Commit 49f6cba6 authored by Mark Rutland's avatar Mark Rutland Committed by Will Deacon
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arm64: handle sys and undef traps consistently

If an EL0 instruction in the SYS class triggers an exception, do_sysintr
looks for a sys64_hook matching the instruction, and if none is found,
injects a SIGILL. This mirrors what we do for undefined instruction
encodings in do_undefinstr, where we look for an undef_hook matching the
instruction, and if none is found, inject a SIGILL.

Over time, new SYS instruction encodings may be allocated. Prior to
allocation, exceptions resulting from these would be handled by
do_undefinstr, whereas after allocation these may be handled by

To ensure that we have consistent behaviour if and when this happens, it
would be beneficial to have do_sysinstr fall back to do_undefinstr.
Signed-off-by: default avatarMark Rutland <>
Acked-by: default avatarCatalin Marinas <>
Reviewed-by: default avatarSuzuki Poulose <>
Signed-off-by: default avatarWill Deacon <>
parent fa715319
......@@ -531,7 +531,12 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
* New SYS instructions may previously have been undefined at EL0. Fall
* back to our usual undefined instruction handler so that we handle
* these consistently.
long compat_arm_syscall(struct pt_regs *regs);
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