Using XOR first is both smaller and more efficient,
though cannot be applied if it clobbers an input.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The SETBC family of instructions requires exactly two insns for
all comparisions, saving 0-3 insns per (neg)setcond.
Tested-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
In the general case we simply negate. However with isel we
may load -1 instead of 1 with no extra effort.
Consolidate EQ0 and NE0 logic. Replace the NE0 zero-extension
with inversion+negation of EQ0, which is never worse and may
eliminate one insn. Provide a special case for -EQ0.
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Inserting a zero into a value, or inserting a value
into zero at offset 0 may be implemented with AND.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
It is more useful to allow low-part deposits into all registers
than to restrict allocation for high-byte deposits.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
i386 and s390x implementations of op_add2 require an earlyclobber,
which is currently missing. This breaks VCKSM in s390x guests. E.g., on
x86_64 the following op:
add2_i32 tmp2,tmp3,tmp2,tmp3,tmp3,tmp2 dead: 0 2 3 4 5 pref=none,0xffff
is translated to:
addl %ebx, %r12d
adcl %r12d, %ebx
Introduce a new C_N1_O1_I4 constraint, and make sure that earlyclobber
of aliased outputs is honored.
Cc: qemu-stable@nongnu.org
Fixes: 82790a8709 ("tcg: Add markup for output requires new register")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230719221310.1968845-7-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Commit 20b6643324 ("tcg/ppc: Reorg goto_tb implementation") modified
goto_tb to ensure only a single instruction was patched to prevent
incorrect behavior if a thread was in the middle of multiple
instructions when they were replaced. However this introduced a race
between loading the jmp target into TCG_REG_TB and patching and
executing the direct branch.
The relevant part of the goto_tb implementation:
ld TCG_REG_TB, TARGET_ADDR_LOCATION(TCG_REG_TB)
patch_location:
mtctr TCG_REG_TB
bctr
tb_target_set_jmp_target() will replace 'patch_location' with a direct
branch if the target is in range. The direct branch now relies on
TCG_REG_TB being set up correctly by the ld. Prior to this commit
multiple instructions were patched in for the direct branch case; these
instructions would initialize TCG_REG_TB to the same value as the branch
target.
Imagine the following sequence:
1) Thread A is executing the goto_tb sequence and loads the jmp
target into TCG_REG_TB.
2) Thread B updates the jmp target address and calls
tb_target_set_jmp_target(). This patches a new direct branch into the
goto_tb sequence.
3) Thread A executes the newly patched direct branch. The value in
TCG_REG_TB still contains the old jmp target.
TCG_REG_TB MUST contain the translation block's tc.ptr. Execution will
eventually crash after performing memory accesses generated from a
faulty value in TCG_REG_TB.
This presents as segfaults or illegal instruction exceptions.
Do not revert commit 20b6643324 as it did fix a different race
condition. Instead remove the direct branch optimization and always use
indirect branches.
The direct branch optimization can be re-added later with a race free
sequence.
Fixes: 20b6643324 ("tcg/ppc: Reorg goto_tb implementation")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1726
Reported-by: Anushree Mathur <anushree.mathur@linux.vnet.ibm.com>
Tested-by: Anushree Mathur <anushree.mathur@linux.vnet.ibm.com>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Co-developed-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Message-Id: <20230717093001.13167-1-jniethe5@gmail.com>
We adjust CONFIG_ATOMIC128 and CONFIG_CMPXCHG128 with
CONFIG_ATOMIC128_OPT in atomic128.h. It is difficult
to tell when those changes have been applied with the
ifdef we must use with CONFIG_CMPXCHG128. So instead
use HAVE_CMPXCHG128, which triggers -Werror-undef when
the proper header has not been included.
Improves tcg_gen_atomic_cmpxchg_i128 for s390x host, which
requires CONFIG_ATOMIC128_OPT. Without this we fall back
to EXCP_ATOMIC to single-step 128-bit atomics, which is
slow enough to cause some tests to time out.
Reported-by: Thomas Huth <thuth@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Move the code from tcg/. Fix a bug in that PPC_FEATURE2_ARCH_3_10
is actually spelled PPC_FEATURE2_ARCH_3_1.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Move to fill a hole in the set of bits.
Reduce the total number of tlb bits by 1.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The virtio devices require proper memory ordering between
the vcpus and the iothreads.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We use the user_ss[] array to hold the user emulation sources,
and the softmmu_ss[] array to hold the system emulation ones.
Hold the latter in the 'system_ss[]' array for parity with user
emulation.
Mechanical change doing:
$ sed -i -e s/softmmu_ss/system_ss/g $(git grep -l softmmu_ss)
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230613133347.82210-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Restructure the ifdef ladder, separating 64-bit from 32-bit,
and ensure _CALL_AIX is set for ELF v1. Fixes the build for
ppc64 big-endian host with clang.
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We require either 2 or 4 registers to hold int128_t.
Failure to do so results in a register allocation assert.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Since adding MO_ATOM_MASK, the maximum MemOpIdx requires 15 bits,
which overflows the 12 bit field allocated for TCI memory ops.
Expand the field to 16 bits for 2-operand memory ops, and place
the value in TCG_REG_TMP for 3-operand memory ops (same as we
already do for 4-operand memory ops).
Cures a debug assert for aarch64, with FEAT_LSE2 enabled.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This finally paves the way for tcg/ to be built once per mode.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The bug was hidden because they happen to have the same values.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
From this remove, it's no longer clear what this is attempting
to protect. The last time a use of this define was added to
the source tree, as opposed to merely moved around, was 2008.
There have been many cleanups since that time and this is
no longer required for the build to succeed.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Create tcg/tcg-op-gvec-common.h, moving everything that does not
concern TARGET_LONG_BITS. Adjust tcg-op-gvec.c to use the new header.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The replacement isn't ideal, as the raw count of bits
is not easily synced with exec/cpu-all.h, but it does
remove from tcg.h the target dependency on TARGET_PAGE_BITS_MIN
which is built into TLB_FLAGS_MASK.
Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This will enable replacement of TARGET_INSN_START_WORDS in tcg.c.
Split out "tcg/insn-start-words.h" and use it in target/.
Reviewed-by: Anton Johansson <anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>