Re: [Qemu-arm] [RFC PATCH 1/2] target/arm: Add stubs to build with CONFIG_SEMIHOSTING disabled

[Philippe Mathieu-Daudé]

On 6/17/19 5:19 PM, Alex Bennée wrote:
> Philippe Mathieu-Daudé <address@hidden> writes:
> 
>> If a distribution wants to build QEMU without semihosting support,
>> it currently gets this build failure:
>>
>>   $ ./configure --target-list=aarch64-softmmu --without-default-devices
>>   $ sed -i 
>> s/CONFIG_SEMIHOSTING=y/CONFIG_SEMIHOSTING=n/default-configs/arm-softmmu.mak
> 
> I'm still not convinced we should be adding support for stuff being done
> outside the normal build process...

If the "KVM/TCG split" series is accepted, then we can add a
--disable-tcg job in the list of "normal builds" and we don't need this
particular patch.

> that said...
> 
>>   $ make subdir-aarch64-softmmu
>>   [...]
>>     LINK    aarch64-softmmu/qemu-system-aarch64
>>   /usr/bin/ld: target/arm/arm-semi.o: in function `do_arm_semihosting':
>>   ./target/arm/arm-semi.c:321: undefined reference to 
>> `qemu_semihosting_console_out'
>>   /usr/bin/ld: ./target/arm/arm-semi.c:318: undefined reference to 
>> `qemu_semihosting_console_out'
>>   collect2: error: ld returned 1 exit status
>>   make[1]: *** [Makefile:204: qemu-system-aarch64] Error 1
>>   make: *** [Makefile:472: subdir-aarch64-softmmu] Error 2
>>
>> Fix it by providing a stub when semihosting is disabled.
>>
>> Reported-by: Miroslav Rezanina <address@hidden>
>> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
>> ---
>>  target/arm/Makefile.objs    |  3 ++-
>>  target/arm/arm-semi-stubs.c | 21 +++++++++++++++++++++
>>  2 files changed, 23 insertions(+), 1 deletion(-)
>>  create mode 100644 target/arm/arm-semi-stubs.c
>>
>> diff --git a/target/arm/Makefile.objs b/target/arm/Makefile.objs
>> index 6bdcc65c2c..39b02b1fa4 100644
>> --- a/target/arm/Makefile.objs
>> +++ b/target/arm/Makefile.objs
>> @@ -1,4 +1,5 @@
>> -obj-y += arm-semi.o
>> +obj-$(CONFIG_SEMIHOSTING) += arm-semi.o
>> +obj-$(call lnot,$(CONFIG_SEMIHOSTING)) += arm-semi-stubs.o
>>  obj-$(CONFIG_SOFTMMU) += machine.o psci.o arch_dump.o monitor.o
>>  obj-$(CONFIG_KVM) += kvm.o
>>  obj-$(call land,$(CONFIG_KVM),$(call lnot,$(TARGET_AARCH64))) += kvm32.o
>> diff --git a/target/arm/arm-semi-stubs.c b/target/arm/arm-semi-stubs.c
>> new file mode 100644
>> index 0000000000..a91ecbd9d5
>> --- /dev/null
>> +++ b/target/arm/arm-semi-stubs.c
>> @@ -0,0 +1,21 @@
>> +/*
>> + *  Arm "Angel" semihosting stubs
>> + *
>> + * Copyright (c) 2019 Red Hat, Inc.
>> + *
>> + * Author:
>> + *   Philippe Mathieu-Daudé <address@hidden>
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
>> + * See the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "cpu.h"
>> +
>> +target_ulong do_arm_semihosting(CPUARMState *env)
>> +{
>> +    g_assert_not_reached();
>> +}
> 
> Could this not just be added to arm-semi.c in an
> 
>   #ifndef CONFIG_SEMIHOSTING
>   target_ulong do_arm_semihosting(CPUARMState *env)
>   {
>       g_assert_not_reached();
>   }
>   #else
>   ... rest of arm-semi.c....
>   #endif

OK, thanks for your reviews!

Phil.