Drop ext4 images and use initramfs for all targets

[tpimh]

As discussed in https://github.com/ClangBuiltLinux/continuous-integration/issues/184#issuecomment-511457479, ext4 images can be dropped and slimmer initramfs images should be used instead.

Most ext4 images were unused. Only arm32_v7, arm64, mipsel and some x86_64 configs used them. They were modified to use initramfs instead.

Travis for basic set of configurations shows no regressions, but I suggest testing the full set that's normally run by cron.

[nathanchance]

I pulled this down locally and started a set of builds before I had to rush off to work. I’ll post the results and formally review it tonight.

[nathanchance]

Full results:

Running 'ARCH=arm32_v5 LD=ld.lld ./driver.sh'... Successful in 2m 14s
Running 'ARCH=arm32_v6 ./driver.sh'... Successful in 1m 26s
Running 'ARCH=arm32_v7 LD=ld.lld ./driver.sh'... Successful in 1m 57s
Running 'ARCH=arm64 LD=ld.lld ./driver.sh'... Successful in 2m 44s
Running 'ARCH=mipsel ./driver.sh'... Successful in 1m 23s
Running 'ARCH=ppc32 ./driver.sh'... Successful in 1m 1s
Running 'ARCH=ppc64 ./driver.sh'... Successful in 1m 54s
Running 'ARCH=ppc64le LD=ld.lld ./driver.sh'... Failed in 3m 20s
Running 'ARCH=x86_64 LD=ld.lld ./driver.sh'... Successful in 1m 53s
Running 'ARCH=arm32_v5 LD=ld.lld REPO=linux-next ./driver.sh'... Successful in 2m 16s
Running 'ARCH=arm32_v6 REPO=linux-next ./driver.sh'... Successful in 1m 25s
Running 'ARCH=arm32_v7 LD=ld.lld REPO=linux-next ./driver.sh'... Successful in 1m 58s
Running 'ARCH=arm64 LD=ld.lld REPO=linux-next ./driver.sh'... Successful in 2m 45s
Running 'ARCH=mipsel REPO=linux-next ./driver.sh'... Successful in 1m 21s
Running 'ARCH=ppc32 REPO=linux-next ./driver.sh'... Successful in 0m 59s
Running 'ARCH=ppc64 REPO=linux-next ./driver.sh'... Successful in 1m 52s
Running 'ARCH=ppc64le LD=ld.lld REPO=linux-next ./driver.sh'... Failed in 3m 18s
Running 'ARCH=x86_64 LD=ld.lld REPO=linux-next ./driver.sh'... Successful in 1m 56s
Running 'ARCH=arm32_v7 REPO=4.19 ./driver.sh'... Successful in 2m 26s
Running 'ARCH=arm64 LD=ld.lld REPO=4.19 ./driver.sh'... Successful in 2m 20s
Running 'ARCH=ppc64le REPO=4.19 ./driver.sh'... Failed in 3m 14s
Running 'ARCH=x86_64 LD=ld.lld REPO=4.19 ./driver.sh'... Successful in 1m 39s
Running 'ARCH=arm32_v7 REPO=4.14 ./driver.sh'... Successful in 2m 11s
Running 'ARCH=arm64 LD=ld.lld REPO=4.14 ./driver.sh'... Successful in 2m 2s
Running 'ARCH=ppc64le REPO=4.14 ./driver.sh'... Failed in 3m 17s
Running 'ARCH=x86_64 LD=ld.lld REPO=4.14 ./driver.sh'... Successful in 1m 38s
Running 'ARCH=arm32_v7 REPO=4.9 ./driver.sh'... Successful in 1m 50s
Running 'ARCH=arm64 REPO=4.9 ./driver.sh'... Successful in 1m 38s
Running 'ARCH=x86_64 LD=ld.lld REPO=4.9 ./driver.sh'... Successful in 1m 15s
Running 'ARCH=arm64 REPO=4.4 ./driver.sh'... Successful in 1m 38s
Running 'ARCH=x86_64 LD=ld.lld REPO=4.4 ./driver.sh'... Successful in 1m 12s
Running 'ARCH=arm64 REPO=android-4.9-q ./driver.sh'... Successful in 2m 47s
Running 'ARCH=arm64 REPO=android-4.14 ./driver.sh'... Successful in 2m 58s
Running 'ARCH=arm64 REPO=android-4.19 ./driver.sh'... Successful in 3m 8s
Running 'ARCH=x86_64 LD=ld.lld REPO=android-4.9-q ./driver.sh'... Successful in 1m 51s
Running 'ARCH=x86_64 LD=ld.lld REPO=android-4.14 ./driver.sh'... Successful in 2m 53s
Running 'ARCH=x86_64 LD=ld.lld REPO=android-4.19 ./driver.sh'... Successful in 2m 37s

Looks like powerpc64le is the only regression but it appears to be a QEMU one because I am using v4.2.0-rc4 and v4.1.1 appears fine:

$ ARCH=ppc64le LD=ld.lld ./driver.sh
...
+ timeout 2m unbuffer qemu-system-ppc64 -m 2G -machine powernv -device ipmi-bmc-sim,id=bmc0 -device isa-ipmi-bt,bmc=bmc0,irq=10 -L images/ppc64le/ -bios skiboot.lid -initrd images/ppc64le/rootfs.cpio -display none -serial mon:stdio -kernel linux/arch/powerpc/boot/zImage.epapr
[    0.014104195,5] OPAL skiboot-v6.2-176-g261ca8e779e5 starting...
[    0.014592522,7] initial console log level: memory 7, driver 5
[    0.014630639,6] CPU: P9 generation processor (max 4 threads/core)
[    0.014647800,7] CPU: Boot CPU PIR is 0x0000 PVR is 0x004e1200
[    0.014742086,7] OPAL table: 0x30100f30 .. 0x30101510, branch table: 0x30002000
[    0.014900926,7] Assigning physical memory map table for nimbus
[    0.015538051,7] FDT: Parsing fdt @0x1000000
[    0.017377792,6] CHIP: Initialised chip 0 from xscom@603fc00000000
[    0.017680180,6] P9 DD2.00 detected
[    0.017696491,5] CHIP: Chip ID 0000 type: P9N DD2.00
[    0.017704748,7] XSCOM: Base address: 0x603fc00000000
[    0.017721911,7] XSTOP: ibm,sw-checkstop-fir prop not found
[    0.017778401,6] MFSI 0:0: Initialized
[    0.017788696,6] MFSI 0:2: Initialized
[    0.017797746,6] MFSI 0:1: Initialized
[    0.018184044,6] LPC: LPC[000]: Initialized
[    0.018191946,7] LPC: access via MMIO @0x6030000000000
[    0.018214891,7] LPC: Default bus on chip 0x0
[    0.018283335,7] CPU: New max PIR set to 0x3
[    0.018681309,7] MEM: parsing reserved memory from reserved-names/-ranges properties
[    0.018740943,7] HOMER: Init chip 0
[    0.018767631,7]   PBA BAR0 : 0x0000203ffd800000
[    0.018775342,7]   PBA MASK0: 0x0000000000300000
[    0.018797931,7]   HOMER Image at 0x203ffd800000 size 4MB
[    0.018839048,4] HOMER image is not reserved! Reserving
[    0.018878353,7]   PBA BAR2 : 0x0000203fff800000
[    0.018883037,7]   PBA MASK2: 0x0000000000700000
[    0.018892651,7]   OCC Common Area at 0x203fff800000 size 8MB
[    0.018919342,4] OCC common area is not reserved! Reserving
[    0.018957641,7] CPU: decrementer bits 56
[    0.019006608,6] CPU: CPU from DT PIR=0x0000 Server#=0x0 State=3
[    0.019087732,6] CPU:  1 secondary threads
[    0.019585672,3] GENERIC BMC PLATFORM: **GUESSING** that there's *maybe* a BMC we can talk to.
[    0.019596073,3] THIS IS ****UNSUPPORTED****, BRINGUP USE ONLY.
[    0.020109340,5] PLAT: Using SuperIO UART
[    0.020346917,7] UART: Using LPC IRQ 4
[    0.024642533,5] PLAT: Detected generic platform
[    0.024761307,5] PLAT: Detected BMC platform generic
[    0.049745843,5] CPU: All 1 processors called in...
[    0.050039462,3] CHIPTOD: Unknown TOD type !
[    0.050140437,3] CHIPTOD: Failed ChipTOD detection !
[    0.050261767,0] Aborting!
CPU 0000 Backtrace:
 S: 0000000031c03cd0 R: 000000003001b2c4   ._abort+0x4c
 S: 0000000031c03d50 R: 0000000030037f40   .chiptod_init+0xf0
 S: 0000000031c03e30 R: 0000000030014ef4   .main_cpu_entry+0x404
 S: 0000000031c03f00 R: 0000000030002718   boot_entry+0x1c0
 --- OPAL boot ---

I'll bisect the breaking commit and report it upstream. I assume that our version of QEMU in the Docker image should be fine but I do not have the time to verify right now.

[nickdesaulniers]

I think this is good to land, now? Or are we still blocked on something?