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2021-08-18s390/sclp: reserve memory occupied by sclp early bufferAlexander Egorenkov1-0/+1
The memory block occupied by the SCLP early buffer that is allocated by the decompressor and then handed over to the decompressed kernel, must be reserved to prevent it from being reused for other purposes. This is necessary because the SCLP early buffer is still in use during kernel initialization. Fixes: f1d3c5323772 ("s390/boot: move sclp early buffer from fixed address in asm to C") Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reported-by: Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-08-05s390: rename dma section to amode31Heiko Carstens10-112/+112
The dma section name is confusing, since the code which resides within that section has nothing to do with direct memory access. Instead the limitation is that the code has to run in 31 bit addressing mode, and therefore has to reside below 2GB. So the name was chosen since ZONE_DMA is the same region. To reduce confusion rename the section to amode31, which hopefully describes better what this is about. Note: this will also change vmcoreinfo strings - SDMA=... gets renamed to SAMODE31=... - EDMA=... gets renamed to EAMODE31=... Acked-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-05s390: replace deprecated CPU-hotplug functionsSebastian Andrzej Siewior6-14/+14
The functions get_online_cpus() and put_online_cpus() have been deprecated during the CPU hotplug rework. They map directly to cpus_read_lock() and cpus_read_unlock(). Replace deprecated CPU-hotplug functions with the official version. The behavior remains unchanged. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20210803141621.780504-5-bigeasy@linutronix.de Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-08-03s390/ftrace: implement hotpatchingIlya Leoshkevich4-16/+279
s390 allows hotpatching the mask of a conditional jump instruction. Make use of this feature in order to avoid the expensive stop_machine() call. The new trampolines are split in 3 stages: - A first stage is a 6-byte relative conditional long branch located at each function's entry point. Its offset always points to the second stage for the corresponding function, and its mask is either all 0s (ftrace off) or all 1s (ftrace on). The code for flipping the mask is borrowed from ftrace_{enable,disable}_ftrace_graph_caller. After flipping, ftrace_arch_code_modify_post_process() syncs with all the other CPUs by sending SIGPs. - Second stages for vmlinux are stored in a separate part of the .text section reserved by the linker script, and in dynamically allocated memory for modules. This prevents the icache pollution. The total size of second stages is about 1.5% of that of the kernel image. Putting second stages in the .bss section is possible and decreases the size of the non-compressed vmlinux, but splits the kernel 1:1 mapping, which is a bad tradeoff. Each second stage contains a call to the third stage, a pointer to the part of the intercepted function right after the first stage, and a pointer to an interceptor function (e.g. ftrace_caller). Second stages are 8-byte aligned for the future direct calls implementation. - There are only two copies of the third stage: in the .text section for vmlinux and in dynamically allocated memory for modules. It can be an expoline, which is relatively large, so inlining it into each second stage is prohibitively expensive. As a result of this organization, phoronix-test-suite with ftrace off does not show any performance degradation. Suggested-by: Sven Schnelle <svens@linux.ibm.com> Suggested-by: Vasily Gorbik <gor@linux.ibm.com> Co-developed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20210728212546.128248-3-iii@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30s390: enable KCSANIlya Leoshkevich2-0/+2
s390x GCC and SystemZ Clang have ThreadSanitizer support now [1] [2], so enable KCSAN for s390. [1] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ea22954e7c58 [2] https://reviews.llvm.org/D105629 Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-30s390/vdso: add .got.plt in vdso linker scriptSumanth Korikkar2-0/+2
KCFLAGS="-mno-pic-data-is-text-relative" make leads to bfd assertion error in s390_got_pointer(): LD arch/s390/kernel/vdso64/vdso64.so.dbg ld: BFD version 2.35-18.fc33 assertion fail elf-s390-common.c:74 readelf -Wr vdso64_generic.o | grep GOT 0000000000000032 000000110000001a R_390_GOTENT 0000000000000000 _vdso_data + 2 (...) Add .got.plt in linker script to avoid this. Suggested-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: make sie capability regular hwcapHeiko Carstens1-10/+2
Commit 7f16d7e787b7 ("s390: show virtualization support in /proc/cpuinfo") introduced special handling for sie capability, saying this should not be exposed via hwcaps, without giving a reason. However this leads to an inconsistent /proc/cpuinfo features line where all features except the sie capability are also present in hwcaps. I really don't see a reason to not add that to hwcaps - it might be quite pointless, but at least this way it is possible to get rid of some special handling. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: remove hwcap stfle checkHeiko Carstens1-1/+1
Remove the not so obvious "(elf_hwcap & (1UL << 2)" which only checks if stfle is available. This used to be required for old code before test_facility() was introduced. test_facility() will do the right thing, regardless if stfle is available or not. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: remove z/Architecture mode active checkHeiko Carstens1-2/+1
Remove a leftover from the common 31/64 bit code. z/Architecture mode is now always active, there is no need to check. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: use consistent coding style / remove commentsHeiko Carstens1-54/+13
Use a consistent coding style within setup_hwcaps() and remove obvious and outdated comments. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: open code initialization of first six hwcap bitsHeiko Carstens1-6/+24
The first six hwcap bits are initialized in a rather odd way: an array contains the stfl(e) bits which need to be set, so that the corresponding bit position (= array index) within hwcaps are set. Better open code it like it is done for all other bits, making it obvious which bit is set when. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: split setup_hwcaps()Heiko Carstens1-9/+15
setup_hwcaps() is a quite large function. Make it smaller by moving the elf platform setup code into an independent setup function. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: move setup_hwcaps()Heiko Carstens2-158/+160
Move setup_hwcaps() to processor.c for two reasons: - make setup.c a bit smaller - have allmost all of the hwcap code in one file Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: add sanity checksHeiko Carstens1-0/+2
Add BUILD_BUG_ON() sanity checks to make sure the hwcap string array contains a string for each hwcap. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: use named initializers for hwcap string arraysHeiko Carstens1-4/+23
Use named initializers to make it obvious which hwcap string array element belongs to which hwcap. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/hwcaps: shorten HWCAP definesHeiko Carstens1-26/+26
Remove s390 part of all HWCAP defines, just to make them shorter and easier to handle. The namespace is anyway per architecture. This is similar to what arm64 has. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390: add HWCAP_S390_PCI_MIO to ELF hwcapsNiklas Schnelle2-1/+3
In order to support the use of enhanced PCI instructions in both kernel- and userspace we need both hardware support and proper setup in the kernel. The latter can be toggled off with the pci=nomio command line option. Thus availability of this feature in userspace depends on all of kernel configuration (CONFIG_PCI), hardware support and the current kernel command line and can thus not rely solely on a facility bit. Instead let's introduce a new ELF hardware capability bit HWCAP_S390_PCI_MIO to tell userspace whether these PCI instructions can be used. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390: make PCI mio support a machine flagNiklas Schnelle1-0/+4
Kernel support for the newer PCI mio instructions can be toggled off with the pci=nomio command line option which needs to integrate with common code PCI option parsing. However this option then toggles static branches which can't be toggled yet in an early_param() call. Thus commit 9964f396f1d0 ("s390: fix setting of mio addressing control") moved toggling the static branches to the PCI init routine. With this setup however we can't check for mio support outside the PCI code during early boot, i.e. before switching the static branches, which we need to be able to export this as an ELF HWCAP. Improve on this by turning mio availability into a machine flag that gets initially set based on CONFIG_PCI and the facility bit and gets toggled off if pci=nomio is found during PCI option parsing allowing simple access to this machine flag after early init. Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/disassembler: add instructionsHeiko Carstens1-0/+2
Add more instructions to the kernel disassembler. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390: report more CPU capabilitiesHeiko Carstens2-1/+5
Add hardware capability bits and feature tags to /proc/cpuinfo for NNPA and Vector-Packed-Decimal-Enhancement Facility 2. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/setup: don't reserve memory that occupied decompressor's headAlexander Egorenkov1-1/+1
There is no useful information within [STARTUP_NORMAL_OFFSET, HEAD_END] now. But the memory region [0, STARTUP_NORMAL_OFFSET] is used by: * lowcore * kdump for swapping memory * stand-alone zipl dumpers for code, data, stack and heap Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/boot: move dma sections from decompressor to decompressed kernelAlexander Egorenkov7-10/+332
This change simplifies the task of making the decompressor relocatable. The decompressor's image contains special DMA sections between _sdma and _edma. This DMA segment is loaded at boot as part of the decompressor and then simply handed over to the decompressed kernel. The decompressor itself never uses it in any way. The primary reason for this is the need to keep the aforementioned DMA segment below 2GB which is required by architecture, and because the decompressor is always loaded at a fixed low physical address, it is guaranteed that the DMA region will not cross the 2GB memory limit. If the DMA region had been placed in the decompressed kernel, then KASLR would make this guarantee impossible to fulfill or it would be restricted to the first 2GB of memory address space. This commit moves all DMA sections between _sdma and _edma from the decompressor's image to the decompressed kernel's image. The complete DMA region is placed in the init section of the decompressed kernel and immediately relocated below 2GB at start-up before it is needed by other parts of the decompressed kernel. The relocation of the DMA region happens even if the decompressed kernel is already located below 2GB in order to keep the first implementation simple. The relocation should not have any noticeable impact on boot time because the DMA segment is only a couple of pages. After relocating the DMA sections, the kernel has to fix all references which point into it. In order to automate this, place all variables pointing into the DMA sections in a special .dma.refs section. All such variables must be defined using the new __dma_ref macro. Only variables containing addresses within the DMA sections must be placed in the new .dma.refs section. Furthermore, move the initialization of control registers from the decompressor to the decompressed kernel because some control registers reference tables that must be placed in the DMA data section to guarantee that their addresses are below 2G. Because the decompressed kernel relocates the DMA sections at startup, the content of control registers CR2, CR5 and CR15 must be updated with new addresses after the relocation. The decompressed kernel initializes all control registers early at boot and then updates the content of CR2, CR5 and CR15 as soon as the DMA relocation has occurred. This practically reverts the commit a80313ff91ab ("s390/kernel: introduce .dma sections"). Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/setup: generate asm offsets from struct parmareaAlexander Egorenkov1-0/+7
To reduce duplication, replace error-prone and hard-coded parameter area offsets with auto-generated ones. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/dump: introduce boot data 'oldmem_data'Alexander Egorenkov4-30/+31
The new boot data struct shall replace global variables OLDMEM_BASE and OLDMEM_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/boot: introduce boot data 'initrd_data'Alexander Egorenkov1-7/+8
The new boot data struct shall replace global variables INITRD_START and INITRD_SIZE. It is initialized in the decompressor and passed to the decompressed kernel. In comparison to the old solution, this one doesn't access data at fixed physical addresses which will become important when the decompressor becomes relocatable. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/uv: de-duplicate checks for Protected Host VirtualizationAlexander Egorenkov1-15/+0
De-duplicate checks for Protected Host Virtualization in decompressor and kernel. Set prot_virt_host=0 in the decompressor in *any* of the following cases and hand it over to the decompressed kernel: * No explicit prot_virt=1 is given on the kernel command-line * Protected Guest Virtualization is enabled * Hardware support not present * kdump or stand-alone dump The decompressed kernel needs to use only is_prot_virt_host() instead of performing again all checks done by the decompressor. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/jump_label: print real address in a case of a jump label bugHeiko Carstens1-1/+1
In case of a jump label print the real address of the piece of code where a mismatch was detected. This is right before the system panics, so there is nothing revealed. Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-27s390/cio: remove unused include linux/spinlock.h from cio.hAlexander Egorenkov1-0/+2
* The linux/spinlock.h header was included indirectly by the decompressor and brought unnecessary build dependencies. * Use proper includes in files which either directly or indirectly included cio.h and were hidden until now by the included linux/spinlock.h, e.g. linux/string.h for memcpy() or asm/page.h for PAGE_SIZE. Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-21Merge tag 's390-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linuxLinus Torvalds4-3/+6
Pull s390 updates from Heiko Carstens: - fix / add expoline usage in "DMA" code - fix compat vdso Makefile to avoid permanent rebuild - fix ftrace_update_ftrace_func to avoid NULL pointer dereference - update defconfigs - trivial coding style fix * tag 's390-5.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390: update defconfigs s390/cpumf: fix semicolon.cocci warnings s390/boot: fix use of expolines in the DMA code s390/ftrace: fix ftrace_update_ftrace_func implementation s390/defconfig: allow early device mapper disks s390/vdso32: add vdso32.lds to targets
2021-07-20s390/cpumf: fix semicolon.cocci warningskernel test robot1-1/+1
arch/s390/kernel/perf_cpum_cf.c:748:2-3: Unneeded semicolon Remove unneeded semicolon. Generated by: scripts/coccinelle/misc/semicolon.cocci Fixes: a029a4eab39e ("s390/cpumf: Allow concurrent access for CPU Measurement Counter Facility") CC: Thomas Richter <tmricht@linux.ibm.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: kernel test robot <lkp@intel.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-15s390/ftrace: fix ftrace_update_ftrace_func implementationVasily Gorbik2-2/+4
s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected. At the same time implementation of ftrace_caller is not compliant with HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of ftrace_update_ftrace_func() and calls ftrace_trace_function() directly. The subtle difference is that during ftrace code patching ftrace replaces function tracer via ftrace_update_ftrace_func() and activates it back afterwards. Unexpected direct calls to ftrace_trace_function() during ftrace code patching leads to nullptr-dereferences when tracing is activated for one of functions which are used during code patching. Those function currently are: copy_from_kernel_nofault() copy_from_kernel_nofault_allowed() preempt_count_sub() [with debug_defconfig] preempt_count_add() [with debug_defconfig] Corresponding KASAN report: BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0 Read of size 4 at addr 0000000000001e08 by task migration/0/15 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d Hardware name: IBM 3906 M04 704 (LPAR) Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218 Call Trace: [<0000000001f77caa>] show_stack+0x16a/0x1d0 [<0000000001f8de42>] dump_stack+0x15a/0x1b0 [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0 [<000000000082b0ca>] kasan_report+0x152/0x1c0 [<00000000004cfd8e>] function_trace_call+0x316/0x3b0 [<0000000001fb7082>] ftrace_caller+0x7a/0x7e [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10 [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0 [<000000000014605c>] ftrace_make_call+0xb4/0x1f8 [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8 [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0 [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78 [<000000000042395c>] multi_cpu_stop+0x224/0x3e0 [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0 [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708 [<00000000002329ea>] kthread+0x342/0x408 [<00000000001066b2>] __ret_from_fork+0x92/0xf0 [<0000000001fb57fa>] ret_from_fork+0xa/0x30 The buggy address belongs to the page: page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff) raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: 0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ^ 0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ================================================================== To fix that introduce ftrace_func callback to be called from ftrace_caller and update it in ftrace_update_ftrace_func(). Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions") Cc: stable@vger.kernel.org Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-13s390: Fix fall-through warnings for ClangGustavo A. R. Silva1-0/+1
Fix the following fallthrough warnings: drivers/s390/net/ctcm_fsms.c:1457:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] drivers/s390/net/qeth_l3_main.c:437:3: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] drivers/s390/char/tape_char.c:374:4: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] arch/s390/kernel/uprobes.c:129:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough] Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-07-12exit/bdflush: Remove the deprecated bdflush system callEric W. Biederman1-1/+1
The bdflush system call has been deprecated for a very long time. Recently Michael Schmitz tested[1] and found that the last known caller of of the bdflush system call is unaffected by it's removal. Since the code is not needed delete it. [1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com Link: https://lkml.kernel.org/r/87sg10quue.fsf_-_@disp2133 Tested-by: Michael Schmitz <schmitzmic@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-07-12s390/vdso32: add vdso32.lds to targetsSven Schnelle1-0/+1
This fixes a permanent rebuild of the 32 bit vdso. The RPM build process was first calling 'make bzImage' and 'make modules' as a second step. This caused a recompilation of vdso32.so, which in turn also changed the build-id of vmlinux. Fixes: 779df2248739 ("s390/vdso: add minimal compat vdso") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-07-10Merge tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linuxLinus Torvalds31-1449/+1598
Pull more s390 updates from Vasily Gorbik: - Fix preempt_count initialization. - Rework call_on_stack() macro to add proper type handling and avoid possible register corruption. - More error prone "register asm" removal and fixes. - Fix syscall restarting when multiple signals are coming in. This adds minimalistic trampolines to vdso so we can return from signal without using the stack which requires pgm check handler hacks when NX is enabled. - Remove HAVE_IRQ_EXIT_ON_IRQ_STACK since this is no longer true after switch to generic entry. - Fix protected virtualization secure storage access exception handling. - Make machine check C handler always enter with DAT enabled and move register validation to C code. - Fix tinyconfig boot problem by avoiding MONITOR CALL without CONFIG_BUG. - Increase asm symbols alignment to 16 to make it consistent with compilers. - Enable concurrent access to the CPU Measurement Counter Facility. - Add support for dynamic AP bus size limit and rework ap_dqap to deal with messages greater than recv buffer. * tag 's390-5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits) s390: preempt: Fix preempt_count initialization s390/linkage: increase asm symbols alignment to 16 s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn() s390: add type checking to CALL_ON_STACK_NORETURN() macro s390: remove old CALL_ON_STACK() macro s390/softirq: use call_on_stack() macro s390/lib: use call_on_stack() macro s390/smp: use call_on_stack() macro s390/kexec: use call_on_stack() macro s390/irq: use call_on_stack() macro s390/mm: use call_on_stack() macro s390: introduce proper type handling call_on_stack() macro s390/irq: simplify on_async_stack() s390/irq: inline do_softirq_own_stack() s390/irq: simplify do_softirq_own_stack() s390/ap: get rid of register asm in ap_dqap() s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTART s390: move restart of execve() syscall s390/signal: remove sigreturn on stack s390/signal: switch to using vdso for sigreturn and syscall restart ...
2021-07-08s390: preempt: Fix preempt_count initializationValentin Schneider2-0/+2
S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the preempt_count of the requested CPU's idle task: it unconditionally writes to the current CPU's. This clearly conflicts with idle_threads_init(), which intends to initialize *all* the idle tasks, including their preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count). Unfortunately, it seems the way s390 does things doesn't let us initialize every possible CPU's preempt_count early on, as the pages where this resides are only allocated when a CPU is brought up and are freed when it is brought down. Let the arch-specific code set a CPU's preempt_count when its lowcore is allocated, and turn init_idle_preempt_count() into an empty stub. Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390: rename CALL_ON_STACK_NORETURN() to call_on_stack_noreturn()Heiko Carstens2-2/+2
Lower case matches the call_on_stack() macro and is easier to read. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/smp: use call_on_stack() macroHeiko Carstens1-4/+8
Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/kexec: use call_on_stack() macroHeiko Carstens1-1/+2
Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/irq: use call_on_stack() macroHeiko Carstens1-3/+5
Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/irq: simplify on_async_stack()Heiko Carstens1-1/+1
Make on_async_stack() a bit more readable, even though as usual it depends if one considers "!!!" readable or not. At least the new construct to check if the async stack is in use or not is a bit shorter and generates slightly better code. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/irq: inline do_softirq_own_stack()Heiko Carstens1-8/+0
Move do_softirq_own_stack() to proper header file so it can be inlined; saving a few cycles. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/irq: simplify do_softirq_own_stack()Heiko Carstens1-11/+1
do_softirq_own_stack() is always called from task context and therefore it is not necessary to check if the async stack is currently used. Remove the check and directly switch to async stack. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390: rename PIF_SYSCALL_RESTART to PIF_EXECVE_PGSTE_RESTARTSven Schnelle1-1/+2
PIF_SYSCALL_RESTART is now only used to restart execve when loading PGSTE binaries. Rename the flag to reflect that, and avoid people thinking that this bit has anything to do with generic syscall restarting. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390: move restart of execve() syscallSven Schnelle1-15/+12
On s390, execve might have to be restarted for PGSTE binaries like kvm. In the past this was done via the PIF_SYSCALL_RESTART bit. However, with the recent changes, syscalls are now restarted differently. Now that execve() is the only call that might get restarted via PIF_SYSCALL_RESTART, move the loop to do_syscall(). This also has the advantage that the restart is no longer visible to userspace. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/signal: remove sigreturn on stackSven Schnelle2-12/+2
{rt_}sigreturn is now called from the vdso, so we no longer need the svc on the stack, and therefore no hack to support that mechanism on machines with non-executable stack. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/signal: switch to using vdso for sigreturn and syscall restartSven Schnelle4-31/+31
with generic entry, there's a bug when it comes to restarting of signals. The failing sequence is: a) a signal is coming in, and no handler is registered, so the lower part of arch_do_signal_or_restart() in arch/s390/kernel/signal.c sets PIF_SYSCALL_RESTART. b) a second signal gets pending while the kernel is still in the exit loop, and for that one, a handler exists. c) The first part of arch_do_signal_or_restart() is called. That part calls handle_signal(), which sets up stack + registers for handling the signal. d) __do_syscall() in arch/s390/kernel/syscall.c checks for PIF_SYSCALL_RESTART right before leaving to userspace. If it is set, it restart's the syscall. However, the registers are already setup for handling a signal from c). The syscall is now restarted with the wrong arguments. Change the code to: - use vdso for syscall_restart() instead of PIF_SYSCALL_RESTART because we cannot rewind and go back to userspace on s390 because the system call number might be encoded in the svc instruction. - for all other syscalls we rewind the PSW and return to userspace. Cc: <stable@kernel.org> # v5.12+ d57778feb987: s390/vdso: always enable vdso Cc: <stable@kernel.org> # v5.12+ 686341f2548b: s390/vdso64: add sigreturn,rt_sigreturn and restart_syscall Cc: <stable@kernel.org> # v5.12+ 43e1f76b0b69: s390/vdso: rename VDSO64_LBASE to VDSO_LBASE Cc: <stable@kernel.org> # v5.12+ 779df2248739: s390/vdso: add minimal compat vdso Cc: <stable@kernel.org> # v5.12+ Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390: convert to setup_initial_init_mm()Kefeng Wang1-4/+1
Use setup_initial_init_mm() helper to simplify code. Link: https://lkml.kernel.org/r/20210608083418.137226-14-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08s390/vdso: add minimal compat vdsoSven Schnelle11-16/+338
Add a small vdso for 31 bit compat application that provides trampolines for calls to sigreturn,rt_sigreturn,syscall_restart. This is requird for moving these syscalls away from the signal frame to the vdso. Note that this patch effectively disables CONFIG_COMPAT when using clang to compile the kernel. clang doesn't support 31 bit mode. We want to redirect sigreturn and restart_syscall to the vdso. However, the kernel cannot parse the ELF vdso file, so we need to generate header files which contain the offsets of the syscall instructions in the vdso page. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-07-08s390/vdso: rename VDSO64_LBASE to VDSO_LBASESven Schnelle1-1/+1
Will be used by both vdso32 and vdso64, so change the name. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
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