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| author | Mark Rutland <mark.rutland@arm.com> | 2022-11-14 13:59:27 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-11-15 13:07:44 +0000 |
| commit | 4488f90c8609e5c420531d604dd19cdfee4ec0e0 (patch) | |
| tree | d0ab191ce3dfe9e5c41d0f1bc880caad5e0d8768 /arch/arm64/kernel/probes/decode-insn.c | |
| parent | 9b948e79d5369bda7a628bf69521172200d07613 (diff) | |
| download | lwn-4488f90c8609e5c420531d604dd19cdfee4ec0e0.tar.gz lwn-4488f90c8609e5c420531d604dd19cdfee4ec0e0.zip | |
arm64: insn: simplify insn group identification
The only code which needs to check for an entire instruction group is
the aarch64_insn_is_steppable() helper function used by kprobes, which
must not be instrumented, and only needs to check for the "Branch,
exception generation and system instructions" class.
Currently we have an out-of-line helper in insn.c which must be marked
as __kprobes, which indexes a table with some bits extracted from the
instruction. In aarch64_insn_is_steppable() we then need to compare the
result with an expected enum value.
It would be simpler to have a predicate for this, as with the other
aarch64_insn_is_*() helpers, which would be always inlined to prevent
inadvertent instrumentation, and would permit better code generation.
This patch adds a predicate function for this instruction group using
the existing __AARCH64_INSN_FUNCS() helpers, and removes the existing
out-of-line helper. As the only class we currently care about is the
branch+exception+sys class, I have only added helpers for this, and left
the other classes unimplemented for now.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20221114135928.3000571-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/probes/decode-insn.c')
| -rw-r--r-- | arch/arm64/kernel/probes/decode-insn.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index 104101f633b1..968d5fffe233 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -24,7 +24,7 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) * currently safe. Lastly, MSR instructions can do any number of nasty * things we can't handle during single-stepping. */ - if (aarch64_get_insn_class(insn) == AARCH64_INSN_CLS_BR_SYS) { + if (aarch64_insn_is_class_branch_sys(insn)) { if (aarch64_insn_is_branch(insn) || aarch64_insn_is_msr_imm(insn) || aarch64_insn_is_msr_reg(insn) || |