GCC7+ will no longer advertise support for 16-byte __atomic operations
if only cmpxchg is supported, as for x86_64. Fortunately, x86_64 still
has support for __sync_compare_and_swap_16 and we can make use of that.
AArch64 does not have, nor ever has had such support, so open-code it.
Backports commit e6cd4bb59b8154fa00da611200beef7eb4e8ec56 from qemu
Coverity does not like the new _Float* types that are used by
recent glibc, and croaks on every single file that includes
stdlib.h. Add dummy typedefs to please it.
Backports commit a1a98357e3fdfce92b5ed0c6728489b9992fecb5 from qemu
Determining the size of a field is useful when you don't have a struct
variable handy. Open-coding this is ugly.
This patch adds the sizeof_field() macro, which is similar to
typeof_field(). Existing instances are updated to use the macro.
Backports commit f18793b096e69c7acfce66cded483ba9fc01762a from qemu
This is part of topoext support. To keep the compatibility, it is better
we support all the combination of nr_cores and nr_threads currently
supported. By allowing more nr_cores and nr_threads, we might end up with
more nodes than we can actually support with the real hardware. We need to
fix up the node id to make this work. We can achieve this by shifting the
socket_id bits left to address more nodes.
Backports commit 631be32155dbafa1fe886f2488127956c9120ba6 from qemu
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.
Backports commit afa4f6653dca095f63f3fe7f2001e9334f5676c1 from qemu
Usually the logging of the CPU state produced by -d cpu is sufficient
to diagnose problems, but sometimes you want to see the state of
the floating point registers as well. We don't want to enable that
by default as it adds a lot of extra data to the log; instead,
allow it to be optionally enabled via -d fpu.
Backports relevant parts of commit ae7651804748c6b479d5ae09aeac4edb9c44f76e from qemu
Some versions of gcc produce a spurious warning if the result of
__atomic_compare_echange_n() is not used and the type involved
is a signed 8 bit value:
error: value computed is not used [-Werror=unused-value]
This has been seen on at least
gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609
Work around this by using an explicit cast to void to indicate
that we don't care about the return value.
We don't currently use our atomic_cmpxchg() macro on any signed
8 bit types, but the upcoming support for the Arm v8.1-Atomics
will require it.
Backports commit cd95fc28fb6d8afced0d70ce52c294d0761a9daa from qemu
_Static_assert() allows us to specify messages, and that may come in
handy. Even without _Static_assert(), encouraging developers to put a
helpful message next to the QEMU_BUILD_BUG_* may make debugging easier
whenever it breaks.
Backports commit 9139b5672360aaa263da1d96cdfdbe16accb6e3b from qemu
QEMU_BUILD_BUG_ON should use C11's _Static_assert, if the compiler supports it,
to provide more readable messages on failure.
We check for _Static_assert in configure, and set CONFIG_STATIC_ASSERT
accordingly. QEMU_BUILD_BUG_ON invokes _Static_assert if CONFIG_STATIC_ASSERT
is defined, and reverts to the old way otherwise.
That way, systems without C11 conforming compiler will still have the old
messages, as verified by intentionally breaking the configure check.
the following example output was generated by inverting the condition in
QEMU_BUILD_BUG_ON:
without _Static_assert:
> In file included from /qemu/include/qemu/osdep.h:36:0,
> from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:89:12: error: negative width in bit-field ‘<anonymous>’
> struct { \
> ^
> /qemu/include/qemu/compiler.h:96:38: note: in expansion of macro QEMU_BUILD_BUG_ON_STRUCT’
> #define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
> ^~~~~~~~~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
> QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
> ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
> atomic_load_acquire(ptr)
> ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
> bool finished = atomic_mb_read(&gei->finished);
> ^~~~~~~~~~~~~~
with _Static_assert:
> In file included from /qemu/include/qemu/osdep.h:36:0,
> from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:94:30: error: static assertion failed: "not expecting: sizeof(*&gei->finished) > sizeof(void *)"
> #define QEMU_BUILD_BUG_ON(x) _Static_assert((x), #x)
> ^
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
> QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
> ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
> atomic_load_acquire(ptr)
> ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
> bool finished = atomic_mb_read(&gei->finished);
> ^~~~~~~~~~~~~~
Backports commit 49e00a18708e27c815828d9440d5c9300d19547c from qemu
Actually enable the global memory barriers if supported by the OS.
Because only recent versions of Linux include the support, they
are disabled by default. Note that it also has to be disabled
for QEMU to run under Wine.
Before this patch, rcutorture reports 85 ns/read for my machine,
after the patch it reports 12.5 ns/read. On the other hand updates
go from 50 *micro*seconds to 20 *milli*seconds.
Backports commit a40161cbe9ccbcbab798c3e4d257c4bba99d153a from qemu
This new header file provides heavy-weight "global" memory barriers that
enforce memory ordering on each running thread belonging to the current
process. For now, use a dummy implementation that issues memory barriers
on both sides (matching what QEMU has been doing so far).
Backports commit c8d3877e48c4f57381d72eaf8d016bff12ce2d7c from qemu
There are qemu_strtoNN functions for various sized integers. This adds two
more for plain int & unsigned int types, with suitable range checking.
Backports commit 473a2a331ee382703f7ca0067ba2545350cfa06c from qemu
As we are going to share FlatView's between AddressSpace's,
and AddressSpaceDispatch is a structure to perform quick lookup
in FlatView, this moves ASD to FlatView.
After previosly open coded ASD rendering, we can also remove
as->next_dispatch as the new FlatView pointer is stored
on a stack and set to an AS atomically.
flatview_destroy() is executed under RCU instead of
address_space_dispatch_free() now.
This makes mem_begin/mem_commit to work with ASD and mem_add with FV
as later on mem_add will be taking FV as an argument anyway.
This should cause no behavioural change.
Backports commit 66a6df1dc6d5b28cc3e65db0d71683fbdddc6b62 from qemu
Clang 3.9 passes the CONFIG_AVX2_OPT configure test. However, the
supplied <cpuid.h> does not contain the bit_AVX2 define that we use
when detecting whether the routine can be enabled.
Introduce a qemu-specific header that uses the compiler's definition
of __cpuid et al, but supplies any missing bit_* definitions needed.
This avoids introducing any extra ifdefs to util/bufferiszero.c, and
allows quite a few to be removed from tcg/i386/tcg-target.inc.c.
Backports commit 5dd8990841a9e331d9d4838a116291698208cbb6 from qemu
We dropped support for ia64 host CPUs in the 2.11 release (removing
the TCG backend for it, and advertising the support as being
completely removed in the changelog). However there are a few bits
and pieces of code still floating about. Remove those, too.
We can drop the check in configure for "ia64 or hppa host?"
entirely, because we don't support hppa hosts either any more.
Backports commit b1cef6d02f84bd842fb94a6109ad4e2ad873e8e5 from qemu
We can now add float16_add/sub and use the common decompose and
canonicalize functions to have a single implementation for
float16/32/64 add and sub functions.
Backports commit 6fff216769cf7eaa3961c85dee7a72838696d365 from qemu
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.
Backports commit cfd88fc6f2722def193f5ef271381d8f6e2a2526 from qemu
This renders many inclusions of qapi/qmp/q*.h superfluous. They'll be
dropped in the next few commits.
Backports commit 9f5c734d591e26186a71f9e36d752f4798df3672 from qemu
With no fixed array allocation, we can't overflow a buffer.
This will be important as optimizations related to host vectors
may expand the number of ops used.
Use QTAILQ to link the ops together.
Backports commit 15fa08f8451babc88d733bd411d4c94976f9d0f8 from qemu
In our various supported host OSes, the time_t type may be either 32
or 64 bit, and could in theory also be either signed or unsigned.
Notably, in OpenBSD time_t is a 64 bit type even if 'long' is 32
bits, so using LONG_MAX for TIME_MAX is incorrect.
Use an approach suggested by Paolo Bonzini which calculates
the maximum value of the type rather than hardcoding it;
to do this we use the TYPE_MAXIMUM macro from Gnulib.
Backports commit e7b47c22e2df14d55e3e4426688c929bf8e3f7fb from qemu
Provide helpers to convert bitmaps to little endian format. It can be
used when we want to send one bitmap via network to some other hosts.
One thing to mention is that, these helpers only solve the problem of
endianess, but it does not solve the problem of different word size on
machines (the bitmaps managing same count of bits may contains different
size when malloced). So we need to take care of the size alignment issue
on the callers for now.
Backports commit d7788151a0807d5d2d410e3f8944d8c8a651f8d2 from qemu
We already have several files that knowingly require assert()
to work, sometimes because refactoring the code for proper
error handling has not been tackled yet; there are probably
other files that have a similar situation but with no comments
documenting the same. In fact, we have places in migration
that handle untrusted input with assertions, where disabling
the assertions risks a worse security hole than the current
behavior of losing the guest to SIGABRT when migration fails
because of the assertion. Promote our current per-file
safety-valve to instead be project-wide, and expand it to also
cover glib's g_assert().
Note that we do NOT want to encourage 'assert(side-effects);'
(that is a bad practice that prevents copy-and-paste of code to
other projects that CAN disable assertions; plus it costs
unnecessary reviewer mental cycles to remember whether a project
special-cases the crippling of asserts); and we would LIKE to
fix migration to not rely on asserts (but that takes a big code
audit). But in the meantime, we DO want to send a message
that anyone that disables assertions has to tweak code in order
to compile, making it obvious that they are taking on additional
risk that we are not going to support. At the same time, leave
comments mentioning NDEBUG in files that we know still need to
be scrubbed, so there is at least something to grep for.
It would be possible to come up with some other mechanism for
doing runtime checking by default, but which does not abort
the program on failure, while leaving side effects in place
(unlike how crippling assert() avoids even the side effects),
perhaps under the name q_verify(); but it was not deemed worth
the effort (developers should not have to learn a replacement
when the standard C macro works just fine, and it would be a lot
of churn for little gain). The patch specifically uses #error
rather than #warn so that a user is forced to tweak the header
to acknowledge the issue, even when not using a -Werror
compilation.
Backports commit 262a69f4282e44426c7a132138581d400053e0a1 from qemu
When using bit-wise operations that exploit the power-of-two
nature of the second argument of ROUND_UP(), we still need to
ensure that the mask is as wide as the first argument (done
by using a ternary to force proper arithmetic promotion).
Unpatched, ROUND_UP(2ULL*1024*1024*1024*1024, 512U) produces 0,
instead of the intended 2TiB, because negation of an unsigned
32-bit quantity followed by widening to 64-bits does not
sign-extend the mask.
Broken since its introduction in commit 292c8e50 (v1.5.0).
Callers that passed the same width type to both macro parameters,
or that had other code to ensure the first parameter's maximum
runtime value did not exceed the second parameter's width, are
unaffected, but I did not audit to see which (if any) existing
clients of the macro could trigger incorrect behavior (I found
the bug while adding a new use of the macro).
While preparing the patch, checkpatch complained about poor
spacing, so I also fixed that here and in the nearby DIV_ROUND_UP.
Backports commit 33a599667a9e70588483a31286dfff8cfc27d513 from qemu
We need to coordinate with the TCG_OVERSIZED_GUEST test in cputlb.c,
and allow 64-bit atomics even though sizeof(void *) == 4.
Backports commit 374aae653499f4d405caf32b7fff0c8639113fe4 from qemu
We already require gcc 4.1 or newer (for the atomic
support), so the fallback codepaths for older gcc
versions than that are now dead code and we can
just delete them.
NB: clang reports itself as gcc 4.2 (regardless of
clang version), so clang won't be using the fallbacks
either.
Backports commit fa54abb8c298f892639ffc4bc2f61448ac3be4a1 from qemu
This makes qemu_strtosz(), qemu_strtosz_mebi() and
qemu_strtosz_metric() similar to qemu_strtoi64(), except negative
values are rejected.
Backports commit f17fd4fdf0df3d2f3444399d04c38d22b9a3e1b7 from qemu
Most callers of qemu_strtosz_suffix() pass QEMU_STRTOSZ_DEFSUFFIX_B.
Capture the pattern in new qemu_strtosz().
Inline qemu_strtosz_suffix() into its only remaining caller.
Backports commit 466dea14e677555dd24465aca75d00a3537ad062 from qemu
With qemu_strtosz(), no suffix means mebibytes. It's used rarely.
I'm going to add a similar function where no suffix means bytes.
Rename qemu_strtosz() to qemu_strtosz_MiB() to make the name
qemu_strtosz() available for the new function.
Backports commit e591591b323772eea733de6027f5e8b50692d0ff from qemu
To parse numbers with metric suffixes, we use
qemu_strtosz_suffix_unit(nptr, &eptr, QEMU_STRTOSZ_DEFSUFFIX_B, 1000)
Capture this in a new function for legibility:
qemu_strtosz_metric(nptr, &eptr)
Replace test_qemu_strtosz_suffix_unit() by test_qemu_strtosz_metric().
Rename qemu_strtosz_suffix_unit() to do_strtosz() and give it internal
linkage.
Backports commit d2734d2629266006b0413433778474d5801c60be from qemu
The name qemu_strtoll() suggests conversion to long long, but it
actually converts to int64_t. Rename to qemu_strtoi64().
The name qemu_strtoull() suggests conversion to unsigned long long,
but it actually converts to uint64_t. Rename to qemu_strtou64().
Backports commit b30d188677456b17c1cd68969e08ddc634cef644 from qemu
It's a familiar pattern: some code uses ARRAY_SIZE, then refactoring
changes the argument from an array to a pointer to a dynamically
allocated buffer. Code keeps compiling but any ARRAY_SIZE calls now
return the size of the pointer divided by element size.
Let's add build time checks to ARRAY_SIZE before we allow more
of these in the code-base.
Backports commit ed63ec0d22ccdce3b2222d9a514423b7fbba3a0d from qemu
QEMU_BUILD_BUG_ON uses a typedef in order to be safe
to use outside functions, but sometimes it's useful
to have a version that can be used within an expression.
Following what Linux does, introduce QEMU_BUILD_BUG_ON_ZERO
that return zero after checking condition at build time.
Backports commit d757573e69f2ef58a4a7b41f6c55d65fa1e1c5c2 from qemu
There are theoretical concerns that some compilers might not trigger
build failures on attempts to define an array of size (x ? -1 : 1) where
x is a variable and make it a variable sized array instead. Let rewrite
using a struct with a negative bit field size instead as there are no
dynamic bit field sizes. This is similar to what Linux does.
Backports commit f291887e8eef5d37d31484638f6e62401b4b99a2 from qemu
Some headers use QEMU_BUILD_BUG_ON. This causes a problem
if the C file including that header happens to have
QEMU_BUILD_BUG_ON at the same line number.
Fix using a widely available extension: __COUNTER__.
If unavailable, provide a stub.
Backports commit 60abf0a5e05134187e274ce5f32524ccf0cae1a6 from qemu
Device models often have to perform multiple access to a single
memory region that is known in advance, but would to use "DMA-style"
functions instead of address_space_map/unmap. This can happen
for example when the data has to undergo endianness conversion.
Introduce a new data structure to cache the result of
address_space_translate without forcing usage of a host address
like address_space_map does.
Backports commit 1f4e496e1fc2eb6c8bf377a0f9695930c380bfd3 from qemu
Force the use of cmpxchg16b on x86_64.
Wikipedia suggests that only very old AMD64 (circa 2004) did not have
this instruction. Further, it's required by Windows 8 so no new cpus
will ever omit it.
If we truely care about these, then we could check this at startup time
and then avoid executing paths that use it.
Backports commit 7ebee43ee3e2fcd7b5063058b7ef74bc43216733 from qemu
Add all of cmpxchg, op_fetch, fetch_op, and xchg.
Handle both endian-ness, and sizes up to 8.
Handle expanding non-atomically, when emulating in serial.
Backports commit c482cb117cc418115ca9c6d21a7a2315414c0a40 from qemu
Allows Int128 to be used more generally, rather than having to
begin with 64-bit inputs and accumulate.
Backports commit 1edaeee0955fba7d834b7c8f4e372e7eae030745 from qemu
