summary refs log tree commit diff stats
path: root/linux-user/signal.c (follow)
Commit message (Collapse)AuthorAgeFilesLines
...
* | Merge remote-tracking branch ↵Peter Maydell2018-03-151-30/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'remotes/vivier2/tags/linux-user-for-2.12-pull-request' into staging # gpg: Signature made Tue 13 Mar 2018 17:33:03 GMT # gpg: using RSA key F30C38BD3F2FBE3C # gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" # gpg: aka "Laurent Vivier <laurent@vivier.eu>" # gpg: aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" # Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F 5173 F30C 38BD 3F2F BE3C * remotes/vivier2/tags/linux-user-for-2.12-pull-request: linux-user: init_guest_space: Add a comment about search strategy linux-user: init_guest_space: Don't try to align if we'll reject it linux-user: init_guest_space: Clean up control flow a bit linux-user: init_guest_commpage: Add a comment about size check linux-user: init_guest_space: Clarify page alignment logic linux-user: init_guest_space: Correctly handle guest_start in commpage initialization linux-user: init_guest_space: Clean up if we can't initialize the commpage linux-user: Rename validate_guest_space => init_guest_commpage linux-user: Use #if to only call validate_guest_space for 32-bit ARM target qemu-binfmt-conf.sh: add qemu-xtensa linux-user: drop unused target_msync function linux-user: fix target_mprotect/target_munmap error return values linux-user: fix assertion in shmdt linux-user: fix mmap/munmap/mprotect/mremap/shmat linux-user: Support f_flags in statfs when available. linux-user: allows to use "--systemd ALL" with qemu-binfmt-conf.sh linux-user: Remove the unused "not implemented" signal handling stubs linux-user: Drop unicore32 code Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| * linux-user: Remove the unused "not implemented" signal handling stubsPeter Maydell2018-03-091-26/+1
| | | | | | | | | | | | | | | | | | | | | | | | Now we've dropped unicore32, all of the architectures we support for linux-user implement the signal handling routines. The dummy "just print a message" versions are unimplemented, so we can drop them entirely. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20180308144733.25615-3-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
| * linux-user: Drop unicore32 codePeter Maydell2018-03-091-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | We dropped the unicore32-linux-user target in commit 5e2b40f7271cf9 in 2016. Nobody has made any attempt to fix the issues that caused us to drop it, so remove the associated code. (The system emulation parts of unicore32 remain.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20180308144733.25615-2-peter.maydell@linaro.org> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* | aarch64-linux-user: Add support for SVE signal frame recordsRichard Henderson2018-03-091-19/+193
| | | | | | | | | | | | | | | | | | | | | | Depending on the currently selected size of the SVE vector registers, we can either store the data within the "standard" allocation, or we may beedn to allocate additional space with an EXTRA record. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180303143823.27055-6-richard.henderson@linaro.org Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* | aarch64-linux-user: Add support for EXTRA signal frame recordsRichard Henderson2018-03-091-11/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The EXTRA record allows for additional space to be allocated beyon what is currently reserved. Add code to emit and read this record type. Nothing uses extra space yet. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180303143823.27055-5-richard.henderson@linaro.org Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* | aarch64-linux-user: Remove struct target_aux_contextRichard Henderson2018-03-091-28/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This changes the qemu signal frame layout to be more like the kernel's, in that the various records are dynamically allocated rather than fixed in place by a structure. For now, all of the allocation is out of uc.tuc_mcontext.__reserved, so the allocation is actually trivial. That will change with SVE support. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180303143823.27055-4-richard.henderson@linaro.org Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* | aarch64-linux-user: Split out helpers for guest signal handlingRichard Henderson2018-03-091-50/+68
|/ | | | | | | | | | | | | | Split out helpers from target_setup_frame and target_restore_sigframe for dealing with general registers, fpsimd registers, and the end record. When we add support for sve registers, the relative positions of these will change. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180303143823.27055-3-richard.henderson@linaro.org Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* RISC-V Linux User EmulationMichael Clark2018-03-071-1/+202
| | | | | | | | Implementation of linux user emulation for RISC-V. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Sagar Karandikar <sagark@eecs.berkeley.edu> Signed-off-by: Michael Clark <mjc@sifive.com>
* target/hppa: Add control registersRichard Henderson2018-01-301-2/+2
| | | | Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
* linux-user/signal.c: Rename MC_* definesPeter Maydell2018-01-301-59/+59
| | | | | | | | | | | | | | | | | | | | | The SPARC code in linux-user/signal.c defines a set of MC_* constants. On some SPARC hosts these are also defined by sys/ucontext.h, resulting in build failures: linux-user/signal.c:2786:0: error: "MC_NGREG" redefined [-Werror] #define MC_NGREG 19 In file included from /usr/include/signal.h:302:0, from include/qemu/osdep.h:86, from linux-user/signal.c:19: /usr/include/sparc64-linux-gnu/sys/ucontext.h:59:0: note: this is the location of the previous definition # define MC_NGREG __MC_NGREG Rename all these constants to SPARC_MC_* to avoid the clash. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1517318239-15764-1-git-send-email-peter.maydell@linaro.org
* target/arm: Add aa{32, 64}_vfp_{dreg, qreg} helpersRichard Henderson2018-01-251-10/+12
| | | | | | | | | | Helpers that return a pointer into env->vfp.regs so that we isolate the logic of how to index the regs array for different cpu modes. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180119045438.28582-7-richard.henderson@linaro.org Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* linux-user: Fix endianess of aarch64 signal trampolineMichael Weiser2018-01-111-3/+7
| | | | | | | | | | | | Since for aarch64 the signal trampoline is synthesized directly into the signal frame we need to make sure the instructions end up little-endian. Otherwise the wrong endianness will cause a SIGILL upon return from the signal handler on big-endian targets. Signed-off-by: Michael Weiser <michael.weiser@gmx.de> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20171220212308.12614-4-michael.weiser@gmx.de Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* linux-user, m68k: correctly manage SR in contextLaurent Vivier2018-01-041-3/+4
| | | | | | | | | | Use cpu_m68k_get_ccr()/cpu_m68k_set_ccr() to setup and restore correctly the value of SR in the context structure. Fix target_rt_setup_ucontext(). Fixes: 3219de458c ("linux-user: correctly manage SR in ucontext") Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180104012913.30763-4-laurent@vivier.eu>
* Remove empty statementsLadi Prosek2017-12-181-1/+1
| | | | | | | | | | | | | Thanks to Laszlo Ersek for spotting the double semicolon in target/i386/kvm.c I have trivially grepped the tree for ';;' in C files. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Ladi Prosek <lprosek@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* linux-user: Restrict usage of sa_restorerRichard Henderson2017-11-071-2/+2
| | | | | | | | | | Reading and writing to an sa_restorer member that isn't supposed to exist corrupts user memory. Introduce TARGET_ARCH_HAS_SA_RESTORER, similar to the kernel's __ARCH_HAS_SA_RESTORER. Reported-by: Helge Deller <deller@gmx.de> Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* target/m68k,linux-user: manage FP registers in ucontextLaurent Vivier2017-10-161-0/+43
| | | | | | Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* Replace 'struct ucontext' with 'ucontext_t' typeKhem Raj2017-07-201-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | glibc used to have: typedef struct ucontext { ... } ucontext_t; glibc now has: typedef struct ucontext_t { ... } ucontext_t; (See https://sourceware.org/bugzilla/show_bug.cgi?id=21457 for detail and rationale for the glibc change) However, QEMU used "struct ucontext" in declarations. This is a private name and compatibility cannot be guaranteed. Switch to only using the standardized type name. Signed-off-by: Khem Raj <raj.khem@gmail.com> Message-id: 20170628204452.41230-1-raj.khem@gmail.com Cc: Kamil Rytarowski <kamil@netbsd.org> Cc: Riku Voipio <riku.voipio@iki.fi> Cc: Laurent Vivier <laurent@vivier.eu> Cc: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> [PMM: Rewrote commit message, based mostly on the one from Nathaniel McCallum] Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* linux-user/sh4: Clean env->flags on signal boundariesRichard Henderson2017-07-181-0/+3
| | | | | | | | | | | | | If a signal is delivered during the execution of a delay slot, or a gUSA region, clear those bits from the environment so that the signal handler does not start in that same state. Cleaning the bits on signal return is paranoid good sense. Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Richard Henderson <rth@twiddle.net> Message-Id: <20170718200255.31647-10-rth@twiddle.net> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
* linux-user/sh4: Notice gUSA regions during signal deliveryRichard Henderson2017-07-181-0/+28
| | | | | | | | | | | We translate gUSA regions atomically in a parallel context. But in a serial context a gUSA region may be interrupted. In that case, restart the region as the kernel would. Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Signed-off-by: Richard Henderson <rth@twiddle.net> Message-Id: <20170718200255.31647-9-rth@twiddle.net> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
* target/openrisc: implement shadow registersStafford Horne2017-05-041-8/+9
| | | | | | | | | | | | | | | | Shadow registers are part of the openrisc spec along with sr[cid], as part of the fast context switching feature. When exceptions occur, instead of having to save registers to the stack if enabled the CID will increment and a new set of registers will be available. This patch only implements shadow registers which can be used as extra scratch registers via the mfspr and mtspr if required. This is implemented in a way where it would be easy to add on the fast context switching, currently cid is hardcoded to 0. This is need for openrisc linux smp kernels to boot correctly. Signed-off-by: Stafford Horne <shorne@gmail.com>
* linux-user: fix do_rt_sigreturn on m68k linux userspace emulationMichael Karcher2017-02-271-2/+1
| | | | | | | | | | | | | | | do_rt_sigreturn uses an uninitialised local variable instead of fetching the old signal mask directly from the signal frame when restoring the mask, so the signal mask is undefined after do_rt_sigreturn. As the signal frame data is in target-endian order, target_to_host_sigset instead of target_to_host_sigset_internal is required. do_sigreturn is correct in using target_to_host_sigset_internal, because get_user already did the endianness conversion. Signed-off-by: Michael Karcher <karcher@physik.fu-berlin.de> Signed-off-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20170225110517.2832-3-laurent@vivier.eu>
* linux-user: correctly manage SR in ucontextLaurent Vivier2017-02-271-2/+3
| | | | | | | | Use cpu_m68k_get_ccr()/cpu_m68k_set_ccr() to setup and restore correctly the value of SR in the ucontext structure Signed-off-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20170225110517.2832-2-laurent@vivier.eu>
* linux-user: Add signal handling support for x86_64Pranith Kumar2017-02-271-51/+227
| | | | | | | | | | | | | Note that x86_64 has only _rt signal handlers. This implementation attempts to share code with the x86_32 implementation. CC: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Allan Wirth <awirth@akamai.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <20170226165345.8757-1-bobby.prani@gmail.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* linux-user: fill target sigcontext struct accordinglyJose Ricardo Ziviani2017-02-161-0/+5
| | | | | | | | | | | | | | | | | | | A segfault is noticed when an emulated program uses any of ucontext regs fields. Risu detected this issue in the following operation when handling a signal: ucontext_t *uc = (ucontext_t*)uc; uc->uc_mcontext.regs->nip += 4; but this works fine: uc->uc_mcontext.gp_regs[PT_NIP] += 4; This patch set regs to a valid location as well as other sigcontext fields. Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-Id: <1485900317-3256-1-git-send-email-joserz@linux.vnet.ibm.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
* nios2: Add usermode binaries emulationMarek Vasut2017-01-241-2/+237
| | | | | | | | | | | | | | | Add missing bits for qemu-user required for emulating Altera Nios2 userspace binaries. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Chris Wulff <crwulff@gmail.com> Cc: Jeff Da Silva <jdasilva@altera.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Sandra Loosemore <sandra@codesourcery.com> Cc: Yves Vandervennet <yvanderv@altera.com> Reviewed-by: Alexander Graf <agraf@suse.de> Message-Id: <20170118220146.489-4-marex@denx.de> Signed-off-by: Richard Henderson <rth@twiddle.net>
* linux-user: Add HPPA signal handlingRichard Henderson2017-01-231-1/+190
| | | | Signed-off-by: Richard Henderson <rth@twiddle.net>
* ppc: Fix signal delivery in ppc-user and ppc64-userBenjamin Herrenschmidt2016-09-231-37/+87
| | | | | | | | | | | | | | | | | | | | | There were a number of bugs in the implementation: - The structure alignment was wrong for 64-bit. - Also 64-bit only does RT signals. - On 64-bit, we need to put a pointer to the (aligned) vector registers in the frame and use it for restoring - We had endian bugs when saving/restoring vector registers - My recent fixes for exception NIP broke sigreturn in user mode causing us to resume one instruction too far. - Add VSR second halves Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* linux-user: Fix incorrect offset of tuc_stack in ARM do_sigframe_return_v2Timothy E Baldwin2016-09-211-4/+14
| | | | | | | | | | | | | struct target_ucontext_v2 is not at the begining of the signal frame, therefore do_sigaltstack was being passed bogus arguments. As the offset depends on the type of signal frame fixed by passing in the beginning of the context from do_sigreturn_v2 and do_rt_sigreturn_v2. Suggested-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Implement force_sigsegv() via force_sig()Peter Maydell2016-09-211-15/+2
| | | | | | | | | | Now that we have a force_sig() with the semantics we need, we can implement force_sigsegv() to call it rather than open-coding the call to queue_signal(). Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: SIGSEGV from sigreturn need not be fatalPeter Maydell2016-09-211-27/+54
| | | | | | | | | | | | | | | | | | | | | | | If the sigreturn syscall fails to read memory then this causes a SIGSEGV, but this is not necessarily a fatal signal -- the guest process can catch it. We don't implement this correctly because the behaviour of QEMU's force_sig() function has drifted away from the kernel function of the same name -- ours now does "always do a guest core dump and abort execution", whereas the kernel version simply forces the guest to take a signal, which may or may not eventually cause a core dump. Rename our force_sig() to dump_core_and_abort(), and provide a force_sig() which acts more like the kernel version as the sigreturn implementations expect it to. Since force_sig() now returns, we must update all the callsites to return -TARGET_QEMU_ESIGRETURN so that the main loop doesn't change the guest registers before the signal handler is invoked. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: ARM: Give SIGSEGV if signal frame setup failsPeter Maydell2016-09-211-6/+17
| | | | | | | | | | | The 32-bit ARM signal frame setup code was just bailing out on error returns from lock_user_struct calls, without generating the SIGSEGV that should happen here. Wire up error return codes to call force_sigsegv(). Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: SIGSEGV on signal entry need not be fatalPeter Maydell2016-09-211-38/+49
| | | | | | | | | | | | | A failed write to memory trying to set up the signal frame should trigger a SIGSEGV, but this need not be fatal: the guest has a chance to catch it. Implement this via a force_sigsegv() function with the same behaviour as the kernel function of that name: make sure that we don't try to re-take a failed SIGSEGV, and force a synchronous signal. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Pass si_type information to queue_signal() explicitlyPeter Maydell2016-09-211-7/+3
| | | | | | | | | | | | Instead of assuming in queue_signal() that all callers are passing a siginfo structure which uses the _sifields._sigfault part of the union (and thus a si_type of QEMU_SI_FAULT), make callers pass the si_type they require in as an argument. [RV adjusted to apply] Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Recheck for pending synchronous signals tooPeter Maydell2016-09-211-2/+5
| | | | | | | | | | | | | In process_pending_signals() we restart the scan of possible pending signals after calling handle_pending_signal() in case some other signal has been generated. This rescan should also include a check for a new synchronous signal since those are in fact the only kind of new signal that the signal frame setup process might produce. Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: report signals being taken in strace outputPeter Maydell2016-09-211-0/+4
| | | | | | | | | | | Native strace reports when the process being traced takes a signal: --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} --- Report something similar when QEMU is doing its internal strace of the guest process and is about to deliver it a signal. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user,s390x: remove useless castLaurent Vivier2016-09-151-1/+1
| | | | | | | | | | This patch is the result of coccinelle script scripts/coccinelle/typecast.cocci CC: Riku Voipio <riku.voipio@iki.fi> CC: Alexander Graf <agraf@suse.de> Signed-off-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
* linux-user: Forget about synchronous signal once it is deliveredPeter Maydell2016-07-191-4/+4
| | | | | | | | | | | | | | | | | | Commit 655ed67c2a248cf which switched synchronous signals to benig recorded in ts->sync_signal rather than in a queue with every other signal had a bug: we failed to clear the flag indicating that a synchronous signal was pending when we delivered it. This meant that we would take the signal again and again every time the guest made a syscall. (This is a bug introduced in my refactoring of Timothy Baldwin's original code.) Fix this by passing in the struct emulated_sigtable* to handle_pending_signal(), so that we clear the pending flag in the ts->sync_signal struct when handling a synchronous signal. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Don't use sigfillset() on uc->uc_sigmaskPeter Maydell2016-06-261-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel and libc have different ideas about what a sigset_t is -- for the kernel it is only _NSIG / 8 bytes in size (usually 8 bytes), but for libc it is much larger, 128 bytes. In most situations the difference doesn't matter, because if you pass a pointer to a libc sigset_t to the kernel it just acts on the first 8 bytes of it, but for the ucontext_t* argument to a signal handler it trips us up. The kernel allocates this ucontext_t on the stack according to its idea of the sigset_t type, but the type of the ucontext_t defined by the libc headers uses the libc type, and so do the manipulator functions like sigfillset(). This means that (1) sizeof(uc->uc_sigmask) is much larger than the actual space used on the stack (2) sigfillset(&uc->uc_sigmask) will write garbage 0xff bytes off the end of the structure, which can trash data that was on the stack before the signal handler was invoked, and may result in a crash after the handler returns To avoid this, we use a memset() of the correct size to fill the signal mask rather than using the libc function. This fixes a problem where we would crash at least some of the time on an i386 host when a signal was taken. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Avoid possible misalignment in host_to_target_siginfo()Peter Maydell2016-06-241-2/+11
| | | | | | | | | | | | | | | | | | | | host_to_target_siginfo() is implemented by a combination of host_to_target_siginfo_noswap() followed by tswap_siginfo(). The first of these two functions assumes that the target_siginfo_t it is writing to is correctly aligned, but the pointer passed into host_to_target_siginfo() is directly from the guest and might be misaligned. Use a local variable to avoid this problem. (tswap_siginfo() does now correctly handle a misaligned destination.) We have to add a memset() to host_to_target_siginfo_noswap() to avoid some false positive "may be used uninitialized" warnings from gcc about subfields of the _sifields union if it chooses to inline both tswap_siginfo() and host_to_target_siginfo_noswap() into host_to_target_siginfo(). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Peter Maydell <riku.voipio@linaro.org>
* coccinelle: Remove unnecessary variables for function return valueEduardo Habkost2016-06-201-11/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Use Coccinelle script to replace 'ret = E; return ret' with 'return E'. The script will do the substitution only when the function return type and variable type are the same. Manual fixups: * audio/audio.c: coding style of "read (...)" and "write (...)" * block/qcow2-cluster.c: wrap line to make it shorter * block/qcow2-refcount.c: change indentation of wrapped line * target-tricore/op_helper.c: fix coding style of "remainder|quotient" * target-mips/dsp_helper.c: reverted changes because I don't want to argue about checkpatch.pl * ui/qemu-pixman.c: fix line indentation * block/rbd.c: restore blank line between declarations and statements Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Message-Id: <1465855078-19435-4-git-send-email-ehabkost@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Unused Coccinelle rule name dropped along with a redundant comment; whitespace touched up in block/qcow2-cluster.c; stale commit message paragraph deleted] Signed-off-by: Markus Armbruster <armbru@redhat.com>
* linux-user: Avoid possible misalignment in target_to_host_siginfo()Peter Maydell2016-06-081-7/+12
| | | | | | | | | Reimplement target_to_host_siginfo() to use __get_user(), which handles possibly misaligned source guest structures correctly. Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Use both si_code and si_signo when converting siginfo_tPeter Maydell2016-06-071-49/+116
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The siginfo_t struct includes a union. The correct way to identify which fields of the union are relevant is complicated, because we have to use a combination of the si_code and si_signo to figure out which of the union's members are valid. (Within the host kernel it is always possible to tell, but the kernel carefully avoids giving userspace the high 16 bits of si_code, so we don't have the information to do this the easy way...) We therefore make our best guess, bearing in mind that a guest can spoof most of the si_codes via rt_sigqueueinfo() if it likes. Once we have made our guess, we record it in the top 16 bits of the si_code, so that tswap_siginfo() later can use it. tswap_siginfo() then strips these top bits out before writing si_code to the guest (sign-extending the lower bits). This fixes a bug where fields were sometimes wrong; in particular the LTP kill10 test went into an infinite loop because its signal handler got a si_pid value of 0 rather than the pid of the sending process. As part of this change, we switch to using __put_user() in the tswap_siginfo code which writes out the byteswapped values to the target memory, in case the target memory pointer is not sufficiently aligned for the host CPU's requirements. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Block signals during sigaction() handlingTimothy E Baldwin2016-06-071-3/+9
| | | | | | | | | | | | | | Block signals while emulating sigaction. This is a non-interruptible syscall, and using block_signals() avoids races where the host signal handler is invoked and tries to examine the signal handler data structures while we are updating them. Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-29-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: expanded commit message] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Queue synchronous signals separatelyTimothy E Baldwin2016-06-071-32/+42
| | | | | | | | | | | | | | | | | | | | | | | | If a synchronous signal and an asynchronous signal arrive near simultaneously, and the signal number of the asynchronous signal is lower than that of the synchronous signal the the handler for the asynchronous would be called first, and then the handler for the synchronous signal would be called within or after the first handler with an incorrect context. This is fixed by queuing synchronous signals separately. Note that this does risk delaying a asynchronous signal until the synchronous signal handler returns rather than handling the signal on another thread, but this seems unlikely to cause problems for real guest programs and is unavoidable unless we could guarantee to roll back and reexecute whatever guest instruction caused the synchronous signal (which would be a bit odd if we've already logged its execution, for instance, and would require careful analysis of all guest CPUs to check it was possible in all cases). Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-24-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: added a comment] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Remove real-time signal queuingTimothy E Baldwin2016-06-071-57/+13
| | | | | | | | | | | | | | | As host signals are now blocked whenever guest signals are blocked, the queue of realtime signals is now in Linux. The QEMU queue is now redundant and can be removed. (We already did not queue non-RT signals, and none of the calls to queue_signal() except the one in host_signal_handler() pass an RT signal number.) Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-23-git-send-email-T.E.Baldwin99@members.leeds.ac.uk Reviewed-by: Peter Maydell <peter.maydell@linaro.org> [PMM: minor commit message tweak] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Remove redundant default action check in queue_signal()Timothy E Baldwin2016-06-071-37/+0
| | | | | | | | | | | | | | Both queue_signal() and process_pending_signals() did check for default actions of signals, this is redundant and also causes fatal and stopping signals to incorrectly cause guest system calls to be interrupted. The code in queue_signal() is removed. Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-21-git-send-email-T.E.Baldwin99@members.leeds.ac.uk Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Fix race between multiple signalsPeter Maydell2016-06-071-49/+114
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If multiple host signals are received in quick succession they would be queued in TaskState then delivered to the guest in spite of signals being supposed to be blocked by the guest signal handler's sa_mask. Fix this by decoupling the guest signal mask from the host signal mask, so we can have protected sections where all host signals are blocked. In particular we block signals from when host_signal_handler() queues a signal from the guest until process_pending_signals() has unqueued it. We also block signals while we are manipulating the guest signal mask in emulation of sigprocmask and similar syscalls. Blocking host signals also ensures the correct behaviour with respect to multiple threads and the overrun count of timer related signals. Alas blocking and queuing in qemu is still needed because of virtual processor exceptions, SIGSEGV and SIGBUS. Blocking signals inside process_pending_signals() protects against concurrency problems that would otherwise happen if host_signal_handler() ran and accessed the signal data structures while process_pending_signals() was manipulating them. Since we now track the guest signal mask separately from that of the host, the sigsuspend system calls must track the signal mask passed to them, because when we process signals as we leave the sigsuspend the guest signal mask in force is that passed to sigsuspend. Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-19-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: make signal_pending a simple flag rather than a word with two flag bits; ensure we don't call block_signals() twice in sigreturn codepaths; document and assert() the guarantee that using do_sigprocmask() to get the current mask never fails; use the qemu atomics.h functions rather than raw volatile variable access; add extra commentary and documentation; block SIGSEGV/SIGBUS in block_signals() and in process_pending_signals() because they can't occur synchronously here; check the right do_sigprocmask() call for errors in ssetmask syscall; expand commit message; fixed sigsuspend() hanging] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Factor out uses of do_sigprocmask() from sigreturn codePeter Maydell2016-06-071-23/+32
| | | | | | | | | | | | | | All the architecture specific handlers for sigreturn include calls to do_sigprocmask(SIGSETMASK, &set, NULL) to set the signal mask from the uc_sigmask in the context being restored. Factor these out into calls to a set_sigmask() function. The next patch will want to add code which is not run when setting the signal mask via do_sigreturn, and this change allows us to separate the two cases. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Fix stray tab-indentPeter Maydell2016-06-071-1/+2
| | | | | | | | Fix a stray tab-indented linux in linux-user/signal.c. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
* linux-user: Move handle_pending_signal() to avoid need for declarationPeter Maydell2016-06-071-23/+21
| | | | | | | | | Move the handle_pending_signal() function above process_pending_signals() to avoid the need for a forward declaration. (Whitespace only change.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>