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2017-02-14linux-user: Fix s390x safe-syscall for z900Richard Henderson
The LT instruction was added in the extended immediate facility introduced with the z9-109 processor. Cc: Riku Voipio <riku.voipio@iki.fi> Reported-by: Michael Tokarev <mjt@tls.msk.ru> Fixes: c9bc3437a905b660561a26cd4ecc64579843267b Suggested-by: Aurelien Jarno <aurelien@aurel32.net> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-07-12linux-user: Clean up hostdep.h header guardsMarkus Armbruster
These headers all use QEMU_HOSTDEP_H as header guard symbol. Reuse of the same guard symbol in multiple headers is okay as long as they cannot be included together. Since we can avoid guard symbol reuse easily, do so: use guard symbol $target_HOSTDEP_H for linux-user/host/$target/hostdep.h. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-07linux-user: Fix i386 safe-syscall.SRichard Henderson
Clang insists that "cmp" is ambiguous with a memory destination, requiring an explicit size suffix. There was a true error in the use of .cfi_def_cfa_offset in the epilogue, but changing to use the proper .cfi_adjust_cfa_offset runs afoul of a clang bug wrt .cfi_restore_state. Better to fold the two epilogues so that we don't trigger the bug. Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-06-26linux-user: Provide safe_syscall for ppc64Richard Henderson
Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-26linux-user: Provide safe_syscall for s390xRichard Henderson
Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-26linux-user: Provide safe_syscall for aarch64Richard Henderson
Signed-off-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org> [RV] Updated syscall argument comment to match code
2016-06-26linux-user: Provide safe_syscall for armRichard Henderson
Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-26linux-user: Provide safe_syscall for i386Richard Henderson
Signed-off-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-26linux-user: fix x86_64 safe_syscallRichard Henderson
Do what the comment says, test for signal_pending non-zero, rather than the current code which tests for bit 0 non-zero. Signed-off-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2016-06-26linux-user: Create a hostdep.h for each host architecturePeter Maydell
In commit 4d330cee37a21 a new hostdep.h file was added, with the intent that host architectures which needed one could provide it, and the build system would automatically fall back to a generic version if there was no version for the host architecture. Although this works, it has a flaw: if a subsequent commit switches an architecture from "uses generic/hostdep.h" to "uses its own hostdep.h" nothing in the makefile dependencies notices this and so doing a rebuild without a manual 'make clean' will fail. So we drop the idea of having a 'generic' version in favour of every architecture we support having its own hostdep.h, even if it doesn't have anything in it. (There are only thirteen of these.) If the dependency files claim that an object file depends on a nonexistent file, our dependency system means that make will rebuild the object file, and regenerate the dependencies in the process. So moving between trees prior to this commit and trees after this commit works without requiring a 'make clean'. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-06-08linux-user: provide frame information in x86-64 safe_syscallPeter Maydell
Use cfi directives in the x86-64 safe_syscall to allow gdb to get backtraces right from within it. (In particular this will be quite a common situation if the user interrupts QEMU while it's in a blocked safe-syscall: at the point of the syscall insn RBP is in use for something else, and so gdb can't find the frame then without assistance.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27linux-user: Provide safe_syscall for fixing races between signals and syscallsTimothy E Baldwin
If a signal is delivered immediately before a blocking system call the handler will only be called after the system call returns, which may be a long time later or never. This is fixed by using a function (safe_syscall) that checks if a guest signal is pending prior to making a system call, and if so does not call the system call and returns -TARGET_ERESTARTSYS. If a signal is received between the check and the system call host_signal_handler() rewinds execution to before the check. This rewinding has the effect of closing the race window so that safe_syscall will reliably either (a) go into the host syscall with no unprocessed guest signals pending or or (b) return -TARGET_ERESTARTSYS so that the caller can deal with the signals. Implementing this requires a per-host-architecture assembly language fragment. This will also resolve the mishandling of the SA_RESTART flag where we would restart a host system call and not call the guest signal handler until the syscall finally completed -- syscall restarting now always happens at the guest syscall level so the guest signal handler will run. (The host syscall will never be restarted because if the host kernel rewinds the PC to point at the syscall insn for a restart then our host_signal_handler() will see this and arrange the guest PC rewind.) This commit contains the infrastructure for implementing safe_syscall and the assembly language fragment for x86-64, but does not change any syscalls to use it. Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-14-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: * Avoid having an architecture if-ladder in configure by putting linux-user/host/$(ARCH) on the include path and including safe-syscall.inc.S from it * Avoid ifdef ladder in signal.c by creating new hostdep.h to hold host-architecture-specific things * Added copyright/license header to safe-syscall.inc.S * Rewrote commit message * Added comments to safe-syscall.inc.S * Changed calling convention of safe_syscall() to match syscall() (returns -1 and host error in errno on failure) * Added a long comment in qemu.h about how to use safe_syscall() to implement guest syscalls. ] RV: squashed Peters "fixup! linux-user: compile on non-x86-64 hosts" patch Signed-off-by: Peter Maydell <peter.maydell@linaro.org>