Changes in v2 -> v3: v2: https://lore.kernel.org/all/20240424173550.16359-1-puranjay@xxxxxxxxxx/ - 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@xxxxxxxxx/ - 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 BPF JIT. Here is an example of calls to bpf_get_smp_processor_id() and percpu_array_map_lookup_elem() before and after this series. 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 (18) r0 = 0xffff800082072008 (bf) r0 = &(void __percpu *)(r0) (61) r0 = *(u32 *)(r0 +0) 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 mov x7, #0xffff8000ffffffff movk x10, #0x802b, lsl #16 movk x7, #0x8207, lsl #16 movk x10, #0x8000, lsl #32 movk x7, #0x2008 blr x10 mrs x10, tpidr_el1 add x7, x0, #0x0 add x7, x7, x10 ldr w7, [x7] 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] BEFORE AFTER -------- ------- glob-arr-inc : 23.817 ± 0.019M/s glob-arr-inc : 24.631 ± 0.027M/s arr-inc : 23.253 ± 0.019M/s arr-inc : 23.742 ± 0.023M/s hash-inc : 12.258 ± 0.010M/s hash-inc : 12.625 ± 0.004M/s [1] https://github.com/anakryiko/linux/commit/8dec900975ef Puranjay Mohan (2): arm64, bpf: add internal-only MOV instruction to resolve per-CPU addrs bpf, arm64: inline bpf_get_smp_processor_id() helper arch/arm64/include/asm/insn.h | 7 +++++++ arch/arm64/lib/insn.c | 11 +++++++++++ arch/arm64/net/bpf_jit.h | 6 ++++++ arch/arm64/net/bpf_jit_comp.c | 14 ++++++++++++++ kernel/bpf/verifier.c | 24 +++++++++++++++++------- 5 files changed, 55 insertions(+), 7 deletions(-) -- 2.40.1
