userspace/cuda: libcuda analysis tree (debug-focused), guest ioctl tracer

Analysis tooling for debugging CUDA execution in Open-IOV guests:
- userspace/cuda/570.144/: fetch a library from a running guest (nc),
  objdump helpers, crash ip -> file vaddr + symbol mapping, and Ghidra
  headless import/analysis/decompile scripts (project kept so single
  functions decompile in seconds). The purpose is debugging correctness
  and performance of CUDA in Open-IOV VMs (not a reimplementation);
  extracted binaries and decompiled output are gitignored.
- tools/guest-diag/ioctl_trace.c: ptrace tracker for the NVIDIA driver
  ioctls of a child (libcuda issues raw syscalls, so LD_PRELOAD sees
  nothing). Decodes RM_ALLOC (class) and RM_CONTROL (cmd) arguments;
  this is how the cuCtxCreate crash sequence was captured.
- tools/test/cuda_drv_test.c: unbuffered + per-call markers so a crash
  identifies the CUDA call it happened in.

1 files changed, 65 insertions, 0 deletions

diff --git a/userspace/cuda/570.144/scripts/disasm.sh b/userspace/cuda/570.144/scripts/disasm.sh
new file mode 100755
index 0000000..01fea69
--- /dev/null
+++ b/userspace/cuda/570.144/scripts/disasm.sh
@@ -0,0 +1,65 @@
+#!/bin/bash
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# disasm.sh - objdump helpers for a library under analysis.
+#
+# Usage:
+#   scripts/disasm.sh <file> <hex-vaddr> [before] [after]
+#       disassemble [vaddr-before, vaddr+after] (default 0x40 each side)
+#   scripts/disasm.sh --bytes <file> <hex-start> <hex-end>
+#       raw bytes in the range
+#   scripts/disasm.sh --symbol <file> <name>
+#       exported symbol address/size (readelf dyn-syms)
+#   scripts/disasm.sh --nearest <file> <hex-vaddr>
+#       nearest preceding exported symbol (FUNC) and the offset into it
+set -e
+
+cmd="${1:?usage: disasm.sh [--bytes|--symbol|--nearest] <file> ...}"
+case "$cmd" in
+--bytes)
+    file="$2"; start="$3"; end="$4"
+    objdump -s --start-address="$start" --stop-address="$end" "$file"
+    ;;
+--symbol)
+    file="$2"; name="$3"
+    readelf -sW --dyn-syms "$file" | awk -v n="$name" '$8 == n {print}'
+    ;;
+--nearest)
+    file="$2"; target="$3"
+    python3 - "$file" "$target" <<'PY'
+import subprocess, sys
+path, t = sys.argv[1], int(sys.argv[2], 16)
+out = subprocess.check_output(["readelf", "-sW", "--dyn-syms", path], text=True)
+syms = []
+for line in out.splitlines():
+    p = line.split()
+    if len(p) >= 8 and p[3] == "FUNC":
+        try:
+            syms.append((int(p[1], 16), int(p[2]), p[7]))
+        except ValueError:
+            pass
+syms.sort()
+prev = None
+for a, s, n in syms:
+    if a <= t:
+        prev = (a, s, n)
+    else:
+        break
+if prev:
+    print("nearest exported: %s at 0x%x size 0x%x (+0x%x)" %
+          (prev[2], prev[0], prev[1], t - prev[0]))
+else:
+    print("no exported symbol before 0x%x" % t)
+PY
+    ;;
+*)
+    file="$1"; vaddr="$2"
+    before="${3:-0x40}"; after="${4:-0x40}"
+    start=$(printf '0x%x' $(( vaddr - before )) 2>/dev/null || echo "$vaddr")
+    end=$(printf '0x%x' $(( vaddr + after )) 2>/dev/null || echo "$vaddr")
+    # allow hex arithmetic with shell
+    start=$(python3 -c "print(hex(int('$vaddr',16)-int('$before',16)))")
+    end=$(python3 -c "print(hex(int('$vaddr',16)+int('$after',16)))")
+    objdump -d -Mintel --start-address="$start" --stop-address="$end" "$file"
+    ;;
+esac