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bpf: inline bpf_get_smp_processor_id() helper

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If BPF JIT supports per-CPU MOV instruction, inline bpf_get_smp_processor_id()
to eliminate unnecessary function calls.

Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
This commit is contained in:
Andrii Nakryiko authored and Alexei Starovoitov committed 2024-04-03 10:29:56 -07:00
1 parent 7bdbf74463
commit 1ae6921009
1 file changed
+24
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kernel/bpf/verifier.c
+24
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@@ -20074,6 +20074,30 @@ patch_map_ops_generic:
goto next_insn;
}
#ifdef CONFIG_X86_64
/* Implement bpf_get_smp_processor_id() inline. */
if (insn->imm == BPF_FUNC_get_smp_processor_id &&
prog->jit_requested && bpf_jit_supports_percpu_insn()) {
/* BPF_FUNC_get_smp_processor_id inlining is an
* optimization, so if pcpu_hot.cpu_number is ever
* changed in some incompatible and hard to support
* way, it's fine to back out this inlining logic
*/
insn_buf[0] = BPF_MOV32_IMM(BPF_REG_0, (u32)(unsigned long)&pcpu_hot.cpu_number);
insn_buf[1] = BPF_MOV64_PERCPU_REG(BPF_REG_0, BPF_REG_0);
insn_buf[2] = BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0);
cnt = 3;
new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
if (!new_prog)
return -ENOMEM;
delta += cnt - 1;
env->prog = prog = new_prog;
insn = new_prog->insnsi + i + delta;
goto next_insn;
}
#endif
/* Implement bpf_get_func_arg inline. */
if (prog_type == BPF_PROG_TYPE_TRACING &&
insn->imm == BPF_FUNC_get_func_arg) {