qemu/target-lm32
Paolo Bonzini 74892d2468 vl: allow other threads to do qemu_system_vmstop_request
There patch protects vmstop_requested with a lock and introduces
qemu_system_vmstop_request_prepare.

Together with the new call to qemu_vmstop_requested in vm_start,
qemu_system_vmstop_request_prepare avoids a race where the VM could remain
stopped even though the iostatus of a block device has already been set
(for example).

qemu_system_vmstop_request_prepare however also lets the caller thread
delay observation of the state change until it has itself communicated
that change to the user.  This delay avoids any possibility of a wrong
reordering of the BLOCK_IO_ERROR event and the subsequent STOP event.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-23 16:36:13 +08:00
..
Makefile.objs target-lm32: add semihosting support 2014-05-24 19:42:29 +02:00
README lm32: remove lm32_sys 2014-05-24 19:43:52 +02:00
TODO target-lm32: add breakpoint/watchpoint support 2014-02-04 19:47:06 +01:00
cpu-qom.h target-lm32: move model features to LM32CPU 2014-02-04 19:34:30 +01:00
cpu.c cputlb: Change tlb_flush() argument to CPUState 2014-03-13 19:52:47 +01:00
cpu.h target-lm32: add semihosting support 2014-05-24 19:42:29 +02:00
gdbstub.c cpu: Introduce CPUClass::gdb_{read,write}_register() 2013-07-27 00:04:17 +02:00
helper.c target-lm32: add semihosting support 2014-05-24 19:42:29 +02:00
helper.h tcg: Invert the inclusion of helper.h 2014-05-28 09:33:54 -07:00
lm32-semi.c tcg: Invert the inclusion of helper.h 2014-05-28 09:33:54 -07:00
machine.c savevm: Remove all the unneeded version_minimum_id_old (rest) 2014-05-14 15:24:51 +02:00
op_helper.c vl: allow other threads to do qemu_system_vmstop_request 2014-06-23 16:36:13 +08:00
translate.c softmmu: introduce cpu_ldst.h 2014-06-05 16:10:33 +02:00

README

LatticeMico32 target
--------------------

General
-------
All opcodes including the JUART CSRs are supported.


JTAG UART
---------
JTAG UART is routed to a serial console device. For the current boards it
is the second one. Ie to enable it in the qemu virtual console window use
the following command line parameters:
  -serial vc -serial vc
This will make serial0 (the lm32_uart) and serial1 (the JTAG UART)
available as virtual consoles.


Semihosting
-----------
Semihosting on this target is supported. Some system calls like read, write
and exit are executed on the host if semihosting is enabled. See
target/lm32-semi.c for all supported system calls. Emulation aware programs
can use this mechanism to shut down the virtual machine and print to the
host console. See the tcg tests for an example.


Special instructions
--------------------
The translation recognizes one special instruction to halt the cpu:
  and r0, r0, r0
On real hardware this instruction is a nop. It is not used by GCC and
should (hopefully) not be used within hand-crafted assembly.
Insert this instruction in your idle loop to reduce the cpu load on the
host.


Ignoring the MSB of the address bus
-----------------------------------
Some SoC ignores the MSB on the address bus. Thus creating a shadow memory
area. As a general rule, 0x00000000-0x7fffffff is cached, whereas
0x80000000-0xffffffff is not cached and used to access IO devices. This
behaviour can be enabled with:
  cpu_lm32_set_phys_msb_ignore(env, 1);