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2020-11-20s390/decompressor: add stacktrace supportVasily Gorbik
Decompressor works on a single statically allocated stack. Stacktrace implementation with -mbackchain just takes few lines of code. Linux version 5.10.0-rc3-22793-g0f84a355b776-dirty (gor@tuxmaker) #27 SMP PREEMPT Mon Nov 9 17:30:18 CET 2020 Kernel fault: interruption code 0005 ilc:2 PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c) R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3 GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a62c 000000000000bf60 0000000000000000 00000000000003c0 0000000000000000 0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018 000000000311c000 0000000000010070 0000000000012f82 000000000000bea8 Call Trace: (sp:000000000000bea8 [<000000000002016e>] 000000000002016e) sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0 Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-07-07kbuild: remove cc-option test of -ffreestandingMasahiro Yamada
Some Makefiles already pass -ffreestanding unconditionally. For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile. No problem report so far about hard-coding this option. So, we can assume all supported compilers know -ffreestanding. I confirmed GCC 4.8 and Clang manuals document this option. Get rid of cc-option from -ffreestanding. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-17s390: make 'install' not depend on vmlinuxMasahiro Yamada
For the same reason as commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"), the install targets should never trigger the rebuild of the kernel. The variable, CONFIGURE, is not set by anyone. Remove it as well. Link: https://lkml.kernel.org/r/20200216144829.27023-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-01-22s390: adjust -mpacked-stack support check for clang 10Vasily Gorbik
clang 10 introduces -mpacked-stack compiler option implementation. At the same time currently it does not support a combination of -mpacked-stack and -mbackchain. This leads to the following build error: clang: error: unsupported option '-mpacked-stack with -mbackchain' for target 's390x-ibm-linux' If/when clang adds support for a combination of -mpacked-stack and -mbackchain it would also require -msoft-float (like gcc does). According to Ulrich Weigand "stack slot assigned to the kernel backchain overlaps the stack slot assigned to the FPR varargs (both are required to be placed immediately after the saved r15 slot if present)." Extend -mpacked-stack compiler option support check to include all 3 options -mpacked-stack -mbackchain -msoft-float which must present to support -mpacked-stack with -mbackchain. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-01s390: remove compat vdso codeHeiko Carstens
Remove compat vdso code, since there is hardly any compat user space left. Still existing compat user space will have to use system calls instead. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-09-13s390: add support for IBM z15 machinesMartin Schwidefsky
Add detection for machine types 0x8562 and 8x8561 and set the ELF platform name to z15. Add the miscellaneous-instruction-extension 3 facility to the list of facilities for z15. And allow to generate code that only runs on a z15 machine. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2019-07-12Merge tag 'kconfig-v5.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kconfig updates from Masahiro Yamada: - always require argument for --defconfig and remove the hard-coded arch/$(ARCH)/defconfig path - make arch/$(SRCARCH)/configs/defconfig the new default of defconfig - some code cleanups * tag 'kconfig-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kconfig: remove meaningless if-conditional in conf_read() kconfig: Fix spelling of sym_is_changable unicore32: rename unicore32_defconfig to defconfig kconfig: make arch/*/configs/defconfig the default of KBUILD_DEFCONFIG kconfig: add static qualifier to expand_string() kconfig: require the argument of --defconfig kconfig: remove always false ifeq ($(KBUILD_DEFCONFIG,) conditional
2019-06-11s390/boot: disable address-of-packed-member warningHeiko Carstens
Get rid of gcc9 warnings like this: arch/s390/boot/ipl_report.c: In function 'find_bootdata_space': arch/s390/boot/ipl_report.c:42:26: warning: taking address of packed member of 'struct ipl_rb_components' may result in an unaligned pointer value [-Waddress-of-packed-member] 42 | for_each_rb_entry(comp, comps) | ^~~~~ This is effectively the s390 variant of commit 20c6c1890455 ("x86/boot: Disable the address-of-packed-member compiler warning"). Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2019-06-09kconfig: make arch/*/configs/defconfig the default of KBUILD_DEFCONFIGMasahiro Yamada
Until recently, if KBUILD_DEFCONFIG was not set by the arch Makefile, the default path arch/*/defconfig was used. The last users of the default are gone by the following commits: - Commit f3e20ad67b4c ("s390: move arch/s390/defconfig to arch/s390/configs/defconfig") - Commit 986a13769c4b ("alpha: move arch/alpha/defconfig to arch/alpha/configs/defconfig") Let's set arch/*/configs/defconfig as a new default. This saves KBUILD_DEFCONFIG for some architectures. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
2019-05-14s390: move arch/s390/defconfig to arch/s390/configs/defconfigMasahiro Yamada
As of Linux 5.1, alpha and s390 are the last architectures that have defconfig in arch/*/ instead of arch/*/configs/. $ find arch -name defconfig | sort arch/alpha/defconfig arch/arm64/configs/defconfig arch/csky/configs/defconfig arch/nds32/configs/defconfig arch/riscv/configs/defconfig arch/s390/defconfig The arch/$(ARCH)/defconfig is the hard-coded default in Kconfig, and I want to deprecate it after evacuating the remaining defconfig into the standard location, arch/*/configs/. Define KBUILD_DEFCONFIG like other architectures, and move defconfig into the configs/ subdirectory. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-05-03s390: boot, purgatory: pass $(CLANG_FLAGS) where neededArnd Bergmann
The purgatory and boot Makefiles do not inherit the original cflags, so clang falls back to the default target architecture when building it, typically this would be x86 when cross-compiling. Add $(CLANG_FLAGS) everywhere so we pass the correct --target=s390x-linux option when cross-compiling. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-29s390/kernel: build a relocatable kernelGerald Schaefer
This patch adds support for building a relocatable kernel with -fPIE. The kernel will be relocated to 0 early in the boot process. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Reviewed-by: Philipp Rudo <prudo@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-04-11s390: remove -fno-strength-reduce flagArnd Bergmann
This was added as a workaround for really old compilers, and it prevents building with clang now. I can see no reason for keeping it, as it has already been removed for most architectures in the pre-git era, so let's remove it everywhere, rather than only for clang. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-11-02s390/kasan: increase instrumented stack size to 64kVasily Gorbik
Increase kasan instrumented kernel stack size from 32k to 64k. Other architectures seems to get away with just doubling kernel stack size under kasan, but on s390 this appears to be not enough due to bigger frame size. The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting stack overflow is fs sync on xfs filesystem: #0 [9a0681e8] 704 bytes check_usage at 34b1fc #1 [9a0684a8] 432 bytes check_usage at 34c710 #2 [9a068658] 1048 bytes validate_chain at 35044a #3 [9a068a70] 312 bytes __lock_acquire at 3559fe #4 [9a068ba8] 440 bytes lock_acquire at 3576ee #5 [9a068d60] 104 bytes _raw_spin_lock at 21b44e0 #6 [9a068dc8] 1992 bytes enqueue_entity at 2dbf72 #7 [9a069590] 1496 bytes enqueue_task_fair at 2df5f0 #8 [9a069b68] 64 bytes ttwu_do_activate at 28f438 #9 [9a069ba8] 552 bytes try_to_wake_up at 298c4c #10 [9a069dd0] 168 bytes wake_up_worker at 23f97c #11 [9a069e78] 200 bytes insert_work at 23fc2e #12 [9a069f40] 648 bytes __queue_work at 2487c0 #13 [9a06a1c8] 200 bytes __queue_delayed_work at 24db28 #14 [9a06a290] 248 bytes mod_delayed_work_on at 24de84 #15 [9a06a388] 24 bytes kblockd_mod_delayed_work_on at 153e2a0 #16 [9a06a3a0] 288 bytes __blk_mq_delay_run_hw_queue at 158168c #17 [9a06a4c0] 192 bytes blk_mq_run_hw_queue at 1581a3c #18 [9a06a580] 184 bytes blk_mq_sched_insert_requests at 15a2192 #19 [9a06a638] 1024 bytes blk_mq_flush_plug_list at 1590f3a #20 [9a06aa38] 704 bytes blk_flush_plug_list at 1555028 #21 [9a06acf8] 320 bytes schedule at 219e476 #22 [9a06ae38] 760 bytes schedule_timeout at 21b0aac #23 [9a06b130] 408 bytes wait_for_common at 21a1706 #24 [9a06b2c8] 360 bytes xfs_buf_iowait at fa1540 #25 [9a06b430] 256 bytes __xfs_buf_submit at fadae6 #26 [9a06b530] 264 bytes xfs_buf_read_map at fae3f6 #27 [9a06b638] 656 bytes xfs_trans_read_buf_map at 10ac9a8 #28 [9a06b8c8] 304 bytes xfs_btree_kill_root at e72426 #29 [9a06b9f8] 288 bytes xfs_btree_lookup_get_block at e7bc5e #30 [9a06bb18] 624 bytes xfs_btree_lookup at e7e1a6 #31 [9a06bd88] 2664 bytes xfs_alloc_ag_vextent_near at dfa070 #32 [9a06c7f0] 144 bytes xfs_alloc_ag_vextent at dff3ca #33 [9a06c880] 1128 bytes xfs_alloc_vextent at e05fce #34 [9a06cce8] 584 bytes xfs_bmap_btalloc at e58342 #35 [9a06cf30] 1336 bytes xfs_bmapi_write at e618de #36 [9a06d468] 776 bytes xfs_iomap_write_allocate at ff678e #37 [9a06d770] 720 bytes xfs_map_blocks at f82af8 #38 [9a06da40] 928 bytes xfs_writepage_map at f83cd6 #39 [9a06dde0] 320 bytes xfs_do_writepage at f85872 #40 [9a06df20] 1320 bytes write_cache_pages at 73dfe8 #41 [9a06e448] 208 bytes xfs_vm_writepages at f7f892 #42 [9a06e518] 88 bytes do_writepages at 73fe6a #43 [9a06e570] 872 bytes __writeback_single_inode at a20cb6 #44 [9a06e8d8] 664 bytes writeback_sb_inodes at a23be2 #45 [9a06eb70] 296 bytes __writeback_inodes_wb at a242e0 #46 [9a06ec98] 928 bytes wb_writeback at a2500e #47 [9a06f038] 848 bytes wb_do_writeback at a260ae #48 [9a06f388] 536 bytes wb_workfn at a28228 #49 [9a06f5a0] 1088 bytes process_one_work at 24a234 #50 [9a06f9e0] 1120 bytes worker_thread at 24ba26 #51 [9a06fe40] 104 bytes kthread at 26545a #52 [9a06fea8] kernel_thread_starter at 21b6b62 To be able to increase the stack size to 64k reuse LLILL instruction in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE (65192) value as unsigned. Reported-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-10-09s390/kasan: double the stack sizeVasily Gorbik
Kasan stack instrumentation pads stack variables with redzones, which increases stack frames size significantly. Stack sizes are increased from 16k to 32k in the code, as well as for the kernel stack overflow detection option (CHECK_STACK). Reviewed-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>
2018-08-24kbuild: rename LDFLAGS to KBUILD_LDFLAGSMasahiro Yamada
Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add additional options to CC") renamed CFLAGS to KBUILD_CFLAGS. Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add additional options to AS") renamed AFLAGS to KBUILD_AFLAGS. Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS. For some reason, LDFLAGS was not renamed. Using a well-known variable like LDFLAGS may result in accidental override of the variable. Kbuild generally uses KBUILD_ prefixed variables for the internally appended options, so here is one more conversion to sanitize the naming convention. I did not touch Makefiles under tools/ since the tools build system is a different world. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-20Merge tag 'trace-v4.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - Restructure of lockdep and latency tracers This is the biggest change. Joel Fernandes restructured the hooks from irqs and preemption disabling and enabling. He got rid of a lot of the preprocessor #ifdef mess that they caused. He turned both lockdep and the latency tracers to use trace events inserted in the preempt/irqs disabling paths. But unfortunately, these started to cause issues in corner cases. Thus, parts of the code was reverted back to where lockdep and the latency tracers just get called directly (without using the trace events). But because the original change cleaned up the code very nicely we kept that, as well as the trace events for preempt and irqs disabling, but they are limited to not being called in NMIs. - Have trace events use SRCU for "rcu idle" calls. This was required for the preempt/irqs off trace events. But it also had to not allow them to be called in NMI context. Waiting till Paul makes an NMI safe SRCU API. - New notrace SRCU API to allow trace events to use SRCU. - Addition of mcount-nop option support - SPDX headers replacing GPL templates. - Various other fixes and clean ups. - Some fixes are marked for stable, but were not fully tested before the merge window opened. * tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits) tracing: Fix SPDX format headers to use C++ style comments tracing: Add SPDX License format tags to tracing files tracing: Add SPDX License format to bpf_trace.c blktrace: Add SPDX License format header s390/ftrace: Add -mfentry and -mnop-mcount support tracing: Add -mcount-nop option support tracing: Avoid calling cc-option -mrecord-mcount for every Makefile tracing: Handle CC_FLAGS_FTRACE more accurately Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Uprobes: Simplify uprobe_register() body tracepoints: Free early tracepoints after RCU is initialized uprobes: Use synchronize_rcu() not synchronize_sched() tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister() ftrace: Remove unused pointer ftrace_swapper_pid tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing/irqsoff: Handle preempt_count for different configs tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing: irqsoff: Account for additional preempt_disable trace: Use rcu_dereference_raw for hooks from trace-event subsystem tracing/kprobes: Fix within_notrace_func() to check only notrace functions ...
2018-08-15s390/ftrace: Add -mfentry and -mnop-mcount supportVasily Gorbik
Utilize -mfentry and -mnop-mcount gcc options together with -mrecord-mcount to get compiler generated calls to the profiling functions as nops which are compatible with current -mhotpatch=0,3 approach. At the same time -mrecord-mcount enables __mcount_loc section generation by the compiler which allows to avoid using scripts/recordmcount.pl script. Link: http://lkml.kernel.org/r/patch-4.thread-aa7b8d.git-aa7b8dbf236f.your-ad-here.call-01533557518-ext-9465@work.hours Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-07-02s390/decompressor: support extra debug flagsVasily Gorbik
Since decompressor cflags and aflags are made from scratch add extra debug flags when CONFIG_DEBUG_INFO is enabled. Also adds support for CONFIG_DEBUG_INFO_DWARF4 option. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/boot: make head.S and als.c be part of the decompressor onlyVasily Gorbik
Since uncompressed kernel image does not have to be bootable anymore, move head.S, head_kdump.S and als.c to boot/ folder and compile them in just in the decompressor. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390: remove uncompressed kernel image buildVasily Gorbik
Dropping support for uncompressed kernel "image" build. Having both image and bzImage makes it complicated to add new code to an early boot phase (which is part of vmlinux for uncompressed kernel and a separate arch/s390/boot/compressed/vmlinux for bzImage). e.g. sclp_early_core.o is used for both, the decompressor phase and the main kernel. The fact of having uncompressed kernel "image" forces us to have a single object file and sacrifice instrumentation flags on such files (so that we could use them early). The story gets much more complicated with the need to utilize some of the string functions. With bzImage only support, we have 2 separate boot stages each built and linked separately, which allows to reuse some shared code, but recompile with appropriate flags. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/decompressor: correct build flagsVasily Gorbik
The decompressor requires its own set of cc and asm flags, to avoid building with features which do not make sense at such an early boot stage (e.g. expoline, ftrace). Currently cc flags are already set for the decompressor, but "cflags-y" is not exported and hence empty. To fix that and to add asm flags, define and export KBUILD_AFLAGS_DECOMPRESSOR and KBUILD_CFLAGS_DECOMPRESSOR and rely on them in the decompressor's Makefile. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390/build: remove obsolete -mkernel-backchain flagVasily Gorbik
-mkernel-backchain cc flag is obsolete since quite a while, and not present in minimal (supported by s390) gcc version 4.3. Removing it. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-06-25s390: disable asm code expolines if cc does not support itVasily Gorbik
To avoid a mixture of asm code with expolines and c code without them, propagate CC_USING_EXPOLINE to KBUILD_AFLAGS and use it to detect whether asm code should have expolines or not. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-05-29kbuild: add endianness flag to CHEKCFLAGSLuc Van Oostenryck
The kernel depends on macros like __BYTE_ORDER__, __BIG_ENDIAN__ or __LITTLE_ENDIAN__. OTOH, sparse doesn't know about the endianness of the kernel and by default uses the same as the machine on which sparse was built. Ensure that sparse can predefine the macros corresponding to how the kernel was configured by adding -m{big,little}-endian to CHECKFLAGS in the main Makefile (and so for all archs). Also, remove the equivalent done in arch specific Makefiles. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-03-28s390: add automatic detection of the spectre defenseMartin Schwidefsky
Automatically decide between nobp vs. expolines if the spectre_v2=auto kernel parameter is specified or CONFIG_EXPOLINE_AUTO=y is set. The decision made at boot time due to CONFIG_EXPOLINE_AUTO=y being set can be overruled with the nobp, nospec and spectre_v2 kernel parameters. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-02-27s390: set bzImage as default image for packagingVasily Gorbik
Even though s390 compressed kernel support has been introduced long ago, by default uncompressed kernel image is used by packaging targets like: "make rpm-pkg", "make deb-pkg" as well as "make image_name". At the same time "make install" would use compressed bzImage by default. To avoid ambiguity, set bzImage as default image for packaging. Signed-off-by: Vasily Gorbik <gor@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-02-07s390: introduce execute-trampolines for branchesMartin Schwidefsky
Add CONFIG_EXPOLINE to enable the use of the new -mindirect-branch= and -mfunction_return= compiler options to create a kernel fortified against the specte v2 attack. With CONFIG_EXPOLINE=y all indirect branches will be issued with an execute type instruction. For z10 or newer the EXRL instruction will be used, for older machines the EX instruction. The typical indirect call basr %r14,%r1 is replaced with a PC relative call to a new thunk brasl %r14,__s390x_indirect_jump_r1 The thunk contains the EXRL/EX instruction to the indirect branch __s390x_indirect_jump_r1: exrl 0,0f j . 0: br %r1 The detour via the execute type instruction has a performance impact. To get rid of the detour the new kernel parameter "nospectre_v2" and "spectre_v2=[on,off,auto]" can be used. If the parameter is specified the kernel and module code will be patched at runtime. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-01-23s390/tools: generate header files in arch/s390/include/generated/Hendrik Brueckner
Previously, the generated dis.h and facilities.h header files have been stored in include/generated. Because they are s390 specific, store them in the arch/s390/include/generated/asm/ directory. Also update references to the header files respectively. To prevent name collisions with those header files in asm/ that include the generated ones, rename the generated headers files and add an -defs suffix. Also update the generators to create the ifdef guards respectively. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-01-23s390/syscalls: add Makefile to generate system call header filesHendrik Brueckner
Generate the system call specific files from the archheaders and archprepare make targets. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-12-13s390/vdso: revise CFI annotations of vDSO functionsHendrik Brueckner
Revise and add CFI CFA and register rule annotations to the vDSO functions for proper stack unwinding and debugging. Because glibc might call the vDSO in special ways, the vDSO code does not rely on a stack frame created by the caller. The TOD clock value can be therefore not stored in the pre-allocated stack area and additional stack space is required. To correctly annotate these situations with CFI, the .cfi_val_offset directive is required to create relative offsets on the value of the stack register %r15. Because the .cfi_val_offset directive is available with recent GNU assembler versions only, additional checks are necessary. Note that if the vDSO is assembled with an older assembler version, stack unwinding and debugging from within the vDSO code might not be possible. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-12-13s390/kernel: emit CFI data in .debug_frame and discard .eh_frame sectionsHendrik Brueckner
Using perf probe and libdw on kernel modules failed to find CFI data for symbols. The CFI data is stored in the .eh_frame section. The elfutils libdw is not able to extract the CFI data correctly, because the .eh_frame section requires "non-simple" relocations for kernel modules. The suggestion is to avoid these "non-simple" relocations by emitting the CFI data in the .debug_frame section. Let gcc emit respective directives by specifying the -fno-asynchronous-unwind-tables option. Using the .debug_frame section for CFI data, the .eh_frame section becomes unused and, thus, discard it for kernel and modules builds The vDSO requires the .eh_frame section and, hence, emit the CFI data in both, the .eh_frame and .debug_frame sections. See also discussion on elfutils/libdw bugzilla: https://sourceware.org/bugzilla/show_bug.cgi?id=22452 Suggested-by: Mark Wielaard <mark@klomp.org> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24s390: Remove redundant license textGreg Kroah-Hartman
Now that the SPDX tag is in all arch/s390/ files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording in the remaining files can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-24s390: add SPDX identifiers to the remaining filesGreg Kroah-Hartman
It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the remaining arch/s390/ files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-08s390/disassembler: generate opcode tables from text fileHeiko Carstens
The current way of adding new instructions to the opcode tables is painful and error prone. Therefore add, similar to binutils, a text file which contains all opcodes and the corresponding mnemonics and instruction formats. A small gen_opcode_table tool then generates a header file with the required enums and opcode table initializers at the prepare step of the kernel build. This way only a simple text file has to be maintained, which can be rather easily extended. Unlike before where there were plenty of opcode tables and a large switch statement to find the correct opcode table, there is now only one opcode table left which contains all instructions. A second opcode offset table now contains offsets within the opcode table to find instructions which have the same opcode prefix. In order to save space all 1-byte opcode instructions are grouped together at the end of the opcode table. This is also quite similar to like it was before. In addition also move and change code and definitions within the disassembler. As a side effect this reduces the size required for the code and opcode tables by ~1.5k. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2017-11-02s390: pass endianness info to sparseLuc Van Oostenryck
s390 is big-endian only but sparse assumes the same endianness as the building machine. This is problematic for code which expect __BYTE_ORDER__ being correctly predefined by the compiler which sparse can then pre-process differently from what gcc would, depending on the building machine endianness. Fix this by letting sparse know about the architecture endianness. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-07-26s390: add support for IBM z14 machinesMartin Schwidefsky
Add detection for machine type 0x3906 and set the ELF platform name to z14. Add the miscellaneous-instruction-extension 2 facility to the list of facilities for z14. And allow to generate code that only runs on a z14 machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-09-06s390: add assembler include path for vx-insn.hMartin Schwidefsky
With git commit 0eab11c7e0d30de14a15ccd8269eef238321a8e1 "s390/vx: allow to include vx-insn.h with .include" and an older gcc we get errors like this: {standard input}:6: Error: can't open asm/vx-insn.h for reading: No such file or directory arch/s390/kernel/fpu.c:57: Error: Unrecognized opcode: `vstm' To solve this issue simply add the path to arch/s390/include to all assembler runs. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-12-18s390/facilities: add helper tool to generate facility listsHeiko Carstens
Modifying the architecture level set facility lists was always very error prone. Given the numbering of the facility bits within the Principles of Operation, where the most significant bit number is 0, it happened a lot of times that wrong bits were set or cleared. Therefore this patch adds a tool "gen_facilities" which generates include/generated/facilites.h. The definition of the bits to be set is contained within arch/s390/include/asm/facilities_src.h and can be easily extended to e.g. also generate such lists for the KVM module. The generated file looks like this: #define FACILITIES_ALS _AC(0xc1006450f0040000,UL) #define FACILITIES_ALS_DWORDS 1 The facility bits defined in this patch match 1:1 to the current masks that can be found in head.S. That is if the tool gets executed with -march=z990 then the generated masks will equal the masks in head.S for CONFIG_MARCH_Z990. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-27s390: add 'install' target to 'make help'Michael Holzheu
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-07-29s390/sclp: convert early sclp console code to CMartin Schwidefsky
The 31-bit assembler code for the early sclp console is error prone as git commit fde24b54d976cc123506695c17db01438a11b673 "s390/sclp: clear upper register halves in _sclp_print_early" has shown. Convert the assembler code to C. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-03-25s390: remove 31 bit supportHeiko Carstens
Remove the 31 bit support in order to reduce maintenance cost and effectively remove dead code. Since a couple of years there is no distribution left that comes with a 31 bit kernel. The 31 bit kernel also has been broken since more than a year before anybody noticed. In addition I added a removal warning to the kernel shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning message") which let everybody know about the plan to remove 31 bit code. We didn't get any response. Given that the last 31 bit only machine was introduced in 1999 let's remove the code. Anybody with 31 bit user space code can still use the compat mode. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-01-29s390/ftrace: hotpatch support for function tracingHeiko Carstens
Make use of gcc's hotpatch support to generate better code for ftrace function tracing. The generated code now contains only a six byte nop in each function prologue instead of a 24 byte code block which will be runtime patched to support function tracing. With the new code generation the runtime overhead for supporting function tracing is close to zero, while the original code did show a significant performance impact. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-01-22s390: add z13 code generation supportMartin Schwidefsky
Allow to generate code that only runs on z13 machines. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-09-09s390: pass march flag to assembly files as wellHeiko Carstens
Currently the march flag gets only passed to C files, but not to assembler files. This means that we can't add new instructions like e.g. aghik to asm files, since the assembler doesn't know of the new instructions if the appropriate march flag isn't specified. So also pass the march flag when compiling assembler files as well. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-10-31s390: allow to set gcc -mtune flagHeiko Carstens
Add a new Kconfig choice group which allows to configure how gcc should tune the generated code (via -mtune option). By default the -mtune parameter will match the -march parameter. This is a rather large patch, but I wouldn't know how to make this shorter unfortunately. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-10-24s390: always set -march compiler optionHeiko Carstens
Currently we only set the -march compiler option if the kbuild system figured out that the compiler actually supports the selected architecture (cc-option test). In result this means that no -march compiler option is set when an unsupported cpu architecture of the current compiler is selected. The kernel compile will afterwards succeed but with the default architecture instead of the (unsupported) selected one. Change this behaviour, so compiles will fail if the compiler does not support the selected cpu architecture. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-04-26s390: remove small stack config optionHeiko Carstens
We've seen repeatedly that 8KB stack size on 64 bit kernels is not sufficient. So simply remove the config option. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-01-12s390: use -fPIC for module compileMartin Schwidefsky
The xfs module uses a lot of tracepoint, with TRACEPOINTS=y and a few debugging options the GOT table of the xfs module will get bigger than 4K. To get a working xfs module it needs to be compiled with -fPIC instead of -fpic. To play safe use -fPIC for all modules. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-11-23s390: add zEC12 code generation supportHeiko Carstens
Allow to generate code that only runs on zEC12 machines. Also add a check which prevents the kernel to run on machines which do not have any of the following new facilities installed: - (48) decimal-floating-point zoned-conversion - (49) execution-hint - (49) load-and-trap - (49) miscellaneous-instruction-extensions - (49) processor-assist - (50) constrained transactional-execution - (73) transactional-execution 48, 49, 50 and 73 are the bit numbers of the facility indications for each of the required facilities. Note that we assume that user-space gets compiled with the same compiler options, therefore we also test for a dfp facility even if the kernel doesn't make use of it. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>