[Buildroot] [PATCH v4 4/9] configs/qemu{x86, x86_64}: add a serial console
From: Romain Naour <hidden>
Date: 2020-02-09 18:03:22
Subsystem:
the rest · Maintainer:
Linus Torvalds
The current Buildroot defconfigs for qemu_x86 and qemu_x86_64
instantiate a console on tty1, which appears on QEMU's
graphical window. Add a console on the serial port (ttyS0) to
be used later for gitlab testing.
This change is need since the script used for gitlab testing
needs to use a serial output with pexpect.
This change is similar to the one made for raspberrypi [1] to
handle HDMI and serial console:
This requires three changes:
1. have two 'console=' entries in the kernel command line: tty1,
then ttyS0;
2. change BR2_TARGET_GENERIC_GETTY_PORT to "console", so it starts
a getty on the last console= passed to the kernel, ttyS0;
3. add a new getty on tty1 to the generated inittab.
Step 2 is actually obtained by removing BR2_TARGET_GENERIC_GETTY_PORT
entirely from the defconfigs, since "console" is the default value.
Step 3 requires a post-build script since the Buildroot makefiles can
configure only one console.
Note: instead of simply adding a new getty on ttyS0 (which would
work) this patch actually changes BR2_TARGET_GENERIC_GETTY_PORT to
instantiate a console on UART, then adds back tty1 via
post-build.sh. This is done only to avoid the "GENERIC_SERIAL" comment
where we instantiate a console on QEMU graphical window, then
instantiate a really-serial console on another line.
The result is these two inittab lines:
console::respawn:/sbin/getty -L console 0 vt100 # GENERIC_SERIAL
tty1::respawn:/sbin/getty -L tty1 0 vt100 # QEMU graphical window
[1] 20878a1017e2bf7eb8c5f870dc6d2641493cb0f9
Signed-off-by: Romain Naour <redacted>
---
board/qemu/x86/post-build.sh | 11 +++++++++++
board/qemu/x86/readme.txt | 2 +-
board/qemu/x86_64/post-build.sh | 11 +++++++++++
board/qemu/x86_64/readme.txt | 2 +-
configs/qemu_x86_64_defconfig | 4 +++-
configs/qemu_x86_defconfig | 4 +++-
6 files changed, 30 insertions(+), 4 deletions(-)
create mode 100755 board/qemu/x86/post-build.sh
create mode 100755 board/qemu/x86_64/post-build.sh
diff --git a/board/qemu/x86/post-build.sh b/board/qemu/x86/post-build.sh
new file mode 100755
index 0000000000..bf83a002c2
--- /dev/null
+++ b/board/qemu/x86/post-build.sh@@ -0,0 +1,11 @@ +#!/bin/sh + +set -u +set -e + +# Add a console on tty1 +if [ -e ${TARGET_DIR}/etc/inittab ]; then + grep -qE '^tty1::' ${TARGET_DIR}/etc/inittab || \ + sed -i '/GENERIC_SERIAL/a\ +tty1::respawn:/sbin/getty -L tty1 0 vt100 # QEMU graphical window' ${TARGET_DIR}/etc/inittab +fi
diff --git a/board/qemu/x86/readme.txt b/board/qemu/x86/readme.txt
index 42fc2439da..3bbafecf91 100644
--- a/board/qemu/x86/readme.txt
+++ b/board/qemu/x86/readme.txt@@ -1,6 +1,6 @@ Run the emulation with: - qemu-system-i386 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda" -net nic,model=virtio -net user + qemu-system-i386 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda console=tty1 console=ttyS0" -serial stdio -net nic,model=virtio -net user Optionally add -smp N to emulate a SMP system with N CPUs.
diff --git a/board/qemu/x86_64/post-build.sh b/board/qemu/x86_64/post-build.sh
new file mode 100755
index 0000000000..bf83a002c2
--- /dev/null
+++ b/board/qemu/x86_64/post-build.sh@@ -0,0 +1,11 @@ +#!/bin/sh + +set -u +set -e + +# Add a console on tty1 +if [ -e ${TARGET_DIR}/etc/inittab ]; then + grep -qE '^tty1::' ${TARGET_DIR}/etc/inittab || \ + sed -i '/GENERIC_SERIAL/a\ +tty1::respawn:/sbin/getty -L tty1 0 vt100 # QEMU graphical window' ${TARGET_DIR}/etc/inittab +fi
diff --git a/board/qemu/x86_64/readme.txt b/board/qemu/x86_64/readme.txt
index 4a1c0c0ff5..93ac22a947 100644
--- a/board/qemu/x86_64/readme.txt
+++ b/board/qemu/x86_64/readme.txt@@ -1,6 +1,6 @@ Run the emulation with: - qemu-system-x86_64 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda" -net nic,model=virtio -net user + qemu-system-x86_64 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda console=tty1 console=ttyS0" -serial stdio -net nic,model=virtio -net user Optionally add -smp N to emulate a SMP system with N CPUs.
diff --git a/configs/qemu_x86_64_defconfig b/configs/qemu_x86_64_defconfig
index cbd0413a90..b561e42e51 100644
--- a/configs/qemu_x86_64_defconfig
+++ b/configs/qemu_x86_64_defconfig@@ -3,12 +3,14 @@ BR2_x86_64=y # System BR2_SYSTEM_DHCP="eth0" -BR2_TARGET_GENERIC_GETTY_PORT="tty1" # Filesystem BR2_TARGET_ROOTFS_EXT2=y # BR2_TARGET_ROOTFS_TAR is not set +# Image +BR2_ROOTFS_POST_BUILD_SCRIPT="board/qemu/x86_64/post-build.sh" + # Linux headers same as kernel, a 4.19 series BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_19=y
diff --git a/configs/qemu_x86_defconfig b/configs/qemu_x86_defconfig
index 6ca3ab9627..52f1744344 100644
--- a/configs/qemu_x86_defconfig
+++ b/configs/qemu_x86_defconfig@@ -4,12 +4,14 @@ BR2_x86_pentiumpro=y # System BR2_SYSTEM_DHCP="eth0" -BR2_TARGET_GENERIC_GETTY_PORT="tty1" # Filesystem BR2_TARGET_ROOTFS_EXT2=y # BR2_TARGET_ROOTFS_TAR is not set +# Image +BR2_ROOTFS_POST_BUILD_SCRIPT="board/qemu/x86/post-build.sh" + # Linux headers same as kernel, a 4.19 series BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_19=y
--
2.24.1