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2024-07-31s390: Keep inittext section writableHeiko Carstens
There is no added security by making the inittext section non-writable, however it does split part of the kernel mapping into 4K mappings instead of 1M mappings: ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1353000 332K PTE RO NX 0x000003ffe1353000-0x000003ffe1400000 692K PTE RW NX 0x000003ffe1400000-0x000003ffe1500000 1M PMD RW NX 0x000003ffe1500000-0x000003ffe1700000 2M PTE RW NX <--- 0x000003ffe1700000-0x000003ffe1800000 1M PMD RW NX 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Keep the inittext writable and enable instruction execution protection (aka noexec) later to prevent this. This also allows to use the generic free_initmem() implementation. ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1353000 332K PTE RO NX 0x000003ffe1353000-0x000003ffe1400000 692K PTE RW NX 0x000003ffe1400000-0x000003ffe1800000 4M PMD RW NX <--- 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/vmlinux.lds.S: Move ro_after_init section behind rodata sectionHeiko Carstens
The .data.rel.ro and .got section were added between the rodata and ro_after_init data section, which adds an RW mapping in between all RO mapping of the kernel image: ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1331000 196K PTE RO NX 0x000003ffe1331000-0x000003ffe13b3000 520K PTE RW NX <--- 0x000003ffe13b3000-0x000003ffe13d5000 136K PTE RO NX 0x000003ffe13d5000-0x000003ffe1400000 172K PTE RW NX 0x000003ffe1400000-0x000003ffe1500000 1M PMD RW NX 0x000003ffe1500000-0x000003ffe1700000 2M PTE RW NX 0x000003ffe1700000-0x000003ffe1800000 1M PMD RW NX 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Move the ro_after_init data section again right behind the rodata section to prevent interleaving RO and RW mappings: ---[ Kernel Image Start ]--- 0x000003ffe0000000-0x000003ffe0e00000 14M PMD RO X 0x000003ffe0e00000-0x000003ffe0ec7000 796K PTE RO X 0x000003ffe0ec7000-0x000003ffe0f00000 228K PTE RO NX 0x000003ffe0f00000-0x000003ffe1300000 4M PMD RO NX 0x000003ffe1300000-0x000003ffe1353000 332K PTE RO NX 0x000003ffe1353000-0x000003ffe1400000 692K PTE RW NX 0x000003ffe1400000-0x000003ffe1500000 1M PMD RW NX 0x000003ffe1500000-0x000003ffe1700000 2M PTE RW NX 0x000003ffe1700000-0x000003ffe1800000 1M PMD RW NX 0x000003ffe1800000-0x000003ffe187e000 504K PTE RW NX ---[ Kernel Image End ]--- Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/mm: Get rid of RELOC_HIDE()Heiko Carstens
Since __va(0) does not translate to NULL anymore remove RELOC_HIDE() which was only added to get rid of a compile warning with clang W=1: arch/s390/mm/vmem.c:666:36: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] 666 | __set_memory_4k(__va(0), __va(0) + ident_map_size); | ~~~~~~~ ^ Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/mm/ptdump: Improve sorting of markersHeiko Carstens
Use the sort() from lib/sort.c to sort markers instead of the private implementation. The current implementation does not sort markers properly if they have to be moved downwards: ---[ Real Memory Copy Area Start ]--- 0x0000035b903ff000-0x0000035b90400000 4K PTE I ---[ vmalloc Area Start ]--- ---[ Real Memory Copy Area End ]--- Add a new member to each marker which indicates if a marker is start of an area. If addresses of areas are equal consider an address which defines the start of an area higher than the address which defines the end of an area. In result the output is sorted as intended: ---[ Real Memory Copy Area Start ]--- 0x0000019cedcff000-0x0000019cedd00000 4K PTE I ---[ Real Memory Copy Area End ]--- ---[ vmalloc Area Start ]--- Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/mm/ptdump: Add support for relocated lowcore mappingHeiko Carstens
The page table dumper contains a hard coded assumption that the first mapped area starts at address zero. With a relocated lowcore this is not true anymore. Subsequently the first entry (lowcore) is printed as if it would contain everything from address zero until the end of the location of the lowcore area. Fix this by adding a single "Kernel Virtual Address Space" entry, which always starts at address zero. It ends when the lowcore area starts which is either address zero, or its relocated address. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/mm/ptdump: Fix handling of identity mapping areaHeiko Carstens
Since virtual and real addresses are not the same anymore the assumption that the kernel image is contained within the identity mapping is also not true anymore. Fix this by adding two explicit areas and at the correct locations: one for the 8kb lowcore area, and one for the identity mapping. Fixes: c98d2ecae08f ("s390/mm: Uncouple physical vs virtual address spaces") Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/alternatives: Remove unused empty header fileHeiko Carstens
Remove the unused and empty arch/s390/kernel/alternative.h header file which was added by mistake. Fixes: 5ade5be4edf8 ("s390: Add infrastructure to patch lowcore accesses") Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-31s390/fpu: Re-add exception handling in load_fpu_state()Heiko Carstens
With the recent rewrite of the fpu code exception handling for the lfpc instruction within load_fpu_state() was erroneously removed. Add it again to prevent that loading invalid floating point register values cause an unhandled specification exception. Fixes: 8c09871a950a ("s390/fpu: limit save and restore to used registers") Cc: stable@vger.kernel.org Reported-by: Aristeu Rozanski <aris@redhat.com> Tested-by: Aristeu Rozanski <aris@redhat.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-26Merge tag 's390-6.11-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull more s390 updates from Vasily Gorbik: - Fix KMSAN build breakage caused by the conflict between s390 and mm-stable trees - Add KMSAN page markers for ptdump - Add runtime constant support - Fix __pa/__va for modules under non-GPL licenses by exporting necessary vm_layout struct with EXPORT_SYMBOL to prevent linkage problems - Fix an endless loop in the CF_DIAG event stop in the CPU Measurement Counter Facility code when the counter set size is zero - Remove the PROTECTED_VIRTUALIZATION_GUEST config option and enable its functionality by default - Support allocation of multiple MSI interrupts per device and improve logging of architecture-specific limitations - Add support for lowcore relocation as a debugging feature to catch all null ptr dereferences in the kernel address space, improving detection beyond the current implementation's limited write access protection - Clean up and rework CPU alternatives to allow for callbacks and early patching for the lowcore relocation * tag 's390-6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (39 commits) s390: Remove protvirt and kvm config guards for uv code s390/boot: Add cmdline option to relocate lowcore s390/kdump: Make kdump ready for lowcore relocation s390/entry: Make system_call() ready for lowcore relocation s390/entry: Make ret_from_fork() ready for lowcore relocation s390/entry: Make __switch_to() ready for lowcore relocation s390/entry: Make restart_int_handler() ready for lowcore relocation s390/entry: Make mchk_int_handler() ready for lowcore relocation s390/entry: Make int handlers ready for lowcore relocation s390/entry: Make pgm_check_handler() ready for lowcore relocation s390/entry: Add base register to CHECK_VMAP_STACK/CHECK_STACK macro s390/entry: Add base register to SIEEXIT macro s390/entry: Add base register to MBEAR macro s390/entry: Make __sie64a() ready for lowcore relocation s390/head64: Make startup code ready for lowcore relocation s390: Add infrastructure to patch lowcore accesses s390/atomic_ops: Disable flag outputs constraint for GCC versions below 14.2.0 s390/entry: Move SIE indicator flag to thread info s390/nmi: Simplify ptregs setup s390/alternatives: Remove alternative facility list ...
2024-07-25Merge tag 'constfy-sysctl-6.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl Pull sysctl constification from Joel Granados: "Treewide constification of the ctl_table argument of proc_handlers using a coccinelle script and some manual code formatting fixups. This is a prerequisite to moving the static ctl_table structs into read-only data section which will ensure that proc_handler function pointers cannot be modified" * tag 'constfy-sysctl-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: sysctl: treewide: constify the ctl_table argument of proc_handlers
2024-07-25Merge tag 'driver-core-6.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the big set of driver core changes for 6.11-rc1. Lots of stuff in here, with not a huge diffstat, but apis are evolving which required lots of files to be touched. Highlights of the changes in here are: - platform remove callback api final fixups (Uwe took many releases to get here, finally!) - Rust bindings for basic firmware apis and initial driver-core interactions. It's not all that useful for a "write a whole driver in rust" type of thing, but the firmware bindings do help out the phy rust drivers, and the driver core bindings give a solid base on which others can start their work. There is still a long way to go here before we have a multitude of rust drivers being added, but it's a great first step. - driver core const api changes. This reached across all bus types, and there are some fix-ups for some not-common bus types that linux-next and 0-day testing shook out. This work is being done to help make the rust bindings more safe, as well as the C code, moving toward the end-goal of allowing us to put driver structures into read-only memory. We aren't there yet, but are getting closer. - minor devres cleanups and fixes found by code inspection - arch_topology minor changes - other minor driver core cleanups All of these have been in linux-next for a very long time with no reported problems" * tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits) ARM: sa1100: make match function take a const pointer sysfs/cpu: Make crash_hotplug attribute world-readable dio: Have dio_bus_match() callback take a const * zorro: make match function take a const pointer driver core: module: make module_[add|remove]_driver take a const * driver core: make driver_find_device() take a const * driver core: make driver_[create|remove]_file take a const * firmware_loader: fix soundness issue in `request_internal` firmware_loader: annotate doctests as `no_run` devres: Correct code style for functions that return a pointer type devres: Initialize an uninitialized struct member devres: Fix memory leakage caused by driver API devm_free_percpu() devres: Fix devm_krealloc() wasting memory driver core: platform: Switch to use kmemdup_array() driver core: have match() callback in struct bus_type take a const * MAINTAINERS: add Rust device abstractions to DRIVER CORE device: rust: improve safety comments MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER firmware: rust: improve safety comments ...
2024-07-24sysctl: treewide: constify the ctl_table argument of proc_handlersJoel Granados
const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Co-developed-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Joel Granados <j.granados@samsung.com>
2024-07-23Merge tag 'kbuild-v6.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove tristate choice support from Kconfig - Stop using the PROVIDE() directive in the linker script - Reduce the number of links for the combination of CONFIG_KALLSYMS and CONFIG_DEBUG_INFO_BTF - Enable the warning for symbol reference to .exit.* sections by default - Fix warnings in RPM package builds - Improve scripts/make_fit.py to generate a FIT image with separate base DTB and overlays - Improve choice value calculation in Kconfig - Fix conditional prompt behavior in choice in Kconfig - Remove support for the uncommon EMAIL environment variable in Debian package builds - Remove support for the uncommon "name <email>" form for the DEBEMAIL environment variable - Raise the minimum supported GNU Make version to 4.0 - Remove stale code for the absolute kallsyms - Move header files commonly used for host programs to scripts/include/ - Introduce the pacman-pkg target to generate a pacman package used in Arch Linux - Clean up Kconfig * tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits) kbuild: doc: gcc to CC change kallsyms: change sym_entry::percpu_absolute to bool type kallsyms: unify seq and start_pos fields of struct sym_entry kallsyms: add more original symbol type/name in comment lines kallsyms: use \t instead of a tab in printf() kallsyms: avoid repeated calculation of array size for markers kbuild: add script and target to generate pacman package modpost: use generic macros for hash table implementation kbuild: move some helper headers from scripts/kconfig/ to scripts/include/ Makefile: add comment to discourage tools/* addition for kernel builds kbuild: clean up scripts/remove-stale-files kconfig: recursive checks drop file/lineno kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec kallsyms: get rid of code for absolute kallsyms kbuild: Create INSTALL_PATH directory if it does not exist kbuild: Abort make on install failures kconfig: remove 'e1' and 'e2' macros from expression deduplication kconfig: remove SYMBOL_CHOICEVAL flag kconfig: add const qualifiers to several function arguments kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups() ...
2024-07-23s390: Remove protvirt and kvm config guards for uv codeJanosch Frank
Removing the CONFIG_PROTECTED_VIRTUALIZATION_GUEST ifdefs and config option as well as CONFIG_KVM ifdefs in uv files. Having this configurable has been more of a pain than a help. It's time to remove the ifdefs and the config option. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/boot: Add cmdline option to relocate lowcoreSven Schnelle
Now that everything has been converted, add the option 'relocate_lowcore' to enable relocating the lowcore. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/kdump: Make kdump ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in store_status() and __do_machine_kdump(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make system_call() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in system_call(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make ret_from_fork() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in ret_from_fork(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make __switch_to() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in __switch_to(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make restart_int_handler() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in restart_int_handler(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make mchk_int_handler() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in mcck_int_handler(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make int handlers ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in the ext/io interrupt handlers. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make pgm_check_handler() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in pgm_check_handler(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Add base register to CHECK_VMAP_STACK/CHECK_STACK macroSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to CHECK_VMAP_STACK and CHECK_STACK. No functional change, because %r0 is passed to the macro. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Add base register to SIEEXIT macroSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to SIEEXIT. No functional change, because %r0 is passed to the macro. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Add base register to MBEAR macroSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to MBEAR. No functional change, because %r0 is passed to the macro. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Make __sie64a() ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in __sie64a(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/head64: Make startup code ready for lowcore relocationSven Schnelle
In preparation of having lowcore at different address than zero, add the base register to all lowcore accesses in startup_continue(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390: Add infrastructure to patch lowcore accessesSven Schnelle
The s390 architecture defines two special per-CPU data pages called the "prefix area". In s390-linux terminology this is usually called "lowcore". This memory area contains system configuration data like old/new PSW's for system call/interrupt/machine check handlers and lots of other data. It is normally mapped to logical address 0. This area can only be accessed when in supervisor mode. This means that kernel code can dereference NULL pointers, because accesses to address 0 are allowed. Parts of lowcore can be write protected, but read accesses and write accesses outside of the write protected areas are not caught. To remove this limitation for debugging and testing, remap lowcore to another address and define a function get_lowcore() which simply returns the address where lowcore is mapped at. This would normally introduce a pointer dereference (=memory read). As lowcore is used for several very often used variables, add code to patch this function during runtime, so we avoid the memory reads. For C code get_lowcore() has to be used, for assembly code it is the GET_LC macro. When using this macro/function a reference is added to alternative patching. All these locations will be patched to the actual lowcore location when the kernel is booted or a module is loaded. To make debugging/bisecting problems easier, this patch adds all the infrastructure but the lowcore address is still hardwired to 0. This way the code can be converted on a per function basis, and the functionality is enabled in a patch after all the functions have been converted. Note that this requires at least z16 because the old lpsw instruction only allowed a 12 bit displacement. z16 introduced lpswey which allows 20 bits (signed), so the lowcore can effectively be mapped from address 0 - 0x7e000. To use 0x7e000 as address, a 6 byte lgfi instruction would have to be used in the alternative. To save two bytes, llilh can be used, but this only allows to set bits 16-31 of the address. In order to use the llilh instruction, use 0x70000 as alternative lowcore address. This is still large enough to catch NULL pointer dereferences into large arrays. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/atomic_ops: Disable flag outputs constraint for GCC versions below 14.2.0Heiko Carstens
GCC may die with an ICE if the flag outputs constraint is used in combination with other inline assemblies. This will be fixed with GCC 14.2.0. Therefore disable the use of the constraint for now. Link: https://gcc.gnu.org/git?p=gcc.git;a=commit;h=cd11413ff7c4353a3e336db415304f788d23a393 Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/entry: Move SIE indicator flag to thread infoHeiko Carstens
CIF_SIE indicates if a thread is running in SIE context. This is the state of a thread and not the CPU. Therefore move this indicator to thread info. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/nmi: Simplify ptregs setupHeiko Carstens
The low level machine check handler code fills the ptregs structure partially with the register contents present at machine check handler entry and partially with contents from the machine check save area. In case of a machine check the contents of all general purpose registers are saved by the CPU to the machine check save area. Therefore simplify the code and fill the ptregs structure by only using the machine check save area as source. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Remove alternative facility listHeiko Carstens
The alternative and the normal facility list are always identical. Remove the alternative facility list, which allows to simplify the alternatives code. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/nospec: Push down alternative handlingHeiko Carstens
The nospec implementation is deeply integrated into the alternatives code: only for nospec an alternative facility list is implemented and used by the alternative code, while it is modified by nospec specific needs. Push down the nospec alternative handling into the nospec by introducing a new alternative type and a specific nospec callback to decide if alternatives should be applied. Also introduce a new global nobp variable which together with facility 82 can be used to decide if nobp is enabled or not. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Allow early alternative patching in decompressorSven Schnelle
Add the required code to patch alternatives early in the decompressor. This is required for the upcoming lowcore relocation changes, where alternatives for facility 193 need to get patched before lowcore alternatives. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Co-developed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Rework to allow for callbacksHeiko Carstens
Rework alternatives to allow for callbacks. With this every alternative entry has additional data encoded: - When (aka context) an alternative is supposed to be applied - The type of an alternative, which allows for type specific handling and callbacks - Extra type specific payload (patch information), which can be passed to callbacks in order to decide if an alternative should be applied or not With this only the "late" context is implemented, which means there is no change to the previous behaviour. All code is just converted to the more generic new infrastructure. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/uaccess: Make s390_kernel_write() usable for decompressorHeiko Carstens
To avoid lots of ifdefs in C code make s390_kernel_write() usable for the decompressor: simply use memcpy() for this case since there is no write protection enabled that early. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Move text sync functionsHeiko Carstens
Move all text sync functions from alternative.c to processor.c. This way there is only minimal code left in alternative.c left, which is a prerequisite to use the C file within boot code as well. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Merge both alternative header filesHeiko Carstens
The two alternative header files must stay in sync. This is easier to achieve within one header file. Therefore merge both of them and have only one file, like most other architectures. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Use consistent namingHeiko Carstens
The alternative code is using the words facility and feature for the same. Rename facility to more generic feature everywhere to have consistent naming. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/alternatives: Remove noaltinstr optionSven Schnelle
The current Kernel doesn't boot without alternative patching on z16 machines. To avoid such bugs in the future, remove the option disable alternative patching. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390: Move CIF flags to struct pcpuSven Schnelle
To allow testing flags for offline CPUs, move the CIF flags to struct pcpu. To avoid having to calculate the array index for each access, add a pointer to the pcpu member for the current cpu to lowcore. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/smp: Switch pcpu_devices to percpuSven Schnelle
In preparation of moving the CIF flags from lowcore to pcpu_devices, convert the pcpu_devices array to use the percpu infrastructure. This is required because using the pcpu_devices array as it is would introduce a performance penalty due to the fact that CPU flags for multiple CPUs would end up in the same cacheline. Note that a pointer to the pcpu struct of the IPL CPU is still required. This is because a restart interrupt can be triggered on an offline CPU. s390 stores the percpu offset in lowcore, but offline CPUs have no lowcore area allocated. So percpu data cannot be used from an offline CPU and we need to get the pcpu pointer for the IPL cpu from somewhere else. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/smp: Handle restart interrupt on ipl cpuSven Schnelle
The current smp code allows to trigger a restart interrupt on CPUs offline in linux. To allow using the percpu infrastructure instead of the pcpu_devices array, switch to the ipl cpu which is always online before calling do_restart(). Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/boot: Do not assume the decompressor range is reservedAlexander Gordeev
When allocating a random memory range for .amode31 sections the minimal randomization address is 0. That does not lead to a possible overlap with the decompressor image (which also starts from 0) since by that time the image range is already reserved. Do not assume the decompressor range is reserved and always provide the minimal randomization address for .amode31 sections beyond the decompressor. That is a prerequisite for moving the lowcore memory address from NULL elsewhere. Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/cpum_cf: Fix endless loop in CF_DIAG event stopThomas Richter
Event CF_DIAG reads out complete counter sets using stcctm instruction. This is done at event start time when the process starts execution and at event stop time when the process is removed from the CPU. During removal the difference of each counter in the counter sets is calculated and saved as raw data in the ring buffer. This works fine unless the number of counters in a counter set is zero. This may happen for the extended counter set. This set is machine specific and the size of the counter set can be zero even when extended counter set is authorized for read access. This case is not handled. cfdiag_diffctr() checks authorization of the extended counter set. If true the functions assumes the extended counter set has been saved in a data buffer. However this is not the case, cfdiag_getctrset() does not save a counter set with counter set size of zero. This mismatch causes an endless loop in the counter set readout during event stop handling. The calculation of the difference of the counters in each counter now verifies the size of the counter set is non-zero. A counter set with size zero is skipped. Fixes: a029a4eab39e ("s390/cpumf: Allow concurrent access for CPU Measurement Counter Facility") Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/ptdump: Add KMSAN page markersIlya Leoshkevich
Add KMSAN vmalloc metadata areas to /sys/kernel/debug/kernel_page_tables. Example output: 0x000003a95fff9000-0x000003a960000000 28K PTE I ---[ vmalloc Area End ]--- ---[ Kmsan vmalloc Shadow Start ]--- 0x000003a960000000-0x000003a960010000 64K PTE RW NX [...] 0x000003d3dfff9000-0x000003d3e0000000 28K PTE I ---[ Kmsan vmalloc Shadow End ]--- ---[ Kmsan vmalloc Origins Start ]--- 0x000003d3e0000000-0x000003d3e0010000 64K PTE RW NX [...] 0x000003fe5fff9000-0x000003fe60000000 28K PTE I ---[ Kmsan vmalloc Origins End ]--- ---[ Kmsan Modules Shadow Start ]--- 0x000003fe60000000-0x000003fe60001000 4K PTE RW NX [...] 0x000003fe60100000-0x000003fee0000000 2047M PMD I ---[ Kmsan Modules Shadow End ]--- ---[ Kmsan Modules Origins Start ]--- 0x000003fee0000000-0x000003fee0001000 4K PTE RW NX [...] 0x000003fee0100000-0x000003ff60000000 2047M PMD I ---[ Kmsan Modules Origins End ]--- ---[ Modules Area Start ]--- 0x000003ff60000000-0x000003ff60001000 4K PTE RO X Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20240723124441.120044-3-iii@linux.ibm.com Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/kmsan: Fix merge conflict with get_lowcore() introductionIlya Leoshkevich
Resolve the conflict between commit 2a48c8c9cf87 ("s390/kmsan: implement the architecture-specific functions") and commit 39976f1278a9 ("s390: Remove S390_lowcore"). Fixes: 2a48c8c9cf87 ("s390/kmsan: implement the architecture-specific functions") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20240723124441.120044-2-iii@linux.ibm.com Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/setup: Fix __pa/__va for modules under non-GPL licensesVasily Gorbik
The struct vm_layout contains fields used in __pa/__va calculations. Such fundamental things have to be exported with EXPORT_SYMBOL to avoid breakages of out-of-tree modules under non-GPL licenses. Fixes: 7de0446f0b26 ("s390/boot: Make identity mapping base address explicit") Acked-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-23s390/pci: Allow allocation of more than 1 MSI interruptGerd Bayer
On a PCI adapter that provides up to 8 MSI interrupt sources the s390 implementation of PCI interrupts rejected to accommodate them, although the underlying hardware is able to support that. For MSI-X it is sufficient to allocate a single irq_desc per msi_desc, but for MSI multiple irq descriptors are attached to and controlled by a single msi descriptor. Add the appropriate loops to maintain multiple irq descriptors and tie/untie them to/from the appropriate AIBV bit, if a device driver allocates more than 1 MSI interrupt. Common PCI code passes on requests to allocate a number of interrupt vectors based on the device drivers' demand and the PCI functions' capabilities. However, the root-complex of s390 systems support just a limited number of interrupt vectors per PCI function. Produce a kernel log message to inform about any architecture-specific capping that might be done. With this change, we had a PCI adapter successfully raising interrupts to its device driver via all 8 sources. Fixes: a384c8924a8b ("s390/PCI: Fix single MSI only check") Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com> Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>