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| author | George Guo <guodongtai@kylinos.cn> | 2026-08-17 22:07:40 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2026-08-17 22:07:40 +0800 |
| commit | 1db6d003e93d033fca25bcfbef73e2780a7e46d7 (patch) | |
| tree | 4462d0110235287545d95275a7cd473aa90e1b01 | |
| parent | 1fec6bbc09e3066a0f39d85741df2a7877c97945 (diff) | |
| download | linux-1db6d003e93d033fca25bcfbef73e2780a7e46d7.tar.gz linux-1db6d003e93d033fca25bcfbef73e2780a7e46d7.zip | |
LoongArch: BPF: Resolve per-CPU addrs for internal-only MOV
Add support for the internal-only BPF_MOV instruction that resolves the
absolute addresses of the per-CPU data from their per-CPU offsets. This
instruction is used only for internal inlining optimizations between the
BPF verifier and the JITs (e.g. inlining bpf_get_smp_processor_id() and
per-CPU map lookups).
LoongArch keeps the per-CPU offset of the current CPU in $r21 register
(a.k.a. __my_cpu_offset), so resolving a per-CPU address only requires
adding $r21 to the source register holding the per-CPU offset. Advertise
the capability via bpf_jit_supports_percpu_insn().
Acked-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | arch/loongarch/include/asm/inst.h | 1 | ||||
| -rw-r--r-- | arch/loongarch/net/bpf_jit.c | 14 |
2 files changed, 15 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/inst.h b/arch/loongarch/include/asm/inst.h index 54f35bcd0f66..585667e361c2 100644 --- a/arch/loongarch/include/asm/inst.h +++ b/arch/loongarch/include/asm/inst.h @@ -411,6 +411,7 @@ enum loongarch_gpr { LOONGARCH_GPR_T6, LOONGARCH_GPR_T7, LOONGARCH_GPR_T8, + LOONGARCH_GPR_U0 = 21, /* Kernel per-CPU base register ($r21) */ LOONGARCH_GPR_FP = 22, LOONGARCH_GPR_S0 = 23, LOONGARCH_GPR_S1, diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index d2ce187d1e23..4e56da413752 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -722,6 +722,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext move_reg(ctx, dst, t1); break; } + if (insn_is_mov_percpu_addr(insn)) { + if (dst != src) + move_reg(ctx, dst, src); +#ifdef CONFIG_SMP + /* dst += __my_cpu_offset, held in $r21 */ + emit_insn(ctx, addd, dst, dst, LOONGARCH_GPR_U0); +#endif + break; + } switch (off) { case 0: move_reg(ctx, dst, src); @@ -2371,6 +2380,11 @@ bool bpf_jit_supports_fsession(void) return true; } +bool bpf_jit_supports_percpu_insn(void) +{ + return true; +} + bool bpf_jit_supports_ptr_xchg(void) { return true; |