[PATCH bpf-next v2 2/2] arm64, bpf: support more atomic operations
Hou Tao
houtao1 at huawei.com
Wed Jan 26 23:53:22 PST 2022
Atomics for eBPF patch series adds support for atomic[64]_fetch_add,
atomic[64]_[fetch_]{and,or,xor} and atomic[64]_{xchg|cmpxchg}, but
it only add support for x86-64, so support these atomic operations
for arm64 as well.
Basically the implementation procedure is almost mechanical translation
of code snippets in atomic_ll_sc.h & atomic_lse.h & cmpxchg.h located
under arch/arm64/include/asm. An extra temporary register is needed
for (BPF_ADD | BPF_FETCH) to save the value of src register, instead of
adding TMP_REG_4 just use BPF_REG_AX instead.
For cpus_have_cap(ARM64_HAS_LSE_ATOMICS) case and no-LSE-ATOMICS case,
both ./test_verifier and "./test_progs -t atomic" are exercised and
passed correspondingly.
Signed-off-by: Hou Tao <houtao1 at huawei.com>
Acked-by: John Fastabend <john.fastabend at gmail.com>
---
arch/arm64/include/asm/insn.h | 45 +++++--
arch/arm64/lib/insn.c | 155 +++++++++++++++++++++---
arch/arm64/net/bpf_jit.h | 43 ++++++-
arch/arm64/net/bpf_jit_comp.c | 216 +++++++++++++++++++++++++++-------
4 files changed, 394 insertions(+), 65 deletions(-)
diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 6b776c8667b2..1416d636f1af 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -280,6 +280,23 @@ enum aarch64_insn_adr_type {
AARCH64_INSN_ADR_TYPE_ADR,
};
+enum aarch64_insn_mem_atomic_op {
+ AARCH64_INSN_MEM_ATOMIC_ADD,
+ AARCH64_INSN_MEM_ATOMIC_BIC,
+ AARCH64_INSN_MEM_ATOMIC_EOR,
+ AARCH64_INSN_MEM_ATOMIC_ORR,
+ AARCH64_INSN_MEM_ATOMIC_SWP,
+};
+
+enum aarch64_insn_mem_order_type {
+ AARCH64_INSN_MEM_ORDER_NONE,
+ AARCH64_INSN_MEM_ORDER_LOAD_ACQ_STORE_REL,
+};
+
+enum aarch64_insn_mb_type {
+ AARCH64_INSN_MB_ISH,
+};
+
#define __AARCH64_INSN_FUNCS(abbr, mask, val) \
static __always_inline bool aarch64_insn_is_##abbr(u32 code) \
{ \
@@ -303,6 +320,11 @@ __AARCH64_INSN_FUNCS(store_post, 0x3FE00C00, 0x38000400)
__AARCH64_INSN_FUNCS(load_post, 0x3FE00C00, 0x38400400)
__AARCH64_INSN_FUNCS(str_reg, 0x3FE0EC00, 0x38206800)
__AARCH64_INSN_FUNCS(ldadd, 0x3F20FC00, 0x38200000)
+__AARCH64_INSN_FUNCS(ldclr, 0x3F20FC00, 0x38201000)
+__AARCH64_INSN_FUNCS(ldeor, 0x3F20FC00, 0x38202000)
+__AARCH64_INSN_FUNCS(ldset, 0x3F20FC00, 0x38203000)
+__AARCH64_INSN_FUNCS(swp, 0x3F20FC00, 0x38208000)
+__AARCH64_INSN_FUNCS(cas, 0x3FA07C00, 0x08A07C00)
__AARCH64_INSN_FUNCS(ldr_reg, 0x3FE0EC00, 0x38606800)
__AARCH64_INSN_FUNCS(ldr_lit, 0xBF000000, 0x18000000)
__AARCH64_INSN_FUNCS(ldrsw_lit, 0xFF000000, 0x98000000)
@@ -474,13 +496,21 @@ u32 aarch64_insn_gen_load_store_ex(enum aarch64_insn_register reg,
enum aarch64_insn_register state,
enum aarch64_insn_size_type size,
enum aarch64_insn_ldst_type type);
-u32 aarch64_insn_gen_ldadd(enum aarch64_insn_register result,
- enum aarch64_insn_register address,
- enum aarch64_insn_register value,
- enum aarch64_insn_size_type size);
-u32 aarch64_insn_gen_stadd(enum aarch64_insn_register address,
- enum aarch64_insn_register value,
- enum aarch64_insn_size_type size);
+u32 aarch64_insn_gen_store_release_ex(enum aarch64_insn_register reg,
+ enum aarch64_insn_register base,
+ enum aarch64_insn_register state,
+ enum aarch64_insn_size_type size);
+u32 aarch64_insn_gen_atomic_ld_op(enum aarch64_insn_register result,
+ enum aarch64_insn_register address,
+ enum aarch64_insn_register value,
+ enum aarch64_insn_size_type size,
+ enum aarch64_insn_mem_atomic_op op,
+ enum aarch64_insn_mem_order_type order);
+u32 aarch64_insn_gen_cas(enum aarch64_insn_register result,
+ enum aarch64_insn_register address,
+ enum aarch64_insn_register value,
+ enum aarch64_insn_size_type size,
+ enum aarch64_insn_mem_order_type order);
u32 aarch64_insn_gen_add_sub_imm(enum aarch64_insn_register dst,
enum aarch64_insn_register src,
int imm, enum aarch64_insn_variant variant,
@@ -541,6 +571,7 @@ u32 aarch64_insn_gen_prefetch(enum aarch64_insn_register base,
enum aarch64_insn_prfm_type type,
enum aarch64_insn_prfm_target target,
enum aarch64_insn_prfm_policy policy);
+u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type);
s32 aarch64_get_branch_offset(u32 insn);
u32 aarch64_set_branch_offset(u32 insn, s32 offset);
diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c
index fccfe363e567..2a7dde58c44b 100644
--- a/arch/arm64/lib/insn.c
+++ b/arch/arm64/lib/insn.c
@@ -328,6 +328,29 @@ static u32 aarch64_insn_encode_ldst_size(enum aarch64_insn_size_type type,
return insn;
}
+static u32 aarch64_insn_encode_ldst_order(enum aarch64_insn_mem_order_type type,
+ u32 insn)
+{
+ u32 order;
+
+ switch (type) {
+ case AARCH64_INSN_MEM_ORDER_NONE:
+ order = 0;
+ break;
+ case AARCH64_INSN_MEM_ORDER_LOAD_ACQ_STORE_REL:
+ order = 3;
+ break;
+ default:
+ pr_err("%s: unknown mem order %d\n", __func__, type);
+ return AARCH64_BREAK_FAULT;
+ }
+
+ insn &= ~GENMASK(23, 22);
+ insn |= order << 22;
+
+ return insn;
+}
+
static inline long branch_imm_common(unsigned long pc, unsigned long addr,
long range)
{
@@ -603,12 +626,49 @@ u32 aarch64_insn_gen_load_store_ex(enum aarch64_insn_register reg,
state);
}
-u32 aarch64_insn_gen_ldadd(enum aarch64_insn_register result,
- enum aarch64_insn_register address,
- enum aarch64_insn_register value,
- enum aarch64_insn_size_type size)
+u32 aarch64_insn_gen_store_release_ex(enum aarch64_insn_register reg,
+ enum aarch64_insn_register base,
+ enum aarch64_insn_register state,
+ enum aarch64_insn_size_type size)
+{
+ u32 insn = aarch64_insn_gen_load_store_ex(reg, base, state, size,
+ AARCH64_INSN_LDST_STORE_EX);
+
+ if (insn == AARCH64_BREAK_FAULT)
+ return insn;
+
+ return insn | BIT(15);
+}
+
+u32 aarch64_insn_gen_atomic_ld_op(enum aarch64_insn_register result,
+ enum aarch64_insn_register address,
+ enum aarch64_insn_register value,
+ enum aarch64_insn_size_type size,
+ enum aarch64_insn_mem_atomic_op op,
+ enum aarch64_insn_mem_order_type order)
{
- u32 insn = aarch64_insn_get_ldadd_value();
+ u32 insn;
+
+ switch (op) {
+ case AARCH64_INSN_MEM_ATOMIC_ADD:
+ insn = aarch64_insn_get_ldadd_value();
+ break;
+ case AARCH64_INSN_MEM_ATOMIC_BIC:
+ insn = aarch64_insn_get_ldclr_value();
+ break;
+ case AARCH64_INSN_MEM_ATOMIC_EOR:
+ insn = aarch64_insn_get_ldeor_value();
+ break;
+ case AARCH64_INSN_MEM_ATOMIC_ORR:
+ insn = aarch64_insn_get_ldset_value();
+ break;
+ case AARCH64_INSN_MEM_ATOMIC_SWP:
+ insn = aarch64_insn_get_swp_value();
+ break;
+ default:
+ pr_err("%s: unimplemented mem atomic op %d\n", __func__, op);
+ return AARCH64_BREAK_FAULT;
+ }
switch (size) {
case AARCH64_INSN_SIZE_32:
@@ -621,6 +681,8 @@ u32 aarch64_insn_gen_ldadd(enum aarch64_insn_register result,
insn = aarch64_insn_encode_ldst_size(size, insn);
+ insn = aarch64_insn_encode_ldst_order(order, insn);
+
insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
result);
@@ -631,16 +693,60 @@ u32 aarch64_insn_gen_ldadd(enum aarch64_insn_register result,
value);
}
-u32 aarch64_insn_gen_stadd(enum aarch64_insn_register address,
- enum aarch64_insn_register value,
- enum aarch64_insn_size_type size)
+static u32 aarch64_insn_encode_cas_order(enum aarch64_insn_mem_order_type type,
+ u32 insn)
{
- /*
- * STADD is simply encoded as an alias for LDADD with XZR as
- * the destination register.
- */
- return aarch64_insn_gen_ldadd(AARCH64_INSN_REG_ZR, address,
- value, size);
+ u32 order;
+
+ switch (type) {
+ case AARCH64_INSN_MEM_ORDER_NONE:
+ order = 0;
+ break;
+ case AARCH64_INSN_MEM_ORDER_LOAD_ACQ_STORE_REL:
+ order = BIT(15) | BIT(22);
+ break;
+ default:
+ pr_err("%s: unknown mem order %d\n", __func__, type);
+ return AARCH64_BREAK_FAULT;
+ }
+
+ insn &= ~(BIT(15) | BIT(22));
+ insn |= order;
+
+ return insn;
+}
+
+u32 aarch64_insn_gen_cas(enum aarch64_insn_register result,
+ enum aarch64_insn_register address,
+ enum aarch64_insn_register value,
+ enum aarch64_insn_size_type size,
+ enum aarch64_insn_mem_order_type order)
+{
+ u32 insn;
+
+ switch (size) {
+ case AARCH64_INSN_SIZE_32:
+ case AARCH64_INSN_SIZE_64:
+ break;
+ default:
+ pr_err("%s: unimplemented size encoding %d\n", __func__, size);
+ return AARCH64_BREAK_FAULT;
+ }
+
+ insn = aarch64_insn_get_cas_value();
+
+ insn = aarch64_insn_encode_ldst_size(size, insn);
+
+ insn = aarch64_insn_encode_cas_order(order, insn);
+
+ insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
+ result);
+
+ insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
+ address);
+
+ return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RS, insn,
+ value);
}
static u32 aarch64_insn_encode_prfm_imm(enum aarch64_insn_prfm_type type,
@@ -1456,3 +1562,24 @@ u32 aarch64_insn_gen_extr(enum aarch64_insn_variant variant,
insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, Rn);
return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, Rm);
}
+
+u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type)
+{
+ u32 opt;
+ u32 insn;
+
+ switch (type) {
+ case AARCH64_INSN_MB_ISH:
+ opt = 0xb;
+ break;
+ default:
+ pr_err("%s: unknown dmb type %d\n", __func__, type);
+ return AARCH64_BREAK_FAULT;
+ }
+
+ insn = aarch64_insn_get_dmb_value();
+ insn &= ~GENMASK(11, 8);
+ insn |= (opt << 8);
+
+ return insn;
+}
diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h
index cc0cf0f5c7c3..308f96587861 100644
--- a/arch/arm64/net/bpf_jit.h
+++ b/arch/arm64/net/bpf_jit.h
@@ -88,10 +88,41 @@
/* [Rn] = Rt; (atomic) Rs = [state] */
#define A64_STXR(sf, Rt, Rn, Rs) \
A64_LSX(sf, Rt, Rn, Rs, STORE_EX)
+/* smp_mb(); [Rn] = Rt; (atomic) Rs = [state] */
+#define A64_STLXR(sf, Rt, Rn, Rs) \
+ aarch64_insn_gen_store_release_ex(Rt, Rn, Rs, A64_SIZE(sf))
-/* LSE atomics */
-#define A64_STADD(sf, Rn, Rs) \
- aarch64_insn_gen_stadd(Rn, Rs, A64_SIZE(sf))
+/*
+ * LSE atomics
+ *
+ * ST{ADD,CLR,SET,EOR} is simply encoded as an alias for
+ * LDD{ADD,CLR,SET,EOR} with XZR as the destination register.
+ */
+#define A64_ST_OP(sf, Rn, Rs, op) \
+ aarch64_insn_gen_atomic_ld_op(A64_ZR, Rn, Rs, \
+ A64_SIZE(sf), AARCH64_INSN_MEM_ATOMIC_##op, \
+ AARCH64_INSN_MEM_ORDER_NONE)
+/* [Rn] <op>= Rs */
+#define A64_STADD(sf, Rn, Rs) A64_ST_OP(sf, Rn, Rs, ADD)
+#define A64_STCLR(sf, Rn, Rs) A64_ST_OP(sf, Rn, Rs, BIC)
+#define A64_STEOR(sf, Rn, Rs) A64_ST_OP(sf, Rn, Rs, EOR)
+#define A64_STSET(sf, Rn, Rs) A64_ST_OP(sf, Rn, Rs, ORR)
+
+#define A64_LD_OP_AL(sf, Rt, Rn, Rs, op) \
+ aarch64_insn_gen_atomic_ld_op(Rt, Rn, Rs, \
+ A64_SIZE(sf), AARCH64_INSN_MEM_ATOMIC_##op, \
+ AARCH64_INSN_MEM_ORDER_LOAD_ACQ_STORE_REL)
+/* Rt = [Rn]; [Rn] <op>= Rs */
+#define A64_LDADDAL(sf, Rt, Rn, Rs) A64_LD_OP_AL(sf, Rt, Rn, Rs, ADD)
+#define A64_LDCLRAL(sf, Rt, Rn, Rs) A64_LD_OP_AL(sf, Rt, Rn, Rs, BIC)
+#define A64_LDEORAL(sf, Rt, Rn, Rs) A64_LD_OP_AL(sf, Rt, Rn, Rs, EOR)
+#define A64_LDSETAL(sf, Rt, Rn, Rs) A64_LD_OP_AL(sf, Rt, Rn, Rs, ORR)
+/* Rt = [Rn]; [Rn] = Rs */
+#define A64_SWPAL(sf, Rt, Rn, Rs) A64_LD_OP_AL(sf, Rt, Rn, Rs, SWP)
+/* Rs = CAS(Rn, Rs, Rt) */
+#define A64_CASAL(sf, Rt, Rn, Rs) \
+ aarch64_insn_gen_cas(Rt, Rn, Rs, A64_SIZE(sf), \
+ AARCH64_INSN_MEM_ORDER_LOAD_ACQ_STORE_REL)
/* Add/subtract (immediate) */
#define A64_ADDSUB_IMM(sf, Rd, Rn, imm12, type) \
@@ -196,6 +227,9 @@
#define A64_ANDS(sf, Rd, Rn, Rm) A64_LOGIC_SREG(sf, Rd, Rn, Rm, AND_SETFLAGS)
/* Rn & Rm; set condition flags */
#define A64_TST(sf, Rn, Rm) A64_ANDS(sf, A64_ZR, Rn, Rm)
+/* Rd = ~Rm (alias of ORN with A64_ZR as Rn) */
+#define A64_MVN(sf, Rd, Rm) \
+ A64_LOGIC_SREG(sf, Rd, A64_ZR, Rm, ORN)
/* Logical (immediate) */
#define A64_LOGIC_IMM(sf, Rd, Rn, imm, type) ({ \
@@ -219,4 +253,7 @@
#define A64_BTI_J A64_HINT(AARCH64_INSN_HINT_BTIJ)
#define A64_BTI_JC A64_HINT(AARCH64_INSN_HINT_BTIJC)
+/* DMB */
+#define A64_DMB_ISH aarch64_insn_gen_dmb(AARCH64_INSN_MB_ISH)
+
#endif /* _BPF_JIT_H */
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 3c2f91b8b00b..e60c464004c2 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -29,6 +29,17 @@
#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
#define TMP_REG_3 (MAX_BPF_JIT_REG + 3)
+#define check_imm(bits, imm) do { \
+ if ((((imm) > 0) && ((imm) >> (bits))) || \
+ (((imm) < 0) && (~(imm) >> (bits)))) { \
+ pr_info("[%2d] imm=%d(0x%x) out of range\n", \
+ i, imm, imm); \
+ return -EINVAL; \
+ } \
+} while (0)
+#define check_imm19(imm) check_imm(19, imm)
+#define check_imm26(imm) check_imm(26, imm)
+
/* Map BPF registers to A64 registers */
static const int bpf2a64[] = {
/* return value from in-kernel function, and exit value from eBPF */
@@ -332,6 +343,163 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
#undef jmp_offset
}
+static int emit_lse_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+ const u8 code = insn->code;
+ const u8 dst = bpf2a64[insn->dst_reg];
+ const u8 src = bpf2a64[insn->src_reg];
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 tmp2 = bpf2a64[TMP_REG_2];
+ const bool isdw = BPF_SIZE(code) == BPF_DW;
+ const s16 off = insn->off;
+ u8 reg;
+
+ if (!off) {
+ reg = dst;
+ } else {
+ emit_a64_mov_i(1, tmp, off, ctx);
+ emit(A64_ADD(1, tmp, tmp, dst), ctx);
+ reg = tmp;
+ }
+
+ switch (insn->imm) {
+ /* lock *(u32/u64 *)(dst_reg + off) <op>= src_reg */
+ case BPF_ADD:
+ emit(A64_STADD(isdw, reg, src), ctx);
+ break;
+ case BPF_AND:
+ emit(A64_MVN(isdw, tmp2, src), ctx);
+ emit(A64_STCLR(isdw, reg, tmp2), ctx);
+ break;
+ case BPF_OR:
+ emit(A64_STSET(isdw, reg, src), ctx);
+ break;
+ case BPF_XOR:
+ emit(A64_STEOR(isdw, reg, src), ctx);
+ break;
+ /* src_reg = atomic_fetch_add(dst_reg + off, src_reg) */
+ case BPF_ADD | BPF_FETCH:
+ emit(A64_LDADDAL(isdw, src, reg, src), ctx);
+ break;
+ case BPF_AND | BPF_FETCH:
+ emit(A64_MVN(isdw, tmp2, src), ctx);
+ emit(A64_LDCLRAL(isdw, src, reg, tmp2), ctx);
+ break;
+ case BPF_OR | BPF_FETCH:
+ emit(A64_LDSETAL(isdw, src, reg, src), ctx);
+ break;
+ case BPF_XOR | BPF_FETCH:
+ emit(A64_LDEORAL(isdw, src, reg, src), ctx);
+ break;
+ /* src_reg = atomic_xchg(dst_reg + off, src_reg); */
+ case BPF_XCHG:
+ emit(A64_SWPAL(isdw, src, reg, src), ctx);
+ break;
+ /* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
+ case BPF_CMPXCHG:
+ emit(A64_CASAL(isdw, src, reg, bpf2a64[BPF_REG_0]), ctx);
+ break;
+ default:
+ pr_err_once("unknown atomic op code %02x\n", insn->imm);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int emit_ll_sc_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+{
+ const u8 code = insn->code;
+ const u8 dst = bpf2a64[insn->dst_reg];
+ const u8 src = bpf2a64[insn->src_reg];
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 tmp2 = bpf2a64[TMP_REG_2];
+ const u8 tmp3 = bpf2a64[TMP_REG_3];
+ const int i = insn - ctx->prog->insnsi;
+ const s32 imm = insn->imm;
+ const s16 off = insn->off;
+ const bool isdw = BPF_SIZE(code) == BPF_DW;
+ u8 reg;
+ s32 jmp_offset;
+
+ if (!off) {
+ reg = dst;
+ } else {
+ emit_a64_mov_i(1, tmp, off, ctx);
+ emit(A64_ADD(1, tmp, tmp, dst), ctx);
+ reg = tmp;
+ }
+
+ if (imm == BPF_ADD || imm == BPF_AND ||
+ imm == BPF_OR || imm == BPF_XOR) {
+ /* lock *(u32/u64 *)(dst_reg + off) <op>= src_reg */
+ emit(A64_LDXR(isdw, tmp2, reg), ctx);
+ if (imm == BPF_ADD)
+ emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
+ else if (imm == BPF_AND)
+ emit(A64_AND(isdw, tmp2, tmp2, src), ctx);
+ else if (imm == BPF_OR)
+ emit(A64_ORR(isdw, tmp2, tmp2, src), ctx);
+ else
+ emit(A64_EOR(isdw, tmp2, tmp2, src), ctx);
+ emit(A64_STXR(isdw, tmp2, reg, tmp3), ctx);
+ jmp_offset = -3;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+ } else if (imm == (BPF_ADD | BPF_FETCH) ||
+ imm == (BPF_AND | BPF_FETCH) ||
+ imm == (BPF_OR | BPF_FETCH) ||
+ imm == (BPF_XOR | BPF_FETCH)) {
+ /* src_reg = atomic_fetch_add(dst_reg + off, src_reg) */
+ const u8 ax = bpf2a64[BPF_REG_AX];
+
+ emit(A64_MOV(isdw, ax, src), ctx);
+ emit(A64_LDXR(isdw, src, reg), ctx);
+ if (imm == (BPF_ADD | BPF_FETCH))
+ emit(A64_ADD(isdw, tmp2, src, ax), ctx);
+ else if (imm == (BPF_AND | BPF_FETCH))
+ emit(A64_AND(isdw, tmp2, src, ax), ctx);
+ else if (imm == (BPF_OR | BPF_FETCH))
+ emit(A64_ORR(isdw, tmp2, src, ax), ctx);
+ else
+ emit(A64_EOR(isdw, tmp2, src, ax), ctx);
+ emit(A64_STLXR(isdw, tmp2, reg, tmp3), ctx);
+ jmp_offset = -3;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+ emit(A64_DMB_ISH, ctx);
+ } else if (imm == BPF_XCHG) {
+ /* src_reg = atomic_xchg(dst_reg + off, src_reg); */
+ emit(A64_MOV(isdw, tmp2, src), ctx);
+ emit(A64_LDXR(isdw, src, reg), ctx);
+ emit(A64_STLXR(isdw, tmp2, reg, tmp3), ctx);
+ jmp_offset = -2;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+ emit(A64_DMB_ISH, ctx);
+ } else if (imm == BPF_CMPXCHG) {
+ /* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
+ const u8 r0 = bpf2a64[BPF_REG_0];
+
+ emit(A64_MOV(isdw, tmp2, r0), ctx);
+ emit(A64_LDXR(isdw, r0, reg), ctx);
+ emit(A64_EOR(isdw, tmp3, r0, tmp2), ctx);
+ jmp_offset = 4;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(isdw, tmp3, jmp_offset), ctx);
+ emit(A64_STLXR(isdw, src, reg, tmp3), ctx);
+ jmp_offset = -4;
+ check_imm19(jmp_offset);
+ emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
+ emit(A64_DMB_ISH, ctx);
+ } else {
+ pr_err_once("unknown atomic op code %02x\n", imm);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void build_epilogue(struct jit_ctx *ctx)
{
const u8 r0 = bpf2a64[BPF_REG_0];
@@ -437,29 +605,16 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
const u8 src = bpf2a64[insn->src_reg];
const u8 tmp = bpf2a64[TMP_REG_1];
const u8 tmp2 = bpf2a64[TMP_REG_2];
- const u8 tmp3 = bpf2a64[TMP_REG_3];
const s16 off = insn->off;
const s32 imm = insn->imm;
const int i = insn - ctx->prog->insnsi;
const bool is64 = BPF_CLASS(code) == BPF_ALU64 ||
BPF_CLASS(code) == BPF_JMP;
- const bool isdw = BPF_SIZE(code) == BPF_DW;
- u8 jmp_cond, reg;
+ u8 jmp_cond;
s32 jmp_offset;
u32 a64_insn;
int ret;
-#define check_imm(bits, imm) do { \
- if ((((imm) > 0) && ((imm) >> (bits))) || \
- (((imm) < 0) && (~(imm) >> (bits)))) { \
- pr_info("[%2d] imm=%d(0x%x) out of range\n", \
- i, imm, imm); \
- return -EINVAL; \
- } \
-} while (0)
-#define check_imm19(imm) check_imm(19, imm)
-#define check_imm26(imm) check_imm(26, imm)
-
switch (code) {
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
@@ -894,33 +1049,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
- if (insn->imm != BPF_ADD) {
- pr_err_once("unknown atomic op code %02x\n", insn->imm);
- return -EINVAL;
- }
-
- /* STX XADD: lock *(u32 *)(dst + off) += src
- * and
- * STX XADD: lock *(u64 *)(dst + off) += src
- */
-
- if (!off) {
- reg = dst;
- } else {
- emit_a64_mov_i(1, tmp, off, ctx);
- emit(A64_ADD(1, tmp, tmp, dst), ctx);
- reg = tmp;
- }
- if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS)) {
- emit(A64_STADD(isdw, reg, src), ctx);
- } else {
- emit(A64_LDXR(isdw, tmp2, reg), ctx);
- emit(A64_ADD(isdw, tmp2, tmp2, src), ctx);
- emit(A64_STXR(isdw, tmp2, reg, tmp3), ctx);
- jmp_offset = -3;
- check_imm19(jmp_offset);
- emit(A64_CBNZ(0, tmp3, jmp_offset), ctx);
- }
+ if (cpus_have_cap(ARM64_HAS_LSE_ATOMICS))
+ ret = emit_lse_atomic(insn, ctx);
+ else
+ ret = emit_ll_sc_atomic(insn, ctx);
+ if (ret)
+ return ret;
break;
default:
--
2.27.0
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