Re: [Qemu-devel] [RFC PATCH 02/11] semihosting: introduce CONFIG_SEMIHOSTING

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/14/19 5:52 PM, Alex Bennée wrote:
> There isn't much point building semihosting for platforms that don't
> support it. Introduce a new symbol and enable it only for the softmmu
> targets that need it.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  default-configs/arm-softmmu.mak         |  1 +
>  default-configs/lm32-softmmu.mak        |  2 +
>  default-configs/m68k-softmmu.mak        |  2 +
>  default-configs/mips-softmmu-common.mak |  1 +
>  default-configs/nios2-softmmu.mak       |  2 +
>  default-configs/xtensa-softmmu.mak      |  2 +
>  hw/Kconfig                              |  1 +
>  hw/semihosting/Kconfig                  |  3 ++
>  hw/semihosting/Makefile.objs            |  2 +-
>  stubs/Makefile.objs                     |  1 +
>  stubs/semihost.c                        | 66 +++++++++++++++++++++++++
>  11 files changed, 82 insertions(+), 1 deletion(-)
>  create mode 100644 hw/semihosting/Kconfig
>  create mode 100644 stubs/semihost.c
> 
> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
> index f23ecfd5c58..1f2e0e7fdeb 100644
> --- a/default-configs/arm-softmmu.mak
> +++ b/default-configs/arm-softmmu.mak
> @@ -39,3 +39,4 @@ CONFIG_MICROBIT=y
>  CONFIG_FSL_IMX25=y
>  CONFIG_FSL_IMX7=y
>  CONFIG_FSL_IMX6UL=y
> +CONFIG_SEMIHOSTING=y
> diff --git a/default-configs/lm32-softmmu.mak b/default-configs/lm32-softmmu.mak
> index 6d259665d60..115b3e34c98 100644
> --- a/default-configs/lm32-softmmu.mak
> +++ b/default-configs/lm32-softmmu.mak
> @@ -4,6 +4,8 @@
>  #
>  #CONFIG_MILKYMIST_TMU2=n        # disabling it actually causes compile-time failures
>  
> +CONFIG_SEMIHOSTING=y
> +
>  # Boards:
>  #
>  CONFIG_LM32=y
> diff --git a/default-configs/m68k-softmmu.mak b/default-configs/m68k-softmmu.mak
> index e17495e2a0b..4049a8f2ba9 100644
> --- a/default-configs/m68k-softmmu.mak
> +++ b/default-configs/m68k-softmmu.mak
> @@ -1,5 +1,7 @@
>  # Default configuration for m68k-softmmu
>  
> +CONFIG_SEMIHOSTING=y
> +
>  # Boards:
>  #
>  CONFIG_AN5206=y
> diff --git a/default-configs/mips-softmmu-common.mak b/default-configs/mips-softmmu-common.mak
> index 8e54a74b7a5..e10ac4b20c0 100644
> --- a/default-configs/mips-softmmu-common.mak
> +++ b/default-configs/mips-softmmu-common.mak
> @@ -35,6 +35,7 @@ CONFIG_MIPS_CPS=y
>  CONFIG_MIPS_ITU=y
>  CONFIG_R4K=y
>  CONFIG_MALTA=y
> +CONFIG_SEMIHOSTING=y
>  CONFIG_PCNET_PCI=y
>  CONFIG_MIPSSIM=y
>  CONFIG_ACPI_SMBUS=y
> diff --git a/default-configs/nios2-softmmu.mak b/default-configs/nios2-softmmu.mak
> index e130d024e62..1bc4082ea99 100644
> --- a/default-configs/nios2-softmmu.mak
> +++ b/default-configs/nios2-softmmu.mak
> @@ -1,5 +1,7 @@
>  # Default configuration for nios2-softmmu
>  
> +CONFIG_SEMIHOSTING=y
> +
>  # Boards:
>  #
>  CONFIG_NIOS2_10M50=y
> diff --git a/default-configs/xtensa-softmmu.mak b/default-configs/xtensa-softmmu.mak
> index 7e4d1cc0979..3aa20a47a7f 100644
> --- a/default-configs/xtensa-softmmu.mak
> +++ b/default-configs/xtensa-softmmu.mak
> @@ -1,5 +1,7 @@
>  # Default configuration for Xtensa
>  
> +CONFIG_SEMIHOSTING=y
> +
>  # Boards:
>  #
>  CONFIG_XTENSA_SIM=y
> diff --git a/hw/Kconfig b/hw/Kconfig
> index 88b9f150070..195f541e50c 100644
> --- a/hw/Kconfig
> +++ b/hw/Kconfig
> @@ -29,6 +29,7 @@ source pci/Kconfig
>  source rdma/Kconfig
>  source scsi/Kconfig
>  source sd/Kconfig
> +source semihosting/Kconfig
>  source smbios/Kconfig
>  source ssi/Kconfig
>  source timer/Kconfig
> diff --git a/hw/semihosting/Kconfig b/hw/semihosting/Kconfig
> new file mode 100644
> index 00000000000..efe0a30734c
> --- /dev/null
> +++ b/hw/semihosting/Kconfig
> @@ -0,0 +1,3 @@
> +
> +config SEMIHOSTING
> +       bool
> diff --git a/hw/semihosting/Makefile.objs b/hw/semihosting/Makefile.objs
> index 546954f4ff4..09c19bf19ed 100644
> --- a/hw/semihosting/Makefile.objs
> +++ b/hw/semihosting/Makefile.objs
> @@ -1 +1 @@
> -common-obj-$(CONFIG_SOFTMMU) += config.o
> +obj-$(CONFIG_SEMIHOSTING) += config.o
> diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
> index 269dfa58326..e0d4f11b348 100644
> --- a/stubs/Makefile.objs
> +++ b/stubs/Makefile.objs
> @@ -39,3 +39,4 @@ stub-obj-y += xen-hvm.o
>  stub-obj-y += pci-host-piix.o
>  stub-obj-y += ram-block.o
>  stub-obj-y += ramfb.o
> +stub-obj-$(CONFIG_SOFTMMU) += semihost.o
> diff --git a/stubs/semihost.c b/stubs/semihost.c
> new file mode 100644
> index 00000000000..1a4e88e5326
> --- /dev/null
> +++ b/stubs/semihost.c
> @@ -0,0 +1,66 @@
> +/*
> + * Semihosting Stubs for SoftMMU
> + *
> + * Copyright (c) 2019 Linaro Ltd
> + *
> + * Stubs for SoftMMU targets that don't actually do semihosting.
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/option.h"
> +#include "qemu/error-report.h"
> +#include "hw/semihosting/semihost.h"
> +
> +/* Empty config */
> +QemuOptsList qemu_semihosting_config_opts = {
> +    .name = "",
> +    .head = QTAILQ_HEAD_INITIALIZER(qemu_semihosting_config_opts.head),
> +    .desc = {
> +        { /* end of list */ }
> +    },
> +};
> +
> +/* Queries to config status default to off */
> +bool semihosting_enabled(void)
> +{
> +    return false;
> +}
> +
> +SemihostingTarget semihosting_get_target(void)
> +{
> +    return SEMIHOSTING_TARGET_AUTO;
> +}
> +
> +/*
> + * All the rest are empty subs. We could g_assert_not_reached() but
> + * that adds extra weight to the final binary. Waste not want not.
> + */
> +void qemu_semihosting_enable(void)
> +{
> +}
> +
> +int qemu_semihosting_config_options(const char *optarg)
> +{
> +    return 1;
> +}
> +
> +const char *semihosting_get_arg(int i)
> +{
> +    return NULL;
> +}
> +
> +int semihosting_get_argc(void)
> +{
> +    return 0;
> +}
> +
> +const char *semihosting_get_cmdline(void)
> +{
> +    return NULL;
> +}
> +
> +void semihosting_arg_fallback(const char *file, const char *cmd)
> +{
> +}
>