configs/arm_foundationv8: bump to Linux 6.12 and model 11.27

- Bump Linux kernel to v6.12.15, update the hash file and add the
  dependency on host-python3.
- Bump the FVP in the readme to version 11.27 build 19.

While at it:
- Rework the readme a bit with explicit build instructions, add a link
  to the model binaries running on AArch64 host and update the model
  command line to specify Arm v8.0 (as we are building for Cortex-A53).
- Turn on hashes verification and update .checkpackageignore
  accordingly.
- Add myself as co-developer for this defconfig.

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
[Julien: remove "Locally calculated" in linux.hash]
Signed-off-by: Julien Olivain <ju.o@free.fr>

.checkpackageignore

@@ -105,7 +105,6 @@ configs/am574x_idk_defconfig lib_defconfig.ForceCheckHash
 configs/andes_ae350_45_defconfig lib_defconfig.ForceCheckHash
 configs/arcturus_ucls1012a_defconfig lib_defconfig.ForceCheckHash
 configs/arcturus_ucp1020_defconfig lib_defconfig.ForceCheckHash
-configs/arm_foundationv8_defconfig lib_defconfig.ForceCheckHash
 configs/aspeed_ast2500evb_defconfig lib_defconfig.ForceCheckHash
 configs/aspeed_ast2600evb_defconfig lib_defconfig.ForceCheckHash
 configs/asus_tinker-s_rk3288_defconfig lib_defconfig.ForceCheckHash

DEVELOPERS

@@ -3332,7 +3332,9 @@ F:	configs/qemu_arm_ebbr_defconfig
 F:	package/edk2-non-osi/
 
 N:	Vincent Stehlé <vincent.stehle@laposte.net>
+F:	board/arm/foundation-v8/
 F:	board/bananapi/bananapi-m2-zero/
+F:	configs/arm_foundationv8_defconfig
 F:	configs/bananapi_m2_zero_defconfig
 F:	configs/uevm5432_defconfig
 F:	package/i7z/

board/arm/foundation-v8/patches/linux/linux.hash

@@ -1,2 +1,2 @@
-# Locally calculated
-sha256  b0bb92d982f88380e5b2059349c3a862e0afa712e0646eb0e082b9c2c5cb5176  linux-6.8.10.tar.xz
+# From https://cdn.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
+sha256  5ff5bd84ea0e22c53437302db5d394d0a92d8b8b1a88ce20d1098298e9f7630a  linux-6.12.15.tar.xz

board/arm/foundation-v8/readme.txt

@@ -1,16 +1,34 @@
+Introduction
+============
+
 This is the support for the ARM Foundation v8 machine emulated by the
 ARM software simulator of the AArch64 architecture.
 
-First, one has to download the AArch64 software simulator from:
+Building
+========
 
-  https://developer.arm.com/-/media/Files/downloads/ecosystem-models/FM_11_25/Foundation_Platform_11.25_15_Linux64.tgz
+  $ make arm_foundationv8_defconfig
+  $ make
 
-Then, use the arm_foundationv8_defconfig configuration to build your
-Buildroot system.
+Generated files under output/images:
+
+* linux-system.axf: An image comprising the boot-wrapper-aarch64 minimal
+                    firmware and bootloader, a Devicetree and the Linux kernel.
+* rootfs.ext2:      The OS root filesystem.
+
+Running on the simulator
+========================
+
+Download the AArch64 software simulator from one of the following sources,
+corresponding to your host computer:
+
+- https://developer.arm.com/-/cdn-downloads/permalink/FVPs-Architecture/FM-11.27/Foundation_Platform_11.27_19_Linux64.tgz
+- https://developer.arm.com/-/cdn-downloads/permalink/FVPs-Architecture/FM-11.27/Foundation_Platform_11.27_19_Linux64_armv8l.tgz
 
 Finally, boot your system with:
 
  ${LOCATION_OF_FOUNDATIONV8_SIMULATOR}/models/Linux64_GCC-9.3/Foundation_Platform \
+    --arm-v8.0 \
     --image output/images/linux-system.axf \
     --block-device output/images/rootfs.ext2 \
     --network=nat \

configs/arm_foundationv8_defconfig

@@ -1,14 +1,16 @@
 BR2_aarch64=y
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_8=y
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_12=y
 BR2_GLOBAL_PATCH_DIR="board/arm/foundation-v8/patches"
+BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
 BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.8.10"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="6.12.15"
 BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG=y
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
 BR2_LINUX_KERNEL_INTREE_DTS_NAME="arm/foundation-v8-gicv3-psci"
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+BR2_LINUX_KERNEL_NEEDS_HOST_PYTHON3=y
 BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_SIZE="128M"
 # BR2_TARGET_ROOTFS_TAR is not set