In the accessor functions ld*_he_p() and st*_he_p() we use memcpy()
to perform a load or store to a pointer which might not be aligned
for the size of the type. We rely on the compiler to optimize this
memcpy() into an efficient load or store instruction where possible.
This is required for good performance, but at the moment it is also
required for correct operation, because some users of these functions
require that the access is atomic if the pointer is aligned, which
will only be the case if the compiler has optimized out the memcpy().
(The particular example where we discovered this is the virtio
vring_avail_idx() which calls virtio_lduw_phys_cached() which
eventually ends up calling lduw_he_p().)
Unfortunately some compile environments, such as the fortify-source
setup used in Alpine Linux, define memcpy() to a wrapper function
in a way that inhibits this compiler optimization.
The correct long-term fix here is to add a set of functions for
doing atomic accesses into AddressSpaces (and to other relevant
families of accessor functions like the virtio_*_phys_cached()
ones), and make sure that callsites which want atomic behaviour
use the correct functions.
In the meantime, switch to using __builtin_memcpy() in the
bswap.h accessor functions. This will make us robust against things
like this fortify library in the short term. In the longer term
it will mean that we don't end up with these functions being really
badly-performing even if the semantics of the out-of-line memcpy()
are correct.
Reported-by: Fernando Casas Schössow <casasfernando@outlook.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190318112938.8298-1-peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
All accessors that have an endian infix DO have an underscore between
{size} and {endian}.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <155119086741.1037569.12734854713022304642.stgit@bahia.lan>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
There's a common pattern in QEMU where a function needs to perform
a data load or store of an N byte integer in a particular endianness.
At the moment this is handled by doing a switch() on the size and
calling the appropriate ld*_p or st*_p function for each size.
Provide a new family of functions ldn_*_p() and stn_*_p() which
take the size as an argument and do the switch() themselves.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180611171007.4165-2-peter.maydell@linaro.org
The main culprit here is bswap.h which pulled in softfloat.h so it
could use the types in its CPU_Float* and ldfl/stfql functions. As
bswap.h is very widely included this added a compile dependency every
time we touch softfloat.h. Move the typedefs for each float type into
their own file so we don't re-build the world every time we tweak the
main softfloat.h header.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Add a documentation comment describing the functions for
converting between the cpu and little or bigendian formats.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1467908460-27048-6-git-send-email-peter.maydell@linaro.org
Now that all uses of cpu_to_*w() and *_to_cpup() have been replaced
with either ld*_p()/st*_p() or by doing direct dereferences and
using the cpu_to_*()/*_to_cpu() byteswap functions, we can remove
the unused implementations.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1467908460-27048-4-git-send-email-peter.maydell@linaro.org
qemu-common.h should only be included by .c files. Its file comment
explains why: "No header file should depend on qemu-common.h, as this
would easily lead to circular header dependencies."
One of the reasons for headers to include it is HOST_LONG_BITS. Move
that to its more natural home qemu/osdep.h, to facilitate removing
these ill-advised includes later on.
This also lets us use HOST_LONG_BITS in bswap.h instead of duplicating
its definition there to avoid cyclic inclusion.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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.
NB: If this commit breaks compilation for your out-of-tree
patchseries or fork, then you need to make sure you add
#include "qemu/osdep.h" to any new .c files that you have.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Add documentation of what the cpu_*_* accessors look like.
Correct some minor errors in the existing documentation of the
direct _p accessor family. Remove the near-duplicate comment
on the _p accessors from cpu-all.h and replace it with a reference
to the comment in bswap.h.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1421334118-3287-16-git-send-email-peter.maydell@linaro.org
We have an unfortunate naming clash between the functions
ldl_p, stl_p, etc defined in bswap.h (which have semantics
"load/store in host endianness") and the #defines of the same
name in cpu-all.h (which have the semantics "load/store in
target endianness").
Fortunately it turns out that the only users of the bswap.h
functions are all within bswap.h itself, so we can simply
rename them to include a _he_ infix for "host endianness".
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
FreeBSD 10.0-RELEASE has bswap16() etc. macros defined in sys/endian.h,
which leads to a conflict with our static inline definitions.
Force using the system version of the macros.
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
Tested-by: Ed Maste <emaste@freebsd.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The functions use uint16_t or uint32_t values, so show this in the function
prototypes. Non-optimizing compilers will avoid unnecessary type
conversions when generating calls of these inline functions.
stq_le_p, stq_be_p already use similar prototypes.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The function uses an uint8_t value, so show this in the function
prototype. Non-optimizing compilers will avoid unnecessary type
conversions from (u)int8_t to int and back to uint8_t when generating
calls of this inline function.
stw_p, stl_p and stq_p already use similar prototypes.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Replace the legacy cpu_to_32wu() with stl_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-10-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy cpu_to_be64wu() with stq_be_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-9-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy cpu_to_be32wu() with stl_be_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-8-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy cpu_to_be16wu() with stw_be_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-7-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy be32_to_cpupu() with ldl_be_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-6-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy le32_to_cpupu() with ldl_le_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-5-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy le16_to_cpupu() with lduw_le_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-4-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy cpu_to_le32wu() with stl_le_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-3-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
Replace the legacy cpu_to_le16wu() with stw_le_p().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1383669517-25598-2-git-send-email-peter.maydell@linaro.org
Signed-off-by: Anthony Liguori <aliguori@amazon.com>
The bswap functions use memcpy but the bswap.h header itself does not seem to
include it in some configuration such as cross compiling for powerpc64
on x86_64 machine.
The patch explicitly includes string.h.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The misnamed HOST_LONG_BITS is really HOST_POINTER_BITS. Here we're
explicitly using an unsigned long, rather than uintptr_t, so it is
more correct to select the swap size via ULONG_MAX.
Acked-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
OpenBSD system compiler (gcc 4.2.1) has problems with concatenation
of macro arguments in macro functions:
CC aes.o
In file included from /src/qemu/include/qemu-common.h:126,
from /src/qemu/aes.c:30:
/src/qemu/include/qemu/bswap.h: In function 'leul_to_cpu':
/src/qemu/include/qemu/bswap.h:461: warning: implicit declaration of function 'bswapHOST_LONG_BITS'
/src/qemu/include/qemu/bswap.h:461: warning: nested extern declaration of 'bswapHOST_LONG_BITS'
Function leul_to_cpu() is only used in kvm-all.c, so the warnings
are not fatal on OpenBSD without -Werror.
Fix by applying glue(). Also add do {} while(0) wrapping and fix
semicolon use while at it.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We've now optimized the ld/st versions; reuse that for the "legacy"
versions. Always use inlines so that we get the type checking that
we expect.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Use the new host endian unaligned access functions instead of
open coding byte-by-byte references. Remove assembly special
cases for i386 and ppc -- we've now exposed the operation to
the compiler sufficiently for these to be optimized automatically.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Move the bswap_N -> bswapN wrappers inside CONFIG_BYTESWAP_H.
Change the ultimate fallback defintions from macros to inline functions.
The proper types recieved by the function arguments means we can remove
unnecessary casts, making the code more readable.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Peter Maydell