kernel.git/arch/s390/kernel/entry.S, branch linux-6.15.y

s390/entry: Fix last breaking event handling in case of stack corruption

2025-05-05T13:46:34Z

In case of stack corruption stack_invalid() is called and the expectation is that register r10 contains the last breaking event address. This dependency is quite subtle and broke a couple of years ago without that anybody noticed. Fix this by getting rid of the dependency and read the last breaking event address from lowcore. Fixes: 56e62a737028 ("s390: convert to generic entry") Acked-by: Ilya Leoshkevich Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens

s390/entry: Fix setting _CIF_MCCK_GUEST with lowcore relocation

2025-03-31T10:20:39Z

When lowcore relocation is enabled, the machine check handler doesn't use the lowcore address when setting _CIF_MCCK_GUEST. Fix this by adding the missing base register. Fixes: 0001b7bbc53a ("s390/entry: Make mchk_int_handler() ready for lowcore relocation") Reported-by: Heiko Carstens Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/traps: Change stack overflow message

2025-03-04T16:34:03Z

When the kernel stack pointer is pointing to invalid memory, a 'Kernel stack overflow' message is printed, which is misleading. Change the message to actually say that the stack pointer is invalid instead. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390: Use system header file variant of include directive

2025-03-04T16:18:08Z

A few include directives use the local search variant even though the files to be included aren't local. Therefore use the normal system header file variant of the include directive. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/lowcore: Convert relocated lowcore alternative to machine feature

2025-03-04T16:18:05Z

Convert the explicit relocated lowcore alternative type to a more generic machine feature. This only reduces the number of alternative types, but has no impact on code generation. Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/Kconfig: Select VMAP_STACK unconditionally

2024-12-10T14:41:58Z

There is no point in supporting !VMAP_STACK kernel builds. VMAP_STACK has proven to work since many years. Also, since KASAN_VMALLOC is supported, kernels built with !VMAP_STACK are completely untested. Therefore select VMAP_STACK unconditionally and remove all config options and code required for !VMAP_STACK builds. Acked-by: Christian Borntraeger Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/entry: Mark IRQ entries to fix stack depot warnings

2024-11-21T11:44:07Z

The stack depot filters out everything outside of the top interrupt context as an uninteresting or irrelevant part of the stack traces. This helps with stack trace de-duplication, avoiding an explosion of saved stack traces that share the same IRQ context code path but originate from different randomly interrupted points, eventually exhausting the stack depot. Filtering uses in_irqentry_text() to identify functions within the .irqentry.text and .softirqentry.text sections, which then become the last stack trace entries being saved. While __do_softirq() is placed into the .softirqentry.text section by common code, populating .irqentry.text is architecture-specific. Currently, the .irqentry.text section on s390 is empty, which prevents stack depot filtering and de-duplication and could result in warnings like: Stack depot reached limit capacity WARNING: CPU: 0 PID: 286113 at lib/stackdepot.c:252 depot_alloc_stack+0x39a/0x3c8 with PREEMPT and KASAN enabled. Fix this by moving the IO/EXT interrupt handlers from .kprobes.text into the .irqentry.text section and updating the kprobes blacklist to include the .irqentry.text section. This is done only for asynchronous interrupts and explicitly not for program checks, which are synchronous and where the context beyond the program check is important to preserve. Despite machine checks being somewhat in between, they are extremely rare, and preserving context when possible is also of value. SVCs and Restart Interrupts are not relevant, one being always at the boundary to user space and the other being a one-time thing. IRQ entries filtering is also optionally used in ftrace function graph, where the same logic applies. Cc: stable@vger.kernel.org # 5.15+ Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390/mm/fault: Handle guest-related program interrupts in KVM

2024-10-29T10:49:18Z

Any program interrupt that happens in the host during the execution of a KVM guest will now short circuit the fault handler and return to KVM immediately. Guest fault handling (including pfault) will happen entirely inside KVM. When sie64a() returns zero, current->thread.gmap_int_code will contain the program interrupt number that caused the exit, or zero if the exit was not caused by a host program interrupt. KVM will now take care of handling all guest faults in vcpu_post_run(). Since gmap faults will not be visible by the rest of the kernel, remove GMAP_FAULT, the linux fault handlers for secure execution faults, the exception table entries for the sie instruction, the nop padding after the sie instruction, and all other references to guest faults from the s390 code. Signed-off-by: Claudio Imbrenda Co-developed-by: Heiko Carstens Link: https://lore.kernel.org/r/20241022120601.167009-6-imbrenda@linux.ibm.com Signed-off-by: Heiko Carstens

s390/entry: Remove __GMAP_ASCE and use _PIF_GUEST_FAULT again

2024-10-29T10:49:18Z

Now that the guest ASCE is passed as a parameter to __sie64a(), _PIF_GUEST_FAULT can be used again to determine whether the fault was a guest or host fault. Since the guest ASCE will not be taken from the gmap pointer in lowcore anymore, __GMAP_ASCE can be removed. For the same reason the guest ASCE needs now to be saved into the cr1 save area unconditionally. Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank Reviewed-by: Heiko Carstens Link: https://lore.kernel.org/r/20241022120601.167009-2-imbrenda@linux.ibm.com Signed-off-by: Heiko Carstens

Merge tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2024-09-21T16:02:54Z

Pull s390 updates from Vasily Gorbik: - Optimize ftrace and kprobes code patching and avoid stop machine for kprobes if sequential instruction fetching facility is available - Add hiperdispatch feature to dynamically adjust CPU capacity in vertical polarization to improve scheduling efficiency and overall performance. Also add infrastructure for handling warning track interrupts (WTI), allowing for graceful CPU preemption - Rework crypto code pkey module and split it into separate, independent modules for sysfs, PCKMO, CCA, and EP11, allowing modules to load only when the relevant hardware is available - Add hardware acceleration for HMAC modes and the full AES-XTS cipher, utilizing message-security assist extensions (MSA) 10 and 11. It introduces new shash implementations for HMAC-SHA224/256/384/512 and registers the hardware-accelerated AES-XTS cipher as the preferred option. Also add clear key token support - Add MSA 10 and 11 processor activity instrumentation counters to perf and update PAI Extension 1 NNPA counters - Cleanup cpu sampling facility code and rework debug/WARN_ON_ONCE statements - Add support for SHA3 performance enhancements introduced with MSA 12 - Add support for the query authentication information feature of MSA 13 and introduce the KDSA CPACF instruction. Provide query and query authentication information in sysfs, enabling tools like cpacfinfo to present this data in a human-readable form - Update kernel disassembler instructions - Always enable EXPOLINE_EXTERN if supported by the compiler to ensure kpatch compatibility - Add missing warning handling and relocated lowcore support to the early program check handler - Optimize ftrace_return_address() and avoid calling unwinder - Make modules use kernel ftrace trampolines - Strip relocs from the final vmlinux ELF file to make it roughly 2 times smaller - Dump register contents and call trace for early crashes to the console - Generate ptdump address marker array dynamically - Fix rcu_sched stalls that might occur when adding or removing large amounts of pages at once to or from the CMM balloon - Fix deadlock caused by recursive lock of the AP bus scan mutex - Unify sync and async register save areas in entry code - Cleanup debug prints in crypto code - Various cleanup and sanitizing patches for the decompressor - Various small ftrace cleanups * tag 's390-6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (84 commits) s390/crypto: Display Query and Query Authentication Information in sysfs s390/crypto: Add Support for Query Authentication Information s390/crypto: Rework RRE and RRF CPACF inline functions s390/crypto: Add KDSA CPACF Instruction s390/disassembler: Remove duplicate instruction format RSY_RDRU s390/boot: Move boot_printk() code to own file s390/boot: Use boot_printk() instead of sclp_early_printk() s390/boot: Rename decompressor_printk() to boot_printk() s390/boot: Compile all files with the same march flag s390: Use MARCH_HAS_*_FEATURES defines s390: Provide MARCH_HAS_*_FEATURES defines s390/facility: Disable compile time optimization for decompressor code s390/boot: Increase minimum architecture to z10 s390/als: Remove obsolete comment s390/sha3: Fix SHA3 selftests failures s390/pkey: Add AES xts and HMAC clear key token support s390/cpacf: Add MSA 10 and 11 new PCKMO functions s390/mm: Add cond_resched() to cmm_alloc/free_pages() s390/pai_ext: Update PAI extension 1 counters s390/pai_crypto: Add support for MSA 10 and 11 pai counters ...