| Message ID | 20240930161051.3777828-2-kristina.martsenko@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Use memory copy instructions in kernel routines | expand |
On Mon, Sep 30, 2024 at 05:10:47PM +0100, Kristina Martsenko wrote: > 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> I think this would benefit from a cc stable: Cc: <stable@vger.kernel.org> # 6.5.x I can add it when applying the patch.
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 8c0a36f72d6f..bc77869dbd43 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 968d5fffe233..77f3c8eb0916 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;
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> --- arch/arm64/include/asm/insn.h | 1 + arch/arm64/kernel/probes/decode-insn.c | 7 +++++-- 2 files changed, 6 insertions(+), 2 deletions(-)