mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-23 02:05:57 +01:00
build-buildroot: clean up old kernel config options
This commit is contained in:
Ciro Santilli 六四事件 法轮功
127
README.adoc
127
README.adoc
@@ -3153,11 +3153,9 @@ More concretely:
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....
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git -C "$(./getvar linux_src_dir)" checkout gem5/v4.15
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./build-buildroot \
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./build-linux \
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--arch arm \
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--gem5 \
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-l \
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-K linux/arch/arm/configs/gem5_defconfig \
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--custom-config-file submodules/linux/arch/arm/configs/gem5_defconfig \
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--linux-build-id gem5-v4.15 \
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;
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git -C "$(./getvar linux_src_dir)" checkout -
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@@ -3219,16 +3217,14 @@ Tested on: link:http://github.com/cirosantilli/linux-kernel-module-cheat/commit/
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==== Graphic mode gem5 aarch64
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For `aarch64` we also need `-c kernel_config_fragment/display`:
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For `aarch64` we also need to configure the kernel with link:linux_config/display[]:
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....
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git -C "$(./getvar linux_src_dir)" checkout gem5/v4.15
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./build-buildroot \
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./build-linux \
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--arch aarch64 \
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-c kernel_config_fragment/display \
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--gem5 \
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-K linux/arch/arm64/configs/gem5_defconfig \
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-l \
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--config-fragment linux_config/display \
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--custom-config-file submodules/linux/arch/arm64/configs/gem5_defconfig \
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--linux-build-id gem5-v4.15 \
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;
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git -C "$(./getvar linux_src_dir)" checkout -
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@@ -3243,9 +3239,9 @@ We cannot use mainline Linux because the <<gem5-arm-linux-kernel-patches>> are r
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gem5 emulates the link:http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0541c/CHDBAIDI.html[HDLCD] ARM Holdings hardware for `arm` and `aarch64`.
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The kernel uses HDLCD to implement the <<drm>> interface, the required kernel config options are present at: link:kernel_config_fragment/display[].
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The kernel uses HDLCD to implement the <<drm>> interface, the required kernel config options are present at: link:linux_config/display[].
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TODO: minimize out the `-K`. If we just remove it on `arm`: it does not work with a failing dmesg:
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TODO: minimize out the `--custom-config-file`. If we just remove it on `arm`: it does not work with a failing dmesg:
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....
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[ 0.066208] [drm] found ARM HDLCD version r0p0
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@@ -3301,7 +3297,7 @@ Once you've seen the `CONFIG_LOGO` penguin as a sanity check, you can try to go
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Build and run:
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....
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./build-buildroot --config-fragment br2/x11
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./build-buildroot --config-fragment buildroot_config/x11
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./run --graphic
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....
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@@ -3331,7 +3327,7 @@ Not sure how well that graphics stack represents real systems, but if it does it
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To x11 packages have an `xserver` prefix as in:
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....
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./build-buildroot --config-fragment br2/x11 -- xserver_xorg-server-reconfigure
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./build-buildroot --config-fragment buildroot_config/x11 -- xserver_xorg-server-reconfigure
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....
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the easiest way to find them out is to just list `"$(./getvar build_dir)/x*`.
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@@ -3724,8 +3720,8 @@ We have managed to come up with minimalistic kernel configs that work for both Q
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Our configs are all based on Buildroot's configs, which were designed for QEMU, and then on top of those we also add:
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* link:kernel_config_fragment/min[]: minimal tweaks required to boot gem5 or for using our slightly different QEMU command line options than Buildroot
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* link:kernel_config_fragment/default[]: optional configs that we add by default to our kernel build because they increase visibility, and don't significantly increase build time nor add significant runtime overhead
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* link:linux_config/min[]: minimal tweaks required to boot gem5 or for using our slightly different QEMU command line options than Buildroot
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* link:linux_config/default[]: optional configs that we add by default to our kernel build because they increase visibility, and don't significantly increase build time nor add significant runtime overhead
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Changes to those files automatically trigger kernel reconfigures even without using the linux-reconfigure target, since timestamps are used to decide if changes happened or not.
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@@ -6822,7 +6818,9 @@ Outcome: for a few seconds, the screen that contains the terminal gets taken ove
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TODO not working for `aarch64`, it takes over the screen for a few seconds and the kernel messages disappear, but the screen stays black all the time.
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....
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./build-buildroot --config 'BR2_PACKAGE_LIBDRM=y' --kernel-modules
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./build-buildroot --config 'BR2_PACKAGE_LIBDRM=y'
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./build-userland --has-package libdrm
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./build-buildroot
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./run --eval-busybox '/libdrm_modeset.out' --graphic
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....
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@@ -6863,7 +6861,7 @@ Tested on: link:http://github.com/cirosantilli/linux-kernel-module-cheat/commit/
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==== kmscube
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....
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./build-buildroot --config-fragment br2/kmscube
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./build-buildroot --config-fragment buildroot_config/kmscube
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....
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Outcome: a colored spinning cube coded in OpenGL + EGL takes over your display and spins forever: https://www.youtube.com/watch?v=CqgJMgfxjsk
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@@ -6932,10 +6930,10 @@ Looks like a more raw alternative to libdrm:
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....
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./build-buildroot --config 'BR2_PACKABE_LIBDRI2=y'
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wget \
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-O "$(./getvar kernel_modules_src_dir)/user/dri2test.c" \
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-O "$(./getvar userland_src_dir)/dri2test.c" \
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https://raw.githubusercontent.com/robclark/libdri2/master/test/dri2test.c \
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;
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./build-buildroot --kernel-modules
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./build-userland
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....
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but then I noticed that that example requires multiple files, and I don't feel like integrating it into our build.
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@@ -7502,7 +7500,8 @@ where link:http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0190b/
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Then compile with:
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....
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./build-buildroot --arch arm --config-fragment br2/gpio -c kernel_config_fragment/gpio -l
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./build-buildroot --arch arm --config-fragment buildroot_config/gpio
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./build-linux --config-fragment linux_config/gpio
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....
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then test it out with:
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@@ -7535,8 +7534,8 @@ static void arm_sysctl_write(void *opaque, hwaddr offset,
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and then rebuild with:
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....
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./build-buildroot --arch arm -c kernel_config_fragment/leds -l
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./build-qemu --arch arm
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./build-linux --arch arm --config-fragment linux_config/leds
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....
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But beware that one of the LEDs has a heartbeat trigger by default (specified on dts), so it will produce a lot of output.
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@@ -8687,7 +8686,7 @@ There are two ways to run PARSEC with this repo:
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....
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./download-dependencies --gem5 --parsec-benchmark
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./build-buildroot --arch arm --config 'BR2_PACKAGE_PARSEC_BENCHMARK=y' --gem5
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./build-buildroot --arch arm --config 'BR2_PACKAGE_PARSEC_BENCHMARK=y'
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./run --arch arm --gem5
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....
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@@ -8718,7 +8717,6 @@ Running a benchmark of a size different than `test`, e.g. `simsmall`, requires a
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--arch arm \
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--config 'BR2_PACKAGE_PARSEC_BENCHMARK=y' \
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--config 'BR2_PACKAGE_PARSEC_BENCHMARK_INPUT_SIZE="simsmall"' \
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--gem5 \
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-- parsec-benchmark-reconfigure \
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;
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....
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@@ -8777,7 +8775,6 @@ If you still want to run this, try it out with:
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--config 'BR2_PACKAGE_PARSEC_BENCHMARK=y' \
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--config 'BR2_PACKAGE_PARSEC_BENCHMARK_PARSECMGMT=y' \
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--config 'BR2_TARGET_ROOTFS_EXT2_SIZE="3G"' \
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--gem5 \
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-- parsec-benchmark-reconfigure \
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;
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....
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@@ -8803,7 +8800,7 @@ rm -rf \
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"$(./getvar buildroot_build_dir)"/images/rootfs.* \
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"$(./getvar buildroot_build_dir)"/target/parsec-* \
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;
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./build-buildroot --arch arm --gem5
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./build-buildroot --arch arm
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....
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====== PARSEC benchmark hacking
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@@ -8832,7 +8829,6 @@ Don't forget to explicitly rebuild PARSEC with:
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./build-buildroot \
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--arch arm \
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--config 'BR2_PACKAGE_PARSEC_BENCHMARK=y' \
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--gem5 \
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-- parsec-benchmark-reconfigure \
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;
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....
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@@ -9459,7 +9455,6 @@ system.cpu.dtb.inst_hits
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Let's have some fun and try to correlate the gem5 cycle count `system.cpu.numCycles` with the link:https://en.wikipedia.org/wiki/Time_Stamp_Counter[x86 `rdtsc` instruction] that is supposed to do the same thing:
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....
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./build-buildroot --gem5
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./build-userland -- rdtsc
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./run --eval '/rdtsc.out;m5 exit;' --gem5
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./gem5-stat
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@@ -9618,30 +9613,6 @@ Not currently exposed here.
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== Buildroot
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=== Rebuild Buildroot packages
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After making changes to a Buildroot package, you must explicitly request it to be rebuilt.
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For example, if you modify the kernel modules, which is a Buildroot package, you must rebuild with:
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....
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./build-buildroot -- kernel_modules-reconfigure
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....
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where `kernel_modules` is the name of our Buildroot package that contains the kernel modules.
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Since rebuilding this package is such a common case, we have a shortcut for it:
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....
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./build-buildroot --kernel-modules
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....
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The rebuild must be requested explicitly, otherwise the package does not rebuild, even if its files were modified.
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This is because Buildroot builds dozens of packages, and just reading there Makefiles and checking the stamps generates too much overhead
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So you must tell Buildroot yourself about the rebuild.
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=== Custom Buildroot configs
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We provide the following mechanisms:
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@@ -10370,8 +10341,6 @@ The build times are calculated after doing `./download-dependencies` and link:ht
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Sample build time at 2c12b21b304178a81c9912817b782ead0286d282: 28 minutes, 15 with full ccache hits. Breakdown: 19% GCC, 13% Linux kernel, 7% uclibc, 6% host-python, 5% host-qemu, 5% host-gdb, 2% host-binutils
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Single file change on `./build-buildroot kernel_modules-reconfigure`: 7 seconds.
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Buildroot automatically stores build timestamps as milliseconds since Epoch. Convert to minutes:
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....
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@@ -10388,7 +10357,7 @@ cat ../linux-kernel-module-cheat-regression/*/build-time.log
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===== Find which packages are making the build slow and big
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....
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./build-buildroot --skip-configure -- graph-build graph-size graph-depends
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./build-buildroot -- graph-build graph-size graph-depends
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cd "$(./getvar buildroot_build_dir)/graphs"
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xdg-open build.pie-packages.pdf
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xdg-open graph-depends.pdf
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@@ -10578,7 +10547,7 @@ ls "$(./getvar buildroot_build_dir)"
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Note that host tools like QEMU and gem5 store all archs in a single directory to factor out build objects, so cleaning one arch will clean all of them.
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To only nuke one one Buildroot package, we can use the link:https://buildroot.org/downloads/manual/manual.html#pkg-build-steps[]`-dirclean`] Buildroot target:
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To only nuke only one Buildroot package, we can use the link:https://buildroot.org/downloads/manual/manual.html#pkg-build-steps[]`-dirclean`] Buildroot target:
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....
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./build-buildroot --no-all -- <package-name>-dirclean
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@@ -10587,7 +10556,7 @@ To only nuke one one Buildroot package, we can use the link:https://buildroot.or
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e.g.:
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....
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./build-buildroot --no-all -- kernel_modules-dirclean
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./build-buildroot --no-all -- sample_package-dirclean
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....
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Verify with:
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@@ -10743,12 +10712,12 @@ If you want to keep two builds around, one for the latest Linux version, and the
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....
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# Build master.
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./build-buildroot
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./build-linux
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# Build another branch.
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git -C "$(./getvar linux_src_dir)" fetch --tags --unshallow
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git -C "$(./getvar linux_src_dir)" checkout v4.16
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./build-buildroot --linux-build-id v4.16
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./build-linux --linux-build-id v4.16
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# Restore master.
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git -C "$(./getvar linux_src_dir)" checkout -
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@@ -10903,42 +10872,6 @@ The price to pay for debuggability is high however: a Linux kernel boot was abou
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so you will likely only use this when it is unavoidable.
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==== Buildroot package build variants
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This hack-ish technique allows us to rebuild just one package at a time:
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....
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./build-buildroot KERNEL_MODULE_VERSION=mybranch
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....
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and now you can see that a new version of `kernel_modules` was built and put inside the image:
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....
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ls "$(./getvar build_dir)/kernel_modules-mybranch"
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....
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Unfortunately we don't have a nice runtime selection with `./run` implemented currently, you have to manually move packages around.
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TODO: is there a way to do it nicely for `*_OVERRIDE_SRCDIR` packages from link:buildroot_override[]? I tried:
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....
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./build-buildroot -l LINUX_VERSION=mybranch
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....
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but it fails with:
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....
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linux/linux.mk:492: *** LINUX_SITE cannot be empty when LINUX_SOURCE is not. Stop.
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....
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and then tried:
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....
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./build-buildroot -l LINUX_VERSION=mybranch LINUX_SITE="$(pwd)/linux"
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....
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but it feels hackish, and the build was slower than normal, looks like the build was single threaded?
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==== Buildroot build variants
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Allows you to have multiple versions of the GCC toolchain or root filesystem.
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@@ -10948,10 +10881,10 @@ Analogous to the <<linux-kernel-build-variants>> but with the `--build-id` optio
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....
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./build-buildroot
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git -C "$(./getvar buildroot_src_dir)" checkout 2018.05
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./build-buildroot --build-id 2018.05
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./build-buildroot --buildroot-build-id 2018.05
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git -C "$(./getvar buildroot_src_dir)" checkout -
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./run
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./run --build-id 2018.05
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./run --buildroot-build-id 2018.05
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....
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=== Directory structure
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