kernel/linux.git/arch/s390/lib, branch v6.18.21

s390/xor: Fix xor_xc_5() inline assembly

2026-03-19T15:08:39+00:00

commit 5f25805303e201f3afaff0a90f7c7ce257468704 upstream. xor_xc_5() contains a larl 1,2f that is not used by the asm and is not declared as a clobber. This can corrupt a compiler-allocated value in %r1 and lead to miscompilation. Remove the instruction. Fixes: 745600ed6965 ("s390/lib: Use exrl instead of ex in xor functions") Cc: stable@vger.kernel.org Reviewed-by: Juergen Christ Reviewed-by: Heiko Carstens Reviewed-by: Sven Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/xor: Fix xor_xc_2() inline assembly constraints

2026-03-19T15:08:39+00:00

commit f775276edc0c505dc0f782773796c189f31a1123 upstream. The inline assembly constraints for xor_xc_2() are incorrect. "bytes", "p1", and "p2" are input operands, while all three of them are modified within the inline assembly. Given that the function consists only of this inline assembly it seems unlikely that this may cause any problems, however fix this in any case. Fixes: 2cfc5f9ce7f5 ("s390/xor: optimized xor routing using the XC instruction") Cc: stable@vger.kernel.org Signed-off-by: Heiko Carstens Reviewed-by: Vasily Gorbik Link: https://lore.kernel.org/r/20260302133500.1560531-2-hca@linux.ibm.com Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390: Remove superfluous newlines from inline assemblies

2025-09-29T11:52:08+00:00

Remove superfluous newlines from inline assemblies. Compilers use the number of lines of inline assemblies as heuristic for the complexity and inline decisions. Therefore inline assemblies should only contain as many lines as required. A lot of inline assemblies contain a superfluous newline for the last line. Remove such newlines to improve compiler inlining decisions. Suggested-by: Juergen Christ Signed-off-by: Heiko Carstens Reviewed-by: Alexander Gordeev Reviewed-by: Juergen Christ Signed-off-by: Alexander Gordeev

Merge tag 's390-6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2025-07-30T03:17:08+00:00

Pull s390 updates from Alexander Gordeev: - Standardize on the __ASSEMBLER__ macro that is provided by GCC and Clang compilers and replace __ASSEMBLY__ with __ASSEMBLER__ in both uapi and non-uapi headers - Explicitly include in architecture and driver files which contain an EXPORT_SYMBOL() and remove the include from the files which do not contain the EXPORT_SYMBOL() - Use the full title of "z/Architecture Principles of Operation" manual and the name of a section where facility bits are listed - Use -D__DISABLE_EXPORTS for files in arch/s390/boot to avoid unnecessary slowing down of the build and confusing external kABI tools that process symtypes data - Print additional unrecoverable machine check information to make the root cause analysis easier - Move cmpxchg_user_key() handling to uaccess library code, since the generated code is large anyway and there is no benefit if it is inlined - Fix a problem when cmpxchg_user_key() is executing a code with a non-default key: if a system is IPL-ed with "LOAD NORMAL", and the previous system used storage keys where the fetch-protection bit was set for some pages, and the cmpxchg_user_key() is located within such page, a protection exception happens - Either the external call or emergency signal order is used to send an IPI to a remote CPU. Use the external order only, since it is at least as good and sometimes even better, than the emergency signal - In case of an early crash the early program check handler prints more or less random value of the last breaking event address, since it is not initialized properly. Copy the last breaking event address from the lowcore to pt_regs to address this - During STP synchronization check udelay() can not be used, since the first CPU modifies tod_clock_base and get_tod_clock_monotonic() might return a non-monotonic time. Instead, busy-loop on other CPUs, while the the first CPU actually handles the synchronization operation - When debugging the early kernel boot using QEMU with the -S flag and GDB attached, skip the decompressor and start directly in kernel - Rename PAI Crypto event 4210 according to z16 and z17 "z/Architecture Principles of Operation" manual - Remove the in-kernel time steering support in favour of the new s390 PTP driver, which allows the kernel clock steered more precisely - Remove a possible false-positive warning in pte_free_defer(), which could be triggered in a valid case KVM guest process is initializing * tag 's390-6.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (29 commits) s390/mm: Remove possible false-positive warning in pte_free_defer() s390/stp: Default to enabled s390/stp: Remove leap second support s390/time: Remove in-kernel time steering s390/sclp: Use monotonic clock in sclp_sync_wait() s390/smp: Use monotonic clock in smp_emergency_stop() s390/time: Use monotonic clock in get_cycles() s390/pai_crypto: Rename PAI Crypto event 4210 scripts/gdb/symbols: make lx-symbols skip the s390 decompressor s390/boot: Introduce jump_to_kernel() function s390/stp: Remove udelay from stp_sync_clock() s390/early: Copy last breaking event address to pt_regs s390/smp: Remove conditional emergency signal order code usage s390/uaccess: Merge cmpxchg_user_key() inline assemblies s390/uaccess: Prevent kprobes on cmpxchg_user_key() functions s390/uaccess: Initialize code pages executed with non-default access key s390/skey: Provide infrastructure for executing with non-default access key s390/uaccess: Make cmpxchg_user_key() library code s390/page: Add memory clobber to page_set_storage_key() s390/page: Cleanup page_set_storage_key() inline assemblies ...

Merge tag 'libcrypto-updates-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux

2025-07-29T00:58:52+00:00

Pull crypto library updates from Eric Biggers: "This is the main crypto library pull request for 6.17. The main focus this cycle is on reorganizing the SHA-1 and SHA-2 code, providing high-quality library APIs for SHA-1 and SHA-2 including HMAC support, and establishing conventions for lib/crypto/ going forward: - Migrate the SHA-1 and SHA-512 code (and also SHA-384 which shares most of the SHA-512 code) into lib/crypto/. This includes both the generic and architecture-optimized code. Greatly simplify how the architecture-optimized code is integrated. Add an easy-to-use library API for each SHA variant, including HMAC support. Finally, reimplement the crypto_shash support on top of the library API. - Apply the same reorganization to the SHA-256 code (and also SHA-224 which shares most of the SHA-256 code). This is a somewhat smaller change, due to my earlier work on SHA-256. But this brings in all the same additional improvements that I made for SHA-1 and SHA-512. There are also some smaller changes: - Move the architecture-optimized ChaCha, Poly1305, and BLAKE2s code from arch/$(SRCARCH)/lib/crypto/ to lib/crypto/$(SRCARCH)/. For these algorithms it's just a move, not a full reorganization yet. - Fix the MIPS chacha-core.S to build with the clang assembler. - Fix the Poly1305 functions to work in all contexts. - Fix a performance regression in the x86_64 Poly1305 code. - Clean up the x86_64 SHA-NI optimized SHA-1 assembly code. Note that since the new organization of the SHA code is much simpler, the diffstat of this pull request is negative, despite the addition of new fully-documented library APIs for multiple SHA and HMAC-SHA variants. These APIs will allow further simplifications across the kernel as users start using them instead of the old-school crypto API. (I've already written a lot of such conversion patches, removing over 1000 more lines of code. But most of those will target 6.18 or later)" * tag 'libcrypto-updates-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux: (67 commits) lib/crypto: arm64/sha512-ce: Drop compatibility macros for older binutils lib/crypto: x86/sha1-ni: Convert to use rounds macros lib/crypto: x86/sha1-ni: Minor optimizations and cleanup crypto: sha1 - Remove sha1_base.h lib/crypto: x86/sha1: Migrate optimized code into library lib/crypto: sparc/sha1: Migrate optimized code into library lib/crypto: s390/sha1: Migrate optimized code into library lib/crypto: powerpc/sha1: Migrate optimized code into library lib/crypto: mips/sha1: Migrate optimized code into library lib/crypto: arm64/sha1: Migrate optimized code into library lib/crypto: arm/sha1: Migrate optimized code into library crypto: sha1 - Use same state format as legacy drivers crypto: sha1 - Wrap library and add HMAC support lib/crypto: sha1: Add HMAC support lib/crypto: sha1: Add SHA-1 library functions lib/crypto: sha1: Rename sha1_init() to sha1_init_raw() crypto: x86/sha1 - Rename conflicting symbol lib/crypto: sha2: Add hmac_sha*_init_usingrawkey() lib/crypto: arm/poly1305: Remove unneeded empty weak function lib/crypto: x86/poly1305: Fix performance regression on short messages ...

lib/crc: s390: Migrate optimized CRC code into lib/crc/

2025-06-30T16:31:57+00:00

Move the s390-optimized CRC code from arch/s390/lib/crc* into its new location in lib/crc/s390/, and wire it up in the new way. This new way of organizing the CRC code eliminates the need to artificially split the code for each CRC variant into separate arch and generic modules, enabling better inlining and dead code elimination. For more details, see "lib/crc: Prepare for arch-optimized code in subdirs of lib/crc/". Reviewed-by: "Martin K. Petersen" Acked-by: Ingo Molnar Acked-by: "Jason A. Donenfeld" Link: https://lore.kernel.org/r/20250607200454.73587-10-ebiggers@kernel.org Signed-off-by: Eric Biggers

lib/crypto: s390: Move arch/s390/lib/crypto/ into lib/crypto/

2025-06-30T16:26:20+00:00

Move the contents of arch/s390/lib/crypto/ into lib/crypto/s390/. The new code organization makes a lot more sense for how this code actually works and is developed. In particular, it makes it possible to build each algorithm as a single module, with better inlining and dead code elimination. For a more detailed explanation, see the patchset which did this for the CRC library code: https://lore.kernel.org/r/20250607200454.73587-1-ebiggers@kernel.org/. Also see the patchset which did this for SHA-512: https://lore.kernel.org/linux-crypto/20250616014019.415791-1-ebiggers@kernel.org/ This is just a preparatory commit, which does the move to get the files into their new location but keeps them building the same way as before. Later commits will make the actual improvements to the way the arch-optimized code is integrated for each algorithm. Acked-by: Ard Biesheuvel Reviewed-by: Martin K. Petersen Reviewed-by: Sohil Mehta Link: https://lore.kernel.org/r/20250619191908.134235-7-ebiggers@kernel.org Signed-off-by: Eric Biggers

Merge branch 'uaccess-key' into features

2025-06-29T11:21:16+00:00

Heiko Carstens says: =================== A rather large series which is supposed to fix the crash below[1], which was seen when running the memop kernel kvm selftest. Problem is that cmpxchg_user_key() is executing code with a non-default key. If a system is IPL'ed with "LOAD NORMAL", and in addition the previous system used storage keys where the fetch-protection bit is set for some pages, and the cmpxchg_user_key() is located within such page a protection exception will happen when executing such code. Idea of this series is to register all code locations running with a non-default key at compile time. All functions, which run with a non-default key, then must explicitly call an init function which initializes the storage key of all pages containing such code locations with default key, which prevents such protection exceptions. Furthermore all functions containing code which may be executed with a non-default access key must be marked with __kprobes to prevent out-of-line execution of any instruction of such functions, which would result in the same problem. By default the kernel will not issue any storage key changing instructions like before, which will preserve the keyless-subset mode optimizations in hosts. Other possible implementations which I discarded: - Moving the code to an own section. This would require an s390 specific change to modpost.c, which complains about section mismatches (EX_TABLE entries in non-default text section). No other architecture has something similar, so let's keep this architecture specific hack local. - Just apply the default storage key to the whole kprobes text section. However this would add special s390 semantics to the kprobes text section, which no other architecture has. History has shown that such hacks fire back sooner or later. Furthermore, and to keep this whole stuff quite simple, this only works for code locations in core kernel code, not within modules. After this series there is no module code left with such code, and as of now I don't see any new kernel code which runs with a non-default access key. Note: the original crash can be reproduced by replacing page_set_storage_key(real, PAGE_DEFAULT_KEY, 1); with page_set_storage_key(real, 8, 1); in arch/s390/kernel/skey.c:__skey_regions_initialize() And then run tools/testing/selftests/kvm/s390/memop from the kernel selftests. [1]: Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 000000000000080b Fault in home space mode while using kernel ASCE. AS:0000000002528007 R3:00000001ffffc007 S:00000001ffffb801 P:000000000000013d Oops: 0004 ilc:1 [#1]SMP Modules linked in: CPU: 3 UID: 0 PID: 791 Comm: memop Not tainted 6.16.0-rc1-00006-g3b568201d0a6-dirty #11 NONE Hardware name: IBM 3931 A01 704 (z/VM 7.4.0) Krnl PSW : 0794f00180000000 000003ffe0f4d91e (__cmpxchg_user_key1+0xbe/0x190) R:0 T:1 IO:1 EX:1 Key:9 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3 Krnl GPRS: 070003ffdfbf6af0 0000000000070000 0000000095b5a300 0000000000000000 00000000f1000000 0000000000000000 0000000000000090 0000000000000000 0000000000000040 0000000000000018 000003ff9b23d000 0000037fe0ef7bd8 000003ffdfbf7500 00000000962e4000 0000037f00ffffff 0000037fe0ef7aa0 Krnl Code: 000003ffe0f4d912: ad03f0a0 stosm 160(%r15),3 000003ffe0f4d916: a7780000 lhi %r7,0 #000003ffe0f4d91a: b20a6000 spka 0(%r6) >000003ffe0f4d91e: b2790100 sacf 256 000003ffe0f4d922: a56f0080 llill %r6,128 000003ffe0f4d926: 5810a000 l %r1,0(%r10) 000003ffe0f4d92a: 141e nr %r1,%r14 000003ffe0f4d92c: c0e7ffffffff xilf %r14,4294967295 Call Trace: [<000003ffe0f4d91e>] __cmpxchg_user_key1+0xbe/0x190 [<000003ffe0189c6e>] cmpxchg_guest_abs_with_key+0x2fe/0x370 [<000003ffe016d28e>] kvm_s390_vm_mem_op_cmpxchg+0x17e/0x350 [<000003ffe0173284>] kvm_arch_vm_ioctl+0x354/0x6f0 [<000003ffe015fedc>] kvm_vm_ioctl+0x2cc/0x6e0 [<000003ffe05348ae>] vfs_ioctl+0x2e/0x70 [<000003ffe0535e70>] __s390x_sys_ioctl+0xe0/0x100 [<000003ffe0f40f06>] __do_syscall+0x136/0x340 [<000003ffe0f4cb2e>] system_call+0x6e/0x90 Last Breaking-Event-Address: [<000003ffe0f4d896>] __cmpxchg_user_key1+0x36/0x190 =================== Signed-off-by: Alexander Gordeev

s390/uaccess: Merge cmpxchg_user_key() inline assemblies

2025-06-29T11:12:02+00:00

The inline assemblies for __cmpxchg_user_key1() and __cmpxchg_user_key2() are identical. Get rid of the duplication and provide a common helper function. Suggested-by: Mete Durlu Acked-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/uaccess: Prevent kprobes on cmpxchg_user_key() functions

2025-06-29T11:12:02+00:00

Code regions within cmpxchg_user_key() functions may be executed with a non-default access key, which may lead to a protection exception if the corresponding page has the fetch-protection bit enabled. There is code in place which initializes the storage keys of such pages when needed. However there is also the possibility of out-of-line execution of such code in case a kprobe is set within such a region. To avoid this problem prevent that any kprobe can be set within the cmpxchg_user_key() functions. Reviewed-by: Claudio Imbrenda Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev