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* s390/setup: Recognize sequential instruction fetching facilityVasily Gorbik2024-08-291-0/+2
| | | | | | | | | | When sequential instruction fetching facility is present, certain guarantees are provided for code patching. In particular, atomic overwrites within 8 aligned bytes is safe from an instruction-fetching point of view. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/early: Dump register contents and call trace for early crashesHeiko Carstens2024-08-221-0/+10
| | | | | | | | | | | | | | If the early program check handler cannot resolve a program check dump register contents and a call trace to the console before loading a disabled wait psw. This makes debugging much easier. Emit an extra message with early_printk() for cases where regular printk() via the early console is not yet working so that at least some information is available. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/early: Add __init to __do_early_pgm_check()Heiko Carstens2024-08-221-1/+1
| | | | | | | | | __do_early_pgm_check() is a function which is only needed during early setup code. Mark it __init in order to save a few bytes. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/traps: Handle early warnings gracefullyHeiko Carstens2024-08-071-2/+15
| | | | | | | | | | | | | | Add missing warning handling to the early program check handler. This way a warning is printed to the console as soon as the early console is setup, and the kernel continues to boot. Before this change a disabled wait psw was loaded instead and the machine was silently stopped without giving an idea about what happened. 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>
* s390/entry: Make early program check handler relocated lowcore awareHeiko Carstens2024-08-071-2/+5
| | | | | | | | | | | Add the missing pieces so the early program check handler also works with a relocated lowcore. Right now the result of an early program check in case of a relocated lowcore would be a program check loop. Fixes: 8f1e70adb1a3 ("s390/boot: Add cmdline option to relocate lowcore") 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>
* s390: Add infrastructure to patch lowcore accessesSven Schnelle2024-07-231-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* s390/alternatives: Remove alternative facility listHeiko Carstens2024-07-231-6/+0
| | | | | | | | | | | 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>
* s390/nospec: Push down alternative handlingHeiko Carstens2024-07-231-2/+0
| | | | | | | | | | | | | | | | | | | 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>
* s390: Replace S390_lowcore by get_lowcore()Sven Schnelle2024-06-181-18/+18
| | | | | | | | Replace all S390_lowcore usages in arch/s390/ by get_lowcore(). Acked-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>
* s390/fpu: move, rename, and merge header filesHeiko Carstens2024-02-161-1/+1
| | | | | | | | | | | | | | | Move, rename, and merge the fpu and vx header files. This way fpu header files have a consistent naming scheme (fpu*.h). Also get rid of the fpu subdirectory and move header files to asm directory, so that all fpu and vx header files can be found at the same location. Merge internal.h header file into other header files, since the internal helpers are used at many locations. so those helper functions are really not internal. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/acrs: cleanup access register handlingHeiko Carstens2024-02-121-1/+2
| | | | | | | | | | | | | | | | | | save_access_regs() and restore_access_regs() are only available by including switch_to.h. This is done by a couple of C files, which have nothing to do with switch_to(), but only need these functions. Move both functions to a new header file and improve the implementation: - Get rid of typedef - Add memory access instrumentation support - Use long displacement instructions lamy/stamy instead of lam/stam - all current users end up with better code because of this Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/fpu: get rid of MACHINE_HAS_VXHeiko Carstens2023-12-111-3/+1
| | | | | | | | | | | | | | | | | Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a short readable wrapper for "test_facility(129)". Facility bit 129 is set if the vector facility is present. test_facility() returns also true for all bits which are set in the architecture level set of the cpu that the kernel is compiled for. This means that test_facility(129) is a compile time constant which returns true for z13 and later, since the vector facility bit is part of the z13 kernel ALS. In result the compiled code will have less runtime checks, and less code. Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
* s390/fpu: remove "novx" optionHeiko Carstens2023-12-111-8/+0
| | | | | | | | | Remove the "novx" kernel command line option: the vector code runs without any problems since many years. Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
* s390/cmma: move parsing of cmma kernel parameter to early boot codeHeiko Carstens2023-11-051-0/+1
| | | | | | | | | | | | | The "cmma=" kernel command line parameter needs to be parsed early for upcoming changes. Therefore move the parsing code. Note that EX_TABLE handling of cmma_test_essa() needs to be open-coded, since the early boot code doesn't have infrastructure for handling expected exceptions. Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: use control register bit definesHeiko Carstens2023-09-191-6/+6
| | | | | | | | | Use control register bit defines instead of plain numbers where possible. 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>
* s390/early: use system_ctl_set_bit() instead of local_ctl_set_bit()Heiko Carstens2023-09-191-6/+6
| | | | | | | | | | | Use system_ctl_set_bit() instead of local_ctl_set_bit() to reflect that the control register changes are supposed to be global. This change is just for documentation purposes, since it still results only in local control register contents being changed. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/ctlreg: add local and system prefix to some functionsHeiko Carstens2023-09-191-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add local and system prefix to some functions to clarify they change control register contents on either the local CPU or the on all CPUs. This results in the following API: Two defines which load and save multiple control registers. The defines correlate with the following C prototypes: void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high); void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high); Two functions which locally set or clear one bit for a specified control register: void local_ctl_set_bit(unsigned int cr, unsigned int bit); void local_ctl_clear_bit(unsigned int cr, unsigned int bit); Two functions which set or clear one bit for a specified control register on all CPUs: void system_ctl_set_bit(unsigned int cr, unsigned int bit); void system_ctl_clear_bit(unsigend int cr, unsigned int bit); 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>
* s390/smp,mcck: fix early IPI handlingHeiko Carstens2023-09-191-9/+3
| | | | | | | | | | | | | | | | | | | Both the external call as well as the emergency signal submask bits in control register 0 are set before any interrupt handler is registered. Change the order and first register the interrupt handler and only then enable the interrupts by setting the corresponding bits in control register 0. This prevents that the second part of the machine check handler for early machine check handling is not executed: the machine check handler sends an IPI to the CPU it runs on. If the corresponding interrupts are enabled, but no interrupt handler is present, the interrupt is ignored. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Acked-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>
* s390/mm: simplify kernel mapping setupHeiko Carstens2023-08-301-3/+1
| | | | | | | | | | | | | | | | | | The kernel mapping is setup in two stages: in the decompressor map all pages with RWX permissions, and within the kernel change all mappings to their final permissions, where most of the mappings are changed from RWX to RWNX. Change this and map all pages RWNX from the beginning, however without enabling noexec via control register modification. This means that effectively all pages are used with RWX permissions like before. When the final permissions have been applied to the kernel mapping enable noexec via control register modification. This allows to remove quite a bit of non-obvious code. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390: remove "noexec" optionHeiko Carstens2023-08-301-2/+1
| | | | | | | | Do the same like x86 with commit 76ea0025a214 ("x86/cpu: Remove "noexec"") and remove the "noexec" kernel command line option. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/kasan: move shadow mapping to decompressorVasily Gorbik2023-03-201-0/+9
| | | | | | | | | | | | | | Since regular paging structs are initialized in decompressor already move KASAN shadow mapping to decompressor as well. This helps to avoid allocating KASAN required memory in 1 large chunk, de-duplicate paging structs creation code and start the uncompressed kernel with KASAN instrumentation right away. This also allows to avoid all pitfalls accidentally calling KASAN instrumented code during KASAN initialization. Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/boot: remove non-functioning image bootable checkVasily Gorbik2023-03-201-14/+0
| | | | | | | | | | | | | | | | | | | | check_image_bootable() has been introduced with commit 627c9b62058e ("s390/boot: block uncompressed vmlinux booting attempts") to make sure that users don't try to boot uncompressed vmlinux ELF image in qemu. It used to be possible quite some time ago. That commit prevented confusion with uncompressed vmlinux image starting to boot and even printing kernel messages until it crashed. Users might have tried to report the problem without realizing they are doing something which was not intended. Since commit f1d3c5323772 ("s390/boot: move sclp early buffer from fixed address in asm to C") check_image_bootable() doesn't function properly anymore, as well as booting uncompressed vmlinux image in qemu doesn't really produce any output and crashes. Moving forward it doesn't make sense to fix check_image_bootable() anymore, so simply remove it. Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/setup: do not complain about parameters handled in decompressorVasily Gorbik2023-02-271-0/+17
| | | | | | | | | | | | | | | | | Currently there are several kernel command line parameters which are only parsed and handled in decompressor and not known to the kernel. This leads to the following error message during kernel boot: Unknown kernel command line parameters "mem=3G nokaslr", will be passed to user space. To avoid confusion, register those parameters with an empty stub so that kernel does not complain about them. Reported-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/mm: add support for RDP (Reset DAT-Protection)Gerald Schaefer2023-02-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RDP instruction allows to reset DAT-protection bit in a PTE, with less CPU synchronization overhead than IPTE instruction. In particular, IPTE can cause machine-wide synchronization overhead, and excessive IPTE usage can negatively impact machine performance. RDP can be used instead of IPTE, if the new PTE only differs in SW bits and _PAGE_PROTECT HW bit, for PTE protection changes from RO to RW. SW PTE bit changes are allowed, e.g. for dirty and young tracking, but none of the other HW-defined part of the PTE must change. This is because the architecture forbids such changes to an active and valid PTE, which is why invalidation with IPTE is always used first, before writing a new entry. The RDP optimization helps mainly for fault-driven SW dirty-bit tracking. Writable PTEs are initially always mapped with HW _PAGE_PROTECT bit set, to allow SW dirty-bit accounting on first write protection fault, where the DAT-protection would then be reset. The reset is now done with RDP instead of IPTE, if RDP instruction is available. RDP cannot always guarantee that the DAT-protection reset is propagated to all CPUs immediately. This means that spurious TLB protection faults on other CPUs can now occur. For this, common code provides a flush_tlb_fix_spurious_fault() handler, which will now be used to do a CPU-local TLB flush. However, this will clear the whole TLB of a CPU, and not just the affected entry. For more fine-grained flushing, by simply doing a (local) RDP again, flush_tlb_fix_spurious_fault() would need to also provide the PTE pointer. Note that spurious TLB protection faults cannot really be distinguished from racing pagetable updates, where another thread already installed the correct PTE. In such a case, the local TLB flush would be unnecessary overhead, but overall reduction of CPU synchronization overhead by not using IPTE is still expected to be beneficial. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/mm: start kernel with DAT enabledAlexander Gordeev2023-01-131-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The setup of the kernel virtual address space is spread throughout the sources, boot stages and config options like this: 1. The available physical memory regions are queried and stored as mem_detect information for later use in the decompressor. 2. Based on the physical memory availability the virtual memory layout is established in the decompressor; 3. If CONFIG_KASAN is disabled the kernel paging setup code populates kernel pgtables and turns DAT mode on. It uses the information stored at step [1]. 4. If CONFIG_KASAN is enabled the kernel early boot kasan setup populates kernel pgtables and turns DAT mode on. It uses the information stored at step [1]. The kasan setup creates early_pg_dir directory and directly overwrites swapper_pg_dir entries to make shadow memory pages available. Move the kernel virtual memory setup to the decompressor and start the kernel with DAT turned on right from the very first istruction. That completely eliminates the boot phase when the kernel runs in DAT-off mode, simplies the overall design and consolidates pgtables setup. The identity mapping is created in the decompressor, while kasan shadow mappings are still created by the early boot kernel code. Share with decompressor the existing kasan memory allocator. It decreases the size of a newly requested memory block from pgalloc_pos and ensures that kernel image is not overwritten. pgalloc_low and pgalloc_pos pointers are made preserved boot variables for that. Use the bootdata infrastructure to setup swapper_pg_dir and invalid_pg_dir directories used by the kernel later. The interim early_pg_dir directory established by the kasan initialization code gets eliminated as result. As the kernel runs in DAT-on mode only the PSW_KERNEL_BITS define gets PSW_MASK_DAT bit by default. Additionally, the setup_lowcore_dat_off() and setup_lowcore_dat_on() routines get merged, since there is no DAT-off mode stage anymore. The memory mappings are created with RW+X protection that allows the early boot code setting up all necessary data and services for the kernel being booted. Just before the paging is enabled the memory protection is changed to RO+X for text, RO+NX for read-only data and RW+NX for kernel data and the identity mapping. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/early: fix sclp_early_sccb variable lifetimeAlexander Gordeev2023-01-131-1/+0
| | | | | | | | | | | | | | | | | | Commit ada1da31ce34 ("s390/sclp: sort out physical vs virtual pointers usage") fixed the notion of virtual address for sclp_early_sccb pointer. However, it did not take into account that kasan_early_init() can also output messages and sclp_early_sccb should be adjusted by the time kasan_early_init() is called. Currently it is not a problem, since virtual and physical addresses on s390 are the same. Nevertheless, should they ever differ, this would cause an invalid pointer access. Fixes: ada1da31ce34 ("s390/sclp: sort out physical vs virtual pointers usage") Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390: move from strlcpy with unused retval to strscpyWolfram Sang2022-08-301-1/+1
| | | | | | | | | | | | | | | | Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Benjamin Block <bblock@linux.ibm.com> Acked-by: Alexandra Winter <wintera@linux.ibm.com> Link: https://lore.kernel.org/r/20220818205948.6360-1-wsa+renesas@sang-engineering.com Link: https://lore.kernel.org/r/20220818210102.7301-1-wsa+renesas@sang-engineering.com [gor@linux.ibm.com: squashed two changes linked above together] Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: simplify early program check handlerHeiko Carstens2022-05-251-3/+2
| | | | | | | | | | | | | | | Due to historic reasons the base program check handler calls a configurable function. Given that there is only the early program check handler left, simplify the code by directly calling that function. The only other user was removed with commit d485235b0054 ("s390: assume diag308 set always works"). Also rename all functions and the asm file to reflect this. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/extable: add and use fixup_exception helper functionHeiko Carstens2022-03-081-5/+1
| | | | | | | | | Add and use fixup_exception helper function in order to remove the duplicated exception handler fixup code at several places. 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>
* s390/base: pass pt_regs to early program check handlerHeiko Carstens2022-03-081-11/+3
| | | | | | | | | | | | | | | | | Pass pt_regs to early program check handler like it is done for every other interrupt and exception handler. Also the passed pt_regs can be changed by the called function and the changes register contents and psw contents will be taken into account when returning. In addition the return psw will not be copied to the program check old psw in lowcore, but to the usual return psw location, like it is also done by the regular program check handler. This allows also to get rid of the code that disabled lowcore protection when changing the return address. 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>
* s390/extable: move EX_TABLE define to asm-extable.hHeiko Carstens2022-03-081-0/+1
| | | | | | | | | | | | | | Follow arm64 and riscv and move the EX_TABLE define to asm-extable.h which is a lot less generic than the current linkage.h. Also make sure that all files which contain EX_TABLE usages actually include the new header file. This should make sure that the files always compile and there won't be any random compile breakage due to other header file dependencies. 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>
* s390/extable: sort amode31 extable earlyHeiko Carstens2022-03-081-0/+6
| | | | | | | | | | | The early program check handler is active before the amode31 extable is sorted. Therefore in case a program check happens early within the amode31 code the extable entry might not be found. Fix this by sorting the amode31 extable early. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: remove invalid email address of Heiko CarstensHeiko Carstens2022-02-061-1/+0
| | | | | | | | | | | Remove my old invalid email address which can be found in a couple of files. Instead of updating it, just remove my contact data completely from source files. We have git and other tools which allow to figure out who is responsible for what with recent contact data. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: support command lines longer than 896 bytesSven Schnelle2021-10-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently s390 supports a fixed maximum command line length of 896 bytes. This isn't enough as some installers are trying to pass all configuration data via kernel command line, and even with zfcp alone it is easy to generate really long command lines. Therefore extend the command line to 4 kbytes. In the parm area where the command line is stored there is no indication of the maximum allowed length, so a new field which contains the maximum length is added. The parm area has always been initialized to zero, so with old kernels this field would read zero. This is important because tools like zipl could read this field. If it contains a number larger than zero zipl knows the maximum length that can be stored in the parm area, otherwise it must assume that it is booting a legacy kernel and only 896 bytes are available. The removing of trailing whitespace in head.S is also removed because code to do this is already present in setup_boot_command_line(). Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/sclp: sort out physical vs virtual pointers usageAlexander Gordeev2021-10-261-0/+1
| | | | | | | | | | | | | | | | | Provide physical addresses whenever the hardware interface expects it or a 32-bit value used for tracking. Variable sclp_early_sccb gets initialized in the decompressor and points to an address in physcal memory. Yet, it is used as virtual memory pointer and therefore should be converted. Note, the other two __bootdata variables sclp_info_sccb and sclp_info_sccb_valid contain plain data, but no pointers and do need any special care. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: make PCI mio support a machine flagNiklas Schnelle2021-07-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | | Kernel support for the newer PCI mio instructions can be toggled off with the pci=nomio command line option which needs to integrate with common code PCI option parsing. However this option then toggles static branches which can't be toggled yet in an early_param() call. Thus commit 9964f396f1d0 ("s390: fix setting of mio addressing control") moved toggling the static branches to the PCI init routine. With this setup however we can't check for mio support outside the PCI code during early boot, i.e. before switching the static branches, which we need to be able to export this as an ELF HWCAP. Improve on this by turning mio availability into a machine flag that gets initially set based on CONFIG_PCI and the facility bit and gets toggled off if pci=nomio is found during PCI option parsing allowing simple access to this machine flag after early init. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390/boot: replace magic string check with a bootdata flagAlexander Egorenkov2021-07-051-1/+3
| | | | | | | | | | | The magic string "S390EP" at offset 0x10008 indicated to the decompressed kernel that it was booted by the decompressor. Introduce a new bootdata flag instead which conveys the same information in an explicit and a cleaner way. But keep the magic string because it is a kernel ABI. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/facilities: move stfl information from lowcore to global dataSven Schnelle2021-06-071-4/+2
| | | | | | | | | | With gcc-11, there are a lot of warnings because the facility functions are accessing lowcore through a null pointer. Fix this by moving the facility arrays away from lowcore. Signed-off-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>
* s390/time: convert tod_clock_base to unionHeiko Carstens2021-02-131-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert tod_clock_base to union tod_clock. This simplifies quite a bit of code and also fixes a bug in read_persistent_clock64(); void read_persistent_clock64(struct timespec64 *ts) { __u64 delta; delta = initial_leap_seconds + TOD_UNIX_EPOCH; get_tod_clock_ext(clk); *(__u64 *) &clk[1] -= delta; if (*(__u64 *) &clk[1] > delta) clk[0]--; ext_to_timespec64(clk, ts); } Assume &clk[1] == 3 and delta == 2; then after the substraction the if condition becomes true and the epoch part of the clock is decremented by one because of an assumed overflow, even though there is none. Fix this by using 128 bit arithmetics and let the compiler do the right thing: void read_persistent_clock64(struct timespec64 *ts) { union tod_clock clk; u64 delta; delta = initial_leap_seconds + TOD_UNIX_EPOCH; store_tod_clock_ext(&clk); clk.eitod -= delta; ext_to_timespec64(&clk, ts); } Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/time: rename store_tod_clock_ext() and use union tod_clockHeiko Carstens2021-02-131-3/+3
| | | | | | | | | Rename store_tod_clock_ext() to store_tod_clock_ext_cc() to reflect that it returns a condition code and also use union tod_clock as parameter. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/time: use stcke instead of stckHeiko Carstens2021-02-091-3/+3
| | | | | | | | | | Use STORE CLOCK EXTENDED instead of STORE CLOCK in early tod clock setup. This is just to remove another usage of stck, trying to remove all usages of STORE CLOCK. This doesn't fix anything. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: remove unused s390_base_ext_handlerVasily Gorbik2020-11-091-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | s390_base_ext_handler_fn haven't been used since its introduction in commit ab14de6c37fa ("[S390] Convert memory detection into C code."). s390_base_ext_handler itself is currently falsely storing 16 registers at __LC_SAVE_AREA_ASYNC rewriting several following lowcore values: cpu_flags, return_psw, return_mcck_psw, sync_enter_timer and async_enter_timer. Besides that s390_base_ext_handler itself is only potentially hiding EXT interrupts which should not have happen in the first place. Any piece of code which requires EXT interrupts before fully functional ext_int_handler is enabled has to do it on its own, like this is done by sclp_early_cmd() which is doing EXT interrupts handling synchronously in sclp_early_wait_irq(). With s390_base_ext_handler removed unexpected EXT interrupt leads to disabled wait with the address 0x1b0 (__LC_EXT_NEW_PSW), which is currently setup in the decompressor. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
* s390: remove cad commandline optionSven Schnelle2020-09-301-13/+0
| | | | | | | | | | remove the cad command line option as the instruction was never published and never used by userspace. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/kasan: fix early pgm check handler executionVasily Gorbik2020-06-231-0/+2
| | | | | | | | | | | | | | | Currently if early_pgm_check_handler is called it ends up in pgm check loop. The problem is that early_pgm_check_handler is instrumented by KASAN but executed without DAT flag enabled which leads to addressing exception when KASAN checks try to access shadow memory. Fix that by executing early handlers with DAT flag on under KASAN as expected. Reported-and-tested-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* s390: remove last diag 0x44 callerHeiko Carstens2019-12-111-16/+0
| | | | | | | | | | | | | | | | | | | diag 0x44 is a voluntary undirected yield of a virtual CPU. This has caused a lot of performance issues in the past. There is only one caller left, and that one is only executed if diag 0x9c (directed yield) is not present. Given that all hypervisors implement diag 0x9c anyway, remove the last diag 0x44 to avoid that more callers will be added. Worst case that could happen now, if diag 0x9c is not present, is that a virtual CPU would loop a bit instead of giving its time slice up. diag 0x44 statistics in debugfs are kept and will always be zero, so that user space can tell that there are no calls. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/early: move access registers setup in C codeVasily Gorbik2019-11-201-0/+9
| | | | | Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/early: move control registers setup in C codeVasily Gorbik2019-11-201-0/+12
| | | | | Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: avoid double handling of "noexec" optionVasily Gorbik2019-10-311-16/+1
| | | | | | | | | | "noexec" option is already parsed during startup and its value is exposed via noexec_disabled variable. Simply reuse that value during machine facilities detection. Suggested-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: clean .bss before running uncompressed kernelVasily Gorbik2019-08-211-0/+16
| | | | | | | | | | | | | | | | | | | | Clean uncompressed kernel .bss section in the startup code before the uncompressed kernel is executed. At this point of time initrd and certificates have been already rescued. Uncompressed kernel .bss size is known from vmlinux_info. It is also taken into consideration during uncompressed kernel positioning by kaslr (so it is safe to clean it). With that uncompressed kernel is starting with .bss section zeroed and no .bss section usage restrictions apply. Which makes chkbss checks for uncompressed kernel objects obsolete and they can be removed. early_nobss.c is also not needed anymore. Parts of it which are still relevant are moved to early.c. Kasan initialization code is now called directly from head64 (early.c is instrumented and should not be executed before kasan shadow memory is set up). Reviewed-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: fix setting of mio addressing controlSebastian Ott2019-07-111-2/+0
| | | | | | | | | | | | Move enablement of mio addressing control from detect_machine_facilities to pci_base_init. detect_machine_facilities runs so early that the static branches have not been toggled yet, thus mio addressing control was always off. In pci_base_init we have to use the SMP aware ctl_set_bit though. Fixes: 833b441ec0f6 ("s390: enable processes for mio instructions") Signed-off-by: Sebastian Ott <sebott@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 19:12:10 +0100