Commit Graph

7 Commits

Author SHA1 Message Date
Laurent Vivier f7e6a401fe linux-user: move TargetFdTrans functions to their own file
This will ease to move out syscall functions from syscall.c

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180823222215.13781-1-laurent@vivier.eu>
2018-09-25 22:36:47 +02:00
Alex Bennée 708b6a643c linux-user: introduce preexit_cleanup
To avoid repeating ourselves move our preexit clean-up code into a
helper function. I figured the continuing effort to split of the
syscalls made it worthwhile creating a new file for it now.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
2018-07-05 15:59:41 +01:00
Laurent Vivier cd71c08964 linux-user: create a dummy per arch cpu_loop.c
Create a cpu_loop-common.h for future use by
these new files and use it in the existing
main.c

Introduce target_cpu_copy_regs():
declare the function in cpu_loop-common.h
and an empty function for each target,
to move all the cpu_loop prologues to this function.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180411185651.21351-2-laurent@vivier.eu>
2018-04-30 09:47:55 +02:00
Laurent Vivier befb7447a0 linux-user: create a dummy per arch signal.c
Create a signal-common.h for future use by these new files
and use it in the existing signal.c

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180424192635.6027-2-laurent@vivier.eu>
2018-04-30 09:47:47 +02:00
Timothy E Baldwin 4d330cee37 linux-user: Provide safe_syscall for fixing races between signals and syscalls
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>
2016-05-27 14:49:51 +03:00
Riku Voipio 18cb008865 linux-user: rename cpu-uname -> uname
To move more uname related functions out of syscall.c,
rename cpu-uname.{c,h} to uname.{c.h}

Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2014-05-02 21:59:36 +03:00
Paolo Bonzini 7fc5152c6d build: move *-user/ objects to nested Makefile.objs
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-06-07 07:17:33 +02:00