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* s390/kernel: remove save_fpu_regs() parameter and use __LC_CURRENT insteadHendrik Brueckner2015-08-031-3/+3
| | | | | | | | | | | | | All calls to save_fpu_regs() specify the fpu structure of the current task pointer as parameter. The task pointer of the current task can also be retrieved from the CPU lowcore directly. Remove the parameter definition, load the __LC_CURRENT task pointer from the CPU lowcore, and rebase the FPU structure onto the task structure. Apply the same approach for the load_fpu_regs() function. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/kernel: lazy restore fpu registersHendrik Brueckner2015-07-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Improve the save and restore behavior of FPU register contents to use the vector extension within the kernel. The kernel does not use floating-point or vector registers and, therefore, saving and restoring the FPU register contents are performed for handling signals or switching processes only. To prepare for using vector instructions and vector registers within the kernel, enhance the save behavior and implement a lazy restore at return to user space from a system call or interrupt. To implement the lazy restore, the save_fpu_regs() sets a CPU information flag, CIF_FPU, to indicate that the FPU registers must be restored. Saving and setting CIF_FPU is performed in an atomic fashion to be interrupt-safe. When the kernel wants to use the vector extension or wants to change the FPU register state for a task during signal handling, the save_fpu_regs() must be called first. The CIF_FPU flag is also set at process switch. At return to user space, the FPU state is restored. In particular, the FPU state includes the floating-point or vector register contents, as well as, vector-enablement and floating-point control. The FPU state restore and clearing CIF_FPU is also performed in an atomic fashion. For KVM, the restore of the FPU register state is performed when restoring the general-purpose guest registers before the SIE instructions is started. Because the path towards the SIE instruction is interruptible, the CIF_FPU flag must be checked again right before going into SIE. If set, the guest registers must be reloaded again by re-entering the outer SIE loop. This is the same behavior as if the SIE critical section is interrupted. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/kernel: introduce fpu-internal.h with fpu helper functionsHendrik Brueckner2015-07-221-31/+11
| | | | | | | | | Introduce a new structure to manage FP and VX registers. Refactor the save and restore of floating point and vector registers with a set of helper functions in fpu-internal.h. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/kernel: use test_fp_ctl() to verify the floating-point control wordHendrik Brueckner2015-07-221-3/+3
| | | | | | | | Use the test_fp_ctl() to test the floating-point control word for validity and use restore_fp_ctl() to set it in load_sigregs. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'exec_domain_rip_v2' of ↵Linus Torvalds2015-04-151-12/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc Pull exec domain removal from Richard Weinberger: "This series removes execution domain support from Linux. The idea behind exec domains was to support different ABIs. The feature was never complete nor stable. Let's rip it out and make the kernel signal handling code less complicated" * 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc: (27 commits) arm64: Removed unused variable sparc: Fix execution domain removal Remove rest of exec domains. arch: Remove exec_domain from remaining archs arc: Remove signal translation and exec_domain xtensa: Remove signal translation and exec_domain xtensa: Autogenerate offsets in struct thread_info x86: Remove signal translation and exec_domain unicore32: Remove signal translation and exec_domain um: Remove signal translation and exec_domain tile: Remove signal translation and exec_domain sparc: Remove signal translation and exec_domain sh: Remove signal translation and exec_domain s390: Remove signal translation and exec_domain mn10300: Remove signal translation and exec_domain microblaze: Remove signal translation and exec_domain m68k: Remove signal translation and exec_domain m32r: Remove signal translation and exec_domain m32r: Autogenerate offsets in struct thread_info frv: Remove signal translation and exec_domain ...
| * s390: Remove signal translation and exec_domainRichard Weinberger2015-04-121-12/+2
| | | | | | | | | | | | | | | | As execution domain support is gone we can remove signal translation from the signal code and remove exec_domain from thread_info. Signed-off-by: Richard Weinberger <richard@nod.at>
* | s390: remove 31 bit supportHeiko Carstens2015-03-251-10/+0
|/ | | | | | | | | | | | | | | | | | | Remove the 31 bit support in order to reduce maintenance cost and effectively remove dead code. Since a couple of years there is no distribution left that comes with a 31 bit kernel. The 31 bit kernel also has been broken since more than a year before anybody noticed. In addition I added a removal warning to the kernel shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning message") which let everybody know about the plan to remove 31 bit code. We didn't get any response. Given that the last 31 bit only machine was introduced in 1999 let's remove the code. Anybody with 31 bit user space code can still use the compat mode. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* all arches, signal: move restart_block to struct task_structAndy Lutomirski2015-02-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* s390/signal: add sparse annotationsMartin Schwidefsky2014-11-031-1/+1
| | | | | | | | | | | | | | | | Fix the following warnings from the sparse code checker: arch/s390/kernel/signal.c:374:38: warning: cast removes address space of expression arch/s390/kernel/signal.c:374:65: warning: incorrect type in initializer (different address spaces) arch/s390/kernel/signal.c:374:65: expected unsigned short [noderef] [usertype] <asn:1>*svc arch/s390/kernel/signal.c:374:65: got void * arch/s390/kernel/compat_signal.c:437:38: warning: cast removes address space of expression arch/s390/kernel/compat_signal.c:437:65: warning: incorrect type in initializer (different address spaces) arch/s390/kernel/compat_signal.c:437:65: expected unsigned short [noderef] [usertype] <asn:1>*svc arch/s390/kernel/compat_signal.c:437:65: got void * Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: add support for vector extensionMartin Schwidefsky2014-10-091-65/+231
| | | | | | | | | | | | | | The vector extension introduces 32 128-bit vector registers and a set of instruction to operate on the vector registers. The kernel can control the use of vector registers for the problem state program with a bit in control register 0. Once enabled for a process the kernel needs to retain the content of the vector registers on context switch. The signal frame is extended to include the vector registers. Two new register sets NT_S390_VXRS_LOW and NT_S390_VXRS_HIGH are added to the regset interface for the debugger and core dumps. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: Use get_signal() signal_setup_done()Richard Weinberger2014-08-061-46/+32
| | | | | | | Use the more generic functions get_signal() signal_setup_done() for signal delivery. Signed-off-by: Richard Weinberger <richard@nod.at>
* s390: split TIF bits into CIF, PIF and TIF bitsMartin Schwidefsky2014-05-201-6/+6
| | | | | | | | | | The oi and ni instructions used in entry[64].S to set and clear bits in the thread-flags are not guaranteed to be atomic in regard to other CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific bits. Updates on the TIF bits are done with atomic instructions, updates on CPU and pt_regs bits are done with non-atomic instructions. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/signal: always restore saved runtime instrumentation psw bitHendrik Brueckner2013-11-201-1/+1
| | | | | | | | | | | | | | | | Commit "s390: fix handling of runtime instrumentation psw bit" (5ebf250dab) changed the behavior of setting the runtime instrumentation psw bit. This commit restores the original logic: 1. When returning from the signal handler, the runtime instrumentation psw bit is restored to its saved state. 2. If the runtime instrumentation psw bit is enabled during the signal handler, it is always turned off when leaving the signal handler. The saved state is restored as described in 1. That also implies that turning on runtime instrumentation in the signal handler is only effective while running in the signal context. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
* s390: fix handling of runtime instrumentation psw bitHeiko Carstens2013-10-241-2/+5
| | | | | | | | | | | | | | | | | | | | | | Fix the following bugs: - When returning from a signal the signal handler copies the saved psw mask from user space and uses parts of it. Especially it restores the RI bit unconditionally. If however the machine doesn't support RI, or RI is disabled for the task, the last lpswe instruction which returns to user space will generate a specification exception. To fix this check if the RI bit is allowed to be set and kill the task if not. - In the compat mode signal handler code the RI bit of the psw mask gets propagated to the mask of the return psw: if user space enables RI in the signal handler, RI will also be enabled after the signal handler is finished. This is a different behaviour than with 64 bit tasks. So change this to match the 64 bit semantics, which restores the original RI bit value. - Fix similar oddities within the ptrace code as well. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: fix save and restore of the floating-point-control registerMartin Schwidefsky2013-10-241-8/+13
| | | | | | | | | | | | | | | | | | | | | | The FPC_VALID_MASK has been used to check the validity of the value to be loaded into the floating-point-control register. With the introduction of the floating-point extension facility and the decimal-floating-point additional bits have been defined which need to be checked in a non straight forward way. So far these bits have been ignored which can cause an incorrect results for decimal- floating-point operations, e.g. an incorrect rounding mode to be set after signal return. The static check with the FPC_VALID_MASK is replaced with a trial load of the floating-point-control value, see test_fp_ctl. In addition an information leak with the padding word between the floating-point-control word and the floating-point registers in the s390_fp_regs is fixed. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/compat,signal: change return values to -EFAULTHeiko Carstens2013-10-241-6/+5
| | | | | | | | | | | | | Instead of returnin the number of bytes not copied and/or -EFAULT let the signal handler helper functions always return -EFAULT if a user space access failed. This doesn't fix a bug in the current code, but makes is harder to get it wrong in the future. Also "smatch" won't complain anymore about the fact that the number of remaining bytes gets returned instead of -EFAULT. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/uaccess: always run the kernel in home spaceMartin Schwidefsky2013-10-241-6/+6
| | | | | | | Simplify the uaccess code by removing the user_mode=home option. The kernel will now always run in the home space mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/uaccess: remove pointless access_ok() checksHeiko Carstens2013-02-281-8/+0
| | | | | | | | access_ok() always returns 'true' on s390. Therefore all calls are quite pointless and can be removed. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: switch to generic old sigaction()Al Viro2013-02-031-31/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* s390: switch to generic old sigsuspendAl Viro2013-02-031-10/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* s390: switch to generic sigaltstackAl Viro2013-02-031-13/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* s390/ptrace: race of single stepping vs signal deliveryMartin Schwidefsky2012-11-231-0/+2
| | | | | | | | | | | | | | | | | | The current single step code is racy in regard to concurrent delivery of signals. If a signal is delivered after a PER program check occurred but before the TIF_PER_TRAP bit has been checked in entry[64].S the code clears TIF_PER_TRAP and then calls do_signal. This is wrong, if the instruction completed (or has been suppressed) a SIGTRAP should be delivered to the debugger in any case. Only if the instruction has been nullified the SIGTRAP may not be send. The new logic always sets TIF_PER_TRAP if the program check indicates PER tracing but removes it again for all program checks that are nullifying. The effect is that for each change in the PSW address we now get a single SIGTRAP. Reported-by: Andreas Arnez <arnez@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/signal: set correct address space controlMartin Schwidefsky2012-11-121-2/+12
| | | | | | | | | | | | | | | | | | If user space is running in primary mode it can switch to secondary or access register mode, this is used e.g. in the clock_gettime code of the vdso. If a signal is delivered to the user space process while it has been running in access register mode the signal handler is executed in access register mode as well which will result in a crash most of the time. Set the address space control bits in the PSW to the default for the execution of the signal handler and make sure that the previous address space control is restored on signal return. Take care that user space can not switch to the kernel address space by modifying the registers in the signal frame. Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/comments: unify copyright messages and remove file namesHeiko Carstens2012-07-201-3/+1
| | | | | | | | | | | | | | Remove the file name from the comment at top of many files. In most cases the file name was wrong anyway, so it's rather pointless. Also unify the IBM copyright statement. We did have a lot of sightly different statements and wanted to change them one after another whenever a file gets touched. However that never happened. Instead people start to take the old/"wrong" statements to use as a template for new files. So unify all of them in one go. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* new helper: signal_delivered()Al Viro2012-06-011-5/+1
| | | | | | | | | | | | | | Does block_sigmask() + tracehook_signal_handler(); called when sigframe has been successfully built. All architectures converted to it; block_sigmask() itself is gone now (merged into this one). I'm still not too happy with the signature, but that's a separate story (IMO we need a structure that would contain signal number + siginfo + k_sigaction, so that get_signal_to_deliver() would fill one, signal_delivered(), handle_signal() and probably setup...frame() - take one). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from setAl Viro2012-06-011-5/+0
| | | | | | | | Only 3 out of 63 do not. Renamed the current variant to __set_current_blocked(), added set_current_blocked() that will exclude unblockable signals, switched open-coded instances to it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* pull clearing RESTORE_SIGMASK into block_sigmask()Al Viro2012-06-011-21/+11
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: sigmask_to_save()Al Viro2012-06-011-6/+1
| | | | | | | replace boilerplate "should we use ->saved_sigmask or ->blocked?" with calls of obvious inlined helper... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: restore_saved_sigmask()Al Viro2012-06-011-4/+1
| | | | | | | | | first fruits of ..._restore_sigmask() helpers: now we can take boilerplate "signal didn't have a handler, clear RESTORE_SIGMASK and restore the blocked mask from ->saved_mask" into a common helper. Open-coded instances switched... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* move key_repace_session_keyring() into tracehook_notify_resume()Al Viro2012-05-231-2/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: sigsuspend()Al Viro2012-05-211-8/+1
| | | | | | | | | guts of saved_sigmask-based sigsuspend/rt_sigsuspend. Takes kernel sigset_t *. Open-coded instances replaced with calling it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* s390: remove dead code from signal handlerMartin Schwidefsky2012-05-161-16/+0
| | | | | | | | | The code in entry[64].S calls do_signal only on return to user space. user_mode(regs) is true for every calls to do_signal, it is unnecessary to recheck user_mode at the start of do_signal and the legacy signal stack switching path in get_sigframe is never reached. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Disintegrate asm/system.h for S390David Howells2012-03-281-0/+1
| | | | | | | Disintegrate asm/system.h for S390. Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-s390@vger.kernel.org
* [S390] Use block_sigmask()Matt Fleming2012-03-111-5/+1
| | | | | | | | | | | | | | | | | | Use the new helper function introduced in commit 5e6292c0f28f ("signal: add block_sigmask() for adding sigmask to current->blocked") which centralises the code for updating current->blocked after successfully delivering a signal and reduces the amount of duplicate code across architectures. In the past some architectures got this code wrong, so using this helper function should stop that from happening again. Cc: Oleg Nesterov <oleg@redhat.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: linux-s390@vger.kernel.org Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* compat: fix compile breakage on s390Heiko Carstens2012-02-271-1/+0
| | | | | | | | | | | The new is_compat_task() define for the !COMPAT case in include/linux/compat.h conflicts with a similar define in arch/s390/include/asm/compat.h. This is the minimal patch which fixes the build issues. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [S390] cleanup trap handlingMartin Schwidefsky2011-12-271-8/+12
| | | | | | | | | | | | Move the program interruption code and the translation exception identifier to the pt_regs structure as 'int_code' and 'int_parm_long' and make the first level interrupt handler in entry[64].S store the two values. That makes it possible to drop 'prot_addr' and 'trap_no' from the thread_struct and to reduce the number of arguments to a lot of functions. Finally un-inline do_trap. Overall this saves 5812 bytes in the .text section of the 64 bit kernel. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] ptrace inferior call interactions with TIF_SYSCALLMartin Schwidefsky2011-12-011-5/+3
| | | | | | | | | The TIF_SYSCALL bit needs to be cleared if the debugger changes the state of the ptraced process in regard to the presence of a system call. Otherwise the system call will be restarted although the debugger set up an inferior call. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] allow all addressing modesMartin Schwidefsky2011-10-301-4/+10
| | | | | | | | | | | | | | | | | The user space program can change its addressing mode between the 24-bit, 31-bit and the 64-bit mode if the kernel is 64 bit. Currently the kernel always forces the standard amode on signal delivery and signal return and on ptrace: 64-bit for a 64-bit process, 31-bit for a compat process and 31-bit kernels. Change the signal and ptrace code to allow the full range of addressing modes. Signal handlers are run in the standard addressing mode for the process. One caveat is that even an 31-bit compat process can switch to the 64-bit mode. The next signal will switch back into the 31-bit mode and there is no room in the 31-bit compat signal frame to store the information that the program came from the 64-bit mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] cleanup psw related bits and piecesMartin Schwidefsky2011-10-301-3/+4
| | | | | | | | | | Split out addressing mode bits from PSW_BASE_BITS, rename PSW_BASE_BITS to PSW_MASK_BASE, get rid of psw_user32_bits, remove unused function enabled_wait(), introduce PSW_MASK_USER, and drop PSW_MASK_MERGE macros. Change psw_kernel_bits / psw_user_bits to contain only the bits that are always set in the respective mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] add TIF_SYSCALL thread flagMartin Schwidefsky2011-10-301-7/+12
| | | | | | | | | | Add an explicit TIF_SYSCALL bit that indicates if a task is inside a system call. The svc_code in the pt_regs structure is now only valid if TIF_SYSCALL is set. With this definition TIF_RESTART_SVC can be replaced with TIF_SYSCALL. Overall do_signal is a bit more readable and it saves a few lines of code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] addressing mode limits and psw address wrappingMartin Schwidefsky2011-10-301-2/+3
| | | | | | | | | An instruction with an address right below the adress limit for the current addressing mode will wrap. The instruction restart logic in the protection fault handler and the signal code need to follow the wrapping rules to find the correct instruction address. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] signal race with restarting system callsMartin Schwidefsky2011-10-301-54/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For a ERESTARTNOHAND/ERESTARTSYS/ERESTARTNOINTR restarting system call do_signal will prepare the restart of the system call with a rewind of the PSW before calling get_signal_to_deliver (where the debugger might take control). For A ERESTART_RESTARTBLOCK restarting system call do_signal will set -EINTR as return code. There are two issues with this approach: 1) strace never sees ERESTARTNOHAND, ERESTARTSYS, ERESTARTNOINTR or ERESTART_RESTARTBLOCK as the rewinding already took place or the return code has been changed to -EINTR 2) if get_signal_to_deliver does not return with a signal to deliver the restart via the repeat of the svc instruction is left in place. This opens a race if another signal is made pending before the system call instruction can be reexecuted. The original system call will be restarted even if the second signal would have ended the system call with -EINTR. These two issues can be solved by dropping the early rewind of the system call before get_signal_to_deliver has been called and by using the TIF_RESTART_SVC magic to do the restart if no signal has to be delivered. The only situation where the system call restart via the repeat of the svc instruction is appropriate is when a SA_RESTART signal is delivered to user space. Unfortunately this breaks inferior calls by the debugger again. The system call number and the length of the system call instruction is lost over the inferior call and user space will see ERESTARTNOHAND/ ERESTARTSYS/ERESTARTNOINTR/ERESTART_RESTARTBLOCK. To correct this a new ptrace interface is added to save/restore the system call number and system call instruction length. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] signal: use set_restore_sigmask() helperHeiko Carstens2011-08-031-1/+1
| | | | | | | | We should call set_restore_sigmask() instead of directly setting TIF_RESTORE_SIGMASK. This change should have been done three years earlier... see 4e4c22 "signals: add set_restore_sigmask". Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [S390] signal: convert to use set_current_blocked()Heiko Carstens2011-08-031-41/+18
| | | | | | Convert to use set_current_blocked() like x86. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [S390] ptrace cleanupMartin Schwidefsky2011-01-051-1/+1
| | | | | | | Overhaul program event recording and the code dealing with the ptrace user space interface. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] add breaking event address for user spaceMartin Schwidefsky2010-05-171-0/+2
| | | | | | | | | | | Copy the last breaking event address from the lowcore to a new field in the thread_struct on each system entry. Add a new ptrace request PTRACE_GET_LAST_BREAK and a new utrace regset REGSET_LAST_BREAK to query the last breaking event. This is useful for debugging wild branches in user space code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] use set_current_state in sigsuspendMartin Schwidefsky2010-01-271-1/+1
| | | | | | | Use set_current_state instead of a direct assignment to set the task state of the current process. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] duplicate SIGTRAP on signal delivery.Martin Schwidefsky2010-01-131-9/+1
| | | | | | | | | | The code in do_signal sets the TIF_SINGLE_STEP bit and calls tracehook_signal_handler after the signal frame has been set up. This causes two SIGTRAP signals to be delivered to the tracer. Stop setting the TIF_SINGLE_STEP bit in do_signal to get the correct number of SIGTRAPs. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]David Howells2009-09-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a keyctl to install a process's session keyring onto its parent. This replaces the parent's session keyring. Because the COW credential code does not permit one process to change another process's credentials directly, the change is deferred until userspace next starts executing again. Normally this will be after a wait*() syscall. To support this, three new security hooks have been provided: cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in the blank security creds and key_session_to_parent() - which asks the LSM if the process may replace its parent's session keyring. The replacement may only happen if the process has the same ownership details as its parent, and the process has LINK permission on the session keyring, and the session keyring is owned by the process, and the LSM permits it. Note that this requires alteration to each architecture's notify_resume path. This has been done for all arches barring blackfin, m68k* and xtensa, all of which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the replacement to be performed at the point the parent process resumes userspace execution. This allows the userspace AFS pioctl emulation to fully emulate newpag() and the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to alter the parent process's PAG membership. However, since kAFS doesn't use PAGs per se, but rather dumps the keys into the session keyring, the session keyring of the parent must be replaced if, for example, VIOCSETTOK is passed the newpag flag. This can be tested with the following program: #include <stdio.h> #include <stdlib.h> #include <keyutils.h> #define KEYCTL_SESSION_TO_PARENT 18 #define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0) int main(int argc, char **argv) { key_serial_t keyring, key; long ret; keyring = keyctl_join_session_keyring(argv[1]); OSERROR(keyring, "keyctl_join_session_keyring"); key = add_key("user", "a", "b", 1, keyring); OSERROR(key, "add_key"); ret = keyctl(KEYCTL_SESSION_TO_PARENT); OSERROR(ret, "KEYCTL_SESSION_TO_PARENT"); return 0; } Compiled and linked with -lkeyutils, you should see something like: [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 355907932 --alswrv 4043 -1 \_ keyring: _uid.4043 [dhowells@andromeda ~]$ /tmp/newpag [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 1055658746 --alswrv 4043 4043 \_ user: a [dhowells@andromeda ~]$ /tmp/newpag hello [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: hello 340417692 --alswrv 4043 4043 \_ user: a Where the test program creates a new session keyring, sticks a user key named 'a' into it and then installs it on its parent. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
* [S390] implement is_compat_taskHeiko Carstens2009-06-121-1/+2
| | | | | | | Implement is_compat_task and use it all over the place. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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