045fa2801a
Try to open /dev/mem to read in the UEFI memory map. If we can't, then we'll read it in the trampoline. Retain reading in /proc/iomem to find reserved areas in Linux. We need to know them for good places to put the kernel. These are not reflected in the UEFI memory map. However, we should not adjust the UEFI memory map since these reserved areas of the Linux kernel are free to be used once we enter the kexec trampoline... Sponsored by: Netflix Reviewed by: tsoome, kevans, andrew Differential Revision: https://reviews.freebsd.org/D38264 |
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.. | ||
arch | ||
conf.c | ||
crt1.c | ||
host_syscall.h | ||
host_syscalls.c | ||
hostcons.c | ||
hostdisk.c | ||
hostfs.c | ||
init.c | ||
kboot.h | ||
kbootfdt.c | ||
main.c | ||
Makefile | ||
README | ||
seg.c | ||
termios_gen.h | ||
termios.c | ||
termios.h | ||
util.c | ||
version |
So to make a Linux initrd: (1) mkdir .../initrd (2) mkdir -p .../initrd/boot/defaults (3) cd src/stand; make install DESTDIR=.../initrd (4) Copy kernel to .../initrd/boot/kernel (5) cd .../initrd (6) cp boot/loader.kboot init (7) find . | sort | cpio -o -H newc | gzip > /tmp/initrd.cpio (8) download or build your linux kernel (9) qemu-system-x86_64 -kernel ~/vmlinuz-5.19.0-051900-generic \ -initrd /tmp/initrd.cpio \ -m 256m -nographic \ -monitor telnet::4444,server,nowait -serial stdio \ -append "console=ttyS0" (though you may need more than 256M of ram to actually boot FreeBSD and do anything interesting with it and the serial console to stdio bit hasn't been the most stable recipe lately). Notes: For #6 you might need to strip loader.kboot if you copy it directly and don't use make install. For #7 the sort is important, and you may need LC_ALL=C for its invocation For #7 gzip is but one of many methods, but it's the simplest to do. For #9, this means we can automate it using methods from src/tools/boot/rootgen.sh when the time comes. #9 also likely generalizes to other architectures For #8, see https://kernel.ubuntu.com/~kernel-ppa/mainline/ to download a kernel suitable for testing... For arm, I've been using the non 64k page kernels and 5.19 seems to not suck. aarch64: qemu-system-aarch64 -m 1024 -cpu cortex-a57 -M virt \ -kernel ~/linuxboot/arm64/kernel/boot/vmlinuz-5.19.0-051900-generic \ -initrd ~/linuxboot/arm64/initrd.img -m 256m -nographic \ -monitor telnet::4444,server,nowait -serial stdio \ -append "console=ttyAMA0" General Add -g -G to have gdb stop and wait for the debugger. This is useful for debugging the trampoline (hbreak will set a hardware break that's durable across code changes). If you set the breakpoint for the trampoline and it never hits, then there's likely no RAM there and you got the PA to load to wrong. When debugging the trampiline and up to that, use gdb /boot/loader. When debugging the kernel, use kernel.full to get all the debugging. hbreak panic() is useful on the latter since you'll see the original panic, not the panic you get from there not being an early console.