| Message ID | 20191216091343.23260-6-bjorn.topel@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | riscv: BPF JIT fix, optimizations and far jumps support | expand |
On Mon, 16 Dec 2019 01:13:39 PST (-0800), Bjorn Topel wrote: > Remove one addi, and instead use the offset part of jalr. > > Signed-off-by: Björn Töpel <bjorn.topel@gmail.com> > --- > arch/riscv/net/bpf_jit_comp.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c > index 2fc0f24ad30f..8aa19c846881 100644 > --- a/arch/riscv/net/bpf_jit_comp.c > +++ b/arch/riscv/net/bpf_jit_comp.c > @@ -552,7 +552,7 @@ static int epilogue_offset(struct rv_jit_context *ctx) > return (to - from) << 2; > } > > -static void __build_epilogue(u8 reg, struct rv_jit_context *ctx) > +static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx) > { > int stack_adjust = ctx->stack_size, store_offset = stack_adjust - 8; > > @@ -589,9 +589,11 @@ static void __build_epilogue(u8 reg, struct rv_jit_context *ctx) > > emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx); > /* Set return value. */ > - if (reg == RV_REG_RA) > + if (!is_tail_call) > emit(rv_addi(RV_REG_A0, RV_REG_A5, 0), ctx); > - emit(rv_jalr(RV_REG_ZERO, reg, 0), ctx); > + emit(rv_jalr(RV_REG_ZERO, is_tail_call ? RV_REG_T3 : RV_REG_RA, > + is_tail_call ? 4 : 0), /* skip TCC init */ > + ctx); > } > > /* return -1 or inverted cond */ > @@ -751,9 +753,8 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) > if (is_12b_check(off, insn)) > return -1; > emit(rv_ld(RV_REG_T3, off, RV_REG_T2), ctx); > - emit(rv_addi(RV_REG_T3, RV_REG_T3, 4), ctx); > emit(rv_addi(RV_REG_TCC, RV_REG_T1, 0), ctx); > - __build_epilogue(RV_REG_T3, ctx); > + __build_epilogue(true, ctx); > return 0; > } > > @@ -1504,7 +1505,7 @@ static void build_prologue(struct rv_jit_context *ctx) > > static void build_epilogue(struct rv_jit_context *ctx) > { > - __build_epilogue(RV_REG_RA, ctx); > + __build_epilogue(false, ctx); > } > > static int build_body(struct rv_jit_context *ctx, bool extra_pass) Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c index 2fc0f24ad30f..8aa19c846881 100644 --- a/arch/riscv/net/bpf_jit_comp.c +++ b/arch/riscv/net/bpf_jit_comp.c @@ -552,7 +552,7 @@ static int epilogue_offset(struct rv_jit_context *ctx) return (to - from) << 2; } -static void __build_epilogue(u8 reg, struct rv_jit_context *ctx) +static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx) { int stack_adjust = ctx->stack_size, store_offset = stack_adjust - 8; @@ -589,9 +589,11 @@ static void __build_epilogue(u8 reg, struct rv_jit_context *ctx) emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx); /* Set return value. */ - if (reg == RV_REG_RA) + if (!is_tail_call) emit(rv_addi(RV_REG_A0, RV_REG_A5, 0), ctx); - emit(rv_jalr(RV_REG_ZERO, reg, 0), ctx); + emit(rv_jalr(RV_REG_ZERO, is_tail_call ? RV_REG_T3 : RV_REG_RA, + is_tail_call ? 4 : 0), /* skip TCC init */ + ctx); } /* return -1 or inverted cond */ @@ -751,9 +753,8 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) if (is_12b_check(off, insn)) return -1; emit(rv_ld(RV_REG_T3, off, RV_REG_T2), ctx); - emit(rv_addi(RV_REG_T3, RV_REG_T3, 4), ctx); emit(rv_addi(RV_REG_TCC, RV_REG_T1, 0), ctx); - __build_epilogue(RV_REG_T3, ctx); + __build_epilogue(true, ctx); return 0; } @@ -1504,7 +1505,7 @@ static void build_prologue(struct rv_jit_context *ctx) static void build_epilogue(struct rv_jit_context *ctx) { - __build_epilogue(RV_REG_RA, ctx); + __build_epilogue(false, ctx); } static int build_body(struct rv_jit_context *ctx, bool extra_pass)
Remove one addi, and instead use the offset part of jalr. Signed-off-by: Björn Töpel <bjorn.topel@gmail.com> --- arch/riscv/net/bpf_jit_comp.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)