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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
do_sysintr.

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: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Mark Rutland 2017-01-27 16:15:38 +00:00 committed by Will Deacon
parent fa715319c1
commit 49f6cba617
1 changed files with 6 additions and 1 deletions
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7
arch/arm64/kernel/traps.c
View File

@ -531,7 +531,12 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
return;
}
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.
*/
do_undefinstr(regs);
}
long compat_arm_syscall(struct pt_regs *regs);