make iso recompiled the kernel and every command each time: iso and
ramroot wiped build/kernel, build/lib and build/cmd to make sure nothing
was compiled for the wrong RAMROOT setting. Only kernel/proc/proc.c and
kernel/dev/ramdisk.c read RAMDISK_ROOT, so only their objects go now.
Even then a no-op make iso took 69 s, because sysroot.stamp lists every
staged file with its mtime and two things re-copied files on every run:
the plain cp in etc-install (now cp -p) and fastfetch's install (now
install -C). A changed stamp rebuilds the Alpine root, the root image
and its zstd -19 compression. A no-op, and a one-file kernel change,
now take about 9 s.
write.sh read the stick back with a buffered cmp, slowly and possibly from
the page cache. It now reads 4 MB at a time with iflag=direct, which
checks the stick itself; --no-verify skips the check.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015f73FesGZGYPkmDvUcj6QX
The staged segments were copied home after ExitBootServices by the
loader itself -- on code, a stack and a copy list the firmware had
placed wherever it liked. On an HP all-in-one some of that was in the
kernel's range: "Placing the kernel", then a triple fault and a reset.
The copy and the jump now run from one page below the kernel's lowest
address, allocated as loader code before the firmware exits: a short
position-independent routine, the copy list, and a stack. It switches
to the loader's page tables and its own stack before copying anything.
Called sysv_abi, because UEFI code is the Microsoft convention and the
first try loaded the framebuffer address into rsp.
The framebuffer address handed over in rbx is 64-bit now too; the
kernel already read the full one from the hand-off block.
Also write.sh: writes schos.iso to a USB stick, after showing the
device and asking for its name to be typed back; refuses partitions,
the system disk and non-removable disks; reads the result back.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
