Currently we rely on all the callsites of cpsr_write() to rebuild the
cached hflags if they change one of the CPSR bits which we use as a
TB flag and cache in hflags. This is a bit awkward when we want to
change the set of CPSR bits that we cache, because it means we need
to re-audit all the cpsr_write() callsites to see which flags they
are writing and whether they now need to rebuild the hflags.
Switch instead to making cpsr_write() call arm_rebuild_hflags()
itself if one of the bits being changed is a cached bit.
We don't do the rebuild for the CPSRWriteRaw write type, because that
kind of write is generally doing something special anyway. For the
CPSRWriteRaw callsites in the KVM code and inbound migration we
definitely don't want to recalculate the hflags; the callsites in
boot.c and arm-powerctl.c have to do a rebuild-hflags call themselves
anyway because of other CPU state changes they make.
This allows us to drop explicit arm_rebuild_hflags() calls in a
couple of places where the only reason we needed to call it was the
CPSR write.
This fixes a bug where we were incorrectly failing to rebuild hflags
in the code path for a gdbstub write to CPSR, which meant that you
could make QEMU assert by breaking into a running guest, altering the
CPSR to change the value of, for example, CPSR.E, and then
continuing.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210817201843.3829-1-peter.maydell@linaro.org
In most cases we were already passing get_sp_from_cpustate
directly to the function. In other cases, we were passing
a local variable which already contained the same value.
In the rest of the cases, we were passing the stack pointer
out of env directly.
Reviewed by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210426025334.1168495-5-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Note that target_restore_altstack uses the host memory
pointer that we have already verified, so TARGET_EFAULT
is not a possible return value.
Note that using -EFAULT was a bug.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210426025334.1168495-3-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
The Arm signal-handling code has some parts ifdeffed with a
TARGET_CONFIG_CPU_32, which is always defined. This is a leftover
from when this code's structure was based on the Linux kernel
signal handling code, where it was intended to support 26-bit
Arm CPUs. The kernel dropped its CONFIG_CPU_32 in kernel commit
4da8b8208eded0ba21e3 in 2009.
QEMU has never had 26-bit CPU support and is unlikely to ever
add it; we certainly aren't going to support 26-bit Linux
binaries via linux-user mode. The ifdef is just unhelpful
noise, so remove it entirely.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200518143014.20689-1-peter.maydell@linaro.org
This fixes signal handlers running with the wrong endianness if the
interrupted code used SETEND to dynamically switch endianness.
Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200511131117.2486486-1-amanieu@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Using the MSR instruction to write to CPSR.E is deprecated, but it is
required to work from any mode including unprivileged code. We were
incorrectly forbidding usermode code from writing it because
CPSR_USER did not include the CPSR_E bit.
We use CPSR_USER in only three places:
* as the mask of what to allow userspace MSR to write to CPSR
* when deciding what bits a linux-user signal-return should be
able to write from the sigcontext structure
* in target_user_copy_regs() when we set up the initial
registers for the linux-user process
In the first two cases not being able to update CPSR.E is a bug, and
in the third case it doesn't matter because CPSR.E is always 0 there.
So we can fix both bugs by adding CPSR_E to CPSR_USER.
Because the cpsr_write() in restore_sigcontext() is now changing
a CPSR bit which is cached in hflags, we need to add an
arm_rebuild_hflags() call there; the callsite in
target_user_copy_regs() was already rebuilding hflags for other
reasons.
(The recommended way to change CPSR.E is to use the 'SETEND'
instruction, which we do correctly allow from usermode code.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200518142801.20503-1-peter.maydell@linaro.org
Use this in the places that were checking ARM_FEATURE_VFP, and
are obviously testing for the existance of the register set
as opposed to testing for some particular instruction extension.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200224222232.13807-2-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The FDPIC restorer needs to deal with a function descriptor, hence we
have to extend 'retcode' such that it can hold the instructions needed
to perform this.
The restorer sequence uses the same thumbness as the exception
handler (mainly to support Thumb-only architectures).
Co-Authored-By: Mickaël Guêné <mickael.guene@st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20180430080404.7323-5-christophe.lyon@st.com>
[lv: moved the change to linux-user/arm/signal.c]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
No code change, only move code from signal.c to
arm/signal.c, except adding includes and
exporting setup_frame() and setup_rt_frame().
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: <20180424192635.6027-4-laurent@vivier.eu>
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>
