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* s390: enforce CONFIG_SMPHeiko Carstens2019-06-071-4/+0
| | | | | | | | | | | | | There never have been distributions that shiped with CONFIG_SMP=n for s390. In addition the kernel currently doesn't even compile with CONFIG_SMP=n for s390. Most likely it wouldn't even work, even if we fix the compile error, since nobody tests it, since there is no use case that I can think of. Therefore simply enforce CONFIG_SMP and get rid of some more or less unused code. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* s390: add missing ENDPROC statements to assembler functionsMartin Schwidefsky2019-05-021-2/+22
| | | | | | | The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/kernel: convert SYSCALL and PGM_CHECK handlers to .quadGerald Schaefer2019-04-291-9/+9
| | | | | | | | | | With a relocatable kernel that could reside at any place in memory, the storage size for the SYSCALL and PGM_CHECK handlers needs to be increased from .long to .quad. 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>
* s390: autogenerate compat syscall wrappersArnd Bergmann2019-01-181-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Any system call that takes a pointer argument on s390 requires a wrapper function to do a 31-to-64 zero-extension, these are currently generated in arch/s390/kernel/compat_wrapper.c. On arm64 and x86, we already generate similar wrappers for all system calls in the place of their definition, just for a different purpose (they load the arguments from pt_regs). We can do the same thing here, by adding an asm/syscall_wrapper.h file with a copy of all the relevant macros to override the generic version. Besides the addition of the compat entry point, these also rename the entry points with a __s390_ or __s390x_ prefix, similar to what we do on arm64 and x86. This in turn requires renaming a few things, and adding a proper ni_syscall() entry point. In order to still compile system call definitions that pass an loff_t argument, the __SC_COMPAT_CAST() macro checks for that and forces an -ENOSYS error, which was the best I could come up with. Those functions must obviously not get called from user space, but instead require hand-written compat_sys_*() handlers, which fortunately already exist. Link: https://lore.kernel.org/lkml/20190116131527.2071570-5-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> [heiko.carstens@de.ibm.com: compile fix for !CONFIG_COMPAT] Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/kasan: increase instrumented stack size to 64kVasily Gorbik2018-11-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* s390: add support for virtually mapped kernel stacksMartin Schwidefsky2018-10-091-17/+36
| | | | | | | | | | | | | | | | | | | | | With virtually mapped kernel stacks the kernel stack overflow detection is now fault based, every stack has a guard page in the vmalloc space. The panic_stack is renamed to nodat_stack and is used for all function that need to run without DAT, e.g. memcpy_real or do_start_kdump. The main effect is a reduction in the kernel image size as with vmap stacks the old style overflow checking that adds two instructions per function is not needed anymore. Result from bloat-o-meter: add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042) In regard to performance the micro-benchmark for fork has a hit of a few microseconds, allocating 4 pages in vmalloc space is more expensive compare to an order-2 page allocation. But with real workload I could not find a noticeable difference. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: wire up rseq system callHeiko Carstens2018-07-041-0/+4
| | | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: Correct register corruption in critical section cleanupChristian Borntraeger2018-06-251-2/+2
| | | | | | | | | | | | | | | | In the critical section cleanup we must not mess with r1. For march=z9 or older, larl + ex (instead of exrl) are used with r1 as a temporary register. This can clobber r1 in several interrupt handlers. Fix this by using r11 as a temp register. r11 is being saved by all callers of cleanup_critical. Fixes: 6dd85fbb87 ("s390: move expoline assembler macros to a header") Cc: stable@vger.kernel.org #v4.16 Reported-by: Oliver Kurz <okurz@suse.com> Reported-by: Petr Tesařík <ptesarik@suse.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: move expoline assembler macros to a headerMartin Schwidefsky2018-05-071-81/+24
| | | | | | | | | | | | To be able to use the expoline branches in different assembler files move the associated macros from entry.S to a new header nospec-insn.h. While we are at it make the macros a bit nicer to use. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2018-04-091-70/+26
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Martin Schwidefsky: - Improvements for the spectre defense: * The spectre related code is consolidated to a single file nospec-branch.c * Automatic enable/disable for the spectre v2 defenses (expoline vs. nobp) * Syslog messages for specve v2 are added * Enable CONFIG_GENERIC_CPU_VULNERABILITIES and define the attribute functions for spectre v1 and v2 - Add helper macros for assembler alternatives and use them to shorten the code in entry.S. - Add support for persistent configuration data via the SCLP Store Data interface. The H/W interface requires a page table that uses 4K pages only, the code to setup such an address space is added as well. - Enable virtio GPU emulation in QEMU. To do this the depends statements for a few common Kconfig options are modified. - Add support for format-3 channel path descriptors and add a binary sysfs interface to export the associated utility strings. - Add a sysfs attribute to control the IFCC handling in case of constant channel errors. - The vfio-ccw changes from Cornelia. - Bug fixes and cleanups. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (40 commits) s390/kvm: improve stack frame constants in entry.S s390/lpp: use assembler alternatives for the LPP instruction s390/entry.S: use assembler alternatives s390: add assembler macros for CPU alternatives s390: add sysfs attributes for spectre s390: report spectre mitigation via syslog s390: add automatic detection of the spectre defense s390: move nobp parameter functions to nospec-branch.c s390/cio: add util_string sysfs attribute s390/chsc: query utility strings via fmt3 channel path descriptor s390/cio: rename struct channel_path_desc s390/cio: fix unbind of io_subchannel_driver s390/qdio: split up CCQ handling for EQBS / SQBS s390/qdio: don't retry EQBS after CCQ 96 s390/qdio: restrict buffer merging to eligible devices s390/qdio: don't merge ERROR output buffers s390/qdio: simplify math in get_*_buffer_frontier() s390/decompressor: trim uncompressed image head during the build s390/crypto: Fix kernel crash on aes_s390 module remove. s390/defkeymap: fix global init to zero ...
| * s390/kvm: improve stack frame constants in entry.SMartin Schwidefsky2018-03-281-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | The code in sie64a uses the stack frame passed to the function to store some temporary data in the empty1 array (see struct stack_frame in asm/processor.h. Replace the __SF_EMPTY+x constants with a properly defined offset: s/__SF_EMPTY/__SF_SIE_CONTROL/, s/__SF_EMPTY+8/__SF_SIE_SAVEAREA/, s/__SF_EMPTY+16/__SF_SIE_REASON/, s/__SF_EMPTY+24/__SF_SIE_FLAGS/. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| * s390/lpp: use assembler alternatives for the LPP instructionMartin Schwidefsky2018-03-281-8/+6
| | | | | | | | | | | | | | | | With the new macros for CPU alternatives the MACHINE_FLAG_LPP check around the LPP instruction can be optimized. After this is done the flag can be removed. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| * s390/entry.S: use assembler alternativesMartin Schwidefsky2018-03-281-49/+7
| | | | | | | | | | | | | | | | Replace the open coded alternatives for the BPOFF, BPON, BPENTER, and BPEXIT macros with the new magic from asm/alternatives-asm.h to make the code easier to read. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/entry.S: fix spurious zeroing of r0Christian Borntraeger2018-03-061-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | when a system call is interrupted we might call the critical section cleanup handler that re-does some of the operations. When we are between .Lsysc_vtime and .Lsysc_do_svc we might also redo the saving of the problem state registers r0-r7: .Lcleanup_system_call: [...] 0: # update accounting time stamp mvc __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER # set up saved register r11 lg %r15,__LC_KERNEL_STACK la %r9,STACK_FRAME_OVERHEAD(%r15) stg %r9,24(%r11) # r11 pt_regs pointer # fill pt_regs mvc __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC ---> stmg %r0,%r7,__PT_R0(%r9) The problem is now, that we might have already zeroed out r0. The fix is to move the zeroing of r0 after sysc_do_svc. Reported-by: Farhan Ali <alifm@linux.vnet.ibm.com> Fixes: 7041d28115e91 ("s390: scrub registers on kernel entry and KVM exit") Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: do not bypass BPENTER for interrupt system callsMartin Schwidefsky2018-02-221-0/+1
| | | | | | | | | | | The system call path can be interrupted before the switch back to the standard branch prediction with BPENTER has been done. The critical section cleanup code skips forward to .Lsysc_do_svc and bypasses the BPENTER. In this case the kernel and all subsequent code will run with the limited branch prediction. Fixes: eacf67eb9b32 ("s390: run user space and KVM guests with modified branch prediction") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/clean-up: use CFI_* macros in entry.SHendrik Brueckner2018-02-221-2/+3
| | | | | | | | | | | | Commit f19fbd5ed642 ("s390: introduce execute-trampolines for branches") introduces .cfi_* assembler directives. Instead of using the directives directly, use the macros from asm/dwarf.h. This also ensures that the dwarf debug information are created in the .debug_frame section. Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches") Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: introduce execute-trampolines for branchesMartin Schwidefsky2018-02-071-25/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* s390: run user space and KVM guests with modified branch predictionMartin Schwidefsky2018-02-051-5/+46
| | | | | | | | | | | | | Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary plumbing in entry.S to be able to run user space and KVM guests with limited branch prediction. To switch a user space process to limited branch prediction the s390_isolate_bp() function has to be call, and to run a vCPU of a KVM guest associated with the current task with limited branch prediction call s390_isolate_bp_guest(). Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: add options to change branch prediction behaviour for the kernelMartin Schwidefsky2018-02-051-0/+48
| | | | | | | | | | | | Add the PPA instruction to the system entry and exit path to switch the kernel to a different branch prediction behaviour. The instructions are added via CPU alternatives and can be disabled with the "nospec" or the "nobp=0" kernel parameter. If the default behaviour selected with CONFIG_KERNEL_NOBP is set to "n" then the "nobp=1" parameter can be used to enable the changed kernel branch prediction. Acked-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: scrub registers on kernel entry and KVM exitMartin Schwidefsky2018-02-051-0/+47
| | | | | | | | | Clear all user space registers on entry to the kernel and all KVM guest registers on KVM guest exit if the register does not contain either a parameter or a result value. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/syscalls: use generated syscall_table.h and unistd.h header filesHendrik Brueckner2018-01-231-2/+2
| | | | | | | | | | | Update the uapi/asm/unistd.h to include the generated compat and 64-bit version of the unistd.h and, as well as, the unistd_nr.h header file. Also remove the arch/s390/kernel/syscalls.S file and use the generated system call table, syscall_table.h, instead. 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>
* s390: rework __switch_to() to allow larger task_struct offsetsHeiko Carstens2017-11-201-8/+7
| | | | | | | | | | | | | If GCC_PLUGIN_RANDSTRUCT is enabled the members of task_struct will be shuffled around. The offsets of the "pid" and "stack" members within task_struct may not necessarily fit into 12 bits anymore, which causes compile errors within __switch_to, since instructions are used, which only have a 12 bit displacement field. Therefore rework __switch_to, to allow for larger offsets. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: remove all code using the access register modeMartin Schwidefsky2017-11-141-5/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The vdso code for the getcpu() and the clock_gettime() call use the access register mode to access the per-CPU vdso data page with the current code. An alternative to the complicated AR mode is to use the secondary space mode. This makes the vdso faster and quite a bit simpler. The downside is that the uaccess code has to be changed quite a bit. Which instructions are used depends on the machine and what kind of uaccess operation is requested. The instruction dictates which ASCE value needs to be loaded into %cr1 and %cr7. The different cases: * User copy with MVCOS for z10 and newer machines The MVCOS instruction can copy between the primary space (aka user) and the home space (aka kernel) directly. For set_fs(KERNEL_DS) the kernel ASCE is loaded into %cr1. For set_fs(USER_DS) the user space is already loaded in %cr1. * User copy with MVCP/MVCS for older machines To be able to execute the MVCP/MVCS instructions the kernel needs to switch to primary mode. The control register %cr1 has to be set to the kernel ASCE and %cr7 to either the kernel ASCE or the user ASCE dependent on set_fs(KERNEL_DS) vs set_fs(USER_DS). * Data access in the user address space for strnlen / futex To use "normal" instruction with data from the user address space the secondary space mode is used. The kernel needs to switch to primary mode, %cr1 has to contain the kernel ASCE and %cr7 either the user ASCE or the kernel ASCE, dependent on set_fs. To load a new value into %cr1 or %cr7 is an expensive operation, the kernel tries to be lazy about it. E.g. for multiple user copies in a row with MVCP/MVCS the replacement of the vdso ASCE in %cr7 with the user ASCE is done only once. On return to user space a CPU bit is checked that loads the vdso ASCE again. To enable and disable the data access via the secondary space two new functions are added, enable_sacf_uaccess and disable_sacf_uaccess. The fact that a context is in secondary space uaccess mode is stored in the mm_segment_t value for the task. The code of an interrupt may use set_fs as long as it returns to the previous state it got with get_fs with another call to set_fs. The code in finish_arch_post_lock_switch simply has to do a set_fs with the current mm_segment_t value for the task. For CPUs with MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode, lazy | user | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | For CPUs without MVCOS: CPU running in | %cr1 ASCE | %cr7 ASCE | --------------------------------------|-----------|-----------| user space | user | vdso | kernel, USER_DS, normal-mode | user | vdso | kernel, USER_DS, normal-mode lazy | kernel | user | kernel, USER_DS, sacf-mode | kernel | user | kernel, KERNEL_DS, normal-mode | kernel | vdso | kernel, KERNEL_DS, normal-mode, lazy | kernel | kernel | kernel, KERNEL_DS, sacf-mode | kernel | kernel | The lines with "lazy" refer to the state after a copy via the secondary space with a delayed reload of %cr1 and %cr7. There are three hardware address spaces that can cause a DAT exception, primary, secondary and home space. The exception can be related to four different fault types: user space fault, vdso fault, kernel fault, and the gmap faults. Dependent on the set_fs state and normal vs. sacf mode there are a number of fault combinations: 1) user address space fault via the primary ASCE 2) gmap address space fault via the primary ASCE 3) kernel address space fault via the primary ASCE for machines with MVCOS and set_fs(KERNEL_DS) 4) vdso address space faults via the secondary ASCE with an invalid address while running in secondary space in problem state 5) user address space fault via the secondary ASCE for user-copy based on the secondary space mode, e.g. futex_ops or strnlen_user 6) kernel address space fault via the secondary ASCE for user-copy with secondary space mode with set_fs(KERNEL_DS) 7) kernel address space fault via the primary ASCE for user-copy with secondary space mode with set_fs(USER_DS) on machines without MVCOS. 8) kernel address space fault via the home space ASCE Replace user_space_fault() with a new function get_fault_type() that can distinguish all four different fault types. With these changes the futex atomic ops from the kernel and the strnlen_user will get a little bit slower, as well as the old style uaccess with MVCP/MVCS. All user accesses based on MVCOS will be as fast as before. On the positive side, the user space vdso code is a lot faster and Linux ceases to use the complicated AR mode. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* s390/mm,kvm: improve detection of KVM guest faultsMartin Schwidefsky2017-11-141-2/+5
| | | | | | | | | | | | | | | The identification of guest fault currently relies on the PF_VCPU flag. This is set in guest_entry_irqoff and cleared in guest_exit_irqoff. Both functions are called by __vcpu_run, the PF_VCPU flag is set for quite a lot of kernel code outside of the guest execution. Replace the PF_VCPU scheme with the PIF_GUEST_FAULT in the pt_regs and make the program check handler code in entry.S set the bit only for exception that occurred between the .Lsie_gmap and .Lsie_done labels. 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>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-11-131-7/+53
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 updates from Heiko Carstens: "Since Martin is on vacation you get the s390 pull request for the v4.15 merge window this time from me. Besides a lot of cleanups and bug fixes these are the most important changes: - a new regset for runtime instrumentation registers - hardware accelerated AES-GCM support for the aes_s390 module - support for the new CEX6S crypto cards - support for FORTIFY_SOURCE - addition of missing z13 and new z14 instructions to the in-kernel disassembler - generate opcode tables for the in-kernel disassembler out of a simple text file instead of having to manually maintain those tables - fast memset16, memset32 and memset64 implementations - removal of named saved segment support - hardware counter support for z14 - queued spinlocks and queued rwlocks implementations for s390 - use the stack_depth tracking feature for s390 BPF JIT - a new s390_sthyi system call which emulates the sthyi (store hypervisor information) instruction - removal of the old KVM virtio transport - an s390 specific CPU alternatives implementation which is used in the new spinlock code" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (88 commits) MAINTAINERS: add virtio-ccw.h to virtio/s390 section s390/noexec: execute kexec datamover without DAT s390: fix transactional execution control register handling s390/bpf: take advantage of stack_depth tracking s390: simplify transactional execution elf hwcap handling s390/zcrypt: Rework struct ap_qact_ap_info. s390/virtio: remove unused header file kvm_virtio.h s390: avoid undefined behaviour s390/disassembler: generate opcode tables from text file s390/disassembler: remove insn_to_mnemonic() s390/dasd: avoid calling do_gettimeofday() s390: vfio-ccw: Do not attempt to free no-op, test and tic cda. s390: remove named saved segment support s390/archrandom: Reconsider s390 arch random implementation s390/pci: do not require AIS facility s390/qdio: sanitize put_indicator s390/qdio: use atomic_cmpxchg s390/nmi: avoid using long-displacement facility s390: pass endianness info to sparse s390/decompressor: remove informational messages ...
| * s390/nmi: avoid using long-displacement facilityVasily Gorbik2017-11-021-1/+1
| | | | | | | | | | | | | | | | | | | | __LC_MCESAD is currently 4528 /* offsetof(struct lowcore, mcesad) */ that would require long-displacement facility for lg, which we don't have on z900. Fixes: 3037a52f9846 ("s390/nmi: do register validation as early as possible") Signed-off-by: Vasily Gorbik <gor@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| * s390/nmi: do register validation as early as possibleMartin Schwidefsky2017-10-191-7/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The validation of the CPU registers in the machine check handler is currently split into two parts. The first part is done at the start of the low level mcck_int_handler function, this includes the CPU timer register and the general purpose registers. The second part is done a bit later in s390_do_machine_check for all the other registers, including the control registers, floating pointer control, vector or floating pointer registers, the access registers, the guarded storage registers, the TOD programmable registers and the clock comparator. This is working fine to far but in theory a future extensions could cause the C code to use registers that are not validated yet. A better approach is to validate all CPU registers in "safe" assembler code before any C function is called. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | Merge tag 'spdx_identifiers-4.14-rc8' of ↵Linus Torvalds2017-11-021-0/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull initial SPDX identifiers from Greg KH: "License cleanup: add SPDX license identifiers to some files 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>" * tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: License cleanup: add SPDX license identifier to uapi header files with a license License cleanup: add SPDX license identifier to uapi header files with no license License cleanup: add SPDX GPL-2.0 license identifier to files with no license
| * | License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* / s390/kvm: fix detection of guest machine checksMartin Schwidefsky2017-10-251-2/+5
|/ | | | | | | | | | | | | | | | | | | | The new detection code for guest machine checks added a check based on %r11 to .Lcleanup_sie to distinguish between normal asynchronous interrupts and machine checks. But the funtion is called from the program check handler as well with an undefined value in %r11. The effect is that all program exceptions pointing to the SIE instruction will set the CIF_MCCK_GUEST bit. The bit stays set for the CPU until the next machine check comes in which will incorrectly be interpreted as a guest machine check. The simplest fix is to stop using .Lcleanup_sie in the program check handler and duplicate a few instructions. Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest") Cc: <stable@vger.kernel.org> # v4.13+ Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge tag 'nmiforkvm' of ↵Martin Schwidefsky2017-06-281-1/+12
|\ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into features Pull kvm patches from Christian Borntraeger: "s390,kvm: provide plumbing for machines checks when running guests" This provides the basic plumbing for handling machine checks when running guests
| * s390/nmi: s390: New low level handling for machine check happening in guestQingFeng Hao2017-06-271-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the logic to check if the machine check happens when the guest is running. If yes, set the exit reason -EINTR in the machine check's interrupt handler. Refactor s390_do_machine_check to avoid panicing the host for some kinds of machine checks which happen when guest is running. Reinject the instruction processing damage's machine checks including Delayed Access Exception instead of damaging the host if it happens in the guest because it could be caused by improper update on TLB entry or other software case and impacts the guest only. Signed-off-by: QingFeng Hao <haoqf@linux.vnet.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
* | s390/fpu: export save_fpu_regs for all configsMartin Schwidefsky2017-06-131-2/+0
| | | | | | | | | | | | | | | | The save_fpu_regs function is a general API that is supposed to be usable for modules as well. Remove the #ifdef that hides the symbol for CONFIG_KVM=n. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/kvm: avoid global config of vm.alloc_pgste=1Martin Schwidefsky2017-06-131-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The system control vm.alloc_pgste is used to control the size of the page tables, either 2K or 4K. The idea is that a KVM host sets the vm.alloc_pgste control to 1 which causes *all* new processes to run with 4K page tables. For a non-kvm system the control should stay off to save on memory used for page tables. Trouble is that distributions choose to set the control globally to be able to run KVM guests. This wastes memory on non-KVM systems. Introduce the PT_S390_PGSTE ELF segment type to "mark" the qemu executable with it. All executables with this (empty) segment in its ELF phdr array will be started with 4K page tables. Any executable without PT_S390_PGSTE will run with the default 2K page tables. This removes the need to set vm.alloc_pgste=1 for a KVM host and minimizes the waste of memory for page tables. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/kvm: do not rely on the ILC on kvm host protection faulsChristian Borntraeger2017-05-171-6/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For most cases a protection exception in the host (e.g. copy on write or dirty tracking) on the sie instruction will indicate an instruction length of 4. Turns out that there are some corner cases (e.g. runtime instrumentation) where this is not necessarily true and the ILC is unpredictable. Let's replace our 4 byte rewind_pad with 3 byte nops to prepare for all possible ILCs. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/cputime: fix incorrect system timeMartin Schwidefsky2017-05-031-3/+18
|/ | | | | | | | | | | | | | | | | | git commit c5328901aa1db134 "[S390] entry[64].S improvements" removed the update of the exit_timer lowcore field from the critical section cleanup of the .Lsysc_restore/.Lsysc_done and .Lio_restore/.Lio_done blocks. If the PSW is updated by the critical section cleanup to point to user space again, the interrupt entry code will do a vtime calculation after the cleanup completed with an exit_timer value which has *not* been updated. Due to this incorrect system time deltas are calculated. If an interrupt occured with an old PSW between .Lsysc_restore/.Lsysc_done or .Lio_restore/.Lio_done update __LC_EXIT_TIMER with the system entry time of the interrupt. Cc: stable@vger.kernel.org # 3.3+ Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-05-021-1/+29
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching Pull livepatch updates from Jiri Kosina: - a per-task consistency model is being added for architectures that support reliable stack dumping (extending this, currently rather trivial set, is currently in the works). This extends the nature of the types of patches that can be applied by live patching infrastructure. The code stems from the design proposal made [1] back in November 2014. It's a hybrid of SUSE's kGraft and RH's kpatch, combining advantages of both: it uses kGraft's per-task consistency and syscall barrier switching combined with kpatch's stack trace switching. There are also a number of fallback options which make it quite flexible. Most of the heavy lifting done by Josh Poimboeuf with help from Miroslav Benes and Petr Mladek [1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz - module load time patch optimization from Zhou Chengming - a few assorted small fixes * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch: add missing printk newlines livepatch: Cancel transition a safe way for immediate patches livepatch: Reduce the time of finding module symbols livepatch: make klp_mutex proper part of API livepatch: allow removal of a disabled patch livepatch: add /proc/<pid>/patch_state livepatch: change to a per-task consistency model livepatch: store function sizes livepatch: use kstrtobool() in enabled_store() livepatch: move patching functions into patch.c livepatch: remove unnecessary object loaded check livepatch: separate enabled and patched states livepatch/s390: add TIF_PATCH_PENDING thread flag livepatch/s390: reorganize TIF thread flag bits livepatch/powerpc: add TIF_PATCH_PENDING thread flag livepatch/x86: add TIF_PATCH_PENDING thread flag livepatch: create temporary klp_update_patch_state() stub x86/entry: define _TIF_ALLWORK_MASK flags explicitly stacktrace/x86: add function for detecting reliable stack traces
| * livepatch/s390: add TIF_PATCH_PENDING thread flagMiroslav Benes2017-03-081-1/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update a task's patch state when returning from a system call or user space interrupt, or after handling a signal. This greatly increases the chances of a patch operation succeeding. If a task is I/O bound, it can be patched when returning from a system call. If a task is CPU bound, it can be patched when returning from an interrupt. If a task is sleeping on a to-be-patched function, the user can send SIGSTOP and SIGCONT to force it to switch. Since there are two ways the syscall can be restarted on return from a signal handling process, it is important to clear the flag before do_signal() is called. Otherwise we could miss the migration if we used SIGSTOP/SIGCONT procedure or fake signal to migrate patching blocking tasks. If we place our hook to sysc_work label in entry before TIF_SIGPENDING is evaluated we kill two birds with one stone. The task is correctly migrated in all return paths from a syscall. Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | s390/cpumf: simplify detection of guest samplesMartin Schwidefsky2017-04-051-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are three different code levels in regard to the identification of guest samples. They differ in the way the LPP instruction is used. 1) Old kernels without the LPP instruction. The guest program parameter is always zero. 2) Newer kernels load the process pid into the program parameter with LPP. The guest program parameter is non-zero if the guest executes in a process != idle. 3) The latest kernels load ((1UL << 31) | pid) with LPP to make the value non-zero even for the idle task. The guest program parameter is non-zero if the guest is running. All kernels load the process pid to CR4 on context switch. The CPU sampling code uses the value in CR4 to decide between guest and host samples in case the guest program parameter is zero. The three cases: 1) CR4==pid, gpp==0 2) CR4==pid, gpp==pid 3) CR4==pid, gpp==((1UL << 31) | pid) The load-control instruction to load the pid into CR4 is expensive and the goal is to remove it. To distinguish the host CR4 from the guest pid for the idle process the maximum value 0xffff for the PASN is used. This adds a fourth case for a guest OS with an updated kernel: 4) CR4==0xffff, gpp=((1UL << 31) | pid) The host kernel will have CR4==0xffff and will use (gpp!=0 || CR4!==0xffff) to identify guest samples. This works nicely with all 4 cases, the only possible issue would be a guest with an old kernel (gpp==0) and a process pid of 0xffff. Well, don't do that.. Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390: use 64-bit lctlg to load task pid to cr4 on context switchMartin Schwidefsky2017-04-051-1/+3
| | | | | | | | | | | | | | The 32-bit lctl instruction is quite a bit slower than the 64-bit counter part lctlg. Use the faster instruction. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390: add a system call for guarded storageMartin Schwidefsky2017-03-221-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a new system call to enable the use of guarded storage for user space processes. The system call takes two arguments, a command and pointer to a guarded storage control block: s390_guarded_storage(int command, struct gs_cb *gs_cb); The second argument is relevant only for the GS_SET_BC_CB command. The commands in detail: 0 - GS_ENABLE Enable the guarded storage facility for the current task. The initial content of the guarded storage control block will be all zeros. After the enablement the user space code can use load-guarded-storage-controls instruction (LGSC) to load an arbitrary control block. While a task is enabled the kernel will save and restore the current content of the guarded storage registers on context switch. 1 - GS_DISABLE Disables the use of the guarded storage facility for the current task. The kernel will cease to save and restore the content of the guarded storage registers, the task specific content of these registers is lost. 2 - GS_SET_BC_CB Set a broadcast guarded storage control block. This is called per thread and stores a specific guarded storage control block in the task struct of the current task. This control block will be used for the broadcast event GS_BROADCAST. 3 - GS_CLEAR_BC_CB Clears the broadcast guarded storage control block. The guarded- storage control block is removed from the task struct that was established by GS_SET_BC_CB. 4 - GS_BROADCAST Sends a broadcast to all thread siblings of the current task. Every sibling that has established a broadcast guarded storage control block will load this control block and will be enabled for guarded storage. The broadcast guarded storage control block is used up, a second broadcast without a refresh of the stored control block with GS_SET_BC_CB will not have any effect. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390: fix in-kernel program checksMartin Schwidefsky2017-03-011-5/+5
|/ | | | | | | | | | | | | | | A program check inside the kernel takes a slightly different path in entry.S compare to a normal user fault. A recent change moved the store of the breaking event address into the path taken for in-kernel program checks as well, but %r14 has not been setup to point to the correct location. A wild store is the consequence. Move the store of the breaking event address to the code path for user space faults. Fixes: 34525e1f7e8d ("s390: store breaking event address only for program checks") Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: restore address space when returning to user spaceHeiko Carstens2017-02-231-11/+18
| | | | | | | | | | | | | | | | | | | | | | | Unbalanced set_fs usages (e.g. early exit from a function and a forgotten set_fs(USER_DS) call) may lead to a situation where the secondary asce is the kernel space asce when returning to user space. This would allow user space to modify kernel space at will. This would only be possible with the above mentioned kernel bug, however we can detect this and fix the secondary asce before returning to user space. Therefore a new TIF_ASCE_SECONDARY which is used within set_fs. When returning to user space check if TIF_ASCE_SECONDARY is set, which would indicate a bug. If it is set print a message to the console, fixup the secondary asce, and then return to user space. This is similar to what is being discussed for x86 and arm: "[RFC] syscalls: Restore address limit after a syscall". Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: rename CIF_ASCE to CIF_ASCE_PRIMARYHeiko Carstens2017-02-231-11/+11
| | | | | | | | | | | This is just a preparation patch in order to keep the "restore address space after syscall" patch small. Rename CIF_ASCE to CIF_ASCE_PRIMARY to be unique and specific when introducing a second CIF_ASCE_SECONDARY CIF flag. Suggested-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/syscall: fix single stepped system callsMartin Schwidefsky2017-02-201-0/+1
| | | | | | | | Fix PER tracing of system calls after git commit 34525e1f7e8dc478 "s390: store breaking event address only for program checks" broke it. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: add no-execute supportMartin Schwidefsky2017-02-081-6/+6
| | | | | | | | | | | | | | | | | Bit 0x100 of a page table, segment table of region table entry can be used to disallow code execution for the virtual addresses associated with the entry. There is one tricky bit, the system call to return from a signal is part of the signal frame written to the user stack. With a non-executable stack this would stop working. To avoid breaking things the protection fault handler checks the opcode that caused the fault for 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn) and injects a system call. This is preferable to the alternative solution with a stub function in the vdso because it works for vdso=off and statically linked binaries as well. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: store breaking event address only for program checksMartin Schwidefsky2017-01-311-38/+12
| | | | | | | | | | | | | The principles of operations specifies that the breaking event address is stored to the address 0x110 in the prefix page only for program checks. The last branch in user space is lost as soon as a branch in kernel space is executed after e.g. an svc. This makes it impossible to accurately maintain the breaking event address for a user space process. Simplify the code, just copy the current breaking event address from 0x110 to the task structure for program checks from user space. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: remove unused labels from entry.SHeiko Carstens2016-12-121-5/+0
| | | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: fix machine check panic stack switchMartin Schwidefsky2016-12-071-1/+1
| | | | | | | | | | | | | | For system damage machine checks or machine checks due to invalid PSW fields the system will be stopped. In order to get an oops message out before killing the system the machine check handler branches to .Lmcck_panic, switches to the panic stack and then does the usual machine check handling. The switch to the panic stack is incomplete, the stack pointer in %r15 is replaced, but the pt_regs pointer in %r11 is not. The result is a program check which will kill the system in a slightly different way. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: fix kernel oops for CONFIG_MARCH_Z900=y buildsMartin Schwidefsky2016-11-251-1/+2
| | | | | | | | | | | The LAST_BREAK macro in entry.S uses a different instruction sequence for CONFIG_MARCH_Z900 builds. The branch target offset to skip the store of the last breaking event address needs to take the different length of the code block into account. Fixes: f8fc82b47149e344 ("s390: move sys_call_table and last_break from thread_info to thread_struct") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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