6.6-stable review patch. If anyone has any objections, please let me know.
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From: Kristina Martsenko kristina.martsenko@arm.com
[ 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@arm.com Link: https://lore.kernel.org/r/20240930161051.3777828-2-kristina.martsenko@arm.co... Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 db1aeacd4cd99..0ccf51afde31a 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -347,6 +347,7 @@ __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;