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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /arch/sh/mm/fault.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
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(). ...
Diffstat (limited to 'arch/sh/mm/fault.c')
-rw-r--r--arch/sh/mm/fault.c504
1 files changed, 504 insertions, 0 deletions
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
new file mode 100644
index 000000000..acd2f5e50
--- /dev/null
+++ b/arch/sh/mm/fault.c
@@ -0,0 +1,504 @@
+/*
+ * Page fault handler for SH with an MMU.
+ *
+ * Copyright (C) 1999 Niibe Yutaka
+ * Copyright (C) 2003 - 2012 Paul Mundt
+ *
+ * Based on linux/arch/i386/mm/fault.c:
+ * Copyright (C) 1995 Linus Torvalds
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/hardirq.h>
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
+#include <linux/kdebug.h>
+#include <linux/uaccess.h>
+#include <asm/io_trapped.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/traps.h>
+
+static void
+force_sig_info_fault(int si_signo, int si_code, unsigned long address)
+{
+ force_sig_fault(si_signo, si_code, (void __user *)address);
+}
+
+/*
+ * This is useful to dump out the page tables associated with
+ * 'addr' in mm 'mm'.
+ */
+static void show_pte(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+
+ if (mm) {
+ pgd = mm->pgd;
+ } else {
+ pgd = get_TTB();
+
+ if (unlikely(!pgd))
+ pgd = swapper_pg_dir;
+ }
+
+ pr_alert("pgd = %p\n", pgd);
+ pgd += pgd_index(addr);
+ pr_alert("[%08lx] *pgd=%0*llx", addr, (u32)(sizeof(*pgd) * 2),
+ (u64)pgd_val(*pgd));
+
+ do {
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ if (pgd_none(*pgd))
+ break;
+
+ if (pgd_bad(*pgd)) {
+ pr_cont("(bad)");
+ break;
+ }
+
+ p4d = p4d_offset(pgd, addr);
+ if (PTRS_PER_P4D != 1)
+ pr_cont(", *p4d=%0*Lx", (u32)(sizeof(*p4d) * 2),
+ (u64)p4d_val(*p4d));
+
+ if (p4d_none(*p4d))
+ break;
+
+ if (p4d_bad(*p4d)) {
+ pr_cont("(bad)");
+ break;
+ }
+
+ pud = pud_offset(p4d, addr);
+ if (PTRS_PER_PUD != 1)
+ pr_cont(", *pud=%0*llx", (u32)(sizeof(*pud) * 2),
+ (u64)pud_val(*pud));
+
+ if (pud_none(*pud))
+ break;
+
+ if (pud_bad(*pud)) {
+ pr_cont("(bad)");
+ break;
+ }
+
+ pmd = pmd_offset(pud, addr);
+ if (PTRS_PER_PMD != 1)
+ pr_cont(", *pmd=%0*llx", (u32)(sizeof(*pmd) * 2),
+ (u64)pmd_val(*pmd));
+
+ if (pmd_none(*pmd))
+ break;
+
+ if (pmd_bad(*pmd)) {
+ pr_cont("(bad)");
+ break;
+ }
+
+ /* We must not map this if we have highmem enabled */
+ if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
+ break;
+
+ pte = pte_offset_kernel(pmd, addr);
+ pr_cont(", *pte=%0*llx", (u32)(sizeof(*pte) * 2),
+ (u64)pte_val(*pte));
+ } while (0);
+
+ pr_cont("\n");
+}
+
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
+{
+ unsigned index = pgd_index(address);
+ pgd_t *pgd_k;
+ p4d_t *p4d, *p4d_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd += index;
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k))
+ return NULL;
+
+ p4d = p4d_offset(pgd, address);
+ p4d_k = p4d_offset(pgd_k, address);
+ if (!p4d_present(*p4d_k))
+ return NULL;
+
+ pud = pud_offset(p4d, address);
+ pud_k = pud_offset(p4d_k, address);
+ if (!pud_present(*pud_k))
+ return NULL;
+
+ if (!pud_present(*pud))
+ set_pud(pud, *pud_k);
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ return NULL;
+
+ if (!pmd_present(*pmd))
+ set_pmd(pmd, *pmd_k);
+ else {
+ /*
+ * The page tables are fully synchronised so there must
+ * be another reason for the fault. Return NULL here to
+ * signal that we have not taken care of the fault.
+ */
+ BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
+ return NULL;
+ }
+
+ return pmd_k;
+}
+
+#ifdef CONFIG_SH_STORE_QUEUES
+#define __FAULT_ADDR_LIMIT P3_ADDR_MAX
+#else
+#define __FAULT_ADDR_LIMIT VMALLOC_END
+#endif
+
+/*
+ * Handle a fault on the vmalloc or module mapping area
+ */
+static noinline int vmalloc_fault(unsigned long address)
+{
+ pgd_t *pgd_k;
+ pmd_t *pmd_k;
+ pte_t *pte_k;
+
+ /* Make sure we are in vmalloc/module/P3 area: */
+ if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT))
+ return -1;
+
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Do _not_ use "current" here. We might be inside
+ * an interrupt in the middle of a task switch..
+ */
+ pgd_k = get_TTB();
+ pmd_k = vmalloc_sync_one(pgd_k, address);
+ if (!pmd_k)
+ return -1;
+
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ return -1;
+
+ return 0;
+}
+
+static void
+show_fault_oops(struct pt_regs *regs, unsigned long address)
+{
+ if (!oops_may_print())
+ return;
+
+ pr_alert("BUG: unable to handle kernel %s at %08lx\n",
+ address < PAGE_SIZE ? "NULL pointer dereference"
+ : "paging request",
+ address);
+ pr_alert("PC:");
+ printk_address(regs->pc, 1);
+
+ show_pte(NULL, address);
+}
+
+static noinline void
+no_context(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs))
+ return;
+
+ if (handle_trapped_io(regs, address))
+ return;
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ bust_spinlocks(1);
+
+ show_fault_oops(regs, address);
+
+ die("Oops", regs, error_code);
+}
+
+static void
+__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, int si_code)
+{
+ /* User mode accesses just cause a SIGSEGV */
+ if (user_mode(regs)) {
+ /*
+ * It's possible to have interrupts off here:
+ */
+ local_irq_enable();
+
+ force_sig_info_fault(SIGSEGV, si_code, address);
+
+ return;
+ }
+
+ no_context(regs, error_code, address);
+}
+
+static noinline void
+bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
+}
+
+static void
+__bad_area(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, int si_code)
+{
+ struct mm_struct *mm = current->mm;
+
+ /*
+ * Something tried to access memory that isn't in our memory map..
+ * Fix it, but check if it's kernel or user first..
+ */
+ mmap_read_unlock(mm);
+
+ __bad_area_nosemaphore(regs, error_code, address, si_code);
+}
+
+static noinline void
+bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+ __bad_area(regs, error_code, address, SEGV_MAPERR);
+}
+
+static noinline void
+bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+ __bad_area(regs, error_code, address, SEGV_ACCERR);
+}
+
+static void
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->mm;
+
+ mmap_read_unlock(mm);
+
+ /* Kernel mode? Handle exceptions or die: */
+ if (!user_mode(regs))
+ no_context(regs, error_code, address);
+
+ force_sig_info_fault(SIGBUS, BUS_ADRERR, address);
+}
+
+static noinline int
+mm_fault_error(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address, vm_fault_t fault)
+{
+ /*
+ * Pagefault was interrupted by SIGKILL. We have no reason to
+ * continue pagefault.
+ */
+ if (fault_signal_pending(fault, regs)) {
+ if (!user_mode(regs))
+ no_context(regs, error_code, address);
+ return 1;
+ }
+
+ /* Release mmap_lock first if necessary */
+ if (!(fault & VM_FAULT_RETRY))
+ mmap_read_unlock(current->mm);
+
+ if (!(fault & VM_FAULT_ERROR))
+ return 0;
+
+ if (fault & VM_FAULT_OOM) {
+ /* Kernel mode? Handle exceptions or die: */
+ if (!user_mode(regs)) {
+ no_context(regs, error_code, address);
+ return 1;
+ }
+
+ /*
+ * We ran out of memory, call the OOM killer, and return the
+ * userspace (which will retry the fault, or kill us if we got
+ * oom-killed):
+ */
+ pagefault_out_of_memory();
+ } else {
+ if (fault & VM_FAULT_SIGBUS)
+ do_sigbus(regs, error_code, address);
+ else if (fault & VM_FAULT_SIGSEGV)
+ bad_area(regs, error_code, address);
+ else
+ BUG();
+ }
+
+ return 1;
+}
+
+static inline int access_error(int error_code, struct vm_area_struct *vma)
+{
+ if (error_code & FAULT_CODE_WRITE) {
+ /* write, present and write, not present: */
+ if (unlikely(!(vma->vm_flags & VM_WRITE)))
+ return 1;
+ return 0;
+ }
+
+ /* ITLB miss on NX page */
+ if (unlikely((error_code & FAULT_CODE_ITLB) &&
+ !(vma->vm_flags & VM_EXEC)))
+ return 1;
+
+ /* read, not present: */
+ if (unlikely(!vma_is_accessible(vma)))
+ return 1;
+
+ return 0;
+}
+
+static int fault_in_kernel_space(unsigned long address)
+{
+ return address >= TASK_SIZE;
+}
+
+/*
+ * This routine handles page faults. It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ */
+asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
+ unsigned long error_code,
+ unsigned long address)
+{
+ unsigned long vec;
+ struct task_struct *tsk;
+ struct mm_struct *mm;
+ struct vm_area_struct * vma;
+ vm_fault_t fault;
+ unsigned int flags = FAULT_FLAG_DEFAULT;
+
+ tsk = current;
+ mm = tsk->mm;
+ vec = lookup_exception_vector();
+
+ /*
+ * We fault-in kernel-space virtual memory on-demand. The
+ * 'reference' page table is init_mm.pgd.
+ *
+ * NOTE! We MUST NOT take any locks for this case. We may
+ * be in an interrupt or a critical region, and should
+ * only copy the information from the master page table,
+ * nothing more.
+ */
+ if (unlikely(fault_in_kernel_space(address))) {
+ if (vmalloc_fault(address) >= 0)
+ return;
+ if (kprobe_page_fault(regs, vec))
+ return;
+
+ bad_area_nosemaphore(regs, error_code, address);
+ return;
+ }
+
+ if (unlikely(kprobe_page_fault(regs, vec)))
+ return;
+
+ /* Only enable interrupts if they were on before the fault */
+ if ((regs->sr & SR_IMASK) != SR_IMASK)
+ local_irq_enable();
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+
+ /*
+ * If we're in an interrupt, have no user context or are running
+ * with pagefaults disabled then we must not take the fault:
+ */
+ if (unlikely(faulthandler_disabled() || !mm)) {
+ bad_area_nosemaphore(regs, error_code, address);
+ return;
+ }
+
+retry:
+ mmap_read_lock(mm);
+
+ vma = find_vma(mm, address);
+ if (unlikely(!vma)) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+ if (likely(vma->vm_start <= address))
+ goto good_area;
+ if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+ if (unlikely(expand_stack(vma, address))) {
+ bad_area(regs, error_code, address);
+ return;
+ }
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+ if (unlikely(access_error(error_code, vma))) {
+ bad_area_access_error(regs, error_code, address);
+ return;
+ }
+
+ set_thread_fault_code(error_code);
+
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+ if (error_code & FAULT_CODE_WRITE)
+ flags |= FAULT_FLAG_WRITE;
+
+ /*
+ * If for any reason at all we couldn't handle the fault,
+ * make sure we exit gracefully rather than endlessly redo
+ * the fault.
+ */
+ fault = handle_mm_fault(vma, address, flags, regs);
+
+ if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
+ if (mm_fault_error(regs, error_code, address, fault))
+ return;
+
+ /* The fault is fully completed (including releasing mmap lock) */
+ if (fault & VM_FAULT_COMPLETED)
+ return;
+
+ if (fault & VM_FAULT_RETRY) {
+ flags |= FAULT_FLAG_TRIED;
+
+ /*
+ * No need to mmap_read_unlock(mm) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+ goto retry;
+ }
+
+ mmap_read_unlock(mm);
+}