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authorHou Tao <houtao1@huawei.com>2022-02-17 10:22:30 +0300
committerWill Deacon <will@kernel.org>2022-02-23 00:25:48 +0300
commitfa1114d9eba5087ba5e81aab4c56f546995e6cd3 (patch)
tree3c28b1a2af95190120e8ad71dce9d8147c8f6602 /arch/arm64/net
parent97e58e395e9c074fd096dad13c54e9f4112cf71d (diff)
downloadlinux-fa1114d9eba5087ba5e81aab4c56f546995e6cd3.tar.xz
arm64: insn: add encoders for atomic operations
It is a preparation patch for eBPF atomic supports under arm64. eBPF needs support atomic[64]_fetch_add, atomic[64]_[fetch_]{and,or,xor} and atomic[64]_{xchg|cmpxchg}. The ordering semantics of eBPF atomics are the same with the implementations in linux kernel. Add three helpers to support LDCLR/LDEOR/LDSET/SWP, CAS and DMB instructions. STADD/STCLR/STEOR/STSET are simply encoded as aliases for LDADD/LDCLR/LDEOR/LDSET with XZR as the destination register, so no extra helper is added. atomic_fetch_add() and other atomic ops needs support for STLXR instruction, so extend enum aarch64_insn_ldst_type to do that. LDADD/LDEOR/LDSET/SWP and CAS instructions are only available when LSE atomics is enabled, so just return AARCH64_BREAK_FAULT directly in these newly-added helpers if CONFIG_ARM64_LSE_ATOMICS is disabled. Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20220217072232.1186625-3-houtao1@huawei.com Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/net')
-rw-r--r--arch/arm64/net/bpf_jit.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h
index cc0cf0f5c7c3..9d9250c7cc72 100644
--- a/arch/arm64/net/bpf_jit.h
+++ b/arch/arm64/net/bpf_jit.h
@@ -89,9 +89,16 @@
#define A64_STXR(sf, Rt, Rn, Rs) \
A64_LSX(sf, Rt, Rn, Rs, STORE_EX)
-/* LSE atomics */
+/*
+ * LSE atomics
+ *
+ * STADD is simply encoded as an alias for LDADD with XZR as
+ * the destination register.
+ */
#define A64_STADD(sf, Rn, Rs) \
- aarch64_insn_gen_stadd(Rn, Rs, A64_SIZE(sf))
+ aarch64_insn_gen_atomic_ld_op(A64_ZR, Rn, Rs, \
+ A64_SIZE(sf), AARCH64_INSN_MEM_ATOMIC_ADD, \
+ AARCH64_INSN_MEM_ORDER_NONE)
/* Add/subtract (immediate) */
#define A64_ADDSUB_IMM(sf, Rd, Rn, imm12, type) \