Commit Graph

250 Commits

Author SHA1 Message Date
Jose Ricardo Ziviani
26920a2961 linux-user: fill target sigcontext struct accordingly
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>
2017-02-16 15:29:30 +01:00
Marek Vasut
a0a839b65b nios2: Add usermode binaries emulation
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>
2017-01-24 13:10:35 -08:00
Richard Henderson
1659e38e1d linux-user: Add HPPA signal handling
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-01-23 09:52:40 -08:00
Benjamin Herrenschmidt
95cda4c44e ppc: Fix signal delivery in ppc-user and ppc64-user
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>
2016-09-23 10:29:40 +10:00
Timothy E Baldwin
45eafb4d32 linux-user: Fix incorrect offset of tuc_stack in ARM do_sigframe_return_v2
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>
2016-09-21 22:17:02 +03:00
Peter Maydell
c4b3574402 linux-user: Implement force_sigsegv() via force_sig()
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>
2016-09-21 22:01:45 +03:00
Peter Maydell
c599d4d6d6 linux-user: SIGSEGV from sigreturn need not be fatal
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>
2016-09-21 22:01:45 +03:00
Peter Maydell
28298c912e linux-user: ARM: Give SIGSEGV if signal frame setup fails
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>
2016-09-21 22:01:45 +03:00
Peter Maydell
0939166997 linux-user: SIGSEGV on signal entry need not be fatal
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>
2016-09-21 22:01:45 +03:00
Peter Maydell
9d2803f720 linux-user: Pass si_type information to queue_signal() explicitly
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>
2016-09-21 22:01:28 +03:00
Peter Maydell
8bd3773cce linux-user: Recheck for pending synchronous signals too
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>
2016-09-21 21:51:49 +03:00
Peter Maydell
0cb581d6bd linux-user: report signals being taken in strace output
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>
2016-09-21 14:25:59 +03:00
Laurent Vivier
c1bc91c35c linux-user,s390x: remove useless cast
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>
2016-09-15 15:32:22 +03:00
Peter Maydell
31efaef1d9 linux-user: Forget about synchronous signal once it is delivered
Commit 655ed67c2a 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>
2016-07-19 15:23:16 +03:00
Peter Maydell
1d48fdd9d8 linux-user: Don't use sigfillset() on uc->uc_sigmask
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>
2016-06-26 13:17:20 +03:00
Peter Maydell
55d72a7eb3 linux-user: Avoid possible misalignment in host_to_target_siginfo()
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>
2016-06-24 11:55:44 +03:00
Eduardo Habkost
9be385980d coccinelle: Remove unnecessary variables for function return value
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>
2016-06-20 16:38:13 +02:00
Peter Maydell
90c0f080fe linux-user: Avoid possible misalignment in target_to_host_siginfo()
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>
2016-06-08 10:13:32 +03:00
Peter Maydell
a70dadc7f1 linux-user: Use both si_code and si_signo when converting siginfo_t
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>
2016-06-07 16:39:08 +03:00
Timothy E Baldwin
ef6a778ea2 linux-user: Block signals during sigaction() handling
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>
2016-06-07 16:39:07 +03:00
Timothy E Baldwin
655ed67c2a linux-user: Queue synchronous signals separately
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>
2016-06-07 16:39:07 +03:00
Timothy E Baldwin
907f5fddaa linux-user: Remove real-time signal queuing
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>
2016-06-07 16:39:07 +03:00
Timothy E Baldwin
c19c1578f8 linux-user: Remove redundant default action check in queue_signal()
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>
2016-06-07 16:39:07 +03:00
Peter Maydell
3d3efba020 linux-user: Fix race between multiple signals
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>
2016-06-07 16:39:07 +03:00
Peter Maydell
9eede5b69f linux-user: Factor out uses of do_sigprocmask() from sigreturn code
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>
2016-06-07 16:39:06 +03:00
Peter Maydell
7ec87e06c7 linux-user: Fix stray tab-indent
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>
2016-06-07 16:39:06 +03:00
Peter Maydell
e902d588dc linux-user: Move handle_pending_signal() to avoid need for declaration
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>
2016-06-07 16:39:06 +03:00
Peter Maydell
eb5525013a linux-user: Factor out handle_signal code from process_pending_signals()
Factor out the code to handle a single signal from the
process_pending_signals() function. The use of goto for flow control
is OK currently, but would get significantly uglier if extended to
allow running the handle_signal code multiple times.

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>
2016-06-07 16:39:06 +03:00
Laurent Vivier
49e55cbacf linux-user,target-ppc: fix use of MSR_LE
setup_frame()/setup_rt_frame()/restore_user_regs() are using
MSR_LE as the similar kernel functions do: as a bitmask.

But in QEMU, MSR_LE is a bit position, so change this
accordingly.

The previous code was doing nothing as MSR_LE is 0,
and "env->msr &= ~MSR_LE" doesn't change the value of msr.

And yes, a user process can change its endianness,
see linux kernel commit:

    fab5db9 [PATCH] powerpc: Implement support for setting little-endian mode via prctl

and prctl(2): PR_SET_ENDIAN, PR_GET_ENDIAN

Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:50:40 +03:00
Chen Gang
5b1d59d0bb linux-user/signal.c: Use s390 target space address instead of host space
The return address is in target space, so the restorer address needs to
be target space, too.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
2016-05-27 14:50:40 +03:00
Chen Gang
166c97edd6 linux-user/signal.c: Use target address instead of host address for microblaze restorer
The return address is in target space, so the restorer address needs to
be target space, too.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:50:40 +03:00
Chen Gang
f1d9d1071c linux-user/signal.c: Generate opcode data for restorer in setup_rt_frame
Original implementation uses do_rt_sigreturn directly in host space,
when a guest program is in unwind procedure in guest space, it will get
an incorrect restore address, then causes unwind failure.

Also cleanup the original incorrect indentation.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:50:39 +03:00
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
Timothy E Baldwin
4134ecfeb9 linux-user: Support for restarting system calls for Microblaze targets
Update the Microblaze main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Note that this in passing fixes a bug where we were corrupting
the guest r[3] on sigreturn with the guest's r[10] because
do_sigreturn() was returning env->regs[10] but the register for
syscall return values is env->regs[3].

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-11-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define;
 drop whitespace changes]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:51 +03:00
Peter Maydell
a9175169cc linux-user: Support for restarting system calls for tilegx targets
Update the tilegx main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * return -TARGET_QEMU_ESIGRETURN from sigreturn rather than current R_RE
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Note that this fixes a bug where a sigreturn which happened to have
an errno value in TILEGX_R_RE would incorrectly cause TILEGX_R_ERR
to get set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:50 +03:00
Timothy E Baldwin
6205086558 linux-user: Support for restarting system calls for CRIS targets
Update the CRIS main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-34-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:50 +03:00
Timothy E Baldwin
47405ab642 linux-user: Support for restarting system calls for S390 targets
Update the S390 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-33-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; remove stray double semicolon; drop
 TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:50 +03:00
Timothy E Baldwin
7ccb84a916 linux-user: Support for restarting system calls for M68K targets
Update the M68K main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-32-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:50 +03:00
Timothy E Baldwin
338c858c94 linux-user: Support for restarting system calls for Alpha targets
Update the Alpha main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-13-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define;
 PC is env->pc, not env->ir[IR_PV]]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:50 +03:00
Timothy E Baldwin
ba41249678 linux-user: Support for restarting system calls for SH4 targets
Update the SH4 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-12-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:49 +03:00
Timothy E Baldwin
c0bea68f9e linux-user: Support for restarting system calls for SPARC targets
Update the SPARC main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-9-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define]
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>
2016-05-27 14:49:49 +03:00
Timothy E Baldwin
f0267ef711 linux-user: Support for restarting system calls for ARM targets
Update the 32-bit and 64-bit ARM main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-6-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:49 +03:00
Timothy E Baldwin
0284b03ba3 linux-user: Support for restarting system calls for x86 targets
Update the x86 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code rather than passing it
   back out as the "return code" from do_sigreturn()
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch EAX

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-5-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: Commit message tweaks; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:49 +03:00
Timothy E Baldwin
da7c8647e5 linux-user: Reindent signal handling
Some of the signal handling was a mess with a mixture of tabs and 8 space
indents.

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-3-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: just rebased]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-05-27 14:49:48 +03:00
Paolo Bonzini
a0e1e6d705 linux-user: arm: fix coding style for some linux-user signal functions
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-03-04 11:30:18 +00:00
Peter Maydell
ae08792301 linux-user: Use restrictive mask when calling cpsr_write()
When linux-user code is calling cpsr_write(), use a restrictive
mask to ensure we are limiting the set of CPSR bits we update.
In particular, don't allow the mode bits to be changed.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <serge.fdrv@gmail.com>
Message-id: 1455556977-3644-5-git-send-email-peter.maydell@linaro.org
2016-02-26 15:09:41 +00:00
Peter Maydell
50866ba5a2 target-arm: Add write_type argument to cpsr_write()
Add an argument to cpsr_write() to indicate what kind of CPSR
write is being requested, since the exact behaviour should
differ for the different cases.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sergey Fedorov <serge.fdrv@gmail.com>
Message-id: 1455556977-3644-3-git-send-email-peter.maydell@linaro.org
2016-02-26 15:09:41 +00:00
Peter Maydell
d39594e9d9 linux-user: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1453832250-766-10-git-send-email-peter.maydell@linaro.org
2016-01-29 15:07:22 +00:00
Laurent Vivier
2a0fa68fb9 linux-user,sh4: fix signal retcode address
To return from a signal, setup_frame() puts an instruction to
be executed in the stack. This sequence calls the syscall sigreturn().

The address of the instruction must be set in the PR register
to be executed.

This patch fixes this: the current code sets the register to the address
of the instruction in the host address space (which can be 64bit whereas
PR is only 32bit), but the virtual CPU can't access this address space,
so we put in PR the address of the instruction in the guest address space.

This patch also removes an useless variable (ret) in the modified functions.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
2016-01-08 15:24:57 +02:00
Paolo Bonzini
c8ee0a445a linux-user: convert DEBUG_SIGNAL logging to tracepoints
"Unimplemented" messages go to stderr, everything else goes to tracepoints

Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-12-17 17:33:48 +01:00