- 09 Feb, 2023 9 commits
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Heiko Carstens authored
arch_cpu_idle_time() returns the idle time of any given cpu if it is in idle, or zero if not. All if this is racy and partially incorrect. Time stamps taken with store clock extended and store clock fast from different cpus are compared, while the architecture states that this is nothing which can be relied on (see Principles of Operation; Chapter 4, "Setting and Inspecting the Clock"). A more fundamental problem is that the timestamp when a cpu is leaving idle is taken early in the assembler part of the interrupt handler, and this value is only transferred many cycles later to the cpu's per-cpu idle data structure. This per cpu data structure is read by arch_cpu_idle() to tell for which period of time a remote cpu is idle: if only an idle_enter value is present, the assumed idle time of the cpu is calculated by taking a local timestamp and returning the difference of the local timestamp and the idle_enter value. This is potentially incorrect, since the remote cpu may have already left idle, but the taken timestamp may not have been transferred to the per-cpu data structure. This in turn means that too much idle time may be reported for a cpu, and a subsequent calculation of system idle time may result in a smaller value. Instead of coming up with even more complex code trying to fix this, just remove this code, and only account idle time of a cpu, after idle state is left. Another minor bug is that it is assumed that timestamps are non-zero, which is not necessarily the case for timestamps taken with store clock fast. This however is just a very minor problem, since this can only happen when the epoch increases. Reviewed-by:
Sven Schnelle <svens@linux.ibm.com> Signed-off-by:
Heiko Carstens <hca@linux.ibm.com>
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Heiko Carstens authored
Use simple assignments to access __vector128 members instead of hard to read casts. Signed-off-by: -
Heiko Carstens authored
Add 64 and 128 bit members to __vector128 struct in order to allow reading of the complete value, or the higher or lower part of vector register contents instead of having to use casts. Add an explicit __aligned(4) statement to avoid that the alignment of the structure changes from 4 to 8. This should make sure that no breakage happens because of this change. Reviewed-by:
Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by:
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Heiko Carstens authored
The diag288_wdt watchdog driver is s390 specific. Document who is responsible for this driver. Signed-off-by: -
Vineeth Vijayan authored
Storage Class Memory driver support for s390 architecture has been there for a while. The original author of this work, Sebastian Ott has left IBM and I am taking over this module. Adding myself as the upstream maintainer for SCM on s390 architecture. Signed-off-by:
Vineeth Vijayan <vneethv@linux.ibm.com> Acked-by:
Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by:
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Heiko Carstens authored
arch_cpu_idle() is marked noinstr and therefore must only call functions which are also not instrumented. Make sure that cpu flag helper functions are always inlined to avoid that the compiler generates an out-of-line function for e.g. the call within arch_cpu_idle(). Reviewed-by:
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Heiko Carstens authored
linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()") adds a new warning which hits on s390's arch_cpu_idle() function: RCU not on for: arch_cpu_idle+0x0/0x28 WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258 Modules linked in: CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4 Hardware name: IBM 8561 T01 703 (z/VM 7.3.0) Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3 Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000 0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000 0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0 0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8 Krnl Code: 00000000002b55b0: c02000840051 larl %r2,0000000001335652 00000000002b55b6: c0e5fff512d1 brasl %r14,0000000000157b58 #00000000002b55bc: af000000 mc 0,0 >00000000002b55c0: a7f4ffe7 brc 15,00000000002b558e 00000000002b55c4: 0707 bcr 0,%r7 00000000002b55c6: 0707 bcr 0,%r7 00000000002b55c8: eb6ff0480024 stmg %r6,%r15,72(%r15) 00000000002b55ce: b90400ef lgr %r14,%r15 Call Trace: [<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258 ([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258) [<0000000000f5f0fc>] ftrace_common+0x1c/0x20 [<00000000001044f6>] arch_cpu_idle+0x6/0x28 [<0000000000f4acf6>] default_idle_call+0x76/0x128 [<00000000001cc374>] do_idle+0xf4/0x1b0 [<00000000001cc6ce>] cpu_startup_entry+0x36/0x40 [<0000000000119d00>] smp_start_secondary+0x140/0x150 [<0000000000f5d2ae>] restart_int_handler+0x6e/0x90 Mark arch_cpu_idle() noinstr like all other architectures with CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this. Reviewed-by: -
Heiko Carstens authored
There is no reason to do idle time accounting in arch_cpu_idle(). Do idle time accounting in account_idle_time_irq(), where it belongs to. The accounted values don't change between account_idle_time_irq() and arch_cpu_idle(); so the result is the same. Reviewed-by:
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Heiko Carstens authored
Signed-off-by:
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- 06 Feb, 2023 23 commits
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Alexander Egorenkov authored
Change naming of the internal diag288 helper functions to improve overall readability and reduce confusion: * Rename __diag288() to diag288(). * Get rid of the misnamed helper __diag288_lpar() that was used not only on LPARs but also zVM and KVM systems. * Rename __diag288_vm() to diag288_str(). Reviewed-by:
Alexander Egorenkov <egorenar@linux.ibm.com> Reviewed-by:
Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230203073958.1585738-6-egorenar@linux.ibm.comSigned-off-by:
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Alexander Egorenkov authored
Call diag_stat_inc() from __diag288() to reduce code duplication. Reviewed-by:
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Alexander Egorenkov authored
Simplify and de-duplicate code by introducing a common single command buffer allocated once at initialization. Moreover, simplify the interface of __diag288_vm() by accepting ASCII strings as the command parameter and converting it to the EBCDIC format within the function itself. Reviewed-by:
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Alexander Egorenkov authored
Remove power management because s390 no longer supports hibernation since commit 39421627 ("s390: remove broken hibernate / power management support"). Reviewed-by:
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Alexander Egorenkov authored
Using register asm statements has been proven to be very error prone, especially when using code instrumentation where gcc may add function calls, which clobbers register contents in an unexpected way. Therefore, get rid of register asm statements in watchdog code, and make sure this bug class cannot happen. Moreover, remove the register r1 from the clobber list because this register is not changed by DIAG 288. Reviewed-by:
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Heiko Carstens authored
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Vasily Gorbik authored
Fixes: bb1520d5 ("s390/mm: start kernel with DAT enabled") Reviewed-by:
Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
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Vasily Gorbik authored
Facilities setup has to be done after "facilities" command line option parsing, it might set extra or remove existing facilities bits for testing purposes. Fixes: bb1520d5 ("s390/mm: start kernel with DAT enabled") Reviewed-by:
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Vasily Gorbik authored
KASAN common code is able to handle memory hotplug and create KASAN shadow memory on a fly. Online memory ranges are available from mem_detect, use this information to avoid mapping KASAN shadow for standby memory. Reviewed-by:
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Vasily Gorbik authored
If kernel is build without KASAN support there is a chance that kernel image is going to be positioned by KASLR code to overlap with identity mapping page tables. When kernel is build with KASAN support enabled memory which is potentially going to be used for page tables and KASAN shadow mapping is accounted for in KASLR with the use of kasan_estimate_memory_needs(). Split this function and introduce vmem_estimate_memory_needs() to cover decompressor's vmem identity mapping page tables. Fixes: bb1520d5 ("s390/mm: start kernel with DAT enabled") Reviewed-by:
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Vasily Gorbik authored
Add a function to get online memory in total. It is supposed to be used in the decompressor as well as during early kernel startup. Reviewed-by:
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Vasily Gorbik authored
Introduce mem_detect_truncate() to cut any online memory ranges above established identity mapping size, so that mem_detect users wouldn't have to do it over and over again. Suggested-by:
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Vasily Gorbik authored
Allocation of mem_detect extended area was not considered neither in commit 9641b8cc ("s390/ipl: read IPL report at early boot") nor in commit b2d24b97 ("s390/kernel: add support for kernel address space layout randomization (KASLR)"). As a result mem_detect extended theoretically may overlap with ipl report or randomized kernel image position. But as mem_detect code will allocate extended area only upon exceeding 255 online regions (which should alternate with offline memory regions) it is not seen in practice. To make sure mem_detect extended area does not overlap with ipl report or randomized kernel position extend usage of "safe_addr". Make initrd handling and mem_detect extended area allocation code move it further right and make KASLR takes in into consideration as well. Fixes: 9641b8cc ("s390/ipl: read IPL report at early boot") Fixes: b2d24b97 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Reviewed-by:
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Vasily Gorbik authored
In case sclp_early_get_memsize() fails but diag260() succeeds make sure some sane value is returned. This error scenario is highly unlikely, but this change makes system able to boot in such case. Suggested-by:
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Heiko Carstens authored
Get rid of this sparse warning: arch/s390/kernel/diag.c:69:29: warning: symbol '__diag8c_tmp_amode31' was not declared. Should it be static? Fixes: fbaee746 ("s390/tty3270: add support for diag 8c") Signed-off-by:
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Heiko Carstens authored
Compiling the kernel with CONFIG_KPROBES disabled, but CONFIG_RETHOOK enabled, results in this sparse warning: arch/s390/kernel/rethook.c:26:15: warning: no previous prototype for 'arch_rethook_trampoline_callback' [-Wmissing-prototypes] 26 | unsigned long arch_rethook_trampoline_callback(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Add a local rethook header file similar to riscv to address this. Reported-by:kernel test robot <lkp@intel.com> Fixes: 1a280f48 ("s390/kprobes: replace kretprobe with rethook") Link: https://lore.kernel.org/all/202302030102.69dZIuJk-lkp@intel.comSigned-off-by:
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Vasily Gorbik authored
Kasan shadow memory area has been moved to the end of kernel address space since commit 9a39abb7 ("s390/boot: simplify and fix kernel memory layout setup"), therefore skipping any memory ranges above VMALLOC_START in empty page tables cleanup code already handles KASAN shadow memory intersection case and explicit checks could be removed. Reviewed-by:
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Vasily Gorbik authored
Commit b9ff8100 ("s390/vmem: cleanup empty page tables") introduced empty page tables cleanup in vmem code, but when the kernel is built with KASAN enabled the code has no effect due to wrong KASAN shadow memory intersection condition, which effectively ignores any memory range below KASAN shadow. Fix intersection condition to make code work as anticipated. Fixes: b9ff8100 ("s390/vmem: cleanup empty page tables") Reviewed-by:
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Vasily Gorbik authored
Kasan shadow memory area has been moved to the end of kernel address space since commit 9a39abb7 ("s390/boot: simplify and fix kernel memory layout setup"). Change kasan memory layout note accordingly. Reviewed-by:
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Vasily Gorbik authored
Currently if for some reason sclp_early_read_info() fails, sclp_early_get_memsize() will not set max_physmem_end and it will stay uninitialized. Any garbage value other than 0 will lead to detect_memory() taking wrong path or returning a garbage value as max_physmem_end. To avoid that simply initialize max_physmem_end. Fixes: 73045a08 ("s390: unify identity mapping limits handling") Reported-by:
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Heiko Carstens authored
Given that strlcpy() is deprecated use strscpy() instead. Signed-off-by: -
Sven Schnelle authored
commit 87fd22e0 ("s390/ipl: add eckd support") missed to add the loadparm attribute to the new eckd ipl/reipl data. Fixes: 87fd22e0 ("s390/ipl: add eckd support") Cc: <stable@vger.kernel.org> Signed-off-by:
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Sven Schnelle authored
In the current code each reipl type implements its own pair of loadparm show/store functions. Add a macro to deduplicate the code a bit. Reviewed-by:
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- 31 Jan, 2023 6 commits
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Alexander Gordeev authored
Function __get_mem_detect_block() resets start and end output parameters in case of invalid mem_detect array index is provided. That violates the rule of sparing the output on fail path and leads e.g to a below anomaly: for_each_mem_detect_block(i, &start, &end) continue; One would expect start and end contain addresses of the last memory block (if available), but in fact the two will be reset to zeroes. That is not how an iterator is expected to work. Reviewed-by:
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Vineeth Vijayan authored
Unbinding an I/O subchannel with a child-CCW device in disconnected state sometimes causes a kernel-panic. The race condition was seen mostly during testing, when setting all the CHPIDs of a device to offline and at the same time, the unbinding the I/O subchannel driver. The kernel-panic occurs because of double delete, the I/O subchannel driver calls device_del on the CCW device while another device_del invocation for the same device is in-flight. For instance, disabling all the CHPIDs will trigger the ccw_device_remove function, which will call a ccw_device_unregister(), which ends up calling the device_del() which is asynchronous via cdev's todo workqueue. And unbinding the I/O subchannel driver calls io_subchannel_remove() function which calls the ccw_device_unregister() and device_del(). This double delete can be prevented by serializing all CCW device registration/unregistration calls into the driver core. This patch introduces a mutex which will be used for this purpose. Signed-off-by:
Boris Fiuczynski <fiuczy@linux.ibm.com> Reviewed-by:
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Vasily Gorbik authored
---[ Real Memory Copy Area Start ]--- 0x001bfffffffff000-0x001c000000000000 4K PTE I ---[ Kasan Shadow Start ]--- ---[ Real Memory Copy Area End ]--- 0x001c000000000000-0x001c000200000000 8G PMD RW NX ... ---[ Kasan Shadow End ]--- ptdump does a stable sort of markers. Move kasan markers after memcpy real to avoid swapping. Reviewed-by:
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Vasily Gorbik authored
setup_vmem() already calls populate for all online memory regions. pgtable_populate_end() could be removed. Also rename pgtable_populate_begin() to pgtable_populate_init(). Reviewed-by:
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Vasily Gorbik authored
Commit bb1520d5 ("s390/mm: start kernel with DAT enabled") doesn't consider online memory holes due to potential memory offlining and erroneously creates pgtables for stand-by memory, which bear RW+X attribute and trigger a warning: RANGE SIZE STATE REMOVABLE BLOCK 0x0000000000000000-0x0000000c3fffffff 49G online yes 0-48 0x0000000c40000000-0x0000000c7fffffff 1G offline 49 0x0000000c80000000-0x0000000fffffffff 14G online yes 50-63 0x0000001000000000-0x00000013ffffffff 16G offline 64-79 s390/mm: Found insecure W+X mapping at address 0xc40000000 WARNING: CPU: 14 PID: 1 at arch/s390/mm/dump_pagetables.c:142 note_page+0x2cc/0x2d8 Map only online memory ranges which fit within identity mapping limit. Fixes: bb1520d5 ("s390/mm: start kernel with DAT enabled") Reviewed-by:
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Vasily Gorbik authored
Historically calls to __decompress() didn't specify "out_len" parameter on many architectures including s390, expecting that no writes beyond uncompressed kernel image are performed. This has changed since commit 2aa14b1a ("zstd: import usptream v1.5.2") which includes zstd library commit 6a7ede3dfccb ("Reduce size of dctx by reutilizing dst buffer (#2751)"). Now zstd decompression code might store literal buffer in the unwritten portion of the destination buffer. Since "out_len" is not set, it is considered to be unlimited and hence free to use for optimization needs. On s390 this might corrupt initrd or ipl report which are often placed right after the decompressor buffer. Luckily the size of uncompressed kernel image is already known to the decompressor, so to avoid the problem simply specify it in the "out_len" parameter. Link: https://github.com/facebook/zstd/commit/6a7ede3dfccbSigned-off-by:
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- 30 Jan, 2023 2 commits
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Alexander Egorenkov authored
The DIAG 288 statement consumes an EBCDIC string the address of which is passed in a register. Use a "memory" clobber to tell the compiler that memory is accessed within the inline assembly. Signed-off-by:
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Alexander Egorenkov authored
With CONFIG_VMAP_STACK=y the stack is allocated from the vmalloc space. Data passed to a hardware or a hypervisor interface that requires V=R can no longer be allocated on the stack. Use kmalloc() to get memory for a diag288 command. Signed-off-by:
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