Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 655 insertions, 0 deletions

diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
new file mode 100644
index 000000000..5060956b8
--- /dev/null
+++ b/arch/s390/mm/extmem.c
@@ -0,0 +1,655 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Author(s)......: Carsten Otte <cotte@de.ibm.com>
+ * 		    Rob M van der Heij <rvdheij@nl.ibm.com>
+ * 		    Steven Shultz <shultzss@us.ibm.com>
+ * Bugreports.to..: <Linux390@de.ibm.com>
+ * Copyright IBM Corp. 2002, 2004
+ */
+
+#define KMSG_COMPONENT "extmem"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/memblock.h>
+#include <linux/ctype.h>
+#include <linux/ioport.h>
+#include <linux/refcount.h>
+#include <linux/pgtable.h>
+#include <asm/diag.h>
+#include <asm/page.h>
+#include <asm/ebcdic.h>
+#include <asm/errno.h>
+#include <asm/extmem.h>
+#include <asm/cpcmd.h>
+#include <asm/setup.h>
+
+#define DCSS_PURGESEG   0x08
+#define DCSS_LOADSHRX	0x20
+#define DCSS_LOADNSRX	0x24
+#define DCSS_FINDSEGX	0x2c
+#define DCSS_SEGEXTX	0x38
+#define DCSS_FINDSEGA   0x0c
+
+struct qrange {
+	unsigned long  start; /* last byte type */
+	unsigned long  end;   /* last byte reserved */
+};
+
+struct qout64 {
+	unsigned long segstart;
+	unsigned long segend;
+	int segcnt;
+	int segrcnt;
+	struct qrange range[6];
+};
+
+struct qin64 {
+	char qopcode;
+	char rsrv1[3];
+	char qrcode;
+	char rsrv2[3];
+	char qname[8];
+	unsigned int qoutptr;
+	short int qoutlen;
+};
+
+struct dcss_segment {
+	struct list_head list;
+	char dcss_name[8];
+	char res_name[16];
+	unsigned long start_addr;
+	unsigned long end;
+	refcount_t ref_count;
+	int do_nonshared;
+	unsigned int vm_segtype;
+	struct qrange range[6];
+	int segcnt;
+	struct resource *res;
+};
+
+static DEFINE_MUTEX(dcss_lock);
+static LIST_HEAD(dcss_list);
+static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
+					"EW/EN-MIXED" };
+static int loadshr_scode = DCSS_LOADSHRX;
+static int loadnsr_scode = DCSS_LOADNSRX;
+static int purgeseg_scode = DCSS_PURGESEG;
+static int segext_scode = DCSS_SEGEXTX;
+
+/*
+ * Create the 8 bytes, ebcdic VM segment name from
+ * an ascii name.
+ */
+static void
+dcss_mkname(char *name, char *dcss_name)
+{
+	int i;
+
+	for (i = 0; i < 8; i++) {
+		if (name[i] == '\0')
+			break;
+		dcss_name[i] = toupper(name[i]);
+	}
+	for (; i < 8; i++)
+		dcss_name[i] = ' ';
+	ASCEBC(dcss_name, 8);
+}
+
+
+/*
+ * search all segments in dcss_list, and return the one
+ * namend *name. If not found, return NULL.
+ */
+static struct dcss_segment *
+segment_by_name (char *name)
+{
+	char dcss_name[9];
+	struct list_head *l;
+	struct dcss_segment *tmp, *retval = NULL;
+
+	BUG_ON(!mutex_is_locked(&dcss_lock));
+	dcss_mkname (name, dcss_name);
+	list_for_each (l, &dcss_list) {
+		tmp = list_entry (l, struct dcss_segment, list);
+		if (memcmp(tmp->dcss_name, dcss_name, 8) == 0) {
+			retval = tmp;
+			break;
+		}
+	}
+	return retval;
+}
+
+
+/*
+ * Perform a function on a dcss segment.
+ */
+static inline int
+dcss_diag(int *func, void *parameter,
+           unsigned long *ret1, unsigned long *ret2)
+{
+	unsigned long rx, ry;
+	int rc;
+
+	rx = (unsigned long) parameter;
+	ry = (unsigned long) *func;
+
+	diag_stat_inc(DIAG_STAT_X064);
+	asm volatile(
+		"	diag	%0,%1,0x64\n"
+		"	ipm	%2\n"
+		"	srl	%2,28\n"
+		: "+d" (rx), "+d" (ry), "=d" (rc) : : "cc");
+	*ret1 = rx;
+	*ret2 = ry;
+	return rc;
+}
+
+static inline int
+dcss_diag_translate_rc (int vm_rc) {
+	if (vm_rc == 44)
+		return -ENOENT;
+	return -EIO;
+}
+
+
+/* do a diag to get info about a segment.
+ * fills start_address, end and vm_segtype fields
+ */
+static int
+query_segment_type (struct dcss_segment *seg)
+{
+	unsigned long dummy, vmrc;
+	int diag_cc, rc, i;
+	struct qout64 *qout;
+	struct qin64 *qin;
+
+	qin = kmalloc(sizeof(*qin), GFP_KERNEL | GFP_DMA);
+	qout = kmalloc(sizeof(*qout), GFP_KERNEL | GFP_DMA);
+	if ((qin == NULL) || (qout == NULL)) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
+	/* initialize diag input parameters */
+	qin->qopcode = DCSS_FINDSEGA;
+	qin->qoutptr = (unsigned long) qout;
+	qin->qoutlen = sizeof(struct qout64);
+	memcpy (qin->qname, seg->dcss_name, 8);
+
+	diag_cc = dcss_diag(&segext_scode, qin, &dummy, &vmrc);
+
+	if (diag_cc < 0) {
+		rc = diag_cc;
+		goto out_free;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Querying a DCSS type failed with rc=%ld\n", vmrc);
+		rc = dcss_diag_translate_rc (vmrc);
+		goto out_free;
+	}
+
+	if (qout->segcnt > 6) {
+		rc = -EOPNOTSUPP;
+		goto out_free;
+	}
+
+	if (qout->segcnt == 1) {
+		seg->vm_segtype = qout->range[0].start & 0xff;
+	} else {
+		/* multi-part segment. only one type supported here:
+		    - all parts are contiguous
+		    - all parts are either EW or EN type
+		    - maximum 6 parts allowed */
+		unsigned long start = qout->segstart >> PAGE_SHIFT;
+		for (i=0; i<qout->segcnt; i++) {
+			if (((qout->range[i].start & 0xff) != SEG_TYPE_EW) &&
+			    ((qout->range[i].start & 0xff) != SEG_TYPE_EN)) {
+				rc = -EOPNOTSUPP;
+				goto out_free;
+			}
+			if (start != qout->range[i].start >> PAGE_SHIFT) {
+				rc = -EOPNOTSUPP;
+				goto out_free;
+			}
+			start = (qout->range[i].end >> PAGE_SHIFT) + 1;
+		}
+		seg->vm_segtype = SEG_TYPE_EWEN;
+	}
+
+	/* analyze diag output and update seg */
+	seg->start_addr = qout->segstart;
+	seg->end = qout->segend;
+
+	memcpy (seg->range, qout->range, 6*sizeof(struct qrange));
+	seg->segcnt = qout->segcnt;
+
+	rc = 0;
+
+ out_free:
+	kfree(qin);
+	kfree(qout);
+	return rc;
+}
+
+/*
+ * get info about a segment
+ * possible return values:
+ * -ENOSYS  : we are not running on VM
+ * -EIO     : could not perform query diagnose
+ * -ENOENT  : no such segment
+ * -EOPNOTSUPP: multi-part segment cannot be used with linux
+ * -ENOMEM  : out of memory
+ * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
+ */
+int
+segment_type (char* name)
+{
+	int rc;
+	struct dcss_segment seg;
+
+	if (!MACHINE_IS_VM)
+		return -ENOSYS;
+
+	dcss_mkname(name, seg.dcss_name);
+	rc = query_segment_type (&seg);
+	if (rc < 0)
+		return rc;
+	return seg.vm_segtype;
+}
+
+/*
+ * check if segment collides with other segments that are currently loaded
+ * returns 1 if this is the case, 0 if no collision was found
+ */
+static int
+segment_overlaps_others (struct dcss_segment *seg)
+{
+	struct list_head *l;
+	struct dcss_segment *tmp;
+
+	BUG_ON(!mutex_is_locked(&dcss_lock));
+	list_for_each(l, &dcss_list) {
+		tmp = list_entry(l, struct dcss_segment, list);
+		if ((tmp->start_addr >> 20) > (seg->end >> 20))
+			continue;
+		if ((tmp->end >> 20) < (seg->start_addr >> 20))
+			continue;
+		if (seg == tmp)
+			continue;
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * real segment loading function, called from segment_load
+ */
+static int
+__segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long *end)
+{
+	unsigned long start_addr, end_addr, dummy;
+	struct dcss_segment *seg;
+	int rc, diag_cc;
+
+	start_addr = end_addr = 0;
+	seg = kmalloc(sizeof(*seg), GFP_KERNEL | GFP_DMA);
+	if (seg == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	dcss_mkname (name, seg->dcss_name);
+	rc = query_segment_type (seg);
+	if (rc < 0)
+		goto out_free;
+
+	if (segment_overlaps_others(seg)) {
+		rc = -EBUSY;
+		goto out_free;
+	}
+
+	seg->res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+	if (seg->res == NULL) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+	seg->res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
+	seg->res->start = seg->start_addr;
+	seg->res->end = seg->end;
+	memcpy(&seg->res_name, seg->dcss_name, 8);
+	EBCASC(seg->res_name, 8);
+	seg->res_name[8] = '\0';
+	strlcat(seg->res_name, " (DCSS)", sizeof(seg->res_name));
+	seg->res->name = seg->res_name;
+	rc = seg->vm_segtype;
+	if (rc == SEG_TYPE_SC ||
+	    ((rc == SEG_TYPE_SR || rc == SEG_TYPE_ER) && !do_nonshared))
+		seg->res->flags |= IORESOURCE_READONLY;
+
+	/* Check for overlapping resources before adding the mapping. */
+	if (request_resource(&iomem_resource, seg->res)) {
+		rc = -EBUSY;
+		goto out_free_resource;
+	}
+
+	rc = vmem_add_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	if (rc)
+		goto out_resource;
+
+	if (do_nonshared)
+		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	else
+		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	if (diag_cc < 0) {
+		dcss_diag(&purgeseg_scode, seg->dcss_name,
+				&dummy, &dummy);
+		rc = diag_cc;
+		goto out_mapping;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Loading DCSS %s failed with rc=%ld\n", name, end_addr);
+		rc = dcss_diag_translate_rc(end_addr);
+		dcss_diag(&purgeseg_scode, seg->dcss_name,
+				&dummy, &dummy);
+		goto out_mapping;
+	}
+	seg->start_addr = start_addr;
+	seg->end = end_addr;
+	seg->do_nonshared = do_nonshared;
+	refcount_set(&seg->ref_count, 1);
+	list_add(&seg->list, &dcss_list);
+	*addr = seg->start_addr;
+	*end  = seg->end;
+	if (do_nonshared)
+		pr_info("DCSS %s of range %px to %px and type %s loaded as "
+			"exclusive-writable\n", name, (void*) seg->start_addr,
+			(void*) seg->end, segtype_string[seg->vm_segtype]);
+	else {
+		pr_info("DCSS %s of range %px to %px and type %s loaded in "
+			"shared access mode\n", name, (void*) seg->start_addr,
+			(void*) seg->end, segtype_string[seg->vm_segtype]);
+	}
+	goto out;
+ out_mapping:
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+ out_resource:
+	release_resource(seg->res);
+ out_free_resource:
+	kfree(seg->res);
+ out_free:
+	kfree(seg);
+ out:
+	return rc;
+}
+
+/*
+ * this function loads a DCSS segment
+ * name         : name of the DCSS
+ * do_nonshared : 0 indicates that the dcss should be shared with other linux images
+ *                1 indicates that the dcss should be exclusive for this linux image
+ * addr         : will be filled with start address of the segment
+ * end          : will be filled with end address of the segment
+ * return values:
+ * -ENOSYS  : we are not running on VM
+ * -EIO     : could not perform query or load diagnose
+ * -ENOENT  : no such segment
+ * -EOPNOTSUPP: multi-part segment cannot be used with linux
+ * -EBUSY   : segment cannot be used (overlaps with dcss or storage)
+ * -ERANGE  : segment cannot be used (exceeds kernel mapping range)
+ * -EPERM   : segment is currently loaded with incompatible permissions
+ * -ENOMEM  : out of memory
+ * 0 .. 6   : type of segment as defined in include/asm-s390/extmem.h
+ */
+int
+segment_load (char *name, int do_nonshared, unsigned long *addr,
+		unsigned long *end)
+{
+	struct dcss_segment *seg;
+	int rc;
+
+	if (!MACHINE_IS_VM)
+		return -ENOSYS;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL)
+		rc = __segment_load (name, do_nonshared, addr, end);
+	else {
+		if (do_nonshared == seg->do_nonshared) {
+			refcount_inc(&seg->ref_count);
+			*addr = seg->start_addr;
+			*end  = seg->end;
+			rc    = seg->vm_segtype;
+		} else {
+			*addr = *end = 0;
+			rc    = -EPERM;
+		}
+	}
+	mutex_unlock(&dcss_lock);
+	return rc;
+}
+
+/*
+ * this function modifies the shared state of a DCSS segment. note that
+ * name         : name of the DCSS
+ * do_nonshared : 0 indicates that the dcss should be shared with other linux images
+ *                1 indicates that the dcss should be exclusive for this linux image
+ * return values:
+ * -EIO     : could not perform load diagnose (segment gone!)
+ * -ENOENT  : no such segment (segment gone!)
+ * -EAGAIN  : segment is in use by other exploiters, try later
+ * -EINVAL  : no segment with the given name is currently loaded - name invalid
+ * -EBUSY   : segment can temporarily not be used (overlaps with dcss)
+ * 0	    : operation succeeded
+ */
+int
+segment_modify_shared (char *name, int do_nonshared)
+{
+	struct dcss_segment *seg;
+	unsigned long start_addr, end_addr, dummy;
+	int rc, diag_cc;
+
+	start_addr = end_addr = 0;
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL) {
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+	if (do_nonshared == seg->do_nonshared) {
+		pr_info("DCSS %s is already in the requested access "
+			"mode\n", name);
+		rc = 0;
+		goto out_unlock;
+	}
+	if (refcount_read(&seg->ref_count) != 1) {
+		pr_warn("DCSS %s is in use and cannot be reloaded\n", name);
+		rc = -EAGAIN;
+		goto out_unlock;
+	}
+	release_resource(seg->res);
+	if (do_nonshared)
+		seg->res->flags &= ~IORESOURCE_READONLY;
+	else
+		if (seg->vm_segtype == SEG_TYPE_SR ||
+		    seg->vm_segtype == SEG_TYPE_ER)
+			seg->res->flags |= IORESOURCE_READONLY;
+
+	if (request_resource(&iomem_resource, seg->res)) {
+		pr_warn("DCSS %s overlaps with used memory resources and cannot be reloaded\n",
+			name);
+		rc = -EBUSY;
+		kfree(seg->res);
+		goto out_del_mem;
+	}
+
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	if (do_nonshared)
+		diag_cc = dcss_diag(&loadnsr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	else
+		diag_cc = dcss_diag(&loadshr_scode, seg->dcss_name,
+				&start_addr, &end_addr);
+	if (diag_cc < 0) {
+		rc = diag_cc;
+		goto out_del_res;
+	}
+	if (diag_cc > 1) {
+		pr_warn("Reloading DCSS %s failed with rc=%ld\n",
+			name, end_addr);
+		rc = dcss_diag_translate_rc(end_addr);
+		goto out_del_res;
+	}
+	seg->start_addr = start_addr;
+	seg->end = end_addr;
+	seg->do_nonshared = do_nonshared;
+	rc = 0;
+	goto out_unlock;
+ out_del_res:
+	release_resource(seg->res);
+	kfree(seg->res);
+ out_del_mem:
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	list_del(&seg->list);
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	kfree(seg);
+ out_unlock:
+	mutex_unlock(&dcss_lock);
+	return rc;
+}
+
+/*
+ * Decrease the use count of a DCSS segment and remove
+ * it from the address space if nobody is using it
+ * any longer.
+ */
+void
+segment_unload(char *name)
+{
+	unsigned long dummy;
+	struct dcss_segment *seg;
+
+	if (!MACHINE_IS_VM)
+		return;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+	if (seg == NULL) {
+		pr_err("Unloading unknown DCSS %s failed\n", name);
+		goto out_unlock;
+	}
+	if (!refcount_dec_and_test(&seg->ref_count))
+		goto out_unlock;
+	release_resource(seg->res);
+	kfree(seg->res);
+	vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1);
+	list_del(&seg->list);
+	dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy);
+	kfree(seg);
+out_unlock:
+	mutex_unlock(&dcss_lock);
+}
+
+/*
+ * save segment content permanently
+ */
+void
+segment_save(char *name)
+{
+	struct dcss_segment *seg;
+	char cmd1[160];
+	char cmd2[80];
+	int i, response;
+
+	if (!MACHINE_IS_VM)
+		return;
+
+	mutex_lock(&dcss_lock);
+	seg = segment_by_name (name);
+
+	if (seg == NULL) {
+		pr_err("Saving unknown DCSS %s failed\n", name);
+		goto out;
+	}
+
+	sprintf(cmd1, "DEFSEG %s", name);
+	for (i=0; i<seg->segcnt; i++) {
+		sprintf(cmd1+strlen(cmd1), " %lX-%lX %s",
+			seg->range[i].start >> PAGE_SHIFT,
+			seg->range[i].end >> PAGE_SHIFT,
+			segtype_string[seg->range[i].start & 0xff]);
+	}
+	sprintf(cmd2, "SAVESEG %s", name);
+	response = 0;
+	cpcmd(cmd1, NULL, 0, &response);
+	if (response) {
+		pr_err("Saving a DCSS failed with DEFSEG response code "
+		       "%i\n", response);
+		goto out;
+	}
+	cpcmd(cmd2, NULL, 0, &response);
+	if (response) {
+		pr_err("Saving a DCSS failed with SAVESEG response code "
+		       "%i\n", response);
+		goto out;
+	}
+out:
+	mutex_unlock(&dcss_lock);
+}
+
+/*
+ * print appropriate error message for segment_load()/segment_type()
+ * return code
+ */
+void segment_warning(int rc, char *seg_name)
+{
+	switch (rc) {
+	case -ENOENT:
+		pr_err("DCSS %s cannot be loaded or queried\n", seg_name);
+		break;
+	case -ENOSYS:
+		pr_err("DCSS %s cannot be loaded or queried without "
+		       "z/VM\n", seg_name);
+		break;
+	case -EIO:
+		pr_err("Loading or querying DCSS %s resulted in a "
+		       "hardware error\n", seg_name);
+		break;
+	case -EOPNOTSUPP:
+		pr_err("DCSS %s has multiple page ranges and cannot be "
+		       "loaded or queried\n", seg_name);
+		break;
+	case -EBUSY:
+		pr_err("%s needs used memory resources and cannot be "
+		       "loaded or queried\n", seg_name);
+		break;
+	case -EPERM:
+		pr_err("DCSS %s is already loaded in a different access "
+		       "mode\n", seg_name);
+		break;
+	case -ENOMEM:
+		pr_err("There is not enough memory to load or query "
+		       "DCSS %s\n", seg_name);
+		break;
+	case -ERANGE:
+		pr_err("DCSS %s exceeds the kernel mapping range (%lu) "
+		       "and cannot be loaded\n", seg_name, VMEM_MAX_PHYS);
+		break;
+	default:
+		break;
+	}
+}
+
+EXPORT_SYMBOL(segment_load);
+EXPORT_SYMBOL(segment_unload);
+EXPORT_SYMBOL(segment_save);
+EXPORT_SYMBOL(segment_type);
+EXPORT_SYMBOL(segment_modify_shared);
+EXPORT_SYMBOL(segment_warning);