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aarch64: split irq_spx into a real save/dispatch/restore/ERET trampoline

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Punch list §25 item 0.5 complete.

irq_spx now branches (one instruction, well inside the 128-byte vector slot)
to irq_spx_trampoline, a 672-byte-frame save/restore sequence that calls a
C handler and returns via ERET. The other fifteen vectors are untouched,
still routing to the existing fatal handler.

EL selection (B3) happens once, in aarch64_install_vectors(), not per
interrupt: aarch64_current_el() (item 0.4) picks VBAR_EL1 or VBAR_EL2, and
the same answer is cached in a byte flag (el2_mode_flag) that the trampoline
reads to choose ELR_EL1/SPSR_EL1 vs ELR_EL2/SPSR_EL2 -- the two forms are
genuinely different MRS/MSR encodings, not runtime-selectable operands, so
this is the cheapest correct design: decide once at install time, branch
twice (save, restore) per interrupt afterward. VBAR_EL1 was previously
written unconditionally; this closes that half of item 0.4's known gap.
EL2 is coded from the architecture reference and cannot be boot-tested in
this environment (QEMU's aarch64 virt/EDK2 combination here yields EL1) --
reported as unverified rather than asserted as tested.

FP/SIMD save is not optional (B2, carried from item 0.4's finding that the
build has no -mgeneral-regs-only): the AAPCS64 caller-saved set -- v0-v7,
v16-v31, full 128 bits each -- plus FPSR/FPCR is saved and restored around
the C handler call. v8-v15 are callee-saved by the ABI and deliberately
excluded: the handler, being ordinary compiled C, preserves those itself.

aarch64_irq_handler() (interrupts.c) is deliberately empty. Distinguishing
which interrupt fired needs the GIC's IAR, which does not exist until item
0.6; nothing unmasks or routes any source to this vector yet, so the
function is not reachable during a normal boot. Per the item's own text,
no attempt was made to manufacture an interrupt to exercise this path early
-- 0.6 (GIC) and 0.7 (timer) are what prove it took and returned one.

Verified: every hand-computed frame offset (0, 16, 32 ... 640, frame size
0x2a0=672) checked against the actual disassembly of the built kernel, not
just visually reviewed -- save and restore sequences mirror exactly, and
aarch64_install_vectors' branch on the detected EL, the flag write, and the
trampoline's read of the same flag address all confirmed consistent. Boots
clean on real QEMU output, no regression: dict_hash 0x3d4e1daf289da94f
unchanged from the item 0.1-0.4 baseline, and the item 0.4 EL banner
("AArch64: running at EL1") still prints correctly ahead of "IDT installed.".

Only aarch64-scoped files touched (isr.S, interrupts.c) -- no shared loader
or header changed, so amd64 and riscv64 are provably unaffected; not
rebuilt for this item.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Robert Allan James
2026-08-03 18:47:29 -04:00
co-authored by Claude Sonnet 5
parent f43f3f4482
commit 8d8f3aaae2
6 changed files with 10640 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
experiments/bare_metal/runs/doe-aarch64-20260803-184604.csv
+59
View File
@@ -0,0 +1,59 @@
tick_number,elapsed_ns,tick_interval_ns,cache_hits_delta,bucket_hits_delta,word_executions_delta,hot_word_count,avg_word_heat_q48,window_width,actual_window_size,predicted_label_hits,jitter_bits,apic_ticks,time_trust_q48,variance_q48,vm_call_depth_max,hera_heat_q48,hermes_heat_q48,artemis_heat_q48
1,10000,10000,0,0,183,4,45,731,731,0,0,0,65536,0,0,65536,0,0
2,20000,10000,0,0,173,5,44,582,582,0,0,0,65536,0,0,65536,0,0
3,30000,10000,0,0,184,6,60,582,582,0,0,0,65536,0,0,65536,0,0
4,40000,10000,0,0,174,8,71,4096,0,0,0,0,65536,0,0,65536,0,0
5,50000,10000,0,0,150,9,78,582,582,0,0,0,65536,0,0,65536,0,0
6,60000,10000,0,0,159,11,73,4096,0,0,0,0,65536,0,0,65536,0,0
7,70000,10000,0,0,188,15,71,685,685,0,0,0,65536,0,0,65536,0,0
8,80000,10000,0,0,214,16,83,685,685,0,0,0,65536,0,0,65536,0,0
9,90000,10000,0,0,216,19,82,4096,0,0,0,0,65536,0,0,65536,0,0
10,100000,10000,0,0,222,21,84,567,567,0,0,0,65536,0,0,65536,0,0
11,110000,10000,0,0,207,23,86,731,731,0,0,0,65536,0,0,65536,0,0
12,120000,10000,0,0,189,26,83,4096,0,0,0,0,65536,0,0,65536,0,0
13,130000,10000,0,0,221,28,80,731,731,0,0,0,65536,0,0,65536,0,0
14,140000,10000,0,0,204,29,83,685,685,0,0,0,65536,0,0,65536,0,0
15,150000,10000,0,0,203,30,82,731,731,0,0,0,65536,0,0,65536,0,0
16,160000,10000,0,0,201,32,83,567,567,0,0,0,65536,0,0,65536,0,0
17,170000,10000,0,0,190,34,86,731,731,0,0,0,65536,0,0,65536,0,0
18,180000,10000,0,0,170,35,73,582,582,0,0,0,65536,0,0,65536,0,0
19,190000,10000,0,0,154,28,44,731,731,0,0,0,65536,0,0,65536,0,0
20,200000,10000,0,0,154,28,41,567,567,0,0,0,65536,0,0,65536,0,0
21,210000,10000,0,0,153,32,39,4096,0,0,0,0,65536,0,0,65536,0,0
22,220000,10000,0,0,167,35,42,582,582,0,0,0,65536,0,0,65536,0,0
23,230000,10000,0,0,176,37,41,685,685,0,0,0,65536,0,0,65536,0,0
24,240000,10000,0,0,175,37,39,731,731,0,0,0,65536,0,0,65536,0,0
25,250000,10000,0,0,196,38,37,731,731,0,0,0,65536,0,0,65536,0,0
26,260000,10000,0,0,192,41,37,4096,0,0,0,0,65536,0,0,65536,0,0
27,270000,10000,0,0,158,40,38,685,685,0,0,0,65536,0,0,65536,0,0
28,280000,10000,0,0,158,40,35,4096,0,0,0,0,65536,0,0,65536,0,0
29,290000,10000,0,0,164,41,37,4096,0,0,0,0,65536,0,0,65536,0,0
30,300000,10000,0,0,154,43,39,685,685,0,0,0,65536,0,0,65536,0,0
31,310000,10000,0,0,172,46,35,582,582,0,0,0,65536,0,0,65536,0,0
32,320000,10000,0,0,180,49,34,567,567,0,0,0,65536,0,0,65536,0,0
33,330000,10000,0,0,145,51,35,567,567,0,0,0,65536,0,0,65536,0,0
34,340000,10000,0,0,203,53,37,582,582,0,0,0,65536,0,0,65536,0,0
35,350000,10000,0,0,154,55,39,731,731,0,0,0,65536,0,0,65536,0,0
36,360000,10000,0,0,144,57,37,4096,0,0,0,0,65536,0,0,65536,0,0
37,370000,10000,0,0,144,57,35,4096,0,0,0,0,65536,0,0,65536,0,0
38,380000,10000,0,0,132,57,34,4096,0,0,0,0,65536,0,0,65536,0,0
39,390000,10000,0,0,180,57,32,4096,0,0,0,0,65536,0,0,65536,0,0
40,400000,10000,0,0,220,63,29,4096,0,0,0,0,65536,0,0,65536,0,0
41,410000,10000,0,0,215,64,28,4096,24,0,0,0,65536,0,0,65536,0,0
42,420000,10000,0,0,208,68,29,4096,24,0,0,0,65536,0,0,65536,0,0
43,430000,10000,0,0,177,72,27,4096,24,0,0,0,65536,0,0,65536,0,0
44,440000,10000,0,0,199,77,28,4096,24,0,0,0,65536,0,0,65536,0,0
45,450000,10000,0,0,223,82,26,4096,30,0,0,0,65536,0,0,65536,0,0
46,460000,10000,0,0,202,85,24,4096,67,0,0,0,65536,0,0,65536,0,0
47,470000,10000,0,0,218,91,25,4096,198,0,0,0,65536,0,0,65536,0,0
48,480000,10000,0,0,221,92,26,4096,350,0,0,0,65536,0,0,65536,0,0
49,490000,10000,0,0,225,97,26,4096,528,0,0,0,65536,0,0,65536,0,0
50,500000,10000,0,0,214,100,27,4096,694,0,0,0,65536,0,0,65536,0,0
51,510000,10000,0,0,227,102,28,4096,883,0,0,0,65536,0,0,65536,0,0
52,520000,10000,0,0,208,102,29,4096,1043,0,0,0,65536,0,0,65536,0,0
53,530000,10000,0,0,207,102,30,4096,1202,0,0,0,65536,0,0,65536,0,0
54,540000,10000,0,0,200,102,31,4096,1319,0,0,0,65536,0,0,65536,0,0
55,550000,10000,0,0,205,103,32,4096,1464,0,0,0,65536,0,0,65536,0,0
56,560000,10000,0,0,211,103,32,4096,1620,0,0,0,65536,0,0,65536,0,0
57,570000,10000,0,0,193,110,33,4096,1712,0,0,0,65536,0,0,65536,0,0
58,580000,10000,0,0,190,5,67,4096,1775,0,0,0,65536,0,0,65536,0,0
1 tick_number elapsed_ns tick_interval_ns cache_hits_delta bucket_hits_delta word_executions_delta hot_word_count avg_word_heat_q48 window_width actual_window_size predicted_label_hits jitter_bits apic_ticks time_trust_q48 variance_q48 vm_call_depth_max hera_heat_q48 hermes_heat_q48 artemis_heat_q48
2 1 10000 10000 0 0 183 4 45 731 731 0 0 0 65536 0 0 65536 0 0
3 2 20000 10000 0 0 173 5 44 582 582 0 0 0 65536 0 0 65536 0 0
4 3 30000 10000 0 0 184 6 60 582 582 0 0 0 65536 0 0 65536 0 0
5 4 40000 10000 0 0 174 8 71 4096 0 0 0 0 65536 0 0 65536 0 0
6 5 50000 10000 0 0 150 9 78 582 582 0 0 0 65536 0 0 65536 0 0
7 6 60000 10000 0 0 159 11 73 4096 0 0 0 0 65536 0 0 65536 0 0
8 7 70000 10000 0 0 188 15 71 685 685 0 0 0 65536 0 0 65536 0 0
9 8 80000 10000 0 0 214 16 83 685 685 0 0 0 65536 0 0 65536 0 0
10 9 90000 10000 0 0 216 19 82 4096 0 0 0 0 65536 0 0 65536 0 0
11 10 100000 10000 0 0 222 21 84 567 567 0 0 0 65536 0 0 65536 0 0
12 11 110000 10000 0 0 207 23 86 731 731 0 0 0 65536 0 0 65536 0 0
13 12 120000 10000 0 0 189 26 83 4096 0 0 0 0 65536 0 0 65536 0 0
14 13 130000 10000 0 0 221 28 80 731 731 0 0 0 65536 0 0 65536 0 0
15 14 140000 10000 0 0 204 29 83 685 685 0 0 0 65536 0 0 65536 0 0
16 15 150000 10000 0 0 203 30 82 731 731 0 0 0 65536 0 0 65536 0 0
17 16 160000 10000 0 0 201 32 83 567 567 0 0 0 65536 0 0 65536 0 0
18 17 170000 10000 0 0 190 34 86 731 731 0 0 0 65536 0 0 65536 0 0
19 18 180000 10000 0 0 170 35 73 582 582 0 0 0 65536 0 0 65536 0 0
20 19 190000 10000 0 0 154 28 44 731 731 0 0 0 65536 0 0 65536 0 0
21 20 200000 10000 0 0 154 28 41 567 567 0 0 0 65536 0 0 65536 0 0
22 21 210000 10000 0 0 153 32 39 4096 0 0 0 0 65536 0 0 65536 0 0
23 22 220000 10000 0 0 167 35 42 582 582 0 0 0 65536 0 0 65536 0 0
24 23 230000 10000 0 0 176 37 41 685 685 0 0 0 65536 0 0 65536 0 0
25 24 240000 10000 0 0 175 37 39 731 731 0 0 0 65536 0 0 65536 0 0
26 25 250000 10000 0 0 196 38 37 731 731 0 0 0 65536 0 0 65536 0 0
27 26 260000 10000 0 0 192 41 37 4096 0 0 0 0 65536 0 0 65536 0 0
28 27 270000 10000 0 0 158 40 38 685 685 0 0 0 65536 0 0 65536 0 0
29 28 280000 10000 0 0 158 40 35 4096 0 0 0 0 65536 0 0 65536 0 0
30 29 290000 10000 0 0 164 41 37 4096 0 0 0 0 65536 0 0 65536 0 0
31 30 300000 10000 0 0 154 43 39 685 685 0 0 0 65536 0 0 65536 0 0
32 31 310000 10000 0 0 172 46 35 582 582 0 0 0 65536 0 0 65536 0 0
33 32 320000 10000 0 0 180 49 34 567 567 0 0 0 65536 0 0 65536 0 0
34 33 330000 10000 0 0 145 51 35 567 567 0 0 0 65536 0 0 65536 0 0
35 34 340000 10000 0 0 203 53 37 582 582 0 0 0 65536 0 0 65536 0 0
36 35 350000 10000 0 0 154 55 39 731 731 0 0 0 65536 0 0 65536 0 0
37 36 360000 10000 0 0 144 57 37 4096 0 0 0 0 65536 0 0 65536 0 0
38 37 370000 10000 0 0 144 57 35 4096 0 0 0 0 65536 0 0 65536 0 0
39 38 380000 10000 0 0 132 57 34 4096 0 0 0 0 65536 0 0 65536 0 0
40 39 390000 10000 0 0 180 57 32 4096 0 0 0 0 65536 0 0 65536 0 0
41 40 400000 10000 0 0 220 63 29 4096 0 0 0 0 65536 0 0 65536 0 0
42 41 410000 10000 0 0 215 64 28 4096 24 0 0 0 65536 0 0 65536 0 0
43 42 420000 10000 0 0 208 68 29 4096 24 0 0 0 65536 0 0 65536 0 0
44 43 430000 10000 0 0 177 72 27 4096 24 0 0 0 65536 0 0 65536 0 0
45 44 440000 10000 0 0 199 77 28 4096 24 0 0 0 65536 0 0 65536 0 0
46 45 450000 10000 0 0 223 82 26 4096 30 0 0 0 65536 0 0 65536 0 0
47 46 460000 10000 0 0 202 85 24 4096 67 0 0 0 65536 0 0 65536 0 0
48 47 470000 10000 0 0 218 91 25 4096 198 0 0 0 65536 0 0 65536 0 0
49 48 480000 10000 0 0 221 92 26 4096 350 0 0 0 65536 0 0 65536 0 0
50 49 490000 10000 0 0 225 97 26 4096 528 0 0 0 65536 0 0 65536 0 0
51 50 500000 10000 0 0 214 100 27 4096 694 0 0 0 65536 0 0 65536 0 0
52 51 510000 10000 0 0 227 102 28 4096 883 0 0 0 65536 0 0 65536 0 0
53 52 520000 10000 0 0 208 102 29 4096 1043 0 0 0 65536 0 0 65536 0 0
54 53 530000 10000 0 0 207 102 30 4096 1202 0 0 0 65536 0 0 65536 0 0
55 54 540000 10000 0 0 200 102 31 4096 1319 0 0 0 65536 0 0 65536 0 0
56 55 550000 10000 0 0 205 103 32 4096 1464 0 0 0 65536 0 0 65536 0 0
57 56 560000 10000 0 0 211 103 32 4096 1620 0 0 0 65536 0 0 65536 0 0
58 57 570000 10000 0 0 193 110 33 4096 1712 0 0 0 65536 0 0 65536 0 0
59 58 580000 10000 0 0 190 5 67 4096 1775 0 0 0 65536 0 0 65536 0 0