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gen_portal_tramp: fix mips bug with nop padding #39

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Merged
lacraig2 merged 1 commit into from
Mar 31, 2026
Merged

gen_portal_tramp: fix mips bug with nop padding #39

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12 changes: 11 additions & 1 deletion scripts/gen_portal_tramp.py
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Original file line number Diff line number Diff line change
Expand Up @@ -5,9 +5,19 @@

print("// Auto-generated trampoline functions\n")
print("#define PORTAL_TRAMPOLINE_COUNT {0}\n".format(COUNT))

# Conditionally apply the NOP padding only for MIPS targets to fix the kprobe branch bug.
# For all other architectures, emit an empty asm block that still embeds the unique ID
# to universally defeat Identical Code Folding (ICF).
print("#if defined(__mips__)")
print("#define TRAMP_BODY(i) asm volatile(\"nop\\n\\tnop\\n\\tnop\\n\\tnop\" : : \"i\"(i))")
print("#else")
print("#define TRAMP_BODY(i) asm volatile(\"\" : : \"i\"(i))")
print("#endif\n")

for i in range(COUNT):
print(f"void portal_tramp_fn_{i:x}(void);")
print(f"void portal_tramp_fn_{i:x}(void) {{}}")
print(f"void portal_tramp_fn_{i:x}(void) {{ TRAMP_BODY({i}); }}")

print("\nvoid (*portal_tramp_table[{0}])(void) = {{".format(COUNT))
for i in range(COUNT):
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