arch: common: dedicated SEMIHOST symbol

Control the usage of semihosting with a dedicated symbol, instead of
implying semihosting from the usage of `SEMIHOST_CONSOLE`. This allows
semihosting to be used without the semihost console.

Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>

arch/Kconfig

@@ -148,6 +148,8 @@ config ARCH_IS_SET
 
 menu "General Architecture Options"
 
+source "$(ARCH_DIR)/common/Kconfig"
+
 module = ARCH
 module-str = arch
 source "subsys/logging/Kconfig.template.log_config"

arch/common/Kconfig

@@ -0,0 +1,17 @@
+# Common architecture configuration options
+
+# Copyright (c) 2022, CSIRO.
+# SPDX-License-Identifier: Apache-2.0
+
+config SEMIHOST
+	bool "Semihosting support for ARM and RISC-V targets"
+	depends on ARM || ARM64 || RISCV
+	help
+	  Semihosting is a mechanism that enables code running on an ARM or
+	  RISC-V target to communicate and use the Input/Output facilities on
+	  a host computer that is running a debugger.
+	  Additional information can be found in:
+	  https://developer.arm.com/documentation/dui0471/m/what-is-semihosting-
+	  https://github.com/riscv/riscv-semihosting-spec/blob/main/riscv-semihosting-spec.adoc
+	  This option is compatible with hardware and with QEMU, through the
+	  (automatic) use of the -semihosting-config switch when invoking it.

cmake/emu/qemu.cmake

@@ -70,7 +70,7 @@ endif()
 list(APPEND QEMU_FLAGS -serial chardev:con)
 
 # Connect semihosting console to the console chardev if configured.
-if(CONFIG_SEMIHOST_CONSOLE)
+if(CONFIG_SEMIHOST)
   list(APPEND QEMU_FLAGS
     -semihosting-config enable=on,target=auto,chardev=con
     )

drivers/console/Kconfig

@@ -298,17 +298,10 @@ config NATIVE_POSIX_CONSOLE_INIT_PRIORITY
 config SEMIHOST_CONSOLE
 	bool "Use semihosting for console"
 	select CONSOLE_HAS_DRIVER
-	depends on CPU_CORTEX_M || ARM64 || RISCV
+	depends on SEMIHOST
 	help
 	  Enable this option to use semihosting for console.
-	  Semihosting is a mechanism that enables code running on an ARM or
+	  See SEMIHOST for a more complete description of semihosting.
-	  RISC-V target to communicate and use the Input/Output facilities
-	  on a host computer that is running a debugger.
-	  Additional information can be found in:
-	  https://developer.arm.com/docs/dui0471/k/what-is-semihosting/what-is-semihosting
-	  https://github.com/riscv/riscv-semihosting-spec/blob/main/riscv-semihosting-spec.adoc
-	  This option is compatible with hardware and with QEMU, through the
-	  (automatic) use of the -semihosting-config switch when invoking it.
 
 module = UART_CONSOLE
 module-str = UART console

tests/drivers/console/prj_semihost.conf

@@ -2,4 +2,5 @@ CONFIG_TEST=y
 CONFIG_CONSOLE=y
 CONFIG_SERIAL=n
 CONFIG_UART_CONSOLE=n
+CONFIG_SEMIHOST=y
 CONFIG_SEMIHOST_CONSOLE=y