Files
bootloader/test/test_planner.py
BlackMark 5f9e736d66 pureboot: artifact roles, wrong-chip refusal, and misplaced-loader re-homing
The README's deployment section now says what each build artifact is for:
the .hex is the programmer artifact (self-addressed into the top slot),
the .bin the self-update image — bare slot bytes a programmer would put
at address 0, where a boot-sectioned mega cannot even heal itself (SPM
only runs from the boot section) but a patched-vector chip runs the
position-independent copy and re-homes a build through the ordinary
--update-loader flow: the staging install and the word-0 redirect both
execute outside page 0's slot, so the running-slot guard never blocks it.
pbrehome.py is the acceptance test (misplaced at 0, guard intact,
re-home, app flash over the stale copy, banner); the staging slot is the
one position that cannot re-home itself, documented. The preflight's
wrong-chip refusal and loader_image's handling of padded images (peeled
to the slot content by the embedded base) are documented and the padded
case pinned in the planner.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-21 21:18:10 +02:00

212 lines
11 KiB
Python

#!/usr/bin/env python3
"""Host-tool unit tests — the pure planning and policy logic, no simulator:
the flash-programming orders and their recovery properties, the reset-vector
surgery, the staging-slot composition, the mega boot-fuse decode, and the
update preflight's error/warning matrix (fuse combinations simavr cannot
model reach it here as synthetic bytes).
Usage: test_planner.py <tool_py>
"""
import sys
def fail(message):
print(f"FAIL: {message}")
sys.exit(1)
def expect_error(what, fn, *needles):
try:
fn()
except Exception as error:
for needle in needles:
if needle not in str(error):
fail(f"{what}: error lacks {needle!r}: {error}")
return
fail(f"{what}: no error raised")
def info_of(pb, base, page, patch, flash, signature=(0x1E, 0x93, 0x0B), word_flash=False):
scale = 2 if word_flash else 1
wire_base = base // scale
flags = (1 if patch else 0) | (2 if word_flash else 0)
raw = bytes((0x50, 0x42, 1, *signature, page & 0xFF, wire_base & 0xFF, wire_base >> 8,
0, 2, flags))
info = pb.Info(raw)
assert info.flash_size == flash
return info
def rjmp_decode(word, at, flash_words):
if word & 0xF000 != 0xC000:
fail(f"not an rjmp: {word:#06x}")
offset = word & 0x0FFF
if offset >= 0x800:
offset -= 0x1000
return (at + 1 + offset) % flash_words
def main():
import os
sys.path.insert(0, os.path.dirname(os.path.abspath(sys.argv[1])))
import pureboot as pb
tiny = info_of(pb, 0x1E00, 64, True, 0x2000)
mega = info_of(pb, 0x7E00, 128, False, 0x8000, signature=(0x1E, 0x95, 0x0F))
# mega_boot: BOOTSZ words and the BOOTRST sense per chip — the fuse byte
# index (EXTENDED on the x8 line except the m328s' HIGH, HIGH elsewhere)
# and the per-family ladders (Atmel-2486/2466/2503/2545/8271/DS40002065/
# 8272/8011/2593/42719). Synthetic 'F' replies: only the boot byte
# carries meaning.
cases = (
((0x1E, 0x93, 0x07), 0x2000, 3, {0b11: 0x1F00, 0b10: 0x1E00, 0b01: 0x1C00, 0b00: 0x1800}), # m8
((0x1E, 0x94, 0x03), 0x4000, 3, {0b11: 0x3F00, 0b10: 0x3E00, 0b01: 0x3C00, 0b00: 0x3800}), # m16
((0x1E, 0x95, 0x02), 0x8000, 3, {0b11: 0x7E00, 0b10: 0x7C00, 0b01: 0x7800, 0b00: 0x7000}), # m32
((0x1E, 0x93, 0x0A), 0x2000, 2, {0b11: 0x1F00, 0b10: 0x1E00, 0b01: 0x1C00, 0b00: 0x1800}), # m88
((0x1E, 0x93, 0x0F), 0x2000, 2, {0b11: 0x1F00, 0b10: 0x1E00, 0b01: 0x1C00, 0b00: 0x1800}), # m88P
((0x1E, 0x94, 0x06), 0x4000, 2, {0b11: 0x3F00, 0b10: 0x3E00, 0b01: 0x3C00, 0b00: 0x3800}), # m168/168A
((0x1E, 0x94, 0x0B), 0x4000, 2, {0b11: 0x3F00, 0b10: 0x3E00, 0b01: 0x3C00, 0b00: 0x3800}), # m168P
((0x1E, 0x95, 0x14), 0x8000, 3, {0b11: 0x7E00, 0b10: 0x7C00, 0b01: 0x7800, 0b00: 0x7000}), # m328
((0x1E, 0x95, 0x0F), 0x8000, 3, {0b11: 0x7E00, 0b10: 0x7C00, 0b01: 0x7800, 0b00: 0x7000}), # m328P
((0x1E, 0x94, 0x0F), 0x4000, 3, {0b11: 0x3F00, 0b10: 0x3E00, 0b01: 0x3C00, 0b00: 0x3800}), # m164A
((0x1E, 0x94, 0x0A), 0x4000, 3, {0b11: 0x3F00, 0b10: 0x3E00, 0b01: 0x3C00, 0b00: 0x3800}), # m164P
((0x1E, 0x95, 0x15), 0x8000, 3, {0b11: 0x7E00, 0b10: 0x7C00, 0b01: 0x7800, 0b00: 0x7000}), # m324A
((0x1E, 0x96, 0x09), 0x10000, 3, {0b11: 0xFC00, 0b10: 0xF800, 0b01: 0xF000, 0b00: 0xE000}), # m644
((0x1E, 0x96, 0x0A), 0x10000, 3, {0b11: 0xFC00, 0b10: 0xF800, 0b01: 0xF000, 0b00: 0xE000}), # m644P
((0x1E, 0x97, 0x06), 0x20000, 3, {0b11: 0x1FC00, 0b10: 0x1F800, 0b01: 0x1F000, 0b00: 0x1E000}), # 1284
((0x1E, 0x97, 0x05), 0x20000, 3, {0b11: 0x1FC00, 0b10: 0x1F800, 0b01: 0x1F000, 0b00: 0x1E000}), # 1284P
)
for signature, flash, which, ladder in cases:
# Word-addressed chips carry the 1 KiB slot (their smallest boot sector).
slot = 1024 if flash > 0x10000 else 512
chip = info_of(pb, flash - slot, 128 if flash < 0x20000 else 0, False, flash,
signature=signature, word_flash=flash > 0x10000)
for bits, start in ladder.items():
fuses = bytearray((0xFF, 0xFF, 0xFF, 0xFF))
fuses[which] = (0xF8 | (bits << 1)) & ~1
prog, at = pb.mega_boot(chip, bytes(fuses))
if not prog or at != start:
fail(f"mega_boot {signature[1]:02x}{signature[2]:02x} BOOTSZ={bits:02b} programmed: {prog} {at:#07x}")
fuses[which] |= 1
prog, at = pb.mega_boot(chip, bytes(fuses))
if prog or at != start:
fail(f"mega_boot {signature[1]:02x}{signature[2]:02b} unprogrammed: {prog} {at:#07x}")
# Word-addressed info decode: the 1284P's base/page ride the wire scaled,
# and its slot is 1 KiB.
big = info_of(pb, 0x1FC00, 0, False, 0x20000, signature=(0x1E, 0x97, 0x05), word_flash=True)
if big.page != 256 or big.base != 0x1FC00 or big.stage != 0x1F800 or big.slot != 1024:
fail(f"word-addressed info decode: page {big.page}, base {big.base:#x}, stage {big.stage:#x}")
# Surgery: word 0 lands on the loader, the trampoline on the original
# entry — checked with an independent decoder.
app = bytes((0xC0 | 0x00, 0xC0)) + bytes((0x12,)) * 300 # rjmp .+0x00C0... entry word 0xC0C0
entry = rjmp_decode(app[0] | (app[1] << 8), 0, tiny.flash_size // 2)
pages = pb.plan_flash(app, tiny)
word0 = pages[0][0] | (pages[0][1] << 8)
if rjmp_decode(word0, 0, tiny.flash_size // 2) != tiny.base // 2:
fail("surgery: patched word 0 misses the loader")
tp = pages[tiny.base - 64]
tramp = tp[62] | (tp[63] << 8)
if rjmp_decode(tramp, (tiny.base - 2) // 2, tiny.flash_size // 2) != entry:
fail("surgery: trampoline misses the original entry")
expect_error("non-rjmp vector", lambda: pb.plan_flash(bytes((0x0C, 0x94)) + app[2:], tiny), "not an rjmp")
looped = bytearray(app)
word = pb.rjmp_to(0, tiny.base // 2, tiny.flash_size // 2)
looped[0], looped[1] = word & 0xFF, word >> 8
expect_error("read-back image", lambda: pb.plan_flash(bytes(looped), tiny), "read-back")
expect_error("oversize image", lambda: pb.plan_flash(bytes(0x1DFF), tiny), "application flash ends")
# Ordering: patched vector puts page 0 first and the trampoline second;
# a boot section puts page 0 last. Blank pages drop only when erased.
order = pb.covered(pages, tiny, skip_blank=False)
if order[0] != 0 or order[1] != tiny.base - 64:
fail(f"tiny order starts {order[:2]}, want page 0 then trampoline page")
if sorted(order[2:]) != order[2:]:
fail("tiny order tail not ascending")
mega_pages = pb.plan_flash(bytes((0xFF,)) * 600, mega)
morder = pb.covered(mega_pages, mega, skip_blank=False)
if morder[-1] != 0 or sorted(morder[:-1]) != morder[:-1]:
fail(f"mega order {morder}, want ascending with page 0 last")
blanky = {0: pages[0], 64: bytes((0xFF,)) * 64, 128: pages[128], tiny.base - 64: tp}
slim = pb.covered(blanky, tiny, skip_blank=True)
if 64 in slim or 0 not in slim or tiny.base - 64 not in slim:
fail(f"skip_blank order wrong: {slim}")
# Staging content: the identical image plus the through-word on a
# patched-vector chip; hard size clamps either way.
image = bytes(range(256)) * 2 # 512 B — too big for a tiny slot
expect_error("tiny staging size", lambda: pb.staging_content(image, tiny), "510")
staged = pb.staging_content(image[:508], tiny)
through = staged[510] | (staged[511] << 8)
if rjmp_decode(through, (tiny.base - 2) // 2, tiny.flash_size // 2) != tiny.base // 2:
fail("through-word misses the resident base")
if pb.staging_content(image, mega) != image:
fail("mega staging content should be the bare image")
expect_error("mega staging size", lambda: pb.staging_content(image + b"!", mega), "512")
# The embedded info block: found in a synthetic binary, absent in noise.
binary = bytes((0xAA,)) * 10 + tiny.raw + bytes((0xBB,)) * 10
found = pb.image_info(binary)
if found is None or found.raw != tiny.raw:
fail("image_info misses the embedded block")
if pb.image_info(bytes((0xAA,)) * 40) is not None:
fail("image_info invents a block")
# loader_image must peel a padded image down to the slot content: a raw
# .bin padded from address 0 (or a whole-flash read-back with the loader
# resident at base) yields the same bytes as the bare slot image.
import tempfile
slot_image = bytes((0xAA,)) * 10 + tiny.raw + bytes((0xCC,)) * 40
padded = bytes((0xFF,)) * tiny.base + slot_image
with tempfile.NamedTemporaryFile(suffix=".bin", delete=False) as f:
f.write(padded)
padded_path = f.name
try:
if pb.loader_image(padded_path) != slot_image:
fail("loader_image does not peel a padded image to the slot content")
finally:
os.unlink(padded_path)
# Update preflight: the full fuse matrix, plus target mismatch.
other = info_of(pb, 0x1E00, 32, True, 0x2000)
expect_error("wrong-target image", lambda: pb.update_preflight(binary, other, None), "another target")
expect_error("mega needs fuses", lambda: pb.update_preflight(bytes((0xAA,)) * 8 + mega.raw, mega, None),
"--assume-fuses")
mega_image = bytes((0xAA,)) * 8 + mega.raw
def fuses(high):
return bytes((0xFF, 0xFF, 0xFF, high))
expect_error("BOOTSZ 512 B", lambda: pb.update_preflight(mega_image, mega, fuses(0xFE)),
"cannot self-update", "BOOTSZ")
notes = pb.update_preflight(mega_image, mega, fuses(0xFD)) # 1 KB, BOOTRST unprogrammed
if not any("BOOTRST unprogrammed" in n for n in notes):
fail(f"1K/unprogrammed notes: {notes}")
notes = pb.update_preflight(mega_image, mega, fuses(0xFC)) # 1 KB, BOOTRST programmed
if not any("staging slot" in n for n in notes):
fail(f"1K/programmed notes: {notes}")
notes = pb.update_preflight(mega_image, mega, fuses(0xFA)) # 2 KB, BOOTRST programmed
if not any("application flash" in n for n in notes):
fail(f"2K/programmed notes: {notes}")
if pb.update_preflight(bytes((0xAA,)) * 8 + tiny.raw, tiny, None) != []:
fail("tiny preflight should pass without fuses")
# The walk-region refusal: BOOTRST aimed below the loader plus app data
# in the walk span errors without --force; erased spans and unprogrammed
# BOOTRST pass.
deep = {0x7800: bytes((1,)) * 128}
expect_error("walk region", lambda: pb.check_walk_region(deep, mega, fuses(0xFA), False), "--force")
pb.check_walk_region(deep, mega, fuses(0xFA), True)
pb.check_walk_region(deep, mega, fuses(0xFB), False) # BOOTRST unprogrammed
pb.check_walk_region({0x7800: bytes((0xFF,)) * 128}, mega, fuses(0xFA), False)
pb.check_walk_region(deep, mega, None, False) # fuses unknown: no check
print("test_planner: all planner and policy checks pass")
if __name__ == "__main__":
main()