- Dec 11, 2020
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Gerald Schaefer authored
Commit cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma") added support for allocating gigantic hugepages using CMA, by specifying the hugetlb_cma= kernel parameter, which will disable any boot-time allocation of gigantic hugepages. This patch enables that option also for s390. Signed-off-by:
Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by:
Heiko Carstens <hca@linux.ibm.com>
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Harald Freudenberger authored
The random longs to be pulled by arch_get_random_long() are prepared in an 4K buffer which is filled from the NIST 800-90 compliant s390 drbg. By default the random long buffer is refilled 256 times before the drbg itself needs a reseed. The reseed of the drbg is done with 32 bytes fetched from the high quality (but slow) trng which is assumed to deliver 100% entropy. So the 32 * 8 = 256 bits of entropy are spread over 256 * 4KB = 1MB serving 131072 arch_get_random_long() invocations before reseeded. How often the 4K random long buffer is refilled with the drbg before the drbg is reseeded can be adjusted. There is a module parameter 's390_arch_rnd_long_drbg_reseed' accessible via /sys/module/arch_random/parameters/rndlong_drbg_reseed or as kernel command line parameter arch_random.rndlong_drbg_reseed=<value> This parameter tells how often the drbg fills the 4K buffer before it is re-seeded by fresh entropy from the trng. A value of 16 results in reseeding the drbg at every 16 * 4 KB = 64 KB with 32 bytes of fresh entropy pulled from the trng. So a value of 16 would result in 256 bits entropy per 64 KB. A value of 256 results in 1MB of drbg output before a reseed of the drbg is done. So this would spread the 256 bits of entropy among 1MB. Setting this parameter to 0 forces the reseed to take place every time the 4K buffer is depleted, so the entropy rises to 256 bits entropy per 4K or 0.5 bit entropy per arch_get_random_long(). With setting this parameter to negative values all this effort is disabled, arch_get_random long() returns false and thus indicating that the arch_get_random_long() feature is disabled at all. arch_get_random_long() is used by random.c among others to provide an initial hash value to be mixed with the entropy pool on every random data pull. For about 64 bytes read from /dev/urandom there is one call to arch_get_random_long(). So these additional random long values count for performance of /dev/urandom with measurable but low penalty. Signed-off-by:
Harald Freudenberger <freude@linux.ibm.com> Reviewed-by:
Ingo Franzki <ifranzki@linux.ibm.com> Reviewed-by:
Juergen Christ <jchrist@linux.ibm.com> Signed-off-by:
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- Dec 10, 2020
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Sven Schnelle authored
Not resetting the SMT siblings might leave them in unpredictable state. One of the observed problems was that the CPU timer wasn't reset and therefore large system time values where accounted during CPU bringup. Cc: <stable@kernel.org> # 4.0 Fixes: 10ad34bc ("s390: add SMT support") Reviewed-by:
Sven Schnelle <svens@linux.ibm.com> Signed-off-by:
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Heiko Carstens authored
Currently only idle_task_exit() explicitly switches (switch_mm) to init_mm. This causes the kernel asce to be loaded into cr7 and therefore it would be used for potential user space accesses. This is currently no problem since idle_task_exit() is nearly the last thing a CPU executes before it is taken down. However things might change - and therefore make sure that always the invalid asce is used for cr7 when active_mm is init_mm. This makes sure that all potential user space accesses will fail, instead of accessing kernel address space. Reviewed-by:
Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by:
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Sven Schnelle authored
When a machine check interrupt is triggered during idle, the code is using the async timer/clock for idle time calculation. It should use the machine check enter timer/clock which is passed to the macro. Fixes: 0b0ed657 ("s390: remove critical section cleanup from entry.S") Cc: <stable@vger.kernel.org> # 5.8 Reviewed-by:
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Sven Schnelle authored
During removal of the critical section cleanup the calculation of mt_cycles during idle was removed. This causes invalid accounting on systems with SMT enabled. Fixes: 0b0ed657 ("s390: remove critical section cleanup from entry.S") Cc: <stable@vger.kernel.org> # 5.8 Reviewed-by:
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Philipp Rudo authored
More and more functionality from the early boot phase gets carried over to the decompressor. With this the complexity of the code and thus the chance to introduce bugs increases. In order to be able to debug these early boot bugs the distributions have to package the decompressors vmlinux together with the other debuginfos. However for that the distributions require the vmlinux to contain a build-id. Per default the section containing the build-id is placed first in the section table. So make sure to move it behind the .text section otherwise the image would be unbootable. Signed-off-by:
Philipp Rudo <prudo@linux.ibm.com> Signed-off-by:
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Philipp Rudo authored
diag308 subcode 0 performes a clear reset which inlcudes the reset of all registers in the system. While this is the preferred behavior when loading a normal kernel via kexec it prevents the crash kernel to store the register values in the dump. To prevent this use subcode 1 when loading a crash kernel instead. Fixes: ee337f54 ("s390/kexec_file: Add crash support to image loader") Cc: <stable@vger.kernel.org> # 4.17 Signed-off-by:
Xiaoying Yan <yiyan@redhat.com> Tested-by:
Lianbo Jiang <lijiang@redhat.com> Signed-off-by:
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Qinglang Miao authored
Use of sch->dev reference after the put_device() call could trigger the use-after-free bugs. Fix this by simply adjusting the position of put_device. Fixes: 37db8985 ("s390/cio: add basic protected virtualization support") Reported-by:
Hulk Robot <hulkci@huawei.com> Suggested-by:
Cornelia Huck <cohuck@redhat.com> Signed-off-by:
Qinglang Miao <miaoqinglang@huawei.com> Reviewed-by:
Vineeth Vijayan <vneethv@linux.ibm.com> [vneethv@linux.ibm.com: Slight modification in the commit-message] Signed-off-by:
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- Dec 03, 2020
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Vineeth Vijayan authored
As part of removing broken pm-support from s390 arch, remove the pm callbacks from ccw-bus driver.The power-management functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Signed-off-by:
Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by:
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Vineeth Vijayan authored
The power-management functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove the unused pm callbacks from css-bus driver. Signed-off-by:
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Vineeth Vijayan authored
The power-management functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove these unused pm callbacks from io-subchannel drivers. Signed-off-by:
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Vineeth Vijayan authored
As part of removing the broken pm-support from s390 arch, remove the pm-calls from chsc subchannel driver. The power-management functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Signed-off-by:
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Vineeth Vijayan authored
The Power-management related functions are unused since 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove them from the unit-record device driver. Signed-off-by:
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Vineeth Vijayan authored
The power-management related functions are unused since 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove them from tape drivers. Signed-off-by:
Jan Höppner <hoeppner@linux.ibm.com> Signed-off-by:
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Vineeth Vijayan authored
The 'commit 39421627 ("s390: remove broken hibernate / power management support")' removes the pm-support. Remove the unused functions in eadm-sch drivers. Signed-off-by:
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Vineeth Vijayan authored
The power-management functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove the unsued pm functions from the console drivers. Signed-off-by:
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Vineeth Vijayan authored
The power-management related functions are unused since the 'commit 39421627 ("s390: remove broken hibernate / power management support")'. Remove them from dasd drivers. Signed-off-by:
Stefan Haberland <sth@linux.ibm.com> Signed-off-by:
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Vineeth Vijayan authored
As part of removing the power management support from s390 arch, remove PM callbacks from the scsi/zfcp driver. Signed-off-by:
Steffen Maier <maier@linux.ibm.com> Signed-off-by:
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- Nov 30, 2020
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Julian Wiedmann authored
Instead of creating the sysfs attributes for the AP bus by hand, describe them in .bus_groups and let the driver core handle it. Signed-off-by:
Julian Wiedmann <jwi@linux.ibm.com> Signed-off-my: Harald Freudenberger <freude@linux.ibm.com> Signed-off-by:
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Heiko Carstens authored
clang W=1 warns about missing prototypes: >> arch/s390/kernel/vdso64/getcpu.c:8:5: warning: no previous prototype for function '__s390_vdso_getcpu' [-Wmissing-prototypes] int __s390_vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused) ^ Add a local header file in order to get rid of this warnings. Reported-by:kernel test robot <lkp@intel.com> Signed-off-by:
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Niklas Schnelle authored
With the addition of more complete SR-IOV support, we are recommending to raise this limit for distributions to 512, as the previous default of 128 can easily be hit with just the VFs of a single PCI physical function. With at least one distribution now shipping with this, supporting only one fourth as many PCI functions on a default upstream build may lead to confusion and reduced testing of the higher limit so increase the default to 512. Acked-by:
Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by:
Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by:
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- Nov 23, 2020
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Heiko Carstens authored
Implement the previously removed getcpu vdso syscall by using the TOD programmable field to pass the cpu number to user space. Reviewed-by:
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Heiko Carstens authored
Verify on exit to user space that always - the primary ASCE (cr1) is set to kernel ASCE - the secondary ASCE (cr7) is set to user ASCE If this is not the case: panic since something went terribly wrong. Reviewed-by:
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Heiko Carstens authored
Create a region 3 page table which contains only invalid entries, and use that via "s390_invalid_asce" instead of the kernel ASCE whenever there is either - no user address space available, e.g. during early startup - as an intermediate ASCE when address spaces are switched This makes sure that user space accesses in such situations are guaranteed to fail. Reviewed-by:
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Heiko Carstens authored
Remove set_fs support from s390. With doing this rework address space handling and simplify it. As a result address spaces are now setup like this: CPU running in | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE ----------------------------|-----------|-----------|----------- user space | user | user | kernel kernel, normal execution | kernel | user | kernel kernel, kvm guest execution | gmap | user | kernel To achieve this the getcpu vdso syscall is removed in order to avoid secondary address mode and a separate vdso address space in for user space. The getcpu vdso syscall will be implemented differently with a subsequent patch. The kernel accesses user space always via secondary address space. This happens in different ways: - with mvcos in home space mode and directly read/write to secondary address space - with mvcs/mvcp in primary space mode and copy from primary space to secondary space or vice versa - with e.g. cs in secondary space mode and access secondary space Switching translation modes happens with sacf before and after instructions which access user space, like before. Lazy handling of control register reloading is removed in the hope to make everything simpler, but at the cost of making kernel entry and exit a bit slower. That is: on kernel entry the primary asce is always changed to contain the kernel asce, and on kernel exit the primary asce is changed again so it contains the user asce. In kernel mode there is only one exception to the primary asce: when kvm guests are executed the primary asce contains the gmap asce (which describes the guest address space). The primary asce is reset to kernel asce whenever kvm guest execution is interrupted, so that this doesn't has to be taken into account for any user space accesses. Reviewed-by:
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Heiko Carstens authored
* fixes: s390: fix fpu restore in entry.S Signed-off-by: -
Sven Schnelle authored
We need to disable interrupts in load_fpu_regs(). Otherwise an interrupt might come in after the registers are loaded, but before CIF_FPU is cleared in load_fpu_regs(). When the interrupt returns, CIF_FPU will be cleared and the registers will never be restored. The entry.S code usually saves the interrupt state in __SF_EMPTY on the stack when disabling/restoring interrupts. sie64a however saves the pointer to the sie control block in __SF_SIE_CONTROL, which references the same location. This is non-obvious to the reader. To avoid thrashing the sie control block pointer in load_fpu_regs(), move the __SIE_* offsets eight bytes after __SF_EMPTY on the stack. Cc: <stable@vger.kernel.org> # 5.8 Fixes: 0b0ed657 ("s390: remove critical section cleanup from entry.S") Reported-by:
Pierre Morel <pmorel@linux.ibm.com> Signed-off-by:
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- Nov 21, 2020
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Heiko Carstens authored
While allmodconfig and allyesconfig build for s390 there are also various bots running compile tests with randconfig, where PCI is disabled. This reveals that a lot of drivers should actually depend on HAS_IOMEM. Adding this to each device driver would be a never ending story, therefore just disable COMPILE_TEST for s390. The reasoning is more or less the same as described in commit bc083a64 ("init/Kconfig: make COMPILE_TEST depend on !UML"). Reported-by:
Arnd Bergmann <arnd@kernel.org> Signed-off-by:
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Alexander Gordeev authored
Rename some variable and functions to better clarify what they are and what they do. Signed-off-by:
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Alexander Gordeev authored
Reviewed-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
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Julian Wiedmann authored
Instead of creating the sysfs attributes for the stp root_dev by hand, pass them to subsys_system_register() as parameter. This also ensures that the attributes are available when the KOBJ_ADD event is raised. Signed-off-by:
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Vasily Gorbik authored
Add kernel command line and last breaking event. The kernel command line is taken from early_command_line and printed only if kernel is not running as protected virtualization guest and if it has been already initialized from the "COMMAND_LINE". Linux version 5.10.0-rc3-22794-gecaa72788df0-dirty (gor@tuxmaker) #28 SMP PREEMPT Mon Nov 9 17:41:20 CET 2020 Kernel command line: audit_enable=0 audit=0 selinux=0 crashkernel=296M root=/dev/dasda1 dasd=ec5b memblock=debug die Kernel fault: interruption code 0005 ilc:2 PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c) R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3 GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a65c 000000000000bf60 0000000000000000 00000000000003c0 0000000000000000 0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018 000000000311c000 0000000000010070 0000000000012f82 000000000000bea8 Call Trace: (sp:000000000000bea8 [<000000000002016e>] 000000000002016e) sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0 Last Breaking-Event-Address: [<00000000000135ba>] strcmp+0x22/0x24 Reviewed-by:Alexander Egorenkov <egorenar@linux.ibm.com> Acked-by:
Viktor Mihajlovski <mihajlov@linux.ibm.com> Signed-off-by:
Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
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Vasily Gorbik authored
Decompressor works on a single statically allocated stack. Stacktrace implementation with -mbackchain just takes few lines of code. Linux version 5.10.0-rc3-22793-g0f84a355b776-dirty (gor@tuxmaker) #27 SMP PREEMPT Mon Nov 9 17:30:18 CET 2020 Kernel fault: interruption code 0005 ilc:2 PSW : 0000000180000000 0000000000012f92 (parse_boot_command_line+0x27a/0x46c) R:0 T:0 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 RI:0 EA:3 GPRS: 0000000000000000 00ffffffffffffff 0000000000000000 000000000001a62c 000000000000bf60 0000000000000000 00000000000003c0 0000000000000000 0000000000000080 000000000002322d 000000007f29ef20 0000000000efd018 000000000311c000 0000000000010070 0000000000012f82 000000000000bea8 Call Trace: (sp:000000000000bea8 [<000000000002016e>] 000000000002016e) sp:000000000000bf18 [<0000000000012408>] startup_kernel+0x88/0x2fc sp:000000000000bf60 [<00000000000100c4>] startup_normal+0xb0/0xb0 Reviewed-by: -
Vasily Gorbik authored
Information printed by print_pgm_check_info() is crucial for debugging decompressor problems. Printing instruction addresses is better than nothing, but turns further debugging into tedious job of figuring out which function those addresses correspond to. This change adds simplistic symbols resolution support. And adds %pS format specifier support to decompressor_printk(). Decompressor symbols list is extracted and sorted with nm -n -S: ... 0000000000010000 0000000000000014 T startup 0000000000010014 00000000000000b0 t startup_normal 0000000000010180 00000000000000b2 t startup_kdump ... Then functions are filtered and contracted to a form: "10000 14 startup\0""10014 b0 startup_normal\0""10180 b2 startup_kdump\0" ... Which makes it trivial to find beginning of an entry and names are 0 terminated, so could be used as is. Symbols are binary-searched. To get symbols list with final addresses and then get it into the decompressor's image the same trick as for kallsyms is used. Decompressor's vmlinux is linked twice. Symbols are stored in .decompressor.syms section, current size is about 2kb. Reviewed-by:
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Vasily Gorbik authored
Use SYM_CODE_* annotations for asm functions, so that function lengths are recognized correctly. Also currently the most part of startup is marked as startup_kdump. Move misplaced startup_kdump where it belongs. $ nm -n -S arch/s390/boot/compressed/vmlinux Before: 0000000000010000 T startup 0000000000010010 T startup_kdump After: 0000000000010000 0000000000000014 T startup 0000000000010014 00000000000000b0 t startup_normal 0000000000010180 00000000000000b2 t startup_kdump Reviewed-by:
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Vasily Gorbik authored
The decompressor does not have any special debug means. Running the kernel under qemu with gdb is helpful but tedious exercise if done repeatedly. It is also not applicable to debugging under LPAR and z/VM. One special thing which stands out is a working sclp_early_printk, which could be used once the kernel switches to 64-bit addressing mode. But sclp_early_printk does not provide any string formating capabilities. Formatting and printing string without printk-alike function is a not fun. The lack of printk-alike function means people would save up on testing and introduce more bugs. So, finally, provide decompressor_printk function, which fits on one screen and trades features for simplicity. It only supports "%s", "%x" and "%lx" specifiers and zero padding for hex values. Reviewed-by:
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Vasily Gorbik authored
Currently the kernel minimal compiler requirement is gcc 4.9 or clang 10.0.1. * gcc -mhotpatch option is supported since 4.8. * A combination of -pg -mrecord-mcount -mnop-mcount -mfentry flags is supported since gcc 9 and since clang 10. Drop support for old -pg function prologues. Which leaves binary compatible -mhotpatch / -mnop-mcount -mfentry prologues in a form: brcl 0,0 Which are also do not require initial nop optimization / conversion and presence of _mcount symbol. Signed-off-by:
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Vasily Gorbik authored
Currently we have to consider too many different values which in the end only affect identity mapping size. These are: 1. max_physmem_end - end of physical memory online or standby. Always <= end of the last online memory block (get_mem_detect_end()). 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the kernel is able to support. 3. "mem=" kernel command line option which limits physical memory usage. 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as crash kernel. 5. "hsa" size which is a memory limit when the kernel is executed during zfcp/nvme dump. Through out kernel startup and run we juggle all those values at once but that does not bring any amusement, only confusion and complexity. Unify all those values to a single one we should really care, that is our identity mapping size. Signed-off-by:
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Julian Wiedmann authored
Instead of creating the sysfs attributes for the prng devices by hand, describe them in .groups and let the misdevice core handle it. This also ensures that the attributes are available when the KOBJ_ADD event is raised. Signed-off-by:
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