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arm64: probes: Disable kprobes/uprobes on MOPS instructions 

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: b7564127ff ("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.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Kristina Martsenko 2024-09-30 17:10:47 +01:00 committed by Catalin Marinas
parent 9852d85ec9
commit c56c599d90
2 changed files with 6 additions and 2 deletions
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1
arch/arm64/include/asm/insn.h
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@ -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)

7
arch/arm64/kernel/probes/decode-insn.c
View File

@ -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;