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Merge branch 'bpf-inline-helpers-in-arm64-and-riscv-jits'
Puranjay Mohan says: ==================== bpf: Inline helpers in arm64 and riscv JITs Changes in v5 -> v6: arm64 v5: https://lore.kernel.org/all/20240430234739.79185-1-puranjay@kernel.org/ riscv v2: https://lore.kernel.org/all/20240430175834.33152-1-puranjay@kernel.org/ - Combine riscv and arm64 changes in single series - Some coding style fixes Changes in v4 -> v5: v4: https://lore.kernel.org/all/20240429131647.50165-1-puranjay@kernel.org/ - Implement the inlining of the bpf_get_smp_processor_id() in the JIT. NOTE: This needs to be based on: https://lore.kernel.org/all/20240430175834.33152-1-puranjay@kernel.org/ to be built. Manual run of bpf-ci with this series rebased on above: https://github.com/kernel-patches/bpf/pull/6929 Changes in v3 -> v4: v3: https://lore.kernel.org/all/20240426121349.97651-1-puranjay@kernel.org/ - Fix coding style issue related to C89 standards. Changes in v2 -> v3: v2: https://lore.kernel.org/all/20240424173550.16359-1-puranjay@kernel.org/ - Fixed the xlated dump of percpu mov to "r0 = &(void __percpu *)(r0)" - Made ARM64 and x86-64 use the same code for inlining. The only difference that remains is the per-cpu address of the cpu_number. Changes in v1 -> v2: v1: https://lore.kernel.org/all/20240405091707.66675-1-puranjay12@gmail.com/ - Add a patch to inline bpf_get_smp_processor_id() - Fix an issue in MRS instruction encoding as pointed out by Will - Remove CONFIG_SMP check because arm64 kernel always compiles with CONFIG_SMP This series adds the support of internal only per-CPU instructions and inlines the bpf_get_smp_processor_id() helper call for ARM64 and RISC-V BPF JITs. Here is an example of calls to bpf_get_smp_processor_id() and percpu_array_map_lookup_elem() before and after this series on ARM64. BPF ===== BEFORE AFTER -------- ------- int cpu = bpf_get_smp_processor_id(); int cpu = bpf_get_smp_processor_id(); (85) call bpf_get_smp_processor_id#229032 (85) call bpf_get_smp_processor_id#8 p = bpf_map_lookup_elem(map, &zero); p = bpf_map_lookup_elem(map, &zero); (18) r1 = map[id:78] (18) r1 = map[id:153] (18) r2 = map[id:82][0]+65536 (18) r2 = map[id:157][0]+65536 (85) call percpu_array_map_lookup_elem#313512 (07) r1 += 496 (61) r0 = *(u32 *)(r2 +0) (35) if r0 >= 0x1 goto pc+5 (67) r0 <<= 3 (0f) r0 += r1 (79) r0 = *(u64 *)(r0 +0) (bf) r0 = &(void __percpu *)(r0) (05) goto pc+1 (b7) r0 = 0 ARM64 JIT =========== BEFORE AFTER -------- ------- int cpu = bpf_get_smp_processor_id(); int cpu = bpf_get_smp_processor_id(); mov x10, #0xfffffffffffff4d0 mrs x10, sp_el0 movk x10, #0x802b, lsl #16 ldr w7, [x10, #24] movk x10, #0x8000, lsl #32 blr x10 add x7, x0, #0x0 p = bpf_map_lookup_elem(map, &zero); p = bpf_map_lookup_elem(map, &zero); mov x0, #0xffff0003ffffffff mov x0, #0xffff0003ffffffff movk x0, #0xce5c, lsl #16 movk x0, #0xe0f3, lsl #16 movk x0, #0xca00 movk x0, #0x7c00 mov x1, #0xffff8000ffffffff mov x1, #0xffff8000ffffffff movk x1, #0x8bdb, lsl #16 movk x1, #0xb0c7, lsl #16 movk x1, #0x6000 movk x1, #0xe000 mov x10, #0xffffffffffff3ed0 add x0, x0, #0x1f0 movk x10, #0x802d, lsl #16 ldr w7, [x1] movk x10, #0x8000, lsl #32 cmp x7, #0x1 blr x10 b.cs 0x0000000000000090 add x7, x0, #0x0 lsl x7, x7, #3 add x7, x7, x0 ldr x7, [x7] mrs x10, tpidr_el1 add x7, x7, x10 b 0x0000000000000094 mov x7, #0x0 Performance improvement found using benchmark[1] ./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc +---------------+-------------------+-------------------+--------------+ | Name | Before | After | % change | |---------------+-------------------+-------------------+--------------| | glob-arr-inc | 23.380 ± 1.675M/s | 25.893 ± 0.026M/s | + 10.74% | | arr-inc | 23.928 ± 0.034M/s | 25.213 ± 0.063M/s | + 5.37% | | hash-inc | 12.352 ± 0.005M/s | 12.609 ± 0.013M/s | + 2.08% | +---------------+-------------------+-------------------+--------------+ [1] https://github.com/anakryiko/linux/commit/8dec900975ef RISCV64 JIT output for `call bpf_get_smp_processor_id` ======================================================= Before After -------- ------- auipc t1,0x848c ld a5,32(tp) jalr 604(t1) mv a5,a0 Benchmark using [1] on Qemu. ./benchs/run_bench_trigger.sh glob-arr-inc arr-inc hash-inc +---------------+------------------+------------------+--------------+ | Name | Before | After | % change | |---------------+------------------+------------------+--------------| | glob-arr-inc | 1.077 ± 0.006M/s | 1.336 ± 0.010M/s | + 24.04% | | arr-inc | 1.078 ± 0.002M/s | 1.332 ± 0.015M/s | + 23.56% | | hash-inc | 0.494 ± 0.004M/s | 0.653 ± 0.001M/s | + 32.18% | +---------------+------------------+------------------+--------------+ ==================== Link: https://lore.kernel.org/r/20240502151854.9810-1-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov
commit
55302bc1ca
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@ -135,6 +135,12 @@ enum aarch64_insn_special_register {
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AARCH64_INSN_SPCLREG_SP_EL2 = 0xF210
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};
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enum aarch64_insn_system_register {
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AARCH64_INSN_SYSREG_TPIDR_EL1 = 0x4684,
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AARCH64_INSN_SYSREG_TPIDR_EL2 = 0x6682,
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AARCH64_INSN_SYSREG_SP_EL0 = 0x4208,
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};
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enum aarch64_insn_variant {
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AARCH64_INSN_VARIANT_32BIT,
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AARCH64_INSN_VARIANT_64BIT
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@ -686,6 +692,8 @@ u32 aarch64_insn_gen_cas(enum aarch64_insn_register result,
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}
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#endif
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u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type);
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u32 aarch64_insn_gen_mrs(enum aarch64_insn_register result,
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enum aarch64_insn_system_register sysreg);
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s32 aarch64_get_branch_offset(u32 insn);
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u32 aarch64_set_branch_offset(u32 insn, s32 offset);
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@ -1515,3 +1515,14 @@ u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type)
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return insn;
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}
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u32 aarch64_insn_gen_mrs(enum aarch64_insn_register result,
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enum aarch64_insn_system_register sysreg)
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{
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u32 insn = aarch64_insn_get_mrs_value();
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insn &= ~GENMASK(19, 0);
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insn |= sysreg << 5;
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return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT,
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insn, result);
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}
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@ -297,4 +297,12 @@
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#define A64_ADR(Rd, offset) \
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aarch64_insn_gen_adr(0, offset, Rd, AARCH64_INSN_ADR_TYPE_ADR)
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/* MRS */
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#define A64_MRS_TPIDR_EL1(Rt) \
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aarch64_insn_gen_mrs(Rt, AARCH64_INSN_SYSREG_TPIDR_EL1)
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#define A64_MRS_TPIDR_EL2(Rt) \
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aarch64_insn_gen_mrs(Rt, AARCH64_INSN_SYSREG_TPIDR_EL2)
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#define A64_MRS_SP_EL0(Rt) \
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aarch64_insn_gen_mrs(Rt, AARCH64_INSN_SYSREG_SP_EL0)
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#endif /* _BPF_JIT_H */
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@ -890,6 +890,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
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emit(A64_ORR(1, tmp, dst, tmp), ctx);
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emit(A64_MOV(1, dst, tmp), ctx);
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break;
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} else if (insn_is_mov_percpu_addr(insn)) {
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if (dst != src)
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emit(A64_MOV(1, dst, src), ctx);
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if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
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emit(A64_MRS_TPIDR_EL2(tmp), ctx);
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else
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emit(A64_MRS_TPIDR_EL1(tmp), ctx);
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emit(A64_ADD(1, dst, dst, tmp), ctx);
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break;
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}
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switch (insn->off) {
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case 0:
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@ -1219,6 +1228,21 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
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const u8 r0 = bpf2a64[BPF_REG_0];
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bool func_addr_fixed;
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u64 func_addr;
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u32 cpu_offset;
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/* Implement helper call to bpf_get_smp_processor_id() inline */
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if (insn->src_reg == 0 && insn->imm == BPF_FUNC_get_smp_processor_id) {
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cpu_offset = offsetof(struct thread_info, cpu);
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emit(A64_MRS_SP_EL0(tmp), ctx);
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if (is_lsi_offset(cpu_offset, 2)) {
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emit(A64_LDR32I(r0, tmp, cpu_offset), ctx);
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} else {
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emit_a64_mov_i(1, tmp2, cpu_offset, ctx);
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emit(A64_LDR32(r0, tmp, tmp2), ctx);
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}
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break;
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}
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ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
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&func_addr, &func_addr_fixed);
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@ -2559,6 +2583,21 @@ bool bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
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return true;
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}
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bool bpf_jit_supports_percpu_insn(void)
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{
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return true;
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}
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bool bpf_jit_inlines_helper_call(s32 imm)
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{
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switch (imm) {
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case BPF_FUNC_get_smp_processor_id:
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return true;
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default:
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return false;
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}
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}
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void bpf_jit_free(struct bpf_prog *prog)
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{
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if (prog->jited) {
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@ -12,6 +12,7 @@
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#include <linux/stop_machine.h>
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#include <asm/patch.h>
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#include <asm/cfi.h>
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#include <asm/percpu.h>
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#include "bpf_jit.h"
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#define RV_FENTRY_NINSNS 2
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@ -1089,6 +1090,24 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
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emit_or(RV_REG_T1, rd, RV_REG_T1, ctx);
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emit_mv(rd, RV_REG_T1, ctx);
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break;
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} else if (insn_is_mov_percpu_addr(insn)) {
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if (rd != rs)
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emit_mv(rd, rs, ctx);
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#ifdef CONFIG_SMP
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/* Load current CPU number in T1 */
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emit_ld(RV_REG_T1, offsetof(struct thread_info, cpu),
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RV_REG_TP, ctx);
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/* << 3 because offsets are 8 bytes */
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emit_slli(RV_REG_T1, RV_REG_T1, 3, ctx);
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/* Load address of __per_cpu_offset array in T2 */
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emit_addr(RV_REG_T2, (u64)&__per_cpu_offset, extra_pass, ctx);
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/* Add offset of current CPU to __per_cpu_offset */
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emit_add(RV_REG_T1, RV_REG_T2, RV_REG_T1, ctx);
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/* Load __per_cpu_offset[cpu] in T1 */
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emit_ld(RV_REG_T1, 0, RV_REG_T1, ctx);
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/* Add the offset to Rd */
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emit_add(rd, rd, RV_REG_T1, ctx);
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#endif
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}
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if (imm == 1) {
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/* Special mov32 for zext */
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@ -1474,6 +1493,22 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
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bool fixed_addr;
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u64 addr;
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/* Inline calls to bpf_get_smp_processor_id()
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*
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* RV_REG_TP holds the address of the current CPU's task_struct and thread_info is
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* at offset 0 in task_struct.
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* Load cpu from thread_info:
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* Set R0 to ((struct thread_info *)(RV_REG_TP))->cpu
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*
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* This replicates the implementation of raw_smp_processor_id() on RISCV
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*/
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if (insn->src_reg == 0 && insn->imm == BPF_FUNC_get_smp_processor_id) {
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/* Load current CPU number in R0 */
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emit_ld(bpf_to_rv_reg(BPF_REG_0, ctx), offsetof(struct thread_info, cpu),
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RV_REG_TP, ctx);
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break;
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}
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mark_call(ctx);
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ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
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&addr, &fixed_addr);
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@ -2038,3 +2073,18 @@ bool bpf_jit_supports_arena(void)
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{
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return true;
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}
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bool bpf_jit_supports_percpu_insn(void)
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{
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return true;
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}
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bool bpf_jit_inlines_helper_call(s32 imm)
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{
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switch (imm) {
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case BPF_FUNC_get_smp_processor_id:
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return true;
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default:
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return false;
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}
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}
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@ -993,6 +993,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
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struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
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void bpf_jit_compile(struct bpf_prog *prog);
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bool bpf_jit_needs_zext(void);
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bool bpf_jit_inlines_helper_call(s32 imm);
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bool bpf_jit_supports_subprog_tailcalls(void);
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bool bpf_jit_supports_percpu_insn(void);
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bool bpf_jit_supports_kfunc_call(void);
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@ -2941,6 +2941,17 @@ bool __weak bpf_jit_needs_zext(void)
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return false;
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}
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/* Return true if the JIT inlines the call to the helper corresponding to
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* the imm.
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*
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* The verifier will not patch the insn->imm for the call to the helper if
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* this returns true.
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*/
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bool __weak bpf_jit_inlines_helper_call(s32 imm)
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{
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return false;
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}
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/* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
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bool __weak bpf_jit_supports_subprog_tailcalls(void)
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{
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@ -19996,6 +19996,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
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goto next_insn;
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}
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/* Skip inlining the helper call if the JIT does it. */
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if (bpf_jit_inlines_helper_call(insn->imm))
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goto next_insn;
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if (insn->imm == BPF_FUNC_get_route_realm)
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prog->dst_needed = 1;
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if (insn->imm == BPF_FUNC_get_prandom_u32)
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