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, 621 insertions, 0 deletions

diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
new file mode 100644
index 000000000..966191d3a
--- /dev/null
+++ b/fs/pstore/ram_core.c
@@ -0,0 +1,621 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012 Google, Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/memblock.h>
+#include <linux/rslib.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <asm/page.h>
+
+#include "ram_internal.h"
+
+/**
+ * struct persistent_ram_buffer - persistent circular RAM buffer
+ *
+ * @sig:
+ *	signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
+ * @start:
+ *	offset into @data where the beginning of the stored bytes begin
+ * @size:
+ *	number of valid bytes stored in @data
+ */
+struct persistent_ram_buffer {
+	uint32_t    sig;
+	atomic_t    start;
+	atomic_t    size;
+	uint8_t     data[];
+};
+
+#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
+
+static inline size_t buffer_size(struct persistent_ram_zone *prz)
+{
+	return atomic_read(&prz->buffer->size);
+}
+
+static inline size_t buffer_start(struct persistent_ram_zone *prz)
+{
+	return atomic_read(&prz->buffer->start);
+}
+
+/* increase and wrap the start pointer, returning the old value */
+static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
+{
+	int old;
+	int new;
+	unsigned long flags = 0;
+
+	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+		raw_spin_lock_irqsave(&prz->buffer_lock, flags);
+
+	old = atomic_read(&prz->buffer->start);
+	new = old + a;
+	while (unlikely(new >= prz->buffer_size))
+		new -= prz->buffer_size;
+	atomic_set(&prz->buffer->start, new);
+
+	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+		raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
+
+	return old;
+}
+
+/* increase the size counter until it hits the max size */
+static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
+{
+	size_t old;
+	size_t new;
+	unsigned long flags = 0;
+
+	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+		raw_spin_lock_irqsave(&prz->buffer_lock, flags);
+
+	old = atomic_read(&prz->buffer->size);
+	if (old == prz->buffer_size)
+		goto exit;
+
+	new = old + a;
+	if (new > prz->buffer_size)
+		new = prz->buffer_size;
+	atomic_set(&prz->buffer->size, new);
+
+exit:
+	if (!(prz->flags & PRZ_FLAG_NO_LOCK))
+		raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
+}
+
+static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
+	uint8_t *data, size_t len, uint8_t *ecc)
+{
+	int i;
+
+	/* Initialize the parity buffer */
+	memset(prz->ecc_info.par, 0,
+	       prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0]));
+	encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0);
+	for (i = 0; i < prz->ecc_info.ecc_size; i++)
+		ecc[i] = prz->ecc_info.par[i];
+}
+
+static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
+	void *data, size_t len, uint8_t *ecc)
+{
+	int i;
+
+	for (i = 0; i < prz->ecc_info.ecc_size; i++)
+		prz->ecc_info.par[i] = ecc[i];
+	return decode_rs8(prz->rs_decoder, data, prz->ecc_info.par, len,
+				NULL, 0, NULL, 0, NULL);
+}
+
+static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
+	unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	uint8_t *buffer_end = buffer->data + prz->buffer_size;
+	uint8_t *block;
+	uint8_t *par;
+	int ecc_block_size = prz->ecc_info.block_size;
+	int ecc_size = prz->ecc_info.ecc_size;
+	int size = ecc_block_size;
+
+	if (!ecc_size)
+		return;
+
+	block = buffer->data + (start & ~(ecc_block_size - 1));
+	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
+
+	do {
+		if (block + ecc_block_size > buffer_end)
+			size = buffer_end - block;
+		persistent_ram_encode_rs8(prz, block, size, par);
+		block += ecc_block_size;
+		par += ecc_size;
+	} while (block < buffer->data + start + count);
+}
+
+static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+
+	if (!prz->ecc_info.ecc_size)
+		return;
+
+	persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
+				  prz->par_header);
+}
+
+static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	uint8_t *block;
+	uint8_t *par;
+
+	if (!prz->ecc_info.ecc_size)
+		return;
+
+	block = buffer->data;
+	par = prz->par_buffer;
+	while (block < buffer->data + buffer_size(prz)) {
+		int numerr;
+		int size = prz->ecc_info.block_size;
+		if (block + size > buffer->data + prz->buffer_size)
+			size = buffer->data + prz->buffer_size - block;
+		numerr = persistent_ram_decode_rs8(prz, block, size, par);
+		if (numerr > 0) {
+			pr_devel("error in block %p, %d\n", block, numerr);
+			prz->corrected_bytes += numerr;
+		} else if (numerr < 0) {
+			pr_devel("uncorrectable error in block %p\n", block);
+			prz->bad_blocks++;
+		}
+		block += prz->ecc_info.block_size;
+		par += prz->ecc_info.ecc_size;
+	}
+}
+
+static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
+				   struct persistent_ram_ecc_info *ecc_info)
+{
+	int numerr;
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	int ecc_blocks;
+	size_t ecc_total;
+
+	if (!ecc_info || !ecc_info->ecc_size)
+		return 0;
+
+	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
+	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
+	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
+	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
+
+	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
+				  prz->ecc_info.block_size +
+				  prz->ecc_info.ecc_size);
+	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
+	if (ecc_total >= prz->buffer_size) {
+		pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
+		       __func__, prz->ecc_info.ecc_size,
+		       ecc_total, prz->buffer_size);
+		return -EINVAL;
+	}
+
+	prz->buffer_size -= ecc_total;
+	prz->par_buffer = buffer->data + prz->buffer_size;
+	prz->par_header = prz->par_buffer +
+			  ecc_blocks * prz->ecc_info.ecc_size;
+
+	/*
+	 * first consecutive root is 0
+	 * primitive element to generate roots = 1
+	 */
+	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
+				  0, 1, prz->ecc_info.ecc_size);
+	if (prz->rs_decoder == NULL) {
+		pr_info("init_rs failed\n");
+		return -EINVAL;
+	}
+
+	/* allocate workspace instead of using stack VLA */
+	prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size,
+					  sizeof(*prz->ecc_info.par),
+					  GFP_KERNEL);
+	if (!prz->ecc_info.par) {
+		pr_err("cannot allocate ECC parity workspace\n");
+		return -ENOMEM;
+	}
+
+	prz->corrected_bytes = 0;
+	prz->bad_blocks = 0;
+
+	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
+					   prz->par_header);
+	if (numerr > 0) {
+		pr_info("error in header, %d\n", numerr);
+		prz->corrected_bytes += numerr;
+	} else if (numerr < 0) {
+		pr_info_ratelimited("uncorrectable error in header\n");
+		prz->bad_blocks++;
+	}
+
+	return 0;
+}
+
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+	char *str, size_t len)
+{
+	ssize_t ret;
+
+	if (!prz->ecc_info.ecc_size)
+		return 0;
+
+	if (prz->corrected_bytes || prz->bad_blocks)
+		ret = snprintf(str, len, ""
+			"\nECC: %d Corrected bytes, %d unrecoverable blocks\n",
+			prz->corrected_bytes, prz->bad_blocks);
+	else
+		ret = snprintf(str, len, "\nECC: No errors detected\n");
+
+	return ret;
+}
+
+static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
+	const void *s, unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	memcpy_toio(buffer->data + start, s, count);
+	persistent_ram_update_ecc(prz, start, count);
+}
+
+static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
+	const void __user *s, unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	int ret = unlikely(copy_from_user(buffer->data + start, s, count)) ?
+		-EFAULT : 0;
+	persistent_ram_update_ecc(prz, start, count);
+	return ret;
+}
+
+void persistent_ram_save_old(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	size_t size = buffer_size(prz);
+	size_t start = buffer_start(prz);
+
+	if (!size)
+		return;
+
+	if (!prz->old_log) {
+		persistent_ram_ecc_old(prz);
+		prz->old_log = kmalloc(size, GFP_KERNEL);
+	}
+	if (!prz->old_log) {
+		pr_err("failed to allocate buffer\n");
+		return;
+	}
+
+	prz->old_log_size = size;
+	memcpy_fromio(prz->old_log, &buffer->data[start], size - start);
+	memcpy_fromio(prz->old_log + size - start, &buffer->data[0], start);
+}
+
+int notrace persistent_ram_write(struct persistent_ram_zone *prz,
+	const void *s, unsigned int count)
+{
+	int rem;
+	int c = count;
+	size_t start;
+
+	if (unlikely(c > prz->buffer_size)) {
+		s += c - prz->buffer_size;
+		c = prz->buffer_size;
+	}
+
+	buffer_size_add(prz, c);
+
+	start = buffer_start_add(prz, c);
+
+	rem = prz->buffer_size - start;
+	if (unlikely(rem < c)) {
+		persistent_ram_update(prz, s, start, rem);
+		s += rem;
+		c -= rem;
+		start = 0;
+	}
+	persistent_ram_update(prz, s, start, c);
+
+	persistent_ram_update_header_ecc(prz);
+
+	return count;
+}
+
+int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
+	const void __user *s, unsigned int count)
+{
+	int rem, ret = 0, c = count;
+	size_t start;
+
+	if (unlikely(c > prz->buffer_size)) {
+		s += c - prz->buffer_size;
+		c = prz->buffer_size;
+	}
+
+	buffer_size_add(prz, c);
+
+	start = buffer_start_add(prz, c);
+
+	rem = prz->buffer_size - start;
+	if (unlikely(rem < c)) {
+		ret = persistent_ram_update_user(prz, s, start, rem);
+		s += rem;
+		c -= rem;
+		start = 0;
+	}
+	if (likely(!ret))
+		ret = persistent_ram_update_user(prz, s, start, c);
+
+	persistent_ram_update_header_ecc(prz);
+
+	return unlikely(ret) ? ret : count;
+}
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
+{
+	return prz->old_log_size;
+}
+
+void *persistent_ram_old(struct persistent_ram_zone *prz)
+{
+	return prz->old_log;
+}
+
+void persistent_ram_free_old(struct persistent_ram_zone *prz)
+{
+	kfree(prz->old_log);
+	prz->old_log = NULL;
+	prz->old_log_size = 0;
+}
+
+void persistent_ram_zap(struct persistent_ram_zone *prz)
+{
+	atomic_set(&prz->buffer->start, 0);
+	atomic_set(&prz->buffer->size, 0);
+	persistent_ram_update_header_ecc(prz);
+}
+
+#define MEM_TYPE_WCOMBINE	0
+#define MEM_TYPE_NONCACHED	1
+#define MEM_TYPE_NORMAL		2
+
+static void *persistent_ram_vmap(phys_addr_t start, size_t size,
+		unsigned int memtype)
+{
+	struct page **pages;
+	phys_addr_t page_start;
+	unsigned int page_count;
+	pgprot_t prot;
+	unsigned int i;
+	void *vaddr;
+
+	page_start = start - offset_in_page(start);
+	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
+
+	switch (memtype) {
+	case MEM_TYPE_NORMAL:
+		prot = PAGE_KERNEL;
+		break;
+	case MEM_TYPE_NONCACHED:
+		prot = pgprot_noncached(PAGE_KERNEL);
+		break;
+	case MEM_TYPE_WCOMBINE:
+		prot = pgprot_writecombine(PAGE_KERNEL);
+		break;
+	default:
+		pr_err("invalid mem_type=%d\n", memtype);
+		return NULL;
+	}
+
+	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
+	if (!pages) {
+		pr_err("%s: Failed to allocate array for %u pages\n",
+		       __func__, page_count);
+		return NULL;
+	}
+
+	for (i = 0; i < page_count; i++) {
+		phys_addr_t addr = page_start + i * PAGE_SIZE;
+		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
+	}
+	/*
+	 * VM_IOREMAP used here to bypass this region during vread()
+	 * and kmap_atomic() (i.e. kcore) to avoid __va() failures.
+	 */
+	vaddr = vmap(pages, page_count, VM_MAP | VM_IOREMAP, prot);
+	kfree(pages);
+
+	/*
+	 * Since vmap() uses page granularity, we must add the offset
+	 * into the page here, to get the byte granularity address
+	 * into the mapping to represent the actual "start" location.
+	 */
+	return vaddr + offset_in_page(start);
+}
+
+static void *persistent_ram_iomap(phys_addr_t start, size_t size,
+		unsigned int memtype, char *label)
+{
+	void *va;
+
+	if (!request_mem_region(start, size, label ?: "ramoops")) {
+		pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
+			label ?: "ramoops",
+			(unsigned long long)size, (unsigned long long)start);
+		return NULL;
+	}
+
+	if (memtype)
+		va = ioremap(start, size);
+	else
+		va = ioremap_wc(start, size);
+
+	/*
+	 * Since request_mem_region() and ioremap() are byte-granularity
+	 * there is no need handle anything special like we do when the
+	 * vmap() case in persistent_ram_vmap() above.
+	 */
+	return va;
+}
+
+static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
+		struct persistent_ram_zone *prz, int memtype)
+{
+	prz->paddr = start;
+	prz->size = size;
+
+	if (pfn_valid(start >> PAGE_SHIFT))
+		prz->vaddr = persistent_ram_vmap(start, size, memtype);
+	else
+		prz->vaddr = persistent_ram_iomap(start, size, memtype,
+						  prz->label);
+
+	if (!prz->vaddr) {
+		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
+			(unsigned long long)size, (unsigned long long)start);
+		return -ENOMEM;
+	}
+
+	prz->buffer = prz->vaddr;
+	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
+
+	return 0;
+}
+
+static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
+				    struct persistent_ram_ecc_info *ecc_info)
+{
+	int ret;
+	bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
+
+	ret = persistent_ram_init_ecc(prz, ecc_info);
+	if (ret) {
+		pr_warn("ECC failed %s\n", prz->label);
+		return ret;
+	}
+
+	sig ^= PERSISTENT_RAM_SIG;
+
+	if (prz->buffer->sig == sig) {
+		if (buffer_size(prz) == 0) {
+			pr_debug("found existing empty buffer\n");
+			return 0;
+		}
+
+		if (buffer_size(prz) > prz->buffer_size ||
+		    buffer_start(prz) > buffer_size(prz)) {
+			pr_info("found existing invalid buffer, size %zu, start %zu\n",
+				buffer_size(prz), buffer_start(prz));
+			zap = true;
+		} else {
+			pr_debug("found existing buffer, size %zu, start %zu\n",
+				 buffer_size(prz), buffer_start(prz));
+			persistent_ram_save_old(prz);
+		}
+	} else {
+		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
+			 prz->buffer->sig);
+		prz->buffer->sig = sig;
+		zap = true;
+	}
+
+	/* Reset missing, invalid, or single-use memory area. */
+	if (zap)
+		persistent_ram_zap(prz);
+
+	return 0;
+}
+
+void persistent_ram_free(struct persistent_ram_zone **_prz)
+{
+	struct persistent_ram_zone *prz;
+
+	if (!_prz)
+		return;
+
+	prz = *_prz;
+	if (!prz)
+		return;
+
+	if (prz->vaddr) {
+		if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
+			/* We must vunmap() at page-granularity. */
+			vunmap(prz->vaddr - offset_in_page(prz->paddr));
+		} else {
+			iounmap(prz->vaddr);
+			release_mem_region(prz->paddr, prz->size);
+		}
+		prz->vaddr = NULL;
+	}
+	if (prz->rs_decoder) {
+		free_rs(prz->rs_decoder);
+		prz->rs_decoder = NULL;
+	}
+	kfree(prz->ecc_info.par);
+	prz->ecc_info.par = NULL;
+
+	persistent_ram_free_old(prz);
+	kfree(prz->label);
+	kfree(prz);
+	*_prz = NULL;
+}
+
+struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
+			u32 sig, struct persistent_ram_ecc_info *ecc_info,
+			unsigned int memtype, u32 flags, char *label)
+{
+	struct persistent_ram_zone *prz;
+	int ret = -ENOMEM;
+
+	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+	if (!prz) {
+		pr_err("failed to allocate persistent ram zone\n");
+		goto err;
+	}
+
+	/* Initialize general buffer state. */
+	raw_spin_lock_init(&prz->buffer_lock);
+	prz->flags = flags;
+	prz->label = kstrdup(label, GFP_KERNEL);
+
+	ret = persistent_ram_buffer_map(start, size, prz, memtype);
+	if (ret)
+		goto err;
+
+	ret = persistent_ram_post_init(prz, sig, ecc_info);
+	if (ret)
+		goto err;
+
+	pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
+		prz->label, prz->size, (unsigned long long)prz->paddr,
+		sizeof(*prz->buffer), prz->buffer_size,
+		prz->size - sizeof(*prz->buffer) - prz->buffer_size,
+		prz->ecc_info.ecc_size, prz->ecc_info.block_size);
+
+	return prz;
+err:
+	persistent_ram_free(&prz);
+	return ERR_PTR(ret);
+}