[PATCH v4 4/4] arm64: kprobe: clarify the comment of steppable hint instructions
Amit Daniel Kachhap
amit.kachhap at arm.com
Fri Jul 10 04:00:10 EDT 2020
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 at arm.com>
---
Changes since v3:
* New patch.
arch/arm64/kernel/probes/decode-insn.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c
index 263d5fba4c8a..3912a37cb117 100644
--- a/arch/arm64/kernel/probes/decode-insn.c
+++ b/arch/arm64/kernel/probes/decode-insn.c
@@ -42,8 +42,10 @@ 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);
--
2.17.1
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