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arm64: kprobe: clarify the comment of steppable hint instructions

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The existing comment about steppable hint instruction is not complete
and only describes NOP instructions as steppable. As the function
aarch64_insn_is_steppable_hint allows all white-listed instruction
to be probed so the comment is updated to reflect this.

Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-7-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Amit Daniel Kachhap 2020-09-14 14:06:56 +05:30 committed by Will Deacon
parent 6560edca51
commit 03c9c8fad6
1 changed files with 4 additions and 2 deletions
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6
arch/arm64/kernel/probes/decode-insn.c
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@ -43,8 +43,10 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn)
!= AARCH64_INSN_SPCLREG_DAIF;
/*
* The HINT instruction is is problematic when single-stepping,
* except for the NOP case.
* The HINT instruction is steppable only if it is in whitelist
* and the rest of other such instructions are blocked for
* single stepping as they may cause exception or other
* unintended behaviour.
*/
if (aarch64_insn_is_hint(insn))
return aarch64_insn_is_steppable_hint(insn);