kernel.git/arch/s390/kernel/vdso.c, branch linux-6.15.y

mseal sysmap: enable s390

2025-04-01T22:17:16Z

Provide support for CONFIG_MSEAL_SYSTEM_MAPPINGS on s390, covering the vdso. [hca@linux.ibm.com: update supported architectures] Link: https://lkml.kernel.org/r/20250317131917.1332402-1-hca@linux.ibm.com Link: https://lkml.kernel.org/r/20250311123326.2686682-3-hca@linux.ibm.com Signed-off-by: Heiko Carstens Reviewed-by: Lorenzo Stoakes Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Jeff Xu Cc: Liam Howlett Cc: Sven Schnelle Cc: Thomas Weißschuh Cc: Vasily Gorbik Signed-off-by: Andrew Morton

s390/vdso: Switch to generic storage implementation

2025-02-21T08:54:02Z

The generic storage implementation provides the same features as the custom one. However it can be shared between architectures, making maintenance easier. Co-developed-by: Nam Cao Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Acked-by: Heiko Carstens Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-12-13a4669dfc8c@linutronix.de

s390/vdso: Wire up getrandom() vdso implementation

2024-09-13T18:57:31Z

Provide the s390 specific vdso getrandom() architecture backend. _vdso_rng_data required data is placed within the _vdso_data vvar page, by using a hardcoded offset larger than vdso_data. As required the chacha20 implementation does not write to the stack. The implementation follows more or less the arm64 implementations and makes use of vector instructions. It has a fallback to the getrandom() system call for machines where the vector facility is not installed. The check if the vector facility is installed, as well as an optimization for machines with the vector-enhancements facility 2, is implemented with alternatives, avoiding runtime checks. Note that __kernel_getrandom() is implemented without the vdso user wrapper which would setup a stack frame for odd cases (aka very old glibc variants) where the caller has not done that. All callers of __kernel_getrandom() are required to setup a stack frame, like the C ABI requires it. The vdso testcases vdso_test_getrandom and vdso_test_chacha pass. Benchmark on a z16: $ ./vdso_test_getrandom bench-single vdso: 25000000 times in 0.493703559 seconds syscall: 25000000 times in 6.584025337 seconds Signed-off-by: Heiko Carstens Reviewed-by: Harald Freudenberger Signed-off-by: Jason A. Donenfeld

s390/vdso: Allow alternatives in vdso code

2024-09-13T15:28:36Z

Implement the infrastructure required to allow alternatives in vdso code. Signed-off-by: Heiko Carstens Signed-off-by: Jason A. Donenfeld

s390/stackstrace: Detect vdso stack frames

2024-05-14T11:37:07Z

Clear the backchain of the extra stack frame added by the vdso user wrapper code. This allows the user stack walker to detect and skip the non-standard stack frame. Without this an incorrect instruction pointer would be added to stack traces, and stack frame walking would be continued with a more or less random back chain. Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/vdso: Use generic union vdso_data_store

2024-02-20T19:56:00Z

There is already a generic union definition for vdso_data_store in the vdso datapage header. Use this definition to prevent code duplication. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Thomas Gleixner Reviewed-by: Vincenzo Frascino Reviewed-by: Kees Cook Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20240219153939.75719-8-anna-maria@linutronix.de

mm: remove zap_page_range and create zap_vma_pages

2023-01-19T01:12:55Z

zap_page_range was originally designed to unmap pages within an address range that could span multiple vmas. While working on [1], it was discovered that all callers of zap_page_range pass a range entirely within a single vma. In addition, the mmu notification call within zap_page range does not correctly handle ranges that span multiple vmas. When crossing a vma boundary, a new mmu_notifier_range_init/end call pair with the new vma should be made. Instead of fixing zap_page_range, do the following: - Create a new routine zap_vma_pages() that will remove all pages within the passed vma. Most users of zap_page_range pass the entire vma and can use this new routine. - For callers of zap_page_range not passing the entire vma, instead call zap_page_range_single(). - Remove zap_page_range. [1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@oracle.com/ Link: https://lkml.kernel.org/r/20230104002732.232573-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Suggested-by: Peter Xu Acked-by: Michal Hocko Acked-by: Peter Xu Acked-by: Heiko Carstens [s390] Reviewed-by: Christoph Hellwig Cc: Christian Borntraeger Cc: Christian Brauner Cc: Dave Hansen Cc: David Hildenbrand Cc: Eric Dumazet Cc: Matthew Wilcox Cc: Michael Ellerman Cc: Nadav Amit Cc: Palmer Dabbelt Cc: Rik van Riel Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

2022-12-13T00:22:22Z

Pull random number generator updates from Jason Donenfeld: - Replace prandom_u32_max() and various open-coded variants of it, there is now a new family of functions that uses fast rejection sampling to choose properly uniformly random numbers within an interval: get_random_u32_below(ceil) - [0, ceil) get_random_u32_above(floor) - (floor, U32_MAX] get_random_u32_inclusive(floor, ceil) - [floor, ceil] Coccinelle was used to convert all current users of prandom_u32_max(), as well as many open-coded patterns, resulting in improvements throughout the tree. I'll have a "late" 6.1-rc1 pull for you that removes the now unused prandom_u32_max() function, just in case any other trees add a new use case of it that needs to converted. According to linux-next, there may be two trivial cases of prandom_u32_max() reintroductions that are fixable with a 's/.../.../'. So I'll have for you a final conversion patch doing that alongside the removal patch during the second week. This is a treewide change that touches many files throughout. - More consistent use of get_random_canary(). - Updates to comments, documentation, tests, headers, and simplification in configuration. - The arch_get_random*_early() abstraction was only used by arm64 and wasn't entirely useful, so this has been replaced by code that works in all relevant contexts. - The kernel will use and manage random seeds in non-volatile EFI variables, refreshing a variable with a fresh seed when the RNG is initialized. The RNG GUID namespace is then hidden from efivarfs to prevent accidental leakage. These changes are split into random.c infrastructure code used in the EFI subsystem, in this pull request, and related support inside of EFISTUB, in Ard's EFI tree. These are co-dependent for full functionality, but the order of merging doesn't matter. - Part of the infrastructure added for the EFI support is also used for an improvement to the way vsprintf initializes its siphash key, replacing an sleep loop wart. - The hardware RNG framework now always calls its correct random.c input function, add_hwgenerator_randomness(), rather than sometimes going through helpers better suited for other cases. - The add_latent_entropy() function has long been called from the fork handler, but is a no-op when the latent entropy gcc plugin isn't used, which is fine for the purposes of latent entropy. But it was missing out on the cycle counter that was also being mixed in beside the latent entropy variable. So now, if the latent entropy gcc plugin isn't enabled, add_latent_entropy() will expand to a call to add_device_randomness(NULL, 0), which adds a cycle counter, without the absent latent entropy variable. - The RNG is now reseeded from a delayed worker, rather than on demand when used. Always running from a worker allows it to make use of the CPU RNG on platforms like S390x, whose instructions are too slow to do so from interrupts. It also has the effect of adding in new inputs more frequently with more regularity, amounting to a long term transcript of random values. Plus, it helps a bit with the upcoming vDSO implementation (which isn't yet ready for 6.2). - The jitter entropy algorithm now tries to execute on many different CPUs, round-robining, in hopes of hitting even more memory latencies and other unpredictable effects. It also will mix in a cycle counter when the entropy timer fires, in addition to being mixed in from the main loop, to account more explicitly for fluctuations in that timer firing. And the state it touches is now kept within the same cache line, so that it's assured that the different execution contexts will cause latencies. * tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits) random: include in the right header random: align entropy_timer_state to cache line random: mix in cycle counter when jitter timer fires random: spread out jitter callback to different CPUs random: remove extraneous period and add a missing one in comments efi: random: refresh non-volatile random seed when RNG is initialized vsprintf: initialize siphash key using notifier random: add back async readiness notifier random: reseed in delayed work rather than on-demand random: always mix cycle counter in add_latent_entropy() hw_random: use add_hwgenerator_randomness() for early entropy random: modernize documentation comment on get_random_bytes() random: adjust comment to account for removed function random: remove early archrandom abstraction random: use random.trust_{bootloader,cpu} command line option only stackprotector: actually use get_random_canary() stackprotector: move get_random_canary() into stackprotector.h treewide: use get_random_u32_inclusive() when possible treewide: use get_random_u32_{above,below}() instead of manual loop treewide: use get_random_u32_below() instead of deprecated function ...

vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy

2022-12-01T10:35:40Z

find_timens_vvar_page() is not architecture-specific, as can be seen from how all five per-architecture versions of it are the same. (arm64, powerpc and riscv are exactly the same; x86 and s390 have two characters difference inside a comment, less blank lines, and mark the !CONFIG_TIME_NS version as inline.) Refactor the five copies into a central copy in kernel/time/namespace.c. Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20221130115320.2918447-1-jannh@google.com

treewide: use get_random_u32_below() instead of deprecated function

2022-11-18T01:15:15Z

This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld