In cpu_exec() we have a longstanding workaround for compilers which
do not correctly implement the part of the sigsetjmp()/siglongjmp()
spec which requires that local variables which are not changed
between the setjmp and the longjmp retain their value.
I recently ran across the upstream clang bug report for this; add a
link to it to the comment describing the workaround, and generally
expand the comment, so that we have a reasonable chance in future of
understanding why it's there and determining when we can remove it,
assuming clang eventually fixes the bug.
Remove the /* buggy compiler */ comments on the #else and #endif:
they don't add anything to understanding and are somewhat misleading
since they're sandwiching the code path for *non*-buggy compilers.
Backports e6a41a045c298538d303cd8fe8d7ae29a0c066ad
Since commit efc6c070aca ("configure: Add a test for the
minimum compiler version") the minimum compiler version
required for GCC is 4.8.
We can safely remove the special case for GCC 4.6 introduced
in commit 0448f5f8b81 ("cpu-exec: Fix compiler warning
(-Werror=clobbered)").
No change for Clang as we don't know.
Backports 19a84318c674c157f1b04c5c99595379f8ac8bb3
Under some circumstances, the PC is not fixed up properly when
returning from the execution of a block in cpu_tb_exec. This appears
to be caused by the resetting of the PC from the tb.
This change removes the additional fixup in the cases where there
is code tracing or timing active. Either of these cases would result
in the wrong PC being reported.
Closes unicorn-engine#1105.
Backports commit b59632fb645d456338472e3d757c065c0ed74ad5 from unicorn
Calling emu_stop and causing the pc value to be incorrect after the end of the run. (#1157)
Backports commit 83887b8193dfeca3e5e8da851b41f874bcd0514e from unicorn.
* first draft for an invalid instruction hook
* Fixed documentation on return value of invalid insn hook
Backports commit 07f94ad1fc62293cac330df9714d739be6354926 from unicorn
Amusingly, we had already ignored the comment to keep this value
at the end of CPUState. This restores the minimum negative offset
from TCG_AREG0 for code generation.
For the couple of uses within qom/cpu.c, without NEED_CPU_H, add
a pointer from the CPUState object to the IcountDecr object within
CPUNegativeOffsetState.
Backports commit 5e1401969b25f676fee6b1c564441759cf967a43 from qemu
Now that we have curr_cflags, we can include CF_USE_ICOUNT
early and then remove it as necessary.
Backports commit 416986d3f97329655e30da7271a2d11c6d707b06 from qemu
Now that all code generation has been converted to check CF_PARALLEL, we can
generate !CF_PARALLEL code without having yet set !parallel_cpus --
and therefore without having to be in the exclusive region during
cpu_exec_step_atomic.
While at it, merge cpu_exec_step into cpu_exec_step_atomic.
Backports commit ac03ee5331612e44beb393df2b578c951d27dc0d from qemu
We were generating code during tb_invalidate_phys_page_range,
check_watchpoint, cpu_io_recompile, and (seemingly) discarding
the TB, assuming that it would magically be picked up during
the next iteration through the cpu_exec loop.
Instead, record the desired cflags in CPUState so that we request
the proper TB so that there is no more magic.
Backports commit 9b990ee5a3cc6aa38f81266fb0c6ef37a36c45b9 from qemu
This will enable us to decouple code translation from the value
of parallel_cpus at any given time. It will also help us minimize
TB flushes when generating code via EXCP_ATOMIC.
Note that the declaration of parallel_cpus is brought to exec-all.h
to be able to define there the "curr_cflags" inline.
Backports commit 4e2ca83e71b51577b06b1468e836556912bd5b6e from qemu
It's either "GNU *Library* General Public version 2" or "GNU Lesser
General Public version *2.1*", but there was no "version 2.0" of the
"Lesser" library. So assume that version 2.1 is meant here.
Backports commit fb0343d5b4dd4b9b9e96e563d913a3e0c709fe4e from qemu
Rather than test NOCHAIN before linking, do not emit the
goto_tb opcode at all. We already do this for goto_ptr.
Backports commit d7f425fdea991f052241c6479acd9feae834063b from qemu
In icount mode, instructions that access io memory spaces in the middle
of the translation block invoke TB recompilation. After recompilation,
such instructions become last in the TB and are allowed to access io
memory spaces.
When the code includes instruction like i386 'xchg eax, 0xffffd080'
which accesses APIC, QEMU goes into an infinite loop of the recompilation.
This instruction includes two memory accesses - one read and one write.
After the first access, APIC calls cpu_report_tpr_access, which restores
the CPU state to get the current eip. But cpu_restore_state_from_tb
resets the cpu->can_do_io flag which makes the second memory access invalid.
Therefore the second memory access causes a recompilation of the block.
Then these operations repeat again and again.
This patch moves resetting cpu->can_do_io flag from
cpu_restore_state_from_tb to cpu_loop_exit* functions.
It also adds a parameter for cpu_restore_state which controls restoring
icount. There is no need to restore icount when we only query CPU state
without breaking the TB. Restoring it in such cases leads to the
incorrect flow of the virtual time.
In most cases new parameter is true (icount should be recalculated).
But there are two cases in i386 and openrisc when the CPU state is only
queried without the need to break the TB. This patch fixes both of
these cases.
Backports commit afd46fcad2dceffda35c0586f5723c127b6e09d8 from qemu
Function cpu_handle_interrupt calls cc->cpu_exec_interrupt to process
pending hardware interrupts. Under the hood cpu_exec_interrupt uses
cpu->exception_index to pass information to the internal function which
is usually common for exception and interrupt processing.
But this value is not reset after return and may be processed again
by cpu_handle_exception. This does not happen due to overwriting
the exception_index at the end of cpu_handle_interrupt.
But this branch may also overwrite the valid exception_index in some cases.
Therefore this patch:
1. resets exception_index just after the call to cpu_exec_interrupt
2. prevents overwriting the meaningful value of exception_index
Backports commit 5f3bdfd4fa33255542a4b6249913d9ffb11b44f9 from qemu
move tcg-runtime.c, translate-all.(ch) and translate-common.c into
accel/tcg/ subdirectory and updated related trace-events file.
Backports commit 244f144134d0dd182f1af8654e7f9a79fe770368 and applies
relevant changes made in db432672dc50ed86dda17ac821b7eb07411a90af and
d9bb58e51068dfc48746c6af0179926c8dc05bce from qemu
