kernel.git/arch/s390/include/asm, branch linux-6.4.y

s390/uapi: cover statfs padding by growing f_spare

2023-05-17T13:20:17Z

pahole says: struct compat_statfs64 { ... u32 f_spare[4]; /* 68 16 */ /* size: 88, cachelines: 1, members: 12 */ /* padding: 4 */ struct statfs { ... unsigned int f_spare[4]; /* 68 16 */ /* size: 88, cachelines: 1, members: 12 */ /* padding: 4 */ struct statfs64 { ... unsigned int f_spare[4]; /* 68 16 */ /* size: 88, cachelines: 1, members: 12 */ /* padding: 4 */ One has to keep the existence of padding in mind when working with these structs. Grow f_spare arrays to 5 in order to simplify things. Acked-by: Heiko Carstens Signed-off-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/20230504144021.808932-3-iii@linux.ibm.com Signed-off-by: Alexander Gordeev

Merge tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-05-05T19:56:55Z

Pull locking updates from Ingo Molnar: - Introduce local{,64}_try_cmpxchg() - a slightly more optimal primitive, which will be used in perf events ring-buffer code - Simplify/modify rwsems on PREEMPT_RT, to address writer starvation - Misc cleanups/fixes * tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/atomic: Correct (cmp)xchg() instrumentation locking/x86: Define arch_try_cmpxchg_local() locking/arch: Wire up local_try_cmpxchg() locking/generic: Wire up local{,64}_try_cmpxchg() locking/atomic: Add generic try_cmpxchg{,64}_local() support locking/rwbase: Mitigate indefinite writer starvation locking/arch: Rename all internal __xchg() names to __arch_xchg()

Merge tag 's390-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2023-04-30T18:43:31Z

Pull s390 updates from Vasily Gorbik: - Add support for stackleak feature. Also allow specifying architecture-specific stackleak poison function to enable faster implementation. On s390, the mvc-based implementation helps decrease typical overhead from a factor of 3 to just 25% - Convert all assembler files to use SYM* style macros, deprecating the ENTRY() macro and other annotations. Select ARCH_USE_SYM_ANNOTATIONS - Improve KASLR to also randomize module and special amode31 code base load addresses - Rework decompressor memory tracking to support memory holes and improve error handling - Add support for protected virtualization AP binding - Add support for set_direct_map() calls - Implement set_memory_rox() and noexec module_alloc() - Remove obsolete overriding of mem*() functions for KASAN - Rework kexec/kdump to avoid using nodat_stack to call purgatory - Convert the rest of the s390 code to use flexible-array member instead of a zero-length array - Clean up uaccess inline asm - Enable ARCH_HAS_MEMBARRIER_SYNC_CORE - Convert to using CONFIG_FUNCTION_ALIGNMENT and enable DEBUG_FORCE_FUNCTION_ALIGN_64B - Resolve last_break in userspace fault reports - Simplify one-level sysctl registration - Clean up branch prediction handling - Rework CPU counter facility to retrieve available counter sets just once - Other various small fixes and improvements all over the code * tag 's390-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (118 commits) s390/stackleak: provide fast __stackleak_poison() implementation stackleak: allow to specify arch specific stackleak poison function s390: select ARCH_USE_SYM_ANNOTATIONS s390/mm: use VM_FLUSH_RESET_PERMS in module_alloc() s390: wire up memfd_secret system call s390/mm: enable ARCH_HAS_SET_DIRECT_MAP s390/mm: use BIT macro to generate SET_MEMORY bit masks s390/relocate_kernel: adjust indentation s390/relocate_kernel: use SYM* macros instead of ENTRY(), etc. s390/entry: use SYM* macros instead of ENTRY(), etc. s390/purgatory: use SYM* macros instead of ENTRY(), etc. s390/kprobes: use SYM* macros instead of ENTRY(), etc. s390/reipl: use SYM* macros instead of ENTRY(), etc. s390/head64: use SYM* macros instead of ENTRY(), etc. s390/earlypgm: use SYM* macros instead of ENTRY(), etc. s390/mcount: use SYM* macros instead of ENTRY(), etc. s390/crc32le: use SYM* macros instead of ENTRY(), etc. s390/crc32be: use SYM* macros instead of ENTRY(), etc. s390/crypto,chacha: use SYM* macros instead of ENTRY(), etc. s390/amode31: use SYM* macros instead of ENTRY(), etc. ...

locking/arch: Rename all internal xchg() names to arch_xchg()

2023-04-29T07:08:44Z

Decrease the probability of this internal facility to be used by driver code. Signed-off-by: Andrzej Hajda Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Arnd Bergmann Reviewed-by: Andi Shyti Acked-by: Geert Uytterhoeven [m68k] Acked-by: Palmer Dabbelt [riscv] Link: https://lore.kernel.org/r/20230118154450.73842-1-andrzej.hajda@intel.com Cc: Linus Torvalds

s390/stackleak: provide fast __stackleak_poison() implementation

2023-04-20T09:36:35Z

Provide an s390 specific __stackleak_poison() implementation which is faster than the generic variant. For the original implementation with an enforced 4kb stackframe for the getpid() system call the system call overhead increases by a factor of 3 if the stackleak feature is enabled. Using the s390 mvc based variant this is reduced to an increase of 25% instead. This is within the expected area, since the mvc based implementation is more or less a memset64() variant which comes with similar results. See commit 0b77d6701cf8 ("s390: implement memset16, memset32 & memset64"). Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Link: https://lore.kernel.org/r/20230405130841.1350565-3-hca@linux.ibm.com Signed-off-by: Vasily Gorbik

s390/mm: enable ARCH_HAS_SET_DIRECT_MAP

2023-04-20T09:36:29Z

Implement the set_direct_map_*() API, which allows to invalidate and set default permissions to pages within the direct mapping. Note that kernel_page_present(), which is also supposed to be part of this API, is intentionally not implemented. The reason for this is that kernel_page_present() is only used (and currently only makes sense) for suspend/resume, which isn't supported on s390. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mm: use BIT macro to generate SET_MEMORY bit masks

2023-04-20T09:36:29Z

Use BIT macro to generate SET_MEMORY bit masks, which is easier to maintain if bits get added, or removed. Reviewed-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/kasan: remove override of mem*() functions

2023-04-19T15:24:16Z

The kasan mem*() functions are not used anymore since s390 has switched to GENERIC_ENTRY and commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions"). Therefore remove the now dead code, similar to x86. While at it also use the SYM* macros in mem.S. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/kdump: remove nodat stack restriction for calling nodat functions

2023-04-19T15:24:16Z

To allow calling of DAT-off code from kernel the stack needs to be switched to nodat_stack (or other stack mapped as 1:1). Before call_nodat() macro was introduced that was necessary to provide the very same memory address for STNSM and STOSM instructions. If the kernel would stay on a random stack (e.g. a virtually mapped one) then a virtual address provided for STNSM instruction could differ from the physical address needed for the corresponding STOSM instruction. After call_nodat() macro is introduced the kernel stack does not need to be mapped 1:1 anymore, since the macro stores the physical memory address of return PSW in a register before entering DAT-off mode. This way the return LPSWE instruction is able to pick the correct memory location and restore the DAT-on mode. That however might fail in case the 16-byte return PSW happened to cross page boundary: PSW mask and PSW address could end up in two separate non-contiguous physical pages. Align the return PSW on 16-byte boundary so it always fits into a single physical page. As result any stack (including the virtually mapped one) could be used for calling DAT-off code and prior switching to nodat_stack becomes unnecessary. Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/kdump: rework invocation of DAT-off code

2023-04-19T15:24:16Z

Calling kdump kernel is a two-step process that involves invocation of the purgatory code: first time - to verify the new kernel checksum and second time - to call the new kernel itself. The purgatory code operates on real addresses and does not expect any memory protection. Therefore, before the purgatory code is entered the DAT mode is always turned off. However, it is only restored upon return from the new kernel checksum verification. In case the purgatory was called to start the new kernel and failed the control is returned to the old kernel, but the DAT mode continues staying off. The new kernel start failure is unlikely and leads to the disabled wait state anyway. Still that poses a risk, since the kernel code in general is not DAT-off safe and even calling the disabled_wait() function might crash. Introduce call_nodat() macro that allows entering DAT-off mode, calling an arbitrary function and restoring DAT mode back on. Switch all invocations of DAT-off code to that macro and avoid the above described scenario altogether. Name the call_nodat() macro in small letters after the already existing call_on_stack() and put it to the same header file. Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens [hca@linux.ibm.com: some small modifications to call_nodat() macro] Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik