6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kristina Martsenko <kristina.martsenko@xxxxxxx>
[ Upstream commit c56c599d9002d44f559be3852b371db46adac87c ]
FEAT_MOPS instructions require that all three instructions (prologue,
main and epilogue) appear consecutively in memory. Placing a
kprobe/uprobe on one of them doesn't work as only a single instruction
gets executed out-of-line or simulated. So don't allow placing a probe
on a MOPS instruction.
Fixes: b7564127ffcb ("arm64: mops: detect and enable FEAT_MOPS")
Signed-off-by: Kristina Martsenko <kristina.martsenko@xxxxxxx>
Link: https://lore.kernel.org/r/20240930161051.3777828-2-kristina.martsenko@xxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/arm64/include/asm/insn.h | 1 +
arch/arm64/kernel/probes/decode-insn.c | 7 +++++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 8c0a36f72d6fc..bc77869dbd43b 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -353,6 +353,7 @@ __AARCH64_INSN_FUNCS(ldrsw_lit, 0xFF000000, 0x98000000)
__AARCH64_INSN_FUNCS(exclusive, 0x3F800000, 0x08000000)
__AARCH64_INSN_FUNCS(load_ex, 0x3F400000, 0x08400000)
__AARCH64_INSN_FUNCS(store_ex, 0x3F400000, 0x08000000)
+__AARCH64_INSN_FUNCS(mops, 0x3B200C00, 0x19000400)
__AARCH64_INSN_FUNCS(stp, 0x7FC00000, 0x29000000)
__AARCH64_INSN_FUNCS(ldp, 0x7FC00000, 0x29400000)
__AARCH64_INSN_FUNCS(stp_post, 0x7FC00000, 0x28800000)
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c
index 3496d6169e59b..42b69936cee34 100644
--- a/arch/arm64/kernel/probes/decode-insn.c
+++ b/arch/arm64/kernel/probes/decode-insn.c
@@ -58,10 +58,13 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn)
* Instructions which load PC relative literals are not going to work
* when executed from an XOL slot. Instructions doing an exclusive
* load/store are not going to complete successfully when single-step
- * exception handling happens in the middle of the sequence.
+ * exception handling happens in the middle of the sequence. Memory
+ * copy/set instructions require that all three instructions be placed
+ * consecutively in memory.
*/
if (aarch64_insn_uses_literal(insn) ||
- aarch64_insn_is_exclusive(insn))
+ aarch64_insn_is_exclusive(insn) ||
+ aarch64_insn_is_mops(insn))
return false;
return true;
--
2.43.0
