On Wed, Apr 28, 2021 at 12:13 AM Richard Henderson <richard.hender...@linaro.org> wrote: > On 4/27/21 12:11 PM, Philippe Mathieu-Daudé wrote: > > The Inter-Thread Communication unit (TYPE_MIPS_ITU) is an optional > > device that is only selected by a few machines. However it goes > > deep into the translation code, as the MTC0/MTHC0 SAAR helpers > > call itc_reconfigure(). > > > > When building with no machine selecting the ITU component (which > > is implemented in hw/misc/mips_itu.c), we get the following link > > failure: > > > > /usr/bin/ld: target_mips_cp0_helper.c.o: in function `helper_mtc0_saar': > > target/mips/cp0_helper.c:1118: undefined reference to `itc_reconfigure' > > /usr/bin/ld: target_mips_cp0_helper.c.o: in function `helper_mthc0_saar': > > target/mips/cp0_helper.c:1135: undefined reference to `itc_reconfigure' > > > > Fix by adding a stub, built when the ITU isn't selected. > > > > Signed-off-by: Philippe Mathieu-Daudé<f4...@amsat.org> > > --- > > RFC because too much Meson machinery to my taste. > > But how to deal with such architectural devices else? > > > > To reproduce: > > > > $ echo CONFIG_JAZZ=y > default-configs/devices/mips64el-softmmu.mak > > $ echo CONFIG_SEMIHOSTING=y >> default-configs/devices/mips64el-softmmu.mak > > $ configure --without-default-devices > > $ ninja qemu-system-mips64el > > $ ./qemu-system-mips64el -M magnum -S > > --- > > target/mips/cp0_itu-stub.c | 15 +++++++++++++++ > > target/mips/meson.build | 3 +++ > > 2 files changed, 18 insertions(+) > > create mode 100644 target/mips/cp0_itu-stub.c > > Perhaps use __attribute__((weak)) on itc_reconfigure? Then you don't need the > stub at all. You're already protecting the actual call, so there should be no > change needed there. > > We're not using weak so far, but as far as I can tell this is supported by gcc > on windows as well.
Apparently we are: $ git grep attribute.*weak softmmu/memory.c:3286:void __attribute__((weak)) fuzz_dma_read_cb(size_t addr, tests/qtest/libqtest-single.h:16:QTestState *global_qtest __attribute__((common, weak)); I think we should use either stubs or attribute weak, not both.
