- 23 1月, 2018 1 次提交
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由 Hendrik Brueckner 提交于
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: NHendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 20 11月, 2017 1 次提交
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由 Heiko Carstens 提交于
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: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 14 11月, 2017 2 次提交
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由 Martin Schwidefsky 提交于
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: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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由 Martin Schwidefsky 提交于
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: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
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- 02 11月, 2017 2 次提交
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由 Vasily Gorbik 提交于
__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: 3037a52f ("s390/nmi: do register validation as early as possible") Signed-off-by: NVasily Gorbik <gor@linux.vnet.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Greg Kroah-Hartman 提交于
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: NKate Stewart <kstewart@linuxfoundation.org> Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 25 10月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: c929500d ("s390/nmi: s390: New low level handling for machine check happening in guest") Cc: <stable@vger.kernel.org> # v4.13+ Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 19 10月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 27 6月, 2017 1 次提交
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由 QingFeng Hao 提交于
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: NQingFeng Hao <haoqf@linux.vnet.ibm.com> Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
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- 13 6月, 2017 2 次提交
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 17 5月, 2017 1 次提交
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由 Christian Borntraeger 提交于
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: NChristian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 03 5月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
git commit c5328901 "[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: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 05 4月, 2017 2 次提交
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由 Martin Schwidefsky 提交于
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: NChristian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Martin Schwidefsky 提交于
The 32-bit lctl instruction is quite a bit slower than the 64-bit counter part lctlg. Use the faster instruction. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 22 3月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 08 3月, 2017 1 次提交
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由 Miroslav Benes 提交于
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: NMiroslav Benes <mbenes@suse.cz> Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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- 01 3月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: 34525e1f ("s390: store breaking event address only for program checks") Reported-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 23 2月, 2017 2 次提交
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由 Heiko Carstens 提交于
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: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Heiko Carstens 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 20 2月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
Fix PER tracing of system calls after git commit 34525e1f "s390: store breaking event address only for program checks" broke it. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 08 2月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 31 1月, 2017 1 次提交
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 12 12月, 2016 1 次提交
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由 Heiko Carstens 提交于
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 07 12月, 2016 1 次提交
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由 Martin Schwidefsky 提交于
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: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 25 11月, 2016 1 次提交
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由 Martin Schwidefsky 提交于
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: f8fc82b4 ("s390: move sys_call_table and last_break from thread_info to thread_struct") Reported-by: NGuenter Roeck <linux@roeck-us.net> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 23 11月, 2016 1 次提交
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由 Heiko Carstens 提交于
We have the s390 specific THREAD_ORDER define and the THREAD_SIZE_ORDER define which is also used in common code. Both have exactly the same semantics. Therefore get rid of THREAD_ORDER and always use THREAD_SIZE_ORDER instead. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 15 11月, 2016 1 次提交
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由 Martin Schwidefsky 提交于
Move the last two architecture specific fields from the thread_info structure to the thread_struct. All that is left in thread_info is the flags field. Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 11 11月, 2016 2 次提交
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由 Heiko Carstens 提交于
This is the s390 variant of commit 15f4eae7 ("x86: Move thread_info into task_struct"). Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Martin Schwidefsky 提交于
Convert s390 to use a field in the struct lowcore for the CPU preemption count. It is a bit cheaper to access a lowcore field compared to a thread_info variable and it removes the depencency on a task related structure. bloat-o-meter on the vmlinux image for the default configuration (CONFIG_PREEMPT_NONE=y) reports a small reduction in text size: add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220) A larger improvement is achieved with the default configuration but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n: add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144) Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 08 8月, 2016 1 次提交
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由 Al Viro 提交于
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 04 7月, 2016 1 次提交
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由 Heiko Carstens 提交于
After linking there are several symbols for the same address that the __switch_to symbol points to. E.g.: 000000000089b9c0 T __kprobes_text_start 000000000089b9c0 T __lock_text_end 000000000089b9c0 T __lock_text_start 000000000089b9c0 T __sched_text_end 000000000089b9c0 T __switch_to When disassembling with "objdump -d" this results in a missing __switch_to function. It would be named __kprobes_text_start instead. To unconfuse objdump add a nop in front of the kprobes text section. That way __switch_to appears again. Obviously this solution is sort of a hack, since it also depends on link order if this works or not. However it is the best I can come up with for now. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 28 6月, 2016 1 次提交
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由 Heiko Carstens 提交于
Remove a leftover from the code that transferred a couple of TIF bits from the previous task to the next task. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 10 3月, 2016 1 次提交
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由 Martin Schwidefsky 提交于
There is a tricky interaction between the machine check handler and the critical sections of load_fpu_regs and save_fpu_regs functions. If the machine check interrupts one of the two functions the critical section cleanup will complete the function before the machine check handler s390_do_machine_check is called. Trouble is that the machine check handler needs to validate the floating point registers *before* and not *after* the completion of load_fpu_regs/save_fpu_regs. The simplest solution is to rewind the PSW to the start of the load_fpu_regs/save_fpu_regs and retry the function after the return from the machine check handler. Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com> Cc: <stable@vger.kernel.org> # 4.3+ Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 02 3月, 2016 1 次提交
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由 Christian Borntraeger 提交于
commit e22cf8ca ("s390/cpumf: rework program parameter setting to detect guest samples") requires guest changes to get proper guest/host. We can do better: We can use the primary asn value, which is set on all Linux variants to compare this with the host pp value. We now have the following cases: 1. Guest using PP host sample: gpp == 0, asn == hpp --> host guest sample: gpp != 0 --> guest 2. Guest not using PP host sample: gpp == 0, asn == hpp --> host guest sample: gpp == 0, asn != hpp --> guest As soon as the host no longer sets CR4, we must back out this heuristics - let's add a comment in switch_to. Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 27 11月, 2015 1 次提交
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由 Martin Schwidefsky 提交于
It does not make sense to try to relinquish the time slice with diag 0x9c to a CPU in a state that does not allow to schedule the CPU. The scenario where this can happen is a CPU waiting in udelay/mdelay while holding a spin-lock. Add a CIF bit to tag a CPU in enabled wait and use it to detect that the yield of a CPU will not be successful and skip the diagnose call. Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 14 10月, 2015 4 次提交
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由 Heiko Carstens 提交于
When using systemtap it was observed that our udelay implementation is rather suboptimal if being called from a kprobe handler installed by systemtap. The problem observed when a kprobe was installed on lock_acquired(). When the probe was hit the kprobe handler did call udelay, which set up an (internal) timer and reenabled interrupts (only the clock comparator interrupt) and waited for the interrupt. This is an optimization to avoid that the cpu is busy looping while waiting that enough time passes. The problem is that the interrupt handler still does call irq_enter()/irq_exit() which then again can lead to a deadlock, since some accounting functions may take locks as well. If one of these locks is the same, which caused lock_acquired() to be called, we have a nice deadlock. This patch reworks the udelay code for the interrupts disabled case to immediately leave the low level interrupt handler when the clock comparator interrupt happens. That way no C code is being called and the deadlock cannot happen anymore. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Christian Borntraeger 提交于
The program parameter can be used to mark hardware samples with some token. Previously, it was used to mark guest samples only. Improve the program parameter doubleword by combining two parts, the leftmost LPP part and the rightmost PID part. Set the PID part for processes by using the task PID. To distinguish host and guest samples for the kernel (PID part is zero), the guest must always set the program paramater to a non-zero value. Use the leftmost bit in the LPP part of the program parameter to be able to detect guest kernel samples. [brueckner@linux.vnet.ibm.com]: Split __LC_CURRENT and introduced __LC_LPP. Corrected __LC_CURRENT users and adjusted assembler parts. And updated the commit message accordingly. Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Hendrik Brueckner 提交于
Various functions in entry.S perform test-under-mask instructions to test for particular bits in memory. Because test-under-mask uses a mask value of one byte, the mask value and the offset into the memory must be calculated manually. This easily introduces errors and is hard to review and read. Introduce the TSTMSK assembler macro to specify a mask constant and let the macro calculate the offset and the byte mask to generate a test-under-mask instruction. The benefit is that existing symbolic constants can now be used for tests. Also the macro checks for zero mask values and mask values that consist of multiple bytes. Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Hendrik Brueckner 提交于
Previously, the init task did not have an allocated FPU save area and saving an FPU state was not possible. Now if the vector extension is always enabled, provide a static FPU save area to save FPU states of vector instructions that can be executed quite early. Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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