_cpu, &priv->network_cpus_map) ? 0 : 255;
netio_input_config_t config = {
.flags = 0,
.num_receive_packets = priv->network_cpus_credits,
.queue_id = queue_id
};
int ret = 0;
netio_queue_impl_t *queuep;
PDEBUG("tile_net_register(queue_id %d)\n", queue_id);
if (!strcmp(dev->name, "xgbe0"))
info = &__get_cpu_var(hv_xgbe0);
else if (!strcmp(dev->name, "xgbe1"))
info = &__get_cpu_var(hv_xgbe1);
else if (!strcmp(dev->name, "gbe0"))
info = &__get_cpu_var(hv_gbe0);
else if (!strcmp(dev->name, "gbe1"))
info = &__get_cpu_var(hv_gbe1);
else
BUG();
/* Initialize the egress timer. */
init_timer(&info->egress_timer);
info->egress_timer.data = (long)info;
info->egress_timer.function = tile_net_handle_egress_timer;
priv->cpu[my_cpu] = info;
/*
* Register ourselves with LIPP. This does a lot of stuff,
* including invoking the LIPP registration code.
*/
ret = hv_dev_pwrite(priv->hv_devhdl, 0,
(HV_VirtAddr)&config,
sizeof(netio_input_config_t),
NETIO_IPP_INPUT_REGISTER_OFF);
PDEBUG("hv_dev_pwrite(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n",
ret);
if (ret < 0) {
if (ret != NETIO_LINK_DOWN) {
printk(KERN_DEBUG "hv_dev_pwrite "
"NETIO_IPP_INPUT_REGISTER_OFF failure %d\n",
ret);
}
info->link_down = (ret == NETIO_LINK_DOWN);
return;
}
/*
* Get the pointer to our queue's system part.
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&queuep,
sizeof(netio_queue_impl_t *),
NETIO_IPP_INPUT_REGISTER_OFF);
PDEBUG("hv_dev_pread(NETIO_IPP_INPUT_REGISTER_OFF) returned %d\n",
ret);
PDEBUG("queuep %p\n", queuep);
if (ret <= 0) {
/* ISSUE: Shouldn't this be a fatal error? */
pr_err("hv_dev_pread NETIO_IPP_INPUT_REGISTER_OFF failure\n");
return;
}
queue = &info->queue;
queue->__system_part = queuep;
memset(&queue->__user_part, 0, sizeof(netio_queue_user_impl_t));
/* This is traditionally "config.num_receive_packets / 2". */
queue->__user_part.__receive_credit_interval = 4;
queue->__user_part.__receive_credit_remaining =
queue->__user_part.__receive_credit_interval;
/*
* Get a fastio index from the hypervisor.
* ISSUE: Shouldn't this check the result?
*/
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)&queue->__user_part.__fastio_index,
sizeof(queue->__user_part.__fastio_index),
NETIO_IPP_GET_FASTIO_OFF);
PDEBUG("hv_dev_pread(NETIO_IPP_GET_FASTIO_OFF) returned %d\n", ret);
/* Now we are registered. */
info->registered = true;
}
/*
* Deregister with hypervisor on the current CPU.
*
* This simply discards all our credits, so no more packets will be
* delivered to this tile. There may still be packets in our queue.
*
* Also, disable the ingress interrupt.
*/
static void tile_net_deregister(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Do nothing else if not registered. */
if (info == NULL || !info->registered)
return;
{
struct tile_netio_queue *queue = &info->queue;
netio_queue_user_impl_t *qup = &queue->__user_part;
/* Discard all our credits. */
__netio_fastio_return_credits(qup->__fastio_index, -1);
}
}
/*
* Unregister with hypervisor on the current CPU.
*
* Also, disable the ingress interrupt.
*/
static void tile_net_unregister(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
int ret;
int dummy = 0;
/* Disable the ingress interrupt. */
disable_percpu_irq(priv->intr_id);
/* Do nothing else if not registered. */
if (info == NULL || !info->registered)
return;
/* Unregister ourselves with LIPP/LEPP. */
ret = hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_INPUT_UNREGISTER_OFF);
if (ret < 0)
panic("Failed to unregister with LIPP/LEPP!\n");
/* Discard all packets still in our NetIO queue. */
tile_net_discard_packets(dev);
/* Reset state. */
info->num_needed_small_buffers = 0;
info->num_needed_large_buffers = 0;
/* Cancel egress timer. */
del_timer(&info->egress_timer);
info->egress_timer_scheduled = false;
}
/*
* Helper function for "tile_net_stop()".
*
* Also used to handle registration failure in "tile_net_open_inner()",
* when the various extra steps in "tile_net_stop()" are not necessary.
*/
static void tile_net_stop_aux(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int i;
int dummy = 0;
/*
* Unregister all tiles, so LIPP will stop delivering packets.
* Also, delete all the "napi" objects (sequentially, to protect
* "dev->napi_list").
*/
on_each_cpu(tile_net_unregister, (void *)dev, 1);
for_each_online_cpu(i) {
struct tile_net_cpu *info = priv->cpu[i];
if (info != NULL && info->registered) {
netif_napi_del(&info->napi);
info->registered = false;
}
}
/* Stop LIPP/LEPP. */
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_STOP_SHIM_OFF) < 0)
panic("Failed to stop LIPP/LEPP!\n");
priv->partly_opened = 0;
}
/*
* Disable NAPI for the given device on the current cpu.
*/
static void tile_net_stop_disable(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Disable NAPI if needed. */
if (info != NULL && info->napi_enabled) {
napi_disable(&info->napi);
info->napi_enabled = false;
}
}
/*
* Enable NAPI and the ingress interrupt for the given device
* on the current cpu.
*
* ISSUE: Only do this for "network cpus"?
*/
static void tile_net_open_enable(void *dev_ptr)
{
struct net_device *dev = (struct net_device *)dev_ptr;
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
/* Enable NAPI. */
napi_enable(&info->napi);
info->napi_enabled = true;
/* Enable the ingress interrupt. */
enable_percpu_irq(priv->intr_id);
}
/*
* tile_net_open_inner does most of the work of bringing up the interface.
* It's called from tile_net_open(), and also from tile_net_retry_open().
* The return value is 0 if the interface was brought up, < 0 if
* tile_net_open() should return the return value as an error, and > 0 if
* tile_net_open() should return success and schedule a work item to
* periodically retry the bringup.
*/
static int tile_net_open_inner(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info;
struct tile_netio_queue *queue;
int result = 0;
int i;
int dummy = 0;
/*
* First try to register just on the local CPU, and handle any
* semi-expected "link down" failure specially. Note that we
* do NOT call "tile_net_stop_aux()", unlike below.
*/
tile_net_register(dev);
info = priv->cpu[my_cpu];
if (!info->registered) {
if (info->link_down)
return 1;
return -EAGAIN;
}
/*
* Now register everywhere else. If any registration fails,
* even for "link down" (which might not be possible), we
* clean up using "tile_net_stop_aux()". Also, add all the
* "napi" objects (sequentially, to protect "dev->napi_list").
* ISSUE: Only use "netif_napi_add()" for "network cpus"?
*/
smp_call_function(tile_net_register, (void *)dev, 1);
for_each_online_cpu(i) {
struct tile_net_cpu *info = priv->cpu[i];
if (info->registered)
netif_napi_add(dev, &info->napi, tile_net_poll, 64);
else
result = -EAGAIN;
}
if (result != 0) {
tile_net_stop_aux(dev);
return result;
}
queue = &info->queue;
if (priv->intr_id == 0) {
unsigned int irq;
/*
* Acquire the irq allocated by the hypervisor. Every
* queue gets the same irq. The "__intr_id" field is
* "1 << irq", so we use "__ffs()" to extract "irq".
*/
priv->intr_id = queue->__system_part->__intr_id;
BUG_ON(priv->intr_id == 0);
irq = __ffs(priv->intr_id);
/*
* Register the ingress interrupt handler for this
* device, permanently.
*
* We used to call "free_irq()" in "tile_net_stop()",
* and then re-register the handler here every time,
* but that caused DNP errors in "handle_IRQ_event()"
* because "desc->action" was NULL. See bug 9143.
*/
tile_irq_activate(irq, TILE_IRQ_PERCPU);
BUG_ON(request_irq(irq, tile_net_handle_ingress_interrupt,
0, dev->name, (void *)dev) != 0);
}
{
/* Allocate initial buffers. */
int max_buffers =
priv->network_cpus_count * priv->network_cpus_credits;
info->num_needed_small_buffers =
min(LIPP_SMALL_BUFFERS, max_buffers);
info->num_needed_large_buffers =
min(LIPP_LARGE_BUFFERS, max_buffers);
tile_net_provide_needed_buffers(info);
if (info->num_needed_small_buffers != 0 ||
info->num_needed_large_buffers != 0)
panic("Insufficient memory for buffer stack!");
}
/* We are about to be active. */
priv->active = true;
/* Make sure "active" is visible to all tiles. */
mb();
/* On each tile, enable NAPI and the ingress interrupt. */
on_each_cpu(tile_net_open_enable, (void *)dev, 1);
/* Start LIPP/LEPP and activate "ingress" at the shim. */
if (hv_dev_pwrite(priv->hv_devhdl, 0, (HV_VirtAddr)&dummy,
sizeof(dummy), NETIO_IPP_INPUT_INIT_OFF) < 0)
panic("Failed to activate the LIPP Shim!\n");
/* Start our transmit queue. */
netif_start_queue(dev);
return 0;
}
/*
* Called periodically to retry bringing up the NetIO interface,
* if it doesn't come up cleanly during tile_net_open().
*/
static void tile_net_open_retry(struct work_struct *w)
{
struct delayed_work *dw =
container_of(w, struct delayed_work, work);
struct tile_net_priv *priv =
container_of(dw, struct tile_net_priv, retry_work);
/*
* Try to bring the NetIO interface up. If it fails, reschedule
* ourselves to try again later; otherwise, tell Linux we now have
* a working link. ISSUE: What if the return value is negative?
*/
if (tile_net_open_inner(priv->dev) != 0)
schedule_delayed_work(&priv->retry_work,
TILE_NET_RETRY_INTERVAL);
else
netif_carrier_on(priv->dev);
}
/*
* Called when a network interface is made active.
*
* Returns 0 on success, negative value on failure.
*
* The open entry point is called when a network interface is made
* active by the system (IFF_UP). At this point all resources needed
* for transmit and receive operations are allocated, the interrupt
* handler is registered with the OS (if needed), the watchdog timer
* is started, and the stack is notified that the interface is ready.
*
* If the actual link is not available yet, then we tell Linux that
* we have no carrier, and we keep checking until the link comes up.
*/
static int tile_net_open(struct net_device *dev)
{
int ret = 0;
struct tile_net_priv *priv = netdev_priv(dev);
/*
* We rely on priv->partly_opened to tell us if this is the
* first time this interface is being brought up. If it is
* set, the IPP was already initialized and should not be
* initialized again.
*/
if (!priv->partly_opened) {
int count;
int credits;
/* Initialize LIPP/LEPP, and start the Shim. */
ret = tile_net_open_aux(dev);
if (ret < 0) {
pr_err("tile_net_open_aux failed: %d\n", ret);
return ret;
}
/* Analyze the network cpus. */
if (network_cpus_used)
cpumask_copy(&priv->network_cpus_map,
&network_cpus_map);
else
cpumask_copy(&priv->network_cpus_map, cpu_online_mask);
count = cpumask_weight(&priv->network_cpus_map);
/* Limit credits to available buffers, and apply min. */
credits = max(16, (LIPP_LARGE_BUFFERS / count) & ~1);
/* Apply "GBE" max limit. */
/* ISSUE: Use higher limit for XGBE? */
credits = min(NETIO_MAX_RECEIVE_PKTS, credits);
priv->network_cpus_count = count;
priv->network_cpus_credits = credits;
#ifdef TILE_NET_DEBUG
pr_info("Using %d network cpus, with %d credits each\n",
priv->network_cpus_count, priv->network_cpus_credits);
#endif
priv->partly_opened = 1;
} else {
/* FIXME: Is this possible? */
/* printk("Already partly opened.\n"); */
}
/*
* Attempt to bring up the link.
*/
ret = tile_net_open_inner(dev);
if (ret <= 0) {
if (ret == 0)
netif_carrier_on(dev);
return ret;
}
/*
* We were unable to bring up the NetIO interface, but we want to
* try again in a little bit. Tell Linux that we have no carrier
* so it doesn't try to use the interface before the link comes up
* and then remember to try again later.
*/
netif_carrier_off(dev);
schedule_delayed_work(&priv->retry_work, TILE_NET_RETRY_INTERVAL);
return 0;
}
static int tile_net_drain_lipp_buffers(struct tile_net_priv *priv)
{
int n = 0;
/* Drain all the LIPP buffers. */
while (true) {
int buffer;
/* NOTE: This should never fail. */
if (hv_dev_pread(priv->hv_devhdl, 0, (HV_VirtAddr)&buffer,
sizeof(buffer), NETIO_IPP_DRAIN_OFF) < 0)
break;
/* Stop when done. */
if (buffer == 0)
break;
{
/* Convert "linux_buffer_t" to "va". */
void *va = __va((phys_addr_t)(buffer >> 1) << 7);
/* Acquire the associated "skb". */
struct sk_buff **skb_ptr = va - sizeof(*skb_ptr);
struct sk_buff *skb = *skb_ptr;
kfree_skb(skb);
}
n++;
}
return n;
}
/*
* Disables a network interface.
*
* Returns 0, this is not allowed to fail.
*
* The close entry point is called when an interface is de-activated
* by the OS. The hardware is still under the drivers control, but
* needs to be disabled. A global MAC reset is issued to stop the
* hardware, and all transmit and receive resources are freed.
*
* ISSUE: How closely does "netif_running(dev)" mirror "priv->active"?
*
* Before we are called by "__dev_close()", "netif_running()" will
* have been cleared, so no NEW calls to "tile_net_poll()" will be
* made by "netpoll_poll_dev()".
*
* Often, this can cause some tiles to still have packets in their
* queues, so we must call "tile_net_discard_packets()" later.
*
* Note that some other tile may still be INSIDE "tile_net_poll()",
* and in fact, many will be, if there is heavy network load.
*
* Calling "on_each_cpu(tile_net_stop_disable, (void *)dev, 1)" when
* any tile is still "napi_schedule()"'d will induce a horrible crash
* when "msleep()" is called. This includes tiles which are inside
* "tile_net_poll()" which have not yet called "napi_complete()".
*
* So, we must first try to wait long enough for other tiles to finish
* with any current "tile_net_poll()" call, and, hopefully, to clear
* the "scheduled" flag. ISSUE: It is unclear what happens to tiles
* which have called "napi_schedule()" but which had not yet tried to
* call "tile_net_poll()", or which exhausted their budget inside
* "tile_net_poll()" just before this function was called.
*/
static int tile_net_stop(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
PDEBUG("tile_net_stop()\n");
/* Start discarding packets. */
priv->active = false;
/* Make sure "active" is visible to all tiles. */
mb();
/*
* On each tile, make sure no NEW packets get delivered, and
* disable the ingress interrupt.
*
* Note that the ingress interrupt can fire AFTER this,
* presumably due to packets which were recently delivered,
* but it will have no effect.
*/
on_each_cpu(tile_net_deregister, (void *)dev, 1);
/* Optimistically drain LIPP buffers. */
(void)tile_net_drain_lipp_buffers(priv);
/* ISSUE: Only needed if not yet fully open. */
cancel_delayed_work_sync(&priv->retry_work);
/* Can't transmit any more. */
netif_stop_queue(dev);
/* Disable NAPI on each tile. */
on_each_cpu(tile_net_stop_disable, (void *)dev, 1);
/*
* Drain any remaining LIPP buffers. NOTE: This "printk()"
* has never been observed, but in theory it could happen.
*/
if (tile_net_drain_lipp_buffers(priv) != 0)
printk("Had to drain some extra LIPP buffers!\n");
/* Stop LIPP/LEPP. */
tile_net_stop_aux(dev);
/*
* ISSUE: It appears that, in practice anyway, by the time we
* get here, there are no pending completions, but just in case,
* we free (all of) them anyway.
*/
while (tile_net_lepp_free_comps(dev, true))
/* loop */;
/* Wipe the EPP queue. */
memset(priv->eq, 0, sizeof(lepp_queue_t));
/* Evict the EPP queue. */
finv_buffer(priv->eq, EQ_SIZE);
return 0;
}
/*
* Prepare the "frags" info for the resulting LEPP command.
*
* If needed, flush the memory used by the frags.
*/
static unsigned int tile_net_tx_frags(lepp_frag_t *frags,
struct sk_buff *skb,
void *b_data, unsigned int b_len)
{
unsigned int i, n = 0;
struct skb_shared_info *sh = skb_shinfo(skb);
phys_addr_t cpa;
if (b_len != 0) {
if (!hash_default)
finv_buffer_remote(b_data, b_len, 0);
cpa = __pa(b_data);
frags[n].cpa_lo = cpa;
frags[n].cpa_hi = cpa >> 32;
frags[n].length = b_len;
frags[n].hash_for_home = hash_default;
n++;
}
for (i = 0; i < sh->nr_frags; i++) {
skb_frag_t *f = &sh->frags[i];
unsigned long pfn = page_to_pfn(f->page);
/* FIXME: Compute "hash_for_home" properly. */
/* ISSUE: The hypervisor checks CHIP_HAS_REV1_DMA_PACKETS(). */
int hash_for_home = hash_default;
/* FIXME: Hmmm. */
if (!hash_default) {
void *va = pfn_to_kaddr(pfn) + f->page_offset;
BUG_ON(PageHighMem(f->page));
finv_buffer_remote(va, f->size, 0);
}
cpa = ((phys_addr_t)pfn << PAGE_SHIFT) + f->page_offset;
frags[n].cpa_lo = cpa;
frags[n].cpa_hi = cpa >> 32;
frags[n].length = f->size;
frags[n].hash_for_home = hash_for_home;
n++;
}
return n;
}
/*
* This function takes "skb", consisting of a header template and a
* payload, and hands it to LEPP, to emit as one or more segments,
* each consisting of a possibly modified header, plus a piece of the
* payload, via a process known as "tcp segmentation offload".
*
* Usually, "data" will contain the header template, of size "sh_len",
* and "sh->frags" will contain "skb->data_len" bytes of payload, and
* there will be "sh->gso_segs" segments.
*
* Sometimes, if "sendfile()" requires copying, we will be called with
* "data" containing the header and payload, with "frags" being empty.
*
* In theory, "sh->nr_frags" could be 3, but in practice, it seems
* that this will never actually happen.
*
* See "emulate_large_send_offload()" for some reference code, which
* does not handle checksumming.
*
* ISSUE: How do we make sure that high memory DMA does not migrate?
*/
static int tile_net_tx_tso(struct sk_buff *skb, struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_net_stats_t *stats = &info->stats;
struct skb_shared_info *sh = skb_shinfo(skb);
unsigned char *data = skb->data;
/* The ip header follows the ethernet header. */
struct iphdr *ih = ip_hdr(skb);
unsigned int ih_len = ih->ihl * 4;
/* Note that "nh == ih", by definition. */
unsigned char *nh = skb_network_header(skb);
unsigned int eh_len = nh - data;
/* The tcp header follows the ip header. */
struct tcphdr *th = (struct tcphdr *)(nh + ih_len);
unsigned int th_len = th->doff * 4;
/* The total number of header bytes. */
/* NOTE: This may be less than skb_headlen(skb). */
unsigned int sh_len = eh_len + ih_len + th_len;
/* The number of payload bytes at "skb->data + sh_len". */
/* This is non-zero for sendfile() without HIGHDMA. */
unsigned int b_len = skb_headlen(skb) - sh_len;
/* The total number of payload bytes. */
unsigned int d_len = b_len + skb->data_len;
/* The maximum payload size. */
unsigned int p_len = sh->gso_size;
/* The total number of segments. */
unsigned int num_segs = sh->gso_segs;
/* The temporary copy of the command. */
u32 cmd_body[(LEPP_MAX_CMD_SIZE + 3) / 4];
lepp_tso_cmd_t *cmd = (lepp_tso_cmd_t *)cmd_body;
/* Analyze the "frags". */
unsigned int num_frags =
tile_net_tx_frags(cmd->frags, skb, data + sh_len, b_len);
/* The size of the command, including frags and header. */
size_t cmd_size = LEPP_TSO_CMD_SIZE(num_frags, sh_len);
/* The command header. */
lepp_tso_cmd_t cmd_init = {
.tso = true,
.header_size = sh_len,
.ip_offset = eh_len,
.tcp_offset = eh_len + ih_len,
.payload_size = p_len,
.num_frags = num_frags,
};
unsigned long irqflags;
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[8];
unsigned int wanted = 8;
unsigned int i, nolds = 0;
unsigned int cmd_head, cmd_tail, cmd_next;
unsigned int comp_tail;
/* Paranoia. */
BUG_ON(skb->protocol != htons(ETH_P_IP));
BUG_ON(ih->protocol != IPPROTO_TCP);
BUG_ON(skb->ip_summed != CHECKSUM_PARTIAL);
BUG_ON(num_frags > LEPP_MAX_FRAGS);
/*--BUG_ON(num_segs != (d_len + (p_len - 1)) / p_len); */
BUG_ON(num_segs <= 1);
/* Finish preparing the command. */
/* Copy the command header. */
*cmd = cmd_init;
/* Copy the "header". */
memcpy(&cmd->frags[num_frags], data, sh_len);
/* Prefetch and wait, to minimize time spent holding the spinlock. */
prefetch_L1(&eq->comp_tail);
prefetch_L1(&eq->cmd_tail);
mb();
/* Enqueue the command. */
spin_lock_irqsave(&priv->eq_lock, irqflags);
/*
* Handle completions if needed to make room.
* HACK: Spin until there is sufficient room.
*/
if (lepp_num_free_comp_slots(eq) == 0) {
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
if (nolds == 0) {
busy:
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
return NETDEV_TX_BUSY;
}
}
cmd_head = eq->cmd_head;
cmd_tail = eq->cmd_tail;
/* Prepare to advance, detecting full queue. */
cmd_next = cmd_tail + cmd_size;
if (cmd_tail < cmd_head && cmd_next >= cmd_head)
goto busy;
if (cmd_next > LEPP_CMD_LIMIT) {
cmd_next = 0;
if (cmd_next == cmd_head)
goto busy;
}
/* Copy the command. */
memcpy(&eq->cmds[cmd_tail], cmd, cmd_size);
/* Advance. */
cmd_tail = cmd_next;
/* Record "skb" for eventual freeing. */
comp_tail = eq->comp_tail;
eq->comps[comp_tail] = skb;
LEPP_QINC(comp_tail);
eq->comp_tail = comp_tail;
/* Flush before allowing LEPP to handle the command. */
/* ISSUE: Is this the optimal location for the flush? */
__insn_mf();
eq->cmd_tail = cmd_tail;
/* NOTE: Using "4" here is more efficient than "0" or "2", */
/* and, strangely, more efficient than pre-checking the number */
/* of available completions, and comparing it to 4. */
if (nolds == 0)
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4);
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
/* Handle completions. */
for (i = 0; i < nolds; i++)
kfree_skb(olds[i]);
/* Update stats. */
stats->tx_packets += num_segs;
stats->tx_bytes += (num_segs * sh_len) + d_len;
/* Make sure the egress timer is scheduled. */
tile_net_schedule_egress_timer(info);
return NETDEV_TX_OK;
}
/*
* Transmit a packet (called by the kernel via "hard_start_xmit" hook).
*/
static int tile_net_tx(struct sk_buff *skb, struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
int my_cpu = smp_processor_id();
struct tile_net_cpu *info = priv->cpu[my_cpu];
struct tile_net_stats_t *stats = &info->stats;
unsigned long irqflags;
struct skb_shared_info *sh = skb_shinfo(skb);
unsigned int len = skb->len;
unsigned char *data = skb->data;
unsigned int csum_start = skb_checksum_start_offset(skb);
lepp_frag_t frags[LEPP_MAX_FRAGS];
unsigned int num_frags;
lepp_queue_t *eq = priv->eq;
struct sk_buff *olds[8];
unsigned int wanted = 8;
unsigned int i, nolds = 0;
unsigned int cmd_size = sizeof(lepp_cmd_t);
unsigned int cmd_head, cmd_tail, cmd_next;
unsigned int comp_tail;
lepp_cmd_t cmds[LEPP_MAX_FRAGS];
/*
* This is paranoia, since we think that if the link doesn't come
* up, telling Linux we have no carrier will keep it from trying
* to transmit. If it does, though, we can't execute this routine,
* since data structures we depend on aren't set up yet.
*/
if (!info->registered)
return NETDEV_TX_BUSY;
/* Save the timestamp. */
dev->trans_start = jiffies;
#ifdef TILE_NET_PARANOIA
#if CHIP_HAS_CBOX_HOME_MAP()
if (hash_default) {
HV_PTE pte = *virt_to_pte(current->mm, (unsigned long)data);
if (hv_pte_get_mode(pte) != HV_PTE_MODE_CACHE_HASH_L3)
panic("Non-HFH egress buffer! VA=%p Mode=%d PTE=%llx",
data, hv_pte_get_mode(pte), hv_pte_val(pte));
}
#endif
#endif
#ifdef TILE_NET_DUMP_PACKETS
/* ISSUE: Does not dump the "frags". */
dump_packet(data, skb_headlen(skb), "tx");
#endif /* TILE_NET_DUMP_PACKETS */
if (sh->gso_size != 0)
return tile_net_tx_tso(skb, dev);
/* Prepare the commands. */
num_frags = tile_net_tx_frags(frags, skb, data, skb_headlen(skb));
for (i = 0; i < num_frags; i++) {
bool final = (i == num_frags - 1);
lepp_cmd_t cmd = {
.cpa_lo = frags[i].cpa_lo,
.cpa_hi = frags[i].cpa_hi,
.length = frags[i].length,
.hash_for_home = frags[i].hash_for_home,
.send_completion = final,
.end_of_packet = final
};
if (i == 0 && skb->ip_summed == CHECKSUM_PARTIAL) {
cmd.compute_checksum = 1;
cmd.checksum_data.bits.start_byte = csum_start;
cmd.checksum_data.bits.count = len - csum_start;
cmd.checksum_data.bits.destination_byte =
csum_start + skb->csum_offset;
}
cmds[i] = cmd;
}
/* Prefetch and wait, to minimize time spent holding the spinlock. */
prefetch_L1(&eq->comp_tail);
prefetch_L1(&eq->cmd_tail);
mb();
/* Enqueue the commands. */
spin_lock_irqsave(&priv->eq_lock, irqflags);
/*
* Handle completions if needed to make room.
* HACK: Spin until there is sufficient room.
*/
if (lepp_num_free_comp_slots(eq) == 0) {
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 0);
if (nolds == 0) {
busy:
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
return NETDEV_TX_BUSY;
}
}
cmd_head = eq->cmd_head;
cmd_tail = eq->cmd_tail;
/* Copy the commands, or fail. */
for (i = 0; i < num_frags; i++) {
/* Prepare to advance, detecting full queue. */
cmd_next = cmd_tail + cmd_size;
if (cmd_tail < cmd_head && cmd_next >= cmd_head)
goto busy;
if (cmd_next > LEPP_CMD_LIMIT) {
cmd_next = 0;
if (cmd_next == cmd_head)
goto busy;
}
/* Copy the command. */
*(lepp_cmd_t *)&eq->cmds[cmd_tail] = cmds[i];
/* Advance. */
cmd_tail = cmd_next;
}
/* Record "skb" for eventual freeing. */
comp_tail = eq->comp_tail;
eq->comps[comp_tail] = skb;
LEPP_QINC(comp_tail);
eq->comp_tail = comp_tail;
/* Flush before allowing LEPP to handle the command. */
/* ISSUE: Is this the optimal location for the flush? */
__insn_mf();
eq->cmd_tail = cmd_tail;
/* NOTE: Using "4" here is more efficient than "0" or "2", */
/* and, strangely, more efficient than pre-checking the number */
/* of available completions, and comparing it to 4. */
if (nolds == 0)
nolds = tile_net_lepp_grab_comps(eq, olds, wanted, 4);
spin_unlock_irqrestore(&priv->eq_lock, irqflags);
/* Handle completions. */
for (i = 0; i < nolds; i++)
kfree_skb(olds[i]);
/* HACK: Track "expanded" size for short packets (e.g. 42 < 60). */
stats->tx_packets++;
stats->tx_bytes += ((len >= ETH_ZLEN) ? len : ETH_ZLEN);
/* Make sure the egress timer is scheduled. */
tile_net_schedule_egress_timer(info);
return NETDEV_TX_OK;
}
/*
* Deal with a transmit timeout.
*/
static void tile_net_tx_timeout(struct net_device *dev)
{
PDEBUG("tile_net_tx_timeout()\n");
PDEBUG("Transmit timeout at %ld, latency %ld\n", jiffies,
jiffies - dev->trans_start);
/* XXX: ISSUE: This doesn't seem useful for us. */
netif_wake_queue(dev);
}
/*
* Ioctl commands.
*/
static int tile_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
return -EOPNOTSUPP;
}
/*
* Get System Network Statistics.
*
* Returns the address of the device statistics structure.
*/
static struct net_device_stats *tile_net_get_stats(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
u32 rx_packets = 0;
u32 tx_packets = 0;
u32 rx_bytes = 0;
u32 tx_bytes = 0;
int i;
for_each_online_cpu(i) {
if (priv->cpu[i]) {
rx_packets += priv->cpu[i]->stats.rx_packets;
rx_bytes += priv->cpu[i]->stats.rx_bytes;
tx_packets += priv->cpu[i]->stats.tx_packets;
tx_bytes += priv->cpu[i]->stats.tx_bytes;
}
}
priv->stats.rx_packets = rx_packets;
priv->stats.rx_bytes = rx_bytes;
priv->stats.tx_packets = tx_packets;
priv->stats.tx_bytes = tx_bytes;
return &priv->stats;
}
/*
* Change the "mtu".
*
* The "change_mtu" method is usually not needed.
* If you need it, it must be like this.
*/
static int tile_net_change_mtu(struct net_device *dev, int new_mtu)
{
PDEBUG("tile_net_change_mtu()\n");
/* Check ranges. */
if ((new_mtu < 68) || (new_mtu > 1500))
return -EINVAL;
/* Accept the value. */
dev->mtu = new_mtu;
return 0;
}
/*
* Change the Ethernet Address of the NIC.
*
* The hypervisor driver does not support changing MAC address. However,
* the IPP does not do anything with the MAC address, so the address which
* gets used on outgoing packets, and which is accepted on incoming packets,
* is completely up to the NetIO program or kernel driver which is actually
* handling them.
*
* Returns 0 on success, negative on failure.
*/
static int tile_net_set_mac_address(struct net_device *dev, void *p)
{
struct sockaddr *addr = p;
if (!is_valid_ether_addr(addr->sa_data))
return -EINVAL;
/* ISSUE: Note that "dev_addr" is now a pointer. */
memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
return 0;
}
/*
* Obtain the MAC address from the hypervisor.
* This must be done before opening the device.
*/
static int tile_net_get_mac(struct net_device *dev)
{
struct tile_net_priv *priv = netdev_priv(dev);
char hv_dev_name[32];
int len;
__netio_getset_offset_t offset = { .word = NETIO_IPP_PARAM_OFF };
int ret;
/* For example, "xgbe0". */
strcpy(hv_dev_name, dev->name);
len = strlen(hv_dev_name);
/* For example, "xgbe/0". */
hv_dev_name[len] = hv_dev_name[len - 1];
hv_dev_name[len - 1] = '/';
len++;
/* For example, "xgbe/0/native_hash". */
strcpy(hv_dev_name + len, hash_default ? "/native_hash" : "/native");
/* Get the hypervisor handle for this device. */
priv->hv_devhdl = hv_dev_open((HV_VirtAddr)hv_dev_name, 0);
PDEBUG("hv_dev_open(%s) returned %d %p\n",
hv_dev_name, priv->hv_devhdl, &priv->hv_devhdl);
if (priv->hv_devhdl < 0) {
if (priv->hv_devhdl == HV_ENODEV)
printk(KERN_DEBUG "Ignoring unconfigured device %s\n",
hv_dev_name);
else
printk(KERN_DEBUG "hv_dev_open(%s) returned %d\n",
hv_dev_name, priv->hv_devhdl);
return -1;
}
/*
* Read the hardware address from the hypervisor.
* ISSUE: Note that "dev_addr" is now a pointer.
*/
offset.bits.class = NETIO_PARAM;
offset.bits.addr = NETIO_PARAM_MAC;
ret = hv_dev_pread(priv->hv_devhdl, 0,
(HV_VirtAddr)dev->dev_addr, dev->addr_len,
offset.word);
PDEBUG("hv_dev_pread(NETIO_PARAM_MAC) returned %d\n", ret);
if (ret <= 0) {
printk(KERN_DEBUG "hv_dev_pread(NETIO_PARAM_MAC) %s failed\n",
dev->name);
/*
* Since the device is configured by the hypervisor but we
* can't get its MAC address, we are most likely running
* the simulator, so let's generate a random MAC address.
*/
random_ether_addr(dev->dev_addr);
}
return 0;
}
static struct net_device_ops tile_net_ops = {
.ndo_open = tile_net_open,
.ndo_stop = tile_net_stop,
.ndo_start_xmit = tile_net_tx,
.ndo_do_ioctl = tile_net_ioctl,
.ndo_get_stats = tile_net_get_stats,
.ndo_change_mtu = tile_net_change_mtu,
.ndo_tx_timeout = tile_net_tx_timeout,
.ndo_set_mac_address = tile_net_set_mac_address
};
/*
* The setup function.
*
* This uses ether_setup() to assign various fields in dev, including
* setting IFF_BROADCAST and IFF_MULTICAST, then sets some extra fields.
*/
static void tile_net_setup(struct net_device *dev)
{
PDEBUG("tile_net_setup()\n");
ether_setup(dev);
dev->netdev_ops = &tile_net_ops;
dev->watchdog_timeo = TILE_NET_TIMEOUT;
/* We want lockless xmit. */
dev->features |= NETIF_F_LLTX;
/* We support hardware tx checksums. */
dev->features |= NETIF_F_HW_CSUM;
/* We support scatter/gather. */
dev->features |= NETIF_F_SG;
/* We support TSO. */
dev->features |= NETIF_F_TSO;
#ifdef TILE_NET_GSO
/* We support GSO. */
dev->features |= NETIF_F_GSO;
#endif
if (hash_default)
dev->features |= NETIF_F_HIGHDMA;
/* ISSUE: We should support NETIF_F_UFO. */
dev->tx_queue_len = TILE_NET_TX_QUEUE_LEN;
dev->mtu = TILE_NET_MTU;
}
/*
* Allocate the device structure, register the device, and obtain the
* MAC address from the hypervisor.
*/
static struct net_device *tile_net_dev_init(const char *name)
{
int ret;
struct net_device *dev;
struct tile_net_priv *priv;
/*
* Allocate the device structure. This allocates "priv", calls
* tile_net_setup(), and saves "name". Normally, "name" is a
* template, instantiated by register_netdev(), but not for us.
*/
dev = alloc_netdev(sizeof(*priv), name, tile_net_setup);
if (!dev) {
pr_err("alloc_netdev(%s) failed\n", name);
return NULL;
}
priv = netdev_priv(dev);
/* Initialize "priv". */
memset(priv, 0, sizeof(*priv));
/* Save "dev" for "tile_net_open_retry()". */
priv->dev = dev;
INIT_DELAYED_WORK(&priv->retry_work, tile_net_open_retry);
spin_lock_init(&priv->eq_lock);
/* Allocate "eq". */
priv->eq_pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, EQ_ORDER);
if (!priv->eq_pages) {
free_netdev(dev);
return NULL;
}
priv->eq = page_address(priv->eq_pages);
/* Register the network device. */
ret = register_netdev(dev);
if (ret) {
pr_err("register_netdev %s failed %d\n", dev->name, ret);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
return NULL;
}
/* Get the MAC address. */
ret = tile_net_get_mac(dev);
if (ret < 0) {
unregister_netdev(dev);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
return NULL;
}
return dev;
}
/*
* Module cleanup.
*
* FIXME: If compiled as a module, this module cannot be "unloaded",
* because the "ingress interrupt handler" is registered permanently.
*/
static void tile_net_cleanup(void)
{
int i;
for (i = 0; i < TILE_NET_DEVS; i++) {
if (tile_net_devs[i]) {
struct net_device *dev = tile_net_devs[i];
struct tile_net_priv *priv = netdev_priv(dev);
unregister_netdev(dev);
finv_buffer(priv->eq, EQ_SIZE);
__free_pages(priv->eq_pages, EQ_ORDER);
free_netdev(dev);
}
}
}
/*
* Module initialization.
*/
static int tile_net_init_module(void)
{
pr_info("Tilera IPP Net Driver\n");
tile_net_devs[0] = tile_net_dev_init("xgbe0");
tile_net_devs[1] = tile_net_dev_init("xgbe1");
tile_net_devs[2] = tile_net_dev_init("gbe0");
tile_net_devs[3] = tile_net_dev_init("gbe1");
return 0;
}
module_init(tile_net_init_module);
module_exit(tile_net_cleanup);
#ifndef MODULE
/*
* The "network_cpus" boot argument specifies the cpus that are dedicated
* to handle ingress packets.
*
* The parameter should be in the form "network_cpus=m-n[,x-y]", where
* m, n, x, y are integer numbers that represent the cpus that can be
* neither a dedicated cpu nor a dataplane cpu.
*/
static int __init network_cpus_setup(char *str)
{
int rc = cpulist_parse_crop(str, &network_cpus_map);
if (rc != 0) {
pr_warning("network_cpus=%s: malformed cpu list\n",
str);
} else {
/* Remove dedicated cpus. */
cpumask_and(&network_cpus_map, &network_cpus_map,
cpu_possible_mask);
if (cpumask_empty(&network_cpus_map)) {
pr_warning("Ignoring network_cpus='%s'.\n",
str);
} else {
char buf[1024];
cpulist_scnprintf(buf, sizeof(buf), &network_cpus_map);
pr_info("Linux network CPUs: %s\n", buf);
network_cpus_used = true;
}
}
return 0;
}
__setup("network_cpus=", network_cpus_setup);
#endif
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