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linux-next/arch/s390/Kconfig

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
# SPDX-License-Identifier: GPL-2.0
config MMU
def_bool y
config ZONE_DMA
def_bool y
config CPU_BIG_ENDIAN
def_bool y
config LOCKDEP_SUPPORT
def_bool y
config STACKTRACE_SUPPORT
def_bool y
config ARCH_HAS_ILOG2_U32
def_bool n
config ARCH_HAS_ILOG2_U64
def_bool n
config GENERIC_HWEIGHT
def_bool y
config GENERIC_BUG
def_bool y if BUG
config GENERIC_BUG_RELATIVE_POINTERS
def_bool y
config GENERIC_LOCKBREAK
def_bool y if PREEMPTION
config PGSTE
def_bool y if KVM
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
def_bool y
config AUDIT_ARCH
def_bool y
config NO_IOPORT_MAP
def_bool y
config PCI_QUIRKS
def_bool n
config ARCH_SUPPORTS_UPROBES
def_bool y
config KASAN_SHADOW_OFFSET
hex
depends on KASAN
default 0x18000000000000 if KASAN_S390_4_LEVEL_PAGING
default 0x30000000000
config S390
def_bool y
select ARCH_BINFMT_ELF_STATE
mm/debug: add tests validating architecture page table helpers This adds tests which will validate architecture page table helpers and other accessors in their compliance with expected generic MM semantics. This will help various architectures in validating changes to existing page table helpers or addition of new ones. This test covers basic page table entry transformations including but not limited to old, young, dirty, clean, write, write protect etc at various level along with populating intermediate entries with next page table page and validating them. Test page table pages are allocated from system memory with required size and alignments. The mapped pfns at page table levels are derived from a real pfn representing a valid kernel text symbol. This test gets called via late_initcall(). This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected. Any architecture, which is willing to subscribe this test will need to select ARCH_HAS_DEBUG_VM_PGTABLE. For now this is limited to arc, arm64, x86, s390 and powerpc platforms where the test is known to build and run successfully Going forward, other architectures too can subscribe the test after fixing any build or runtime problems with their page table helpers. Folks interested in making sure that a given platform's page table helpers conform to expected generic MM semantics should enable the above config which will just trigger this test during boot. Any non conformity here will be reported as an warning which would need to be fixed. This test will help catch any changes to the agreed upon semantics expected from generic MM and enable platforms to accommodate it thereafter. [anshuman.khandual@arm.com: v17] Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com [anshuman.khandual@arm.com: v18] Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.com Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> [ppc32] Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-05 07:47:15 +08:00
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEVMEM_IS_ALLOWED
mm: expose arch_mmap_rnd when available When an architecture fully supports randomizing the ELF load location, a per-arch mmap_rnd() function is used to find a randomized mmap base. In preparation for randomizing the location of ET_DYN binaries separately from mmap, this renames and exports these functions as arch_mmap_rnd(). Additionally introduces CONFIG_ARCH_HAS_ELF_RANDOMIZE for describing this feature on architectures that support it (which is a superset of ARCH_BINFMT_ELF_RANDOMIZE_PIE, since s390 already supports a separated ET_DYN ASLR from mmap ASLR without the ARCH_BINFMT_ELF_RANDOMIZE_PIE logic). Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15 06:48:00 +08:00
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
select ARCH_HAS_MEM_ENCRYPT
mm: introduce ARCH_HAS_PTE_SPECIAL Currently the PTE special supports is turned on in per architecture header files. Most of the time, it is defined in arch/*/include/asm/pgtable.h depending or not on some other per architecture static definition. This patch introduce a new configuration variable to manage this directly in the Kconfig files. It would later replace __HAVE_ARCH_PTE_SPECIAL. Here notes for some architecture where the definition of __HAVE_ARCH_PTE_SPECIAL is not obvious: arm __HAVE_ARCH_PTE_SPECIAL which is currently defined in arch/arm/include/asm/pgtable-3level.h which is included by arch/arm/include/asm/pgtable.h when CONFIG_ARM_LPAE is set. So select ARCH_HAS_PTE_SPECIAL if ARM_LPAE. powerpc __HAVE_ARCH_PTE_SPECIAL is defined in 2 files: - arch/powerpc/include/asm/book3s/64/pgtable.h - arch/powerpc/include/asm/pte-common.h The first one is included if (PPC_BOOK3S & PPC64) while the second is included in all the other cases. So select ARCH_HAS_PTE_SPECIAL all the time. sparc: __HAVE_ARCH_PTE_SPECIAL is defined if defined(__sparc__) && defined(__arch64__) which are defined through the compiler in sparc/Makefile if !SPARC32 which I assume to be if SPARC64. So select ARCH_HAS_PTE_SPECIAL if SPARC64 There is no functional change introduced by this patch. Link: http://lkml.kernel.org/r/1523433816-14460-2-git-send-email-ldufour@linux.vnet.ibm.com Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Suggested-by: Jerome Glisse <jglisse@redhat.com> Reviewed-by: Jerome Glisse <jglisse@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: David S. Miller <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Albert Ou <albert@sifive.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Christophe LEROY <christophe.leroy@c-s.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08 08:06:08 +08:00
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
2019-01-16 21:15:22 +08:00
select ARCH_HAS_SYSCALL_WRAPPER
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select ARCH_INLINE_READ_LOCK
select ARCH_INLINE_READ_LOCK_BH
select ARCH_INLINE_READ_LOCK_IRQ
select ARCH_INLINE_READ_LOCK_IRQSAVE
select ARCH_INLINE_READ_TRYLOCK
select ARCH_INLINE_READ_UNLOCK
select ARCH_INLINE_READ_UNLOCK_BH
select ARCH_INLINE_READ_UNLOCK_IRQ
select ARCH_INLINE_READ_UNLOCK_IRQRESTORE
select ARCH_INLINE_SPIN_LOCK
select ARCH_INLINE_SPIN_LOCK_BH
select ARCH_INLINE_SPIN_LOCK_IRQ
select ARCH_INLINE_SPIN_LOCK_IRQSAVE
select ARCH_INLINE_SPIN_TRYLOCK
select ARCH_INLINE_SPIN_TRYLOCK_BH
select ARCH_INLINE_SPIN_UNLOCK
select ARCH_INLINE_SPIN_UNLOCK_BH
select ARCH_INLINE_SPIN_UNLOCK_IRQ
select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
select ARCH_INLINE_WRITE_LOCK
select ARCH_INLINE_WRITE_LOCK_BH
select ARCH_INLINE_WRITE_LOCK_IRQ
select ARCH_INLINE_WRITE_LOCK_IRQSAVE
select ARCH_INLINE_WRITE_TRYLOCK
select ARCH_INLINE_WRITE_UNLOCK
select ARCH_INLINE_WRITE_UNLOCK_BH
select ARCH_INLINE_WRITE_UNLOCK_IRQ
select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
select ARCH_STACKWALK
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_NUMA_BALANCING
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF
select ARCH_WANTS_DYNAMIC_TASK_STRUCT
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_IPC_PARSE_VERSION
select BUILDTIME_TABLE_SORT
select CLONE_BACKWARDS2
select DMA_OPS if PCI
select DYNAMIC_FTRACE if FUNCTION_TRACER
select GENERIC_CLOCKEVENTS
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES
select GENERIC_FIND_FIRST_BIT
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
s390/kasan: add initialization code and enable it Kasan needs 1/8 of kernel virtual address space to be reserved as the shadow area. And eventually it requires the shadow memory offset to be known at compile time (passed to the compiler when full instrumentation is enabled). Any value picked as the shadow area offset for 3-level paging would eat up identity mapping on 4-level paging (with 1PB shadow area size). So, the kernel sticks to 3-level paging when kasan is enabled. 3TB border is picked as the shadow offset. The memory layout is adjusted so, that physical memory border does not exceed KASAN_SHADOW_START and vmemmap does not go below KASAN_SHADOW_END. Due to the fact that on s390 paging is set up very late and to cover more code with kasan instrumentation, temporary identity mapping and final shadow memory are set up early. The shadow memory mapping is later carried over to init_mm.pgd during paging_init. For the needs of paging structures allocation and shadow memory population a primitive allocator is used, which simply chops off memory blocks from the end of the physical memory. Kasan currenty doesn't track vmemmap and vmalloc areas. Current memory layout (for 3-level paging, 2GB physical memory). ---[ Identity Mapping ]--- 0x0000000000000000-0x0000000000100000 ---[ Kernel Image Start ]--- 0x0000000000100000-0x0000000002b00000 ---[ Kernel Image End ]--- 0x0000000002b00000-0x0000000080000000 2G <- physical memory border 0x0000000080000000-0x0000030000000000 3070G PUD I ---[ Kasan Shadow Start ]--- 0x0000030000000000-0x0000030010000000 256M PMD RW X <- shadow for 2G memory 0x0000030010000000-0x0000037ff0000000 523776M PTE RO NX <- kasan zero ro page 0x0000037ff0000000-0x0000038000000000 256M PMD RW X <- shadow for 2G modules ---[ Kasan Shadow End ]--- 0x0000038000000000-0x000003d100000000 324G PUD I ---[ vmemmap Area ]--- 0x000003d100000000-0x000003e080000000 ---[ vmalloc Area ]--- 0x000003e080000000-0x000003ff80000000 ---[ Modules Area ]--- 0x000003ff80000000-0x0000040000000000 2G Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-17 21:29:13 +08:00
select HAVE_ARCH_KASAN
select HAVE_ARCH_KASAN_VMALLOC
lib/GCD.c: use binary GCD algorithm instead of Euclidean The binary GCD algorithm is based on the following facts: 1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2) 2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b) 3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b) Even on x86 machines with reasonable division hardware, the binary algorithm runs about 25% faster (80% the execution time) than the division-based Euclidian algorithm. On platforms like Alpha and ARMv6 where division is a function call to emulation code, it's even more significant. There are two variants of the code here, depending on whether a fast __ffs (find least significant set bit) instruction is available. This allows the unpredictable branches in the bit-at-a-time shifting loop to be eliminated. If fast __ffs is not available, the "even/odd" GCD variant is used. I use the following code to benchmark: #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include <time.h> #include <unistd.h> #define swap(a, b) \ do { \ a ^= b; \ b ^= a; \ a ^= b; \ } while (0) unsigned long gcd0(unsigned long a, unsigned long b) { unsigned long r; if (a < b) { swap(a, b); } if (b == 0) return a; while ((r = a % b) != 0) { a = b; b = r; } return b; } unsigned long gcd1(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); for (;;) { a >>= __builtin_ctzl(a); if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd2(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; for (;;) { while (!(a & r)) a >>= 1; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } unsigned long gcd3(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; b >>= __builtin_ctzl(b); if (b == 1) return r & -r; for (;;) { a >>= __builtin_ctzl(a); if (a == 1) return r & -r; if (a == b) return a << __builtin_ctzl(r); if (a < b) swap(a, b); a -= b; } } unsigned long gcd4(unsigned long a, unsigned long b) { unsigned long r = a | b; if (!a || !b) return r; r &= -r; while (!(b & r)) b >>= 1; if (b == r) return r; for (;;) { while (!(a & r)) a >>= 1; if (a == r) return r; if (a == b) return a; if (a < b) swap(a, b); a -= b; a >>= 1; if (a & r) a += b; a >>= 1; } } static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = { gcd0, gcd1, gcd2, gcd3, gcd4, }; #define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0])) #if defined(__x86_64__) #define rdtscll(val) do { \ unsigned long __a,__d; \ __asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \ (val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \ } while(0) static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { unsigned long long start, end; unsigned long long ret; unsigned long gcd_res; rdtscll(start); gcd_res = gcd(a, b); rdtscll(end); if (end >= start) ret = end - start; else ret = ~0ULL - start + 1 + end; *res = gcd_res; return ret; } #else static inline struct timespec read_time(void) { struct timespec time; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time); return time; } static inline unsigned long long diff_time(struct timespec start, struct timespec end) { struct timespec temp; if ((end.tv_nsec - start.tv_nsec) < 0) { temp.tv_sec = end.tv_sec - start.tv_sec - 1; temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec; } else { temp.tv_sec = end.tv_sec - start.tv_sec; temp.tv_nsec = end.tv_nsec - start.tv_nsec; } return temp.tv_sec * 1000000000ULL + temp.tv_nsec; } static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long), unsigned long a, unsigned long b, unsigned long *res) { struct timespec start, end; unsigned long gcd_res; start = read_time(); gcd_res = gcd(a, b); end = read_time(); *res = gcd_res; return diff_time(start, end); } #endif static inline unsigned long get_rand() { if (sizeof(long) == 8) return (unsigned long)rand() << 32 | rand(); else return rand(); } int main(int argc, char **argv) { unsigned int seed = time(0); int loops = 100; int repeats = 1000; unsigned long (*res)[TEST_ENTRIES]; unsigned long long elapsed[TEST_ENTRIES]; int i, j, k; for (;;) { int opt = getopt(argc, argv, "n:r:s:"); /* End condition always first */ if (opt == -1) break; switch (opt) { case 'n': loops = atoi(optarg); break; case 'r': repeats = atoi(optarg); break; case 's': seed = strtoul(optarg, NULL, 10); break; default: /* You won't actually get here. */ break; } } res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops); memset(elapsed, 0, sizeof(elapsed)); srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); /* Do we have args? */ unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); unsigned long long min_elapsed[TEST_ENTRIES]; for (k = 0; k < repeats; k++) { for (i = 0; i < TEST_ENTRIES; i++) { unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]); if (k == 0 || min_elapsed[i] > tmp) min_elapsed[i] = tmp; } } for (i = 0; i < TEST_ENTRIES; i++) elapsed[i] += min_elapsed[i]; } for (i = 0; i < TEST_ENTRIES; i++) printf("gcd%d: elapsed %llu\n", i, elapsed[i]); k = 0; srand(seed); for (j = 0; j < loops; j++) { unsigned long a = get_rand(); unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand(); for (i = 1; i < TEST_ENTRIES; i++) { if (res[j][i] != res[j][0]) break; } if (i < TEST_ENTRIES) { if (k == 0) { k = 1; fprintf(stderr, "Error:\n"); } fprintf(stderr, "gcd(%lu, %lu): ", a, b); for (i = 0; i < TEST_ENTRIES; i++) fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n"); } } if (k == 0) fprintf(stderr, "PASS\n"); free(res); return 0; } Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got: zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 10174 gcd1: elapsed 2120 gcd2: elapsed 2902 gcd3: elapsed 2039 gcd4: elapsed 2812 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9309 gcd1: elapsed 2280 gcd2: elapsed 2822 gcd3: elapsed 2217 gcd4: elapsed 2710 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9589 gcd1: elapsed 2098 gcd2: elapsed 2815 gcd3: elapsed 2030 gcd4: elapsed 2718 PASS zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10 gcd0: elapsed 9914 gcd1: elapsed 2309 gcd2: elapsed 2779 gcd3: elapsed 2228 gcd4: elapsed 2709 PASS [akpm@linux-foundation.org: avoid #defining a CONFIG_ variable] Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com> Signed-off-by: George Spelvin <linux@horizon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 08:03:57 +08:00
select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_SOFT_DIRTY
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_ARCH_VMAP_STACK
select HAVE_ASM_MODVERSIONS
select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
select HAVE_CMPXCHG_DOUBLE
select HAVE_CMPXCHG_LOCAL
select HAVE_DEBUG_KMEMLEAK
select HAVE_DMA_CONTIGUOUS
select HAVE_DYNAMIC_FTRACE
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_FAST_GUP
select HAVE_EFFICIENT_UNALIGNED_ACCESS
select HAVE_FENTRY
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZ4
select HAVE_KERNEL_LZMA
select HAVE_KERNEL_LZO
select HAVE_KERNEL_UNCOMPRESSED
select HAVE_KERNEL_XZ
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
select HAVE_KVM
select HAVE_LIVEPATCH
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_MEMBLOCK_PHYS_MAP
select MMU_GATHER_NO_GATHER
2012-09-28 13:01:03 +08:00
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NOP_MCOUNT
select HAVE_OPROFILE
select HAVE_PCI
select HAVE_PERF_EVENTS
select MMU_GATHER_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
s390/livepatch: Implement reliable stack tracing for the consistency model The livepatch consistency model requires reliable stack tracing architecture support in order to work properly. In order to achieve this, two main issues have to be solved. First, reliable and consistent call chain backtracing has to be ensured. Second, the unwinder needs to be able to detect stack corruptions and return errors. The "zSeries ELF Application Binary Interface Supplement" says: "The stack pointer points to the first word of the lowest allocated stack frame. If the "back chain" is implemented this word will point to the previously allocated stack frame (towards higher addresses), except for the first stack frame, which shall have a back chain of zero (NULL). The stack shall grow downwards, in other words towards lower addresses." "back chain" is optional. GCC option -mbackchain enables it. Quoting Martin Schwidefsky [1]: "The compiler is called with the -mbackchain option, all normal C function will store the backchain in the function prologue. All functions written in assembler code should do the same, if you find one that does not we should fix that. The end result is that a task that *voluntarily* called schedule() should have a proper backchain at all times. Dependent on the use case this may or may not be enough. Asynchronous interrupts may stop the CPU at the beginning of a function, if kernel preemption is enabled we can end up with a broken backchain. The production kernels for IBM Z are all compiled *without* kernel preemption. So yes, we might get away without the objtool support. On a side-note, we do have a line item to implement the ORC unwinder for the kernel, that includes the objtool support. Once we have that we can drop the -mbackchain option for the kernel build. That gives us a nice little performance benefit. I hope that the change from backchain to the ORC unwinder will not be too hard to implement in the livepatch tools." Since -mbackchain is enabled by default when the kernel is compiled, the call chain backtracing should be currently ensured and objtool should not be necessary for livepatch purposes. Regarding the second issue, stack corruptions and non-reliable states have to be recognized by the unwinder. Mainly it means to detect preemption or page faults, the end of the task stack must be reached, return addresses must be valid text addresses and hacks like function graph tracing and kretprobes must be properly detected. Unwinding a running task's stack is not a problem, because there is a livepatch requirement that every checked task is blocked, except for the current task. Due to that, the implementation can be much simpler compared to the existing non-reliable infrastructure. We can consider a task's kernel/thread stack only and skip the other stacks. [1] 20180912121106.31ffa97c@mschwideX1 [not archived on lore.kernel.org] Link: https://lkml.kernel.org/r/20191106095601.29986-5-mbenes@suse.cz Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-11-06 17:56:01 +08:00
select HAVE_RELIABLE_STACKTRACE
select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
select IOMMU_HELPER if PCI
select IOMMU_SUPPORT if PCI
2012-09-28 13:01:03 +08:00
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE if PCI
select NEED_SG_DMA_LENGTH if PCI
select OLD_SIGACTION
select OLD_SIGSUSPEND3
select PCI_DOMAINS if PCI
select PCI_MSI if PCI
select PCI_MSI_ARCH_FALLBACKS
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select TTY
select VIRT_CPU_ACCOUNTING
select ARCH_HAS_SCALED_CPUTIME
printk/nmi: generic solution for safe printk in NMI printk() takes some locks and could not be used a safe way in NMI context. The chance of a deadlock is real especially when printing stacks from all CPUs. This particular problem has been addressed on x86 by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). The patchset brings two big advantages. First, it makes the NMI backtraces safe on all architectures for free. Second, it makes all NMI messages almost safe on all architectures (the temporary buffer is limited. We still should keep the number of messages in NMI context at minimum). Note that there already are several messages printed in NMI context: WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE handlers. These are not easy to avoid. This patch reuses most of the code and makes it generic. It is useful for all messages and architectures that support NMI. The alternative printk_func is set when entering and is reseted when leaving NMI context. It queues IRQ work to copy the messages into the main ring buffer in a safe context. __printk_nmi_flush() copies all available messages and reset the buffer. Then we could use a simple cmpxchg operations to get synchronized with writers. There is also used a spinlock to get synchronized with other flushers. We do not longer use seq_buf because it depends on external lock. It would be hard to make all supported operations safe for a lockless use. It would be confusing and error prone to make only some operations safe. The code is put into separate printk/nmi.c as suggested by Steven Rostedt. It needs a per-CPU buffer and is compiled only on architectures that call nmi_enter(). This is achieved by the new HAVE_NMI Kconfig flag. The are MN10300 and Xtensa architectures. We need to clean up NMI handling there first. Let's do it separately. The patch is heavily based on the draft from Peter Zijlstra, see https://lkml.org/lkml/2015/6/10/327 [arnd@arndb.de: printk-nmi: use %zu format string for size_t] [akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part] Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-21 08:00:33 +08:00
select HAVE_NMI
dma-direct: Force unencrypted DMA under SME for certain DMA masks If a device doesn't support DMA to a physical address that includes the encryption bit (currently bit 47, so 48-bit DMA), then the DMA must occur to unencrypted memory. SWIOTLB is used to satisfy that requirement if an IOMMU is not active (enabled or configured in passthrough mode). However, commit fafadcd16595 ("swiotlb: don't dip into swiotlb pool for coherent allocations") modified the coherent allocation support in SWIOTLB to use the DMA direct coherent allocation support. When an IOMMU is not active, this resulted in dma_alloc_coherent() failing for devices that didn't support DMA addresses that included the encryption bit. Addressing this requires changes to the force_dma_unencrypted() function in kernel/dma/direct.c. Since the function is now non-trivial and SME/SEV specific, update the DMA direct support to add an arch override for the force_dma_unencrypted() function. The arch override is selected when CONFIG_AMD_MEM_ENCRYPT is set. The arch override function resides in the arch/x86/mm/mem_encrypt.c file and forces unencrypted DMA when either SEV is active or SME is active and the device does not support DMA to physical addresses that include the encryption bit. Fixes: fafadcd16595 ("swiotlb: don't dip into swiotlb pool for coherent allocations") Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> [hch: moved the force_dma_unencrypted declaration to dma-mapping.h, fold the s390 fix from Halil Pasic] Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-07-11 03:01:19 +08:00
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
select SWIOTLB
select GENERIC_ALLOCATOR
imply IMA_SECURE_AND_OR_TRUSTED_BOOT
config SCHED_OMIT_FRAME_POINTER
def_bool y
config PGTABLE_LEVELS
int
default 5
source "kernel/livepatch/Kconfig"
menu "Processor type and features"
config HAVE_MARCH_Z900_FEATURES
def_bool n
config HAVE_MARCH_Z990_FEATURES
def_bool n
select HAVE_MARCH_Z900_FEATURES
config HAVE_MARCH_Z9_109_FEATURES
def_bool n
select HAVE_MARCH_Z990_FEATURES
config HAVE_MARCH_Z10_FEATURES
def_bool n
select HAVE_MARCH_Z9_109_FEATURES
config HAVE_MARCH_Z196_FEATURES
def_bool n
select HAVE_MARCH_Z10_FEATURES
config HAVE_MARCH_ZEC12_FEATURES
def_bool n
select HAVE_MARCH_Z196_FEATURES
config HAVE_MARCH_Z13_FEATURES
def_bool n
select HAVE_MARCH_ZEC12_FEATURES
config HAVE_MARCH_Z14_FEATURES
def_bool n
select HAVE_MARCH_Z13_FEATURES
config HAVE_MARCH_Z15_FEATURES
def_bool n
select HAVE_MARCH_Z14_FEATURES
choice
prompt "Processor type"
default MARCH_Z196
config MARCH_Z900
bool "IBM zSeries model z800 and z900"
select HAVE_MARCH_Z900_FEATURES
depends on $(cc-option,-march=z900)
help
Select this to enable optimizations for model z800/z900 (2064 and
2066 series). This will enable some optimizations that are not
available on older ESA/390 (31 Bit) only CPUs.
config MARCH_Z990
bool "IBM zSeries model z890 and z990"
select HAVE_MARCH_Z990_FEATURES
depends on $(cc-option,-march=z990)
help
Select this to enable optimizations for model z890/z990 (2084 and
2086 series). The kernel will be slightly faster but will not work
on older machines.
config MARCH_Z9_109
bool "IBM System z9"
select HAVE_MARCH_Z9_109_FEATURES
depends on $(cc-option,-march=z9-109)
help
Select this to enable optimizations for IBM System z9 (2094 and
2096 series). The kernel will be slightly faster but will not work
on older machines.
config MARCH_Z10
bool "IBM System z10"
select HAVE_MARCH_Z10_FEATURES
depends on $(cc-option,-march=z10)
help
Select this to enable optimizations for IBM System z10 (2097 and
2098 series). The kernel will be slightly faster but will not work
on older machines.
config MARCH_Z196
bool "IBM zEnterprise 114 and 196"
select HAVE_MARCH_Z196_FEATURES
depends on $(cc-option,-march=z196)
help
Select this to enable optimizations for IBM zEnterprise 114 and 196
(2818 and 2817 series). The kernel will be slightly faster but will
not work on older machines.
config MARCH_ZEC12
bool "IBM zBC12 and zEC12"
select HAVE_MARCH_ZEC12_FEATURES
depends on $(cc-option,-march=zEC12)
help
Select this to enable optimizations for IBM zBC12 and zEC12 (2828 and
2827 series). The kernel will be slightly faster but will not work on
older machines.
config MARCH_Z13
bool "IBM z13s and z13"
select HAVE_MARCH_Z13_FEATURES
depends on $(cc-option,-march=z13)
help
Select this to enable optimizations for IBM z13s and z13 (2965 and
2964 series). The kernel will be slightly faster but will not work on
older machines.
config MARCH_Z14
bool "IBM z14 ZR1 and z14"
select HAVE_MARCH_Z14_FEATURES
depends on $(cc-option,-march=z14)
help
Select this to enable optimizations for IBM z14 ZR1 and z14 (3907
and 3906 series). The kernel will be slightly faster but will not
work on older machines.
config MARCH_Z15
bool "IBM z15"
select HAVE_MARCH_Z15_FEATURES
depends on $(cc-option,-march=z15)
help
Select this to enable optimizations for IBM z15 (8562
and 8561 series). The kernel will be slightly faster but will not
work on older machines.
endchoice
config MARCH_Z900_TUNE
def_bool TUNE_Z900 || MARCH_Z900 && TUNE_DEFAULT
config MARCH_Z990_TUNE
def_bool TUNE_Z990 || MARCH_Z990 && TUNE_DEFAULT
config MARCH_Z9_109_TUNE
def_bool TUNE_Z9_109 || MARCH_Z9_109 && TUNE_DEFAULT
config MARCH_Z10_TUNE
def_bool TUNE_Z10 || MARCH_Z10 && TUNE_DEFAULT
config MARCH_Z196_TUNE
def_bool TUNE_Z196 || MARCH_Z196 && TUNE_DEFAULT
config MARCH_ZEC12_TUNE
def_bool TUNE_ZEC12 || MARCH_ZEC12 && TUNE_DEFAULT
config MARCH_Z13_TUNE
def_bool TUNE_Z13 || MARCH_Z13 && TUNE_DEFAULT
config MARCH_Z14_TUNE
def_bool TUNE_Z14 || MARCH_Z14 && TUNE_DEFAULT
config MARCH_Z15_TUNE
def_bool TUNE_Z15 || MARCH_Z15 && TUNE_DEFAULT
choice
prompt "Tune code generation"
default TUNE_DEFAULT
help
Cause the compiler to tune (-mtune) the generated code for a machine.
This will make the code run faster on the selected machine but
somewhat slower on other machines.
This option only changes how the compiler emits instructions, not the
selection of instructions itself, so the resulting kernel will run on
all other machines.
config TUNE_DEFAULT
bool "Default"
help
Tune the generated code for the target processor for which the kernel
will be compiled.
config TUNE_Z900
bool "IBM zSeries model z800 and z900"
depends on $(cc-option,-mtune=z900)
config TUNE_Z990
bool "IBM zSeries model z890 and z990"
depends on $(cc-option,-mtune=z990)
config TUNE_Z9_109
bool "IBM System z9"
depends on $(cc-option,-mtune=z9-109)
config TUNE_Z10
bool "IBM System z10"
depends on $(cc-option,-mtune=z10)
config TUNE_Z196
bool "IBM zEnterprise 114 and 196"
depends on $(cc-option,-mtune=z196)
config TUNE_ZEC12
bool "IBM zBC12 and zEC12"
depends on $(cc-option,-mtune=zEC12)
config TUNE_Z13
bool "IBM z13s and z13"
depends on $(cc-option,-mtune=z13)
config TUNE_Z14
bool "IBM z14 ZR1 and z14"
depends on $(cc-option,-mtune=z14)
config TUNE_Z15
bool "IBM z15"
depends on $(cc-option,-mtune=z15)
endchoice
config 64BIT
def_bool y
config COMPAT
def_bool y
prompt "Kernel support for 31 bit emulation"
select COMPAT_BINFMT_ELF if BINFMT_ELF
select ARCH_WANT_OLD_COMPAT_IPC
select COMPAT_OLD_SIGACTION
select HAVE_UID16
kernel: conditionally support non-root users, groups and capabilities There are a lot of embedded systems that run most or all of their functionality in init, running as root:root. For these systems, supporting multiple users is not necessary. This patch adds a new symbol, CONFIG_MULTIUSER, that makes support for non-root users, non-root groups, and capabilities optional. It is enabled under CONFIG_EXPERT menu. When this symbol is not defined, UID and GID are zero in any possible case and processes always have all capabilities. The following syscalls are compiled out: setuid, setregid, setgid, setreuid, setresuid, getresuid, setresgid, getresgid, setgroups, getgroups, setfsuid, setfsgid, capget, capset. Also, groups.c is compiled out completely. In kernel/capability.c, capable function was moved in order to avoid adding two ifdef blocks. This change saves about 25 KB on a defconfig build. The most minimal kernels have total text sizes in the high hundreds of kB rather than low MB. (The 25k goes down a bit with allnoconfig, but not that much. The kernel was booted in Qemu. All the common functionalities work. Adding users/groups is not possible, failing with -ENOSYS. Bloat-o-meter output: add/remove: 7/87 grow/shrink: 19/397 up/down: 1675/-26325 (-24650) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Iulia Manda <iulia.manda21@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-16 07:16:41 +08:00
depends on MULTIUSER
help
Select this option if you want to enable your system kernel to
handle system-calls from ELF binaries for 31 bit ESA. This option
(and some other stuff like libraries and such) is needed for
executing 31 bit applications. It is safe to say "Y".
config SYSVIPC_COMPAT
def_bool y if COMPAT && SYSVIPC
config SMP
def_bool y
config NR_CPUS
int "Maximum number of CPUs (2-512)"
range 2 512
default "64"
help
This allows you to specify the maximum number of CPUs which this
kernel will support. The maximum supported value is 512 and the
minimum value which makes sense is 2.
This is purely to save memory - each supported CPU adds
approximately sixteen kilobytes to the kernel image.
config HOTPLUG_CPU
def_bool y
config NUMA
bool "NUMA support"
depends on SCHED_TOPOLOGY
default n
help
Enable NUMA support
This option adds NUMA support to the kernel.
config NODES_SHIFT
int
depends on NEED_MULTIPLE_NODES
default "1"
config SCHED_SMT
def_bool n
config SCHED_MC
def_bool n
config SCHED_BOOK
def_bool n
config SCHED_DRAWER
def_bool n
config SCHED_TOPOLOGY
def_bool y
prompt "Topology scheduler support"
select SCHED_SMT
select SCHED_MC
select SCHED_BOOK
select SCHED_DRAWER
help
Topology scheduler support improves the CPU scheduler's decision
making when dealing with machines that have multi-threading,
multiple cores or multiple books.
source "kernel/Kconfig.hz"
config KEXEC
def_bool y
select KEXEC_CORE
config KEXEC_FILE
bool "kexec file based system call"
select KEXEC_CORE
select BUILD_BIN2C
depends on CRYPTO
depends on CRYPTO_SHA256
depends on CRYPTO_SHA256_S390
help
Enable the kexec file based system call. In contrast to the normal
kexec system call this system call takes file descriptors for the
kernel and initramfs as arguments.
config ARCH_HAS_KEXEC_PURGATORY
def_bool y
depends on KEXEC_FILE
config KEXEC_SIG
bool "Verify kernel signature during kexec_file_load() syscall"
depends on KEXEC_FILE && MODULE_SIG_FORMAT
help
This option makes kernel signature verification mandatory for
the kexec_file_load() syscall.
In addition to that option, you need to enable signature
verification for the corresponding kernel image type being
loaded in order for this to work.
config ARCH_RANDOM
def_bool y
prompt "s390 architectural random number generation API"
help
Enable the s390 architectural random number generation API
to provide random data for all consumers within the Linux
kernel.
When enabled the arch_random_* functions declared in linux/random.h
are implemented. The implementation is based on the s390 CPACF
instruction subfunction TRNG which provides a real true random
number generator.
If unsure, say Y.
config KERNEL_NOBP
def_bool n
prompt "Enable modified branch prediction for the kernel by default"
help
If this option is selected the kernel will switch to a modified
branch prediction mode if the firmware interface is available.
The modified branch prediction mode improves the behaviour in
regard to speculative execution.
With the option enabled the kernel parameter "nobp=0" or "nospec"
can be used to run the kernel in the normal branch prediction mode.
With the option disabled the modified branch prediction mode is
enabled with the "nobp=1" kernel parameter.
If unsure, say N.
config EXPOLINE
def_bool n
prompt "Avoid speculative indirect branches in the kernel"
help
Compile the kernel with the expoline compiler options to guard
against kernel-to-user data leaks by avoiding speculative indirect
branches.
Requires a compiler with -mindirect-branch=thunk support for full
protection. The kernel may run slower.
If unsure, say N.
choice
prompt "Expoline default"
depends on EXPOLINE
default EXPOLINE_FULL
config EXPOLINE_OFF
bool "spectre_v2=off"
config EXPOLINE_AUTO
bool "spectre_v2=auto"
config EXPOLINE_FULL
bool "spectre_v2=on"
endchoice
config RELOCATABLE
bool "Build a relocatable kernel"
select MODULE_REL_CRCS if MODVERSIONS
default y
help
This builds a kernel image that retains relocation information
so it can be loaded at an arbitrary address.
The kernel is linked as a position-independent executable (PIE)
and contains dynamic relocations which are processed early in the
bootup process.
The relocations make the kernel image about 15% larger (compressed
10%), but are discarded at runtime.
config RANDOMIZE_BASE
bool "Randomize the address of the kernel image (KASLR)"
depends on RELOCATABLE
default y
help
In support of Kernel Address Space Layout Randomization (KASLR),
this randomizes the address at which the kernel image is loaded,
as a security feature that deters exploit attempts relying on
knowledge of the location of kernel internals.
endmenu
menu "Memory setup"
config ARCH_SPARSEMEM_ENABLE
def_bool y
select SPARSEMEM_VMEMMAP_ENABLE
select SPARSEMEM_VMEMMAP
config ARCH_SPARSEMEM_DEFAULT
def_bool y
config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y if SPARSEMEM
config ARCH_ENABLE_MEMORY_HOTREMOVE
def_bool y
config ARCH_ENABLE_SPLIT_PMD_PTLOCK
def_bool y
config MAX_PHYSMEM_BITS
int "Maximum size of supported physical memory in bits (42-53)"
range 42 53
default "46"
help
This option specifies the maximum supported size of physical memory
in bits. Supported is any size between 2^42 (4TB) and 2^53 (8PB).
Increasing the number of bits also increases the kernel image size.
By default 46 bits (64TB) are supported.
config PACK_STACK
def_bool y
prompt "Pack kernel stack"
help
This option enables the compiler option -mkernel-backchain if it
is available. If the option is available the compiler supports
the new stack layout which dramatically reduces the minimum stack
frame size. With an old compiler a non-leaf function needs a
minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
-mkernel-backchain the minimum size drops to 16 byte on 31 bit
and 24 byte on 64 bit.
Say Y if you are unsure.
config CHECK_STACK
def_bool y
depends on !VMAP_STACK
prompt "Detect kernel stack overflow"
help
This option enables the compiler option -mstack-guard and
-mstack-size if they are available. If the compiler supports them
it will emit additional code to each function prolog to trigger
an illegal operation if the kernel stack is about to overflow.
Say N if you are unsure.
config STACK_GUARD
int "Size of the guard area (128-1024)"
range 128 1024
depends on CHECK_STACK
default "256"
help
This allows you to specify the size of the guard area at the lower
end of the kernel stack. If the kernel stack points into the guard
area on function entry an illegal operation is triggered. The size
needs to be a power of 2. Please keep in mind that the size of an
interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
The minimum size for the stack guard should be 256 for 31 bit and
512 for 64 bit.
config WARN_DYNAMIC_STACK
def_bool n
prompt "Emit compiler warnings for function with dynamic stack usage"
help
This option enables the compiler option -mwarn-dynamicstack. If the
compiler supports this options generates warnings for functions
that dynamically allocate stack space using alloca.
Say N if you are unsure.
endmenu
menu "I/O subsystem"
config QDIO
def_tristate y
prompt "QDIO support"
help
This driver provides the Queued Direct I/O base support for
IBM System z.
To compile this driver as a module, choose M here: the
module will be called qdio.
If unsure, say Y.
if PCI
config PCI_NR_FUNCTIONS
int "Maximum number of PCI functions (1-4096)"
range 1 4096
default "128"
help
This allows you to specify the maximum number of PCI functions which
this kernel will support.
endif # PCI
config HAS_IOMEM
def_bool PCI
config CHSC_SCH
def_tristate m
prompt "Support for CHSC subchannels"
help
This driver allows usage of CHSC subchannels. A CHSC subchannel
is usually present on LPAR only.
The driver creates a device /dev/chsc, which may be used to
obtain I/O configuration information about the machine and
to issue asynchronous chsc commands (DANGEROUS).
You will usually only want to use this interface on a special
LPAR designated for system management.
To compile this driver as a module, choose M here: the
module will be called chsc_sch.
If unsure, say N.
config SCM_BUS
def_bool y
prompt "SCM bus driver"
help
Bus driver for Storage Class Memory.
config EADM_SCH
def_tristate m
prompt "Support for EADM subchannels"
depends on SCM_BUS
help
This driver allows usage of EADM subchannels. EADM subchannels act
as a communication vehicle for SCM increments.
To compile this driver as a module, choose M here: the
module will be called eadm_sch.
config VFIO_CCW
def_tristate n
prompt "Support for VFIO-CCW subchannels"
depends on S390_CCW_IOMMU && VFIO_MDEV
help
This driver allows usage of I/O subchannels via VFIO-CCW.
To compile this driver as a module, choose M here: the
module will be called vfio_ccw.
s390: vfio-ap: base implementation of VFIO AP device driver Introduces a new AP device driver. This device driver is built on the VFIO mediated device framework. The framework provides sysfs interfaces that facilitate passthrough access by guests to devices installed on the linux host. The VFIO AP device driver will serve two purposes: 1. Provide the interfaces to reserve AP devices for exclusive use by KVM guests. This is accomplished by unbinding the devices to be reserved for guest usage from the zcrypt device driver and binding them to the VFIO AP device driver. 2. Implements the functions, callbacks and sysfs attribute interfaces required to create one or more VFIO mediated devices each of which will be used to configure the AP matrix for a guest and serve as a file descriptor for facilitating communication between QEMU and the VFIO AP device driver. When the VFIO AP device driver is initialized: * It registers with the AP bus for control of type 10 (CEX4 and newer) AP queue devices. This limitation was imposed due to: 1. A desire to keep the code as simple as possible; 2. Some older models are no longer supported by the kernel and others are getting close to end of service. 3. A lack of older systems on which to test older devices. The probe and remove callbacks will be provided to support the binding/unbinding of AP queue devices to/from the VFIO AP device driver. * Creates a matrix device, /sys/devices/vfio_ap/matrix, to serve as the parent of the mediated devices created, one for each guest, and to hold the APQNs of the AP devices bound to the VFIO AP device driver. Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Michael Mueller <mimu@linux.ibm.com> Tested-by: Farhan Ali <alifm@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20180925231641.4954-5-akrowiak@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2018-09-26 07:16:19 +08:00
config VFIO_AP
def_tristate n
prompt "VFIO support for AP devices"
depends on S390_AP_IOMMU && VFIO_MDEV_DEVICE && KVM
depends on ZCRYPT
s390: vfio-ap: base implementation of VFIO AP device driver Introduces a new AP device driver. This device driver is built on the VFIO mediated device framework. The framework provides sysfs interfaces that facilitate passthrough access by guests to devices installed on the linux host. The VFIO AP device driver will serve two purposes: 1. Provide the interfaces to reserve AP devices for exclusive use by KVM guests. This is accomplished by unbinding the devices to be reserved for guest usage from the zcrypt device driver and binding them to the VFIO AP device driver. 2. Implements the functions, callbacks and sysfs attribute interfaces required to create one or more VFIO mediated devices each of which will be used to configure the AP matrix for a guest and serve as a file descriptor for facilitating communication between QEMU and the VFIO AP device driver. When the VFIO AP device driver is initialized: * It registers with the AP bus for control of type 10 (CEX4 and newer) AP queue devices. This limitation was imposed due to: 1. A desire to keep the code as simple as possible; 2. Some older models are no longer supported by the kernel and others are getting close to end of service. 3. A lack of older systems on which to test older devices. The probe and remove callbacks will be provided to support the binding/unbinding of AP queue devices to/from the VFIO AP device driver. * Creates a matrix device, /sys/devices/vfio_ap/matrix, to serve as the parent of the mediated devices created, one for each guest, and to hold the APQNs of the AP devices bound to the VFIO AP device driver. Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> Reviewed-by: Halil Pasic <pasic@linux.ibm.com> Tested-by: Michael Mueller <mimu@linux.ibm.com> Tested-by: Farhan Ali <alifm@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20180925231641.4954-5-akrowiak@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2018-09-26 07:16:19 +08:00
help
This driver grants access to Adjunct Processor (AP) devices
via the VFIO mediated device interface.
To compile this driver as a module, choose M here: the module
will be called vfio_ap.
endmenu
menu "Dump support"
config CRASH_DUMP
bool "kernel crash dumps"
select KEXEC
help
Generate crash dump after being started by kexec.
Crash dump kernels are loaded in the main kernel with kexec-tools
into a specially reserved region and then later executed after
a crash by kdump/kexec.
Refer to <file:Documentation/s390/zfcpdump.rst> for more details on this.
This option also enables s390 zfcpdump.
See also <file:Documentation/s390/zfcpdump.rst>
endmenu
config SECCOMP
def_bool y
prompt "Enable seccomp to safely compute untrusted bytecode"
depends on PROC_FS
help
This kernel feature is useful for number crunching applications
that may need to compute untrusted bytecode during their
execution. By using pipes or other transports made available to
the process as file descriptors supporting the read/write
syscalls, it's possible to isolate those applications in
their own address space using seccomp. Once seccomp is
enabled via /proc/<pid>/seccomp, it cannot be disabled
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
If unsure, say Y.
config CCW
def_bool y
config HAVE_PNETID
tristate
default (SMC || CCWGROUP)
menu "Virtualization"
config PROTECTED_VIRTUALIZATION_GUEST
def_bool n
prompt "Protected virtualization guest support"
help
Select this option, if you want to be able to run this
kernel as a protected virtualization KVM guest.
Protected virtualization capable machines have a mini hypervisor
located at machine level (an ultravisor). With help of the
Ultravisor, KVM will be able to run "protected" VMs, special
VMs whose memory and management data are unavailable to KVM.
config PFAULT
def_bool y
prompt "Pseudo page fault support"
help
Select this option, if you want to use PFAULT pseudo page fault
handling under VM. If running native or in LPAR, this option
has no effect. If your VM does not support PFAULT, PAGEEX
pseudo page fault handling will be used.
Note that VM 4.2 supports PFAULT but has a bug in its
implementation that causes some problems.
Everybody who wants to run Linux under VM != VM4.2 should select
this option.
config CMM
def_tristate n
prompt "Cooperative memory management"
help
Select this option, if you want to enable the kernel interface
to reduce the memory size of the system. This is accomplished
by allocating pages of memory and put them "on hold". This only
makes sense for a system running under VM where the unused pages
will be reused by VM for other guest systems. The interface
allows an external monitor to balance memory of many systems.
Everybody who wants to run Linux under VM should select this
option.
config CMM_IUCV
def_bool y
prompt "IUCV special message interface to cooperative memory management"
depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
help
Select this option to enable the special message interface to
the cooperative memory management.
config APPLDATA_BASE
def_bool n
prompt "Linux - VM Monitor Stream, base infrastructure"
depends on PROC_FS
help
This provides a kernel interface for creating and updating z/VM APPLDATA
monitor records. The monitor records are updated at certain time
intervals, once the timer is started.
Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
i.e. enables or disables monitoring on the Linux side.
A custom interval value (in seconds) can be written to
/proc/appldata/interval.
Defaults are 60 seconds interval and timer off.
The /proc entries can also be read from, showing the current settings.
config APPLDATA_MEM
def_tristate m
prompt "Monitor memory management statistics"
depends on APPLDATA_BASE && VM_EVENT_COUNTERS
help
This provides memory management related data to the Linux - VM Monitor
Stream, like paging/swapping rate, memory utilisation, etc.
Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
APPLDATA monitor record, i.e. enables or disables monitoring this record
on the z/VM side.
Default is disabled.
The /proc entry can also be read from, showing the current settings.
This can also be compiled as a module, which will be called
appldata_mem.o.
config APPLDATA_OS
def_tristate m
prompt "Monitor OS statistics"
depends on APPLDATA_BASE
help
This provides OS related data to the Linux - VM Monitor Stream, like
CPU utilisation, etc.
Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
APPLDATA monitor record, i.e. enables or disables monitoring this record
on the z/VM side.
Default is disabled.
This can also be compiled as a module, which will be called
appldata_os.o.
config APPLDATA_NET_SUM
def_tristate m
prompt "Monitor overall network statistics"
depends on APPLDATA_BASE && NET
help
This provides network related data to the Linux - VM Monitor Stream,
currently there is only a total sum of network I/O statistics, no
per-interface data.
Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
APPLDATA monitor record, i.e. enables or disables monitoring this record
on the z/VM side.
Default is disabled.
This can also be compiled as a module, which will be called
appldata_net_sum.o.
[PATCH] s390_hypfs filesystem On zSeries machines there exists an interface which allows the operating system to retrieve LPAR hypervisor accounting data. For example, it is possible to get usage data for physical and virtual cpus. In order to provide this information to user space programs, I implemented a new virtual Linux file system named 's390_hypfs' using the Linux 2.6 libfs framework. The name 's390_hypfs' stands for 'S390 Hypervisor Filesystem'. All the accounting information is put into different virtual files which can be accessed from user space. All data is represented as ASCII strings. When the file system is mounted the accounting information is retrieved and a file system tree is created with the attribute files containing the cpu information. The content of the files remains unchanged until a new update is made. An update can be triggered from user space through writing 'something' into a special purpose update file. We create the following directory structure: <mount-point>/ update cpus/ <cpu-id> type mgmtime <cpu-id> ... hyp/ type systems/ <lpar-name> cpus/ <cpu-id> type mgmtime cputime onlinetime <cpu-id> ... <lpar-name> cpus/ ... - update: File to trigger update - cpus/: Directory for all physical cpus - cpus/<cpu-id>/: Directory for one physical cpu. - cpus/<cpu-id>/type: Type name of physical zSeries cpu. - cpus/<cpu-id>/mgmtime: Physical-LPAR-management time in microseconds. - hyp/: Directory for hypervisor information - hyp/type: Typ of hypervisor (currently only 'LPAR Hypervisor') - systems/: Directory for all LPARs - systems/<lpar-name>/: Directory for one LPAR. - systems/<lpar-name>/cpus/<cpu-id>/: Directory for the virtual cpus - systems/<lpar-name>/cpus/<cpu-id>/type: Typ of cpu. - systems/<lpar-name>/cpus/<cpu-id>/mgmtime: Accumulated number of microseconds during which a physical CPU was assigned to the logical cpu and the cpu time was consumed by the hypervisor and was not provided to the LPAR (LPAR overhead). - systems/<lpar-name>/cpus/<cpu-id>/cputime: Accumulated number of microseconds during which a physical CPU was assigned to the logical cpu and the cpu time was consumed by the LPAR. - systems/<lpar-name>/cpus/<cpu-id>/onlinetime: Accumulated number of microseconds during which the logical CPU has been online. As mount point for the filesystem /sys/hypervisor/s390 is created. The update process is triggered when writing 'something' into the 'update' file at the top level hypfs directory. You can do this e.g. with 'echo 1 > update'. During the update the whole directory structure is deleted and built up again. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Ingo Oeser <ioe-lkml@rameria.de> Cc: Joern Engel <joern@wohnheim.fh-wedel.de> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:05:06 +08:00
config S390_HYPFS_FS
def_bool y
prompt "s390 hypervisor file system support"
[PATCH] s390_hypfs filesystem On zSeries machines there exists an interface which allows the operating system to retrieve LPAR hypervisor accounting data. For example, it is possible to get usage data for physical and virtual cpus. In order to provide this information to user space programs, I implemented a new virtual Linux file system named 's390_hypfs' using the Linux 2.6 libfs framework. The name 's390_hypfs' stands for 'S390 Hypervisor Filesystem'. All the accounting information is put into different virtual files which can be accessed from user space. All data is represented as ASCII strings. When the file system is mounted the accounting information is retrieved and a file system tree is created with the attribute files containing the cpu information. The content of the files remains unchanged until a new update is made. An update can be triggered from user space through writing 'something' into a special purpose update file. We create the following directory structure: <mount-point>/ update cpus/ <cpu-id> type mgmtime <cpu-id> ... hyp/ type systems/ <lpar-name> cpus/ <cpu-id> type mgmtime cputime onlinetime <cpu-id> ... <lpar-name> cpus/ ... - update: File to trigger update - cpus/: Directory for all physical cpus - cpus/<cpu-id>/: Directory for one physical cpu. - cpus/<cpu-id>/type: Type name of physical zSeries cpu. - cpus/<cpu-id>/mgmtime: Physical-LPAR-management time in microseconds. - hyp/: Directory for hypervisor information - hyp/type: Typ of hypervisor (currently only 'LPAR Hypervisor') - systems/: Directory for all LPARs - systems/<lpar-name>/: Directory for one LPAR. - systems/<lpar-name>/cpus/<cpu-id>/: Directory for the virtual cpus - systems/<lpar-name>/cpus/<cpu-id>/type: Typ of cpu. - systems/<lpar-name>/cpus/<cpu-id>/mgmtime: Accumulated number of microseconds during which a physical CPU was assigned to the logical cpu and the cpu time was consumed by the hypervisor and was not provided to the LPAR (LPAR overhead). - systems/<lpar-name>/cpus/<cpu-id>/cputime: Accumulated number of microseconds during which a physical CPU was assigned to the logical cpu and the cpu time was consumed by the LPAR. - systems/<lpar-name>/cpus/<cpu-id>/onlinetime: Accumulated number of microseconds during which the logical CPU has been online. As mount point for the filesystem /sys/hypervisor/s390 is created. The update process is triggered when writing 'something' into the 'update' file at the top level hypfs directory. You can do this e.g. with 'echo 1 > update'. During the update the whole directory structure is deleted and built up again. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Ingo Oeser <ioe-lkml@rameria.de> Cc: Joern Engel <joern@wohnheim.fh-wedel.de> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:05:06 +08:00
select SYS_HYPERVISOR
help
This is a virtual file system intended to provide accounting
information in an s390 hypervisor environment.
source "arch/s390/kvm/Kconfig"
config S390_GUEST
def_bool y
prompt "s390 support for virtio devices"
select TTY
select VIRTUALIZATION
select VIRTIO
help
Enabling this option adds support for virtio based paravirtual device
drivers on s390.
Select this option if you want to run the kernel as a guest under
the KVM hypervisor.
endmenu
menu "Selftests"
config S390_UNWIND_SELFTEST
def_tristate n
prompt "Test unwind functions"
help
This option enables s390 specific stack unwinder testing kernel
module. This option is not useful for distributions or general
kernels, but only for kernel developers working on architecture code.
Say N if you are unsure.
endmenu