Testing, gdbstub and doc tweaks:

- increase timeout on replay kernel acceptance test
   - fixes for binfmt_misc docker images
   - better gdb version detection
   - don't silently skip gdb tests
   - fix for gdbstub auxv handling
   - cleaner handling of check-tcg on tcg disabled builds
   - expand vexpress/versitile docs with examples
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Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-gdbstub-docs-080221-1' into staging

Testing, gdbstub and doc tweaks:

  - increase timeout on replay kernel acceptance test
  - fixes for binfmt_misc docker images
  - better gdb version detection
  - don't silently skip gdb tests
  - fix for gdbstub auxv handling
  - cleaner handling of check-tcg on tcg disabled builds
  - expand vexpress/versitile docs with examples

# gpg: Signature made Mon 08 Feb 2021 11:12:03 GMT
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-gdbstub-docs-080221-1:
  docs/system: document an example booting the versatilepb machine
  docs/system: document an example vexpress-a15 invocation
  tests/Makefile.include: don't use TARGET_DIRS for check-tcg
  scripts/mtest2make.py: export all-%s-targets variable and use it
  tests/tcg: Replace /bin/true by true (required on macOS)
  gdbstub: Fix handle_query_xfer_auxv
  tests/tcg: don't silently skip the gdb tests
  configure: bump the minimum gdb version for check-tcg to 9.1
  configure: make version_ge more tolerant of shady version input
  tests/docker: add a docker-exec-copy-test
  tests/docker: alias docker-help target for consistency
  tests/docker: preserve original name when copying libs
  tests/docker: make _copy_with_mkdir accept missing files
  tests/docker: Fix typo in help message
  tests/docker: Fix _get_so_libs() for docker-binfmt-image
  tests/acceptance: Increase the timeout in the replay tests

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/system/arm/versatile.rst

@@ -27,3 +27,37 @@ The Arm Versatile baseboard is emulated with the following devices:
    devices.
 
 -  PL181 MultiMedia Card Interface with SD card.
+
+Booting a Linux kernel
+----------------------
+
+Building a current Linux kernel with ``versatile_defconfig`` should be
+enough to get something running. Nowadays an out-of-tree build is
+recommended (and also useful if you build a lot of different targets).
+In the following example $BLD points to the build directory and $SRC
+points to the root of the Linux source tree. You can drop $SRC if you
+are running from there.
+
+.. code-block:: bash
+
+  $ make O=$BLD -C $SRC ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- versatile_defconfig
+  $ make O=$BLD -C $SRC ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-
+
+You may want to enable some additional modules if you want to boot
+something from the SCSI interface::
+
+  CONFIG_PCI=y
+  CONFIG_PCI_VERSATILE=y
+  CONFIG_SCSI=y
+  CONFIG_SCSI_SYM53C8XX_2=y
+
+You can then boot with a command line like:
+
+.. code-block:: bash
+
+  $ qemu-system-arm -machine type=versatilepb \
+      -serial mon:stdio \
+      -drive if=scsi,driver=file,filename=debian-buster-armel-rootfs.ext4 \
+      -kernel zImage \
+      -dtb versatile-pb.dtb  \
+      -append "console=ttyAMA0 ro root=/dev/sda"

docs/system/arm/vexpress.rst

@@ -58,3 +58,31 @@ Other differences between the hardware and the QEMU model:
   ``vexpress-a15``, and have IRQs from 40 upwards. If a dtb is
   provided on the command line then QEMU will edit it to include
   suitable entries describing these transports for the guest.
+
+Booting a Linux kernel
+----------------------
+
+Building a current Linux kernel with ``multi_v7_defconfig`` should be
+enough to get something running. Nowadays an out-of-tree build is
+recommended (and also useful if you build a lot of different targets).
+In the following example $BLD points to the build directory and $SRC
+points to the root of the Linux source tree. You can drop $SRC if you
+are running from there.
+
+.. code-block:: bash
+
+  $ make O=$BLD -C $SRC ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- multi_v7_defconfig
+  $ make O=$BLD -C $SRC ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-
+
+By default you will want to boot your rootfs off the sdcard interface.
+Your rootfs will need to be padded to the right size. With a suitable
+DTB you could also add devices to the virtio-mmio bus.
+
+.. code-block:: bash
+
+  $ qemu-system-arm -cpu cortex-a15 -smp 4 -m 4096 \
+      -machine type=vexpress-a15 -serial mon:stdio \
+      -drive if=sd,driver=file,filename=armel-rootfs.ext4 \
+      -kernel zImage  \
+      -dtb vexpress-v2p-ca15-tc1.dtb \
+      -append "console=ttyAMA0 root=/dev/mmcblk0 ro"