From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/admin-guide/kdump/vmcoreinfo.rst | 626 +++++++++++++++++++++++++ 1 file changed, 626 insertions(+) create mode 100644 Documentation/admin-guide/kdump/vmcoreinfo.rst (limited to 'Documentation/admin-guide/kdump/vmcoreinfo.rst') diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst new file mode 100644 index 000000000..86fd88492 --- /dev/null +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst @@ -0,0 +1,626 @@ +========== +VMCOREINFO +========== + +What is it? +=========== + +VMCOREINFO is a special ELF note section. It contains various +information from the kernel like structure size, page size, symbol +values, field offsets, etc. These data are packed into an ELF note +section and used by user-space tools like crash and makedumpfile to +analyze a kernel's memory layout. + +Common variables +================ + +init_uts_ns.name.release +------------------------ + +The version of the Linux kernel. Used to find the corresponding source +code from which the kernel has been built. For example, crash uses it to +find the corresponding vmlinux in order to process vmcore. + +PAGE_SIZE +--------- + +The size of a page. It is the smallest unit of data used by the memory +management facilities. It is usually 4096 bytes of size and a page is +aligned on 4096 bytes. Used for computing page addresses. + +init_uts_ns +----------- + +The UTS namespace which is used to isolate two specific elements of the +system that relate to the uname(2) system call. It is named after the +data structure used to store information returned by the uname(2) system +call. + +User-space tools can get the kernel name, host name, kernel release +number, kernel version, architecture name and OS type from it. + +(uts_namespace, name) +--------------------- + +Offset of the name's member. Crash Utility and Makedumpfile get +the start address of the init_uts_ns.name from this. + +node_online_map +--------------- + +An array node_states[N_ONLINE] which represents the set of online nodes +in a system, one bit position per node number. Used to keep track of +which nodes are in the system and online. + +swapper_pg_dir +-------------- + +The global page directory pointer of the kernel. Used to translate +virtual to physical addresses. + +_stext +------ + +Defines the beginning of the text section. In general, _stext indicates +the kernel start address. Used to convert a virtual address from the +direct kernel map to a physical address. + +vmap_area_list +-------------- + +Stores the virtual area list. makedumpfile gets the vmalloc start value +from this variable and its value is necessary for vmalloc translation. + +mem_map +------- + +Physical addresses are translated to struct pages by treating them as +an index into the mem_map array. Right-shifting a physical address +PAGE_SHIFT bits converts it into a page frame number which is an index +into that mem_map array. + +Used to map an address to the corresponding struct page. + +contig_page_data +---------------- + +Makedumpfile gets the pglist_data structure from this symbol, which is +used to describe the memory layout. + +User-space tools use this to exclude free pages when dumping memory. + +mem_section|(mem_section, NR_SECTION_ROOTS)|(mem_section, section_mem_map) +-------------------------------------------------------------------------- + +The address of the mem_section array, its length, structure size, and +the section_mem_map offset. + +It exists in the sparse memory mapping model, and it is also somewhat +similar to the mem_map variable, both of them are used to translate an +address. + +MAX_PHYSMEM_BITS +---------------- + +Defines the maximum supported physical address space memory. + +page +---- + +The size of a page structure. struct page is an important data structure +and it is widely used to compute contiguous memory. + +pglist_data +----------- + +The size of a pglist_data structure. This value is used to check if the +pglist_data structure is valid. It is also used for checking the memory +type. + +zone +---- + +The size of a zone structure. This value is used to check if the zone +structure has been found. It is also used for excluding free pages. + +free_area +--------- + +The size of a free_area structure. It indicates whether the free_area +structure is valid or not. Useful when excluding free pages. + +list_head +--------- + +The size of a list_head structure. Used when iterating lists in a +post-mortem analysis session. + +nodemask_t +---------- + +The size of a nodemask_t type. Used to compute the number of online +nodes. + +(page, flags|_refcount|mapping|lru|_mapcount|private|compound_dtor|compound_order|compound_head) +------------------------------------------------------------------------------------------------- + +User-space tools compute their values based on the offset of these +variables. The variables are used when excluding unnecessary pages. + +(pglist_data, node_zones|nr_zones|node_mem_map|node_start_pfn|node_spanned_pages|node_id) +----------------------------------------------------------------------------------------- + +On NUMA machines, each NUMA node has a pg_data_t to describe its memory +layout. On UMA machines there is a single pglist_data which describes the +whole memory. + +These values are used to check the memory type and to compute the +virtual address for memory map. + +(zone, free_area|vm_stat|spanned_pages) +--------------------------------------- + +Each node is divided into a number of blocks called zones which +represent ranges within memory. A zone is described by a structure zone. + +User-space tools compute required values based on the offset of these +variables. + +(free_area, free_list) +---------------------- + +Offset of the free_list's member. This value is used to compute the number +of free pages. + +Each zone has a free_area structure array called free_area[MAX_ORDER]. +The free_list represents a linked list of free page blocks. + +(list_head, next|prev) +---------------------- + +Offsets of the list_head's members. list_head is used to define a +circular linked list. User-space tools need these in order to traverse +lists. + +(vmap_area, va_start|list) +-------------------------- + +Offsets of the vmap_area's members. They carry vmalloc-specific +information. Makedumpfile gets the start address of the vmalloc region +from this. + +(zone.free_area, MAX_ORDER) +--------------------------- + +Free areas descriptor. User-space tools use this value to iterate the +free_area ranges. MAX_ORDER is used by the zone buddy allocator. + +prb +--- + +A pointer to the printk ringbuffer (struct printk_ringbuffer). This +may be pointing to the static boot ringbuffer or the dynamically +allocated ringbuffer, depending on when the core dump occurred. +Used by user-space tools to read the active kernel log buffer. + +printk_rb_static +---------------- + +A pointer to the static boot printk ringbuffer. If @prb has a +different value, this is useful for viewing the initial boot messages, +which may have been overwritten in the dynamically allocated +ringbuffer. + +clear_seq +--------- + +The sequence number of the printk() record after the last clear +command. It indicates the first record after the last +SYSLOG_ACTION_CLEAR, like issued by 'dmesg -c'. Used by user-space +tools to dump a subset of the dmesg log. + +printk_ringbuffer +----------------- + +The size of a printk_ringbuffer structure. This structure contains all +information required for accessing the various components of the +kernel log buffer. + +(printk_ringbuffer, desc_ring|text_data_ring|dict_data_ring|fail) +----------------------------------------------------------------- + +Offsets for the various components of the printk ringbuffer. Used by +user-space tools to view the kernel log buffer without requiring the +declaration of the structure. + +prb_desc_ring +------------- + +The size of the prb_desc_ring structure. This structure contains +information about the set of record descriptors. + +(prb_desc_ring, count_bits|descs|head_id|tail_id) +------------------------------------------------- + +Offsets for the fields describing the set of record descriptors. Used +by user-space tools to be able to traverse the descriptors without +requiring the declaration of the structure. + +prb_desc +-------- + +The size of the prb_desc structure. This structure contains +information about a single record descriptor. + +(prb_desc, info|state_var|text_blk_lpos|dict_blk_lpos) +------------------------------------------------------ + +Offsets for the fields describing a record descriptors. Used by +user-space tools to be able to read descriptors without requiring +the declaration of the structure. + +prb_data_blk_lpos +----------------- + +The size of the prb_data_blk_lpos structure. This structure contains +information about where the text or dictionary data (data block) is +located within the respective data ring. + +(prb_data_blk_lpos, begin|next) +------------------------------- + +Offsets for the fields describing the location of a data block. Used +by user-space tools to be able to locate data blocks without +requiring the declaration of the structure. + +printk_info +----------- + +The size of the printk_info structure. This structure contains all +the meta-data for a record. + +(printk_info, seq|ts_nsec|text_len|dict_len|caller_id) +------------------------------------------------------ + +Offsets for the fields providing the meta-data for a record. Used by +user-space tools to be able to read the information without requiring +the declaration of the structure. + +prb_data_ring +------------- + +The size of the prb_data_ring structure. This structure contains +information about a set of data blocks. + +(prb_data_ring, size_bits|data|head_lpos|tail_lpos) +--------------------------------------------------- + +Offsets for the fields describing a set of data blocks. Used by +user-space tools to be able to access the data blocks without +requiring the declaration of the structure. + +atomic_long_t +------------- + +The size of the atomic_long_t structure. Used by user-space tools to +be able to copy the full structure, regardless of its +architecture-specific implementation. + +(atomic_long_t, counter) +------------------------ + +Offset for the long value of an atomic_long_t variable. Used by +user-space tools to access the long value without requiring the +architecture-specific declaration. + +(free_area.free_list, MIGRATE_TYPES) +------------------------------------ + +The number of migrate types for pages. The free_list is described by the +array. Used by tools to compute the number of free pages. + +NR_FREE_PAGES +------------- + +On linux-2.6.21 or later, the number of free pages is in +vm_stat[NR_FREE_PAGES]. Used to get the number of free pages. + +PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask +------------------------------------------------------------------------------ + +Page attributes. These flags are used to filter various unnecessary for +dumping pages. + +PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline) +----------------------------------------------------------------------------- + +More page attributes. These flags are used to filter various unnecessary for +dumping pages. + + +HUGETLB_PAGE_DTOR +----------------- + +The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile +excludes these pages. + +x86_64 +====== + +phys_base +--------- + +Used to convert the virtual address of an exported kernel symbol to its +corresponding physical address. + +init_top_pgt +------------ + +Used to walk through the whole page table and convert virtual addresses +to physical addresses. The init_top_pgt is somewhat similar to +swapper_pg_dir, but it is only used in x86_64. + +pgtable_l5_enabled +------------------ + +User-space tools need to know whether the crash kernel was in 5-level +paging mode. + +node_data +--------- + +This is a struct pglist_data array and stores all NUMA nodes +information. Makedumpfile gets the pglist_data structure from it. + +(node_data, MAX_NUMNODES) +------------------------- + +The maximum number of nodes in system. + +KERNELOFFSET +------------ + +The kernel randomization offset. Used to compute the page offset. If +KASLR is disabled, this value is zero. + +KERNEL_IMAGE_SIZE +----------------- + +Currently unused by Makedumpfile. Used to compute the module virtual +address by Crash. + +sme_mask +-------- + +AMD-specific with SME support: it indicates the secure memory encryption +mask. Makedumpfile tools need to know whether the crash kernel was +encrypted. If SME is enabled in the first kernel, the crash kernel's +page table entries (pgd/pud/pmd/pte) contain the memory encryption +mask. This is used to remove the SME mask and obtain the true physical +address. + +Currently, sme_mask stores the value of the C-bit position. If needed, +additional SME-relevant info can be placed in that variable. + +For example:: + + [ misc ][ enc bit ][ other misc SME info ] + 0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_..._0000 + 63 59 55 51 47 43 39 35 31 27 ... 3 + +x86_32 +====== + +X86_PAE +------- + +Denotes whether physical address extensions are enabled. It has the cost +of a higher page table lookup overhead, and also consumes more page +table space per process. Used to check whether PAE was enabled in the +crash kernel when converting virtual addresses to physical addresses. + +ia64 +==== + +pgdat_list|(pgdat_list, MAX_NUMNODES) +------------------------------------- + +pg_data_t array storing all NUMA nodes information. MAX_NUMNODES +indicates the number of the nodes. + +node_memblk|(node_memblk, NR_NODE_MEMBLKS) +------------------------------------------ + +List of node memory chunks. Filled when parsing the SRAT table to obtain +information about memory nodes. NR_NODE_MEMBLKS indicates the number of +node memory chunks. + +These values are used to compute the number of nodes the crashed kernel used. + +node_memblk_s|(node_memblk_s, start_paddr)|(node_memblk_s, size) +---------------------------------------------------------------- + +The size of a struct node_memblk_s and the offsets of the +node_memblk_s's members. Used to compute the number of nodes. + +PGTABLE_3|PGTABLE_4 +------------------- + +User-space tools need to know whether the crash kernel was in 3-level or +4-level paging mode. Used to distinguish the page table. + +ARM64 +===== + +VA_BITS +------- + +The maximum number of bits for virtual addresses. Used to compute the +virtual memory ranges. + +kimage_voffset +-------------- + +The offset between the kernel virtual and physical mappings. Used to +translate virtual to physical addresses. + +PHYS_OFFSET +----------- + +Indicates the physical address of the start of memory. Similar to +kimage_voffset, which is used to translate virtual to physical +addresses. + +KERNELOFFSET +------------ + +The kernel randomization offset. Used to compute the page offset. If +KASLR is disabled, this value is zero. + +KERNELPACMASK +------------- + +The mask to extract the Pointer Authentication Code from a kernel virtual +address. + +TCR_EL1.T1SZ +------------ + +Indicates the size offset of the memory region addressed by TTBR1_EL1. +The region size is 2^(64-T1SZ) bytes. + +TTBR1_EL1 is the table base address register specified by ARMv8-A +architecture which is used to lookup the page-tables for the Virtual +addresses in the higher VA range (refer to ARMv8 ARM document for +more details). + +MODULES_VADDR|MODULES_END|VMALLOC_START|VMALLOC_END|VMEMMAP_START|VMEMMAP_END +----------------------------------------------------------------------------- + +Used to get the correct ranges: + MODULES_VADDR ~ MODULES_END-1 : Kernel module space. + VMALLOC_START ~ VMALLOC_END-1 : vmalloc() / ioremap() space. + VMEMMAP_START ~ VMEMMAP_END-1 : vmemmap region, used for struct page array. + +arm +=== + +ARM_LPAE +-------- + +It indicates whether the crash kernel supports large physical address +extensions. Used to translate virtual to physical addresses. + +s390 +==== + +lowcore_ptr +----------- + +An array with a pointer to the lowcore of every CPU. Used to print the +psw and all registers information. + +high_memory +----------- + +Used to get the vmalloc_start address from the high_memory symbol. + +(lowcore_ptr, NR_CPUS) +---------------------- + +The maximum number of CPUs. + +powerpc +======= + + +node_data|(node_data, MAX_NUMNODES) +----------------------------------- + +See above. + +contig_page_data +---------------- + +See above. + +vmemmap_list +------------ + +The vmemmap_list maintains the entire vmemmap physical mapping. Used +to get vmemmap list count and populated vmemmap regions info. If the +vmemmap address translation information is stored in the crash kernel, +it is used to translate vmemmap kernel virtual addresses. + +mmu_vmemmap_psize +----------------- + +The size of a page. Used to translate virtual to physical addresses. + +mmu_psize_defs +-------------- + +Page size definitions, i.e. 4k, 64k, or 16M. + +Used to make vtop translations. + +vmemmap_backing|(vmemmap_backing, list)|(vmemmap_backing, phys)|(vmemmap_backing, virt_addr) +-------------------------------------------------------------------------------------------- + +The vmemmap virtual address space management does not have a traditional +page table to track which virtual struct pages are backed by a physical +mapping. The virtual to physical mappings are tracked in a simple linked +list format. + +User-space tools need to know the offset of list, phys and virt_addr +when computing the count of vmemmap regions. + +mmu_psize_def|(mmu_psize_def, shift) +------------------------------------ + +The size of a struct mmu_psize_def and the offset of mmu_psize_def's +member. + +Used in vtop translations. + +sh +== + +node_data|(node_data, MAX_NUMNODES) +----------------------------------- + +See above. + +X2TLB +----- + +Indicates whether the crashed kernel enabled SH extended mode. + +RISCV64 +======= + +VA_BITS +------- + +The maximum number of bits for virtual addresses. Used to compute the +virtual memory ranges. + +PAGE_OFFSET +----------- + +Indicates the virtual kernel start address of the direct-mapped RAM region. + +phys_ram_base +------------- + +Indicates the start physical RAM address. + +MODULES_VADDR|MODULES_END|VMALLOC_START|VMALLOC_END|VMEMMAP_START|VMEMMAP_END|KERNEL_LINK_ADDR +---------------------------------------------------------------------------------------------- + +Used to get the correct ranges: + + * MODULES_VADDR ~ MODULES_END : Kernel module space. + * VMALLOC_START ~ VMALLOC_END : vmalloc() / ioremap() space. + * VMEMMAP_START ~ VMEMMAP_END : vmemmap space, used for struct page array. + * KERNEL_LINK_ADDR : start address of Kernel link and BPF -- cgit v1.2.3