Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161637Ab3DEMBj (ORCPT ); Fri, 5 Apr 2013 08:01:39 -0400 Received: from mail-la0-f48.google.com ([209.85.215.48]:34799 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161750Ab3DEMBX (ORCPT ); Fri, 5 Apr 2013 08:01:23 -0400 MIME-Version: 1.0 In-Reply-To: <1363618233-6375-3-git-send-email-nschichan@freebox.fr> References: <1363618233-6375-1-git-send-email-nschichan@freebox.fr> <1363618233-6375-3-git-send-email-nschichan@freebox.fr> Date: Fri, 5 Apr 2013 14:01:21 +0200 Message-ID: Subject: Re: [PATCH V2 2/3] ARM: net: bpf_jit: make code generation less dependent on struct sk_filter. From: Mircea Gherzan To: Nicolas Schichan Cc: Will Drewry , "linux-kernel@vger.kernel.org >> linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Russell King , "David S. Miller" , Daniel Borkmann Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5172 Lines: 150 2013/3/18 Nicolas Schichan : > This is in preparation of bpf_jit support for seccomp filters. > > Signed-off-by: Nicolas Schichan > --- > arch/arm/net/bpf_jit_32.c | 46 ++++++++++++++++++++++++++++----------------- > 1 file changed, 29 insertions(+), 17 deletions(-) > > diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c > index 6828ef6..0ea29e0 100644 > --- a/arch/arm/net/bpf_jit_32.c > +++ b/arch/arm/net/bpf_jit_32.c > @@ -55,7 +55,8 @@ > #define FLAG_NEED_X_RESET (1 << 0) > > struct jit_ctx { > - const struct sk_filter *skf; > + unsigned short prog_len; > + struct sock_filter *prog_insns; > unsigned idx; > unsigned prologue_bytes; > int ret0_fp_idx; > @@ -131,8 +132,8 @@ static u16 saved_regs(struct jit_ctx *ctx) > { > u16 ret = 0; > > - if ((ctx->skf->len > 1) || > - (ctx->skf->insns[0].code == BPF_S_RET_A)) > + if ((ctx->prog_len > 1) || > + (ctx->prog_insns[0].code == BPF_S_RET_A)) > ret |= 1 << r_A; > > #ifdef CONFIG_FRAME_POINTER > @@ -181,7 +182,7 @@ static inline bool is_load_to_a(u16 inst) > static void build_prologue(struct jit_ctx *ctx) > { > u16 reg_set = saved_regs(ctx); > - u16 first_inst = ctx->skf->insns[0].code; > + u16 first_inst = ctx->prog_insns[0].code; > u16 off; > > #ifdef CONFIG_FRAME_POINTER > @@ -279,7 +280,7 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx) > ctx->imms[i] = k; > > /* constants go just after the epilogue */ > - offset = ctx->offsets[ctx->skf->len]; > + offset = ctx->offsets[ctx->prog_len]; > offset += ctx->prologue_bytes; > offset += ctx->epilogue_bytes; > offset += i * 4; > @@ -419,7 +420,7 @@ static inline void emit_err_ret(u8 cond, struct jit_ctx *ctx) > emit(ARM_MOV_R(ARM_R0, ARM_R0), ctx); > } else { > _emit(cond, ARM_MOV_I(ARM_R0, 0), ctx); > - _emit(cond, ARM_B(b_imm(ctx->skf->len, ctx)), ctx); > + _emit(cond, ARM_B(b_imm(ctx->prog_len, ctx)), ctx); > } > } > > @@ -469,14 +470,13 @@ static inline void update_on_xread(struct jit_ctx *ctx) > static int build_body(struct jit_ctx *ctx) > { > void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w}; > - const struct sk_filter *prog = ctx->skf; > const struct sock_filter *inst; > unsigned i, load_order, off, condt; > int imm12; > u32 k; > > - for (i = 0; i < prog->len; i++) { > - inst = &(prog->insns[i]); > + for (i = 0; i < ctx->prog_len; i++) { > + inst = &(ctx->prog_insns[i]); > /* K as an immediate value operand */ > k = inst->k; > > @@ -769,8 +769,8 @@ cmp_x: > ctx->ret0_fp_idx = i; > emit_mov_i(ARM_R0, k, ctx); > b_epilogue: > - if (i != ctx->skf->len - 1) > - emit(ARM_B(b_imm(prog->len, ctx)), ctx); > + if (i != ctx->prog_len - 1) > + emit(ARM_B(b_imm(ctx->prog_len, ctx)), ctx); > break; > case BPF_S_MISC_TAX: > /* X = A */ > @@ -858,7 +858,7 @@ b_epilogue: > } > > > -void bpf_jit_compile(struct sk_filter *fp) > +static void __bpf_jit_compile(struct jit_ctx *out_ctx) > { > struct jit_ctx ctx; > unsigned tmp_idx; > @@ -867,11 +867,10 @@ void bpf_jit_compile(struct sk_filter *fp) > if (!bpf_jit_enable) > return; > > - memset(&ctx, 0, sizeof(ctx)); > - ctx.skf = fp; > + ctx = *out_ctx; > ctx.ret0_fp_idx = -1; > > - ctx.offsets = kzalloc(4 * (ctx.skf->len + 1), GFP_KERNEL); > + ctx.offsets = kzalloc(4 * (ctx.prog_len + 1), GFP_KERNEL); > if (ctx.offsets == NULL) > return; > > @@ -921,13 +920,26 @@ void bpf_jit_compile(struct sk_filter *fp) > print_hex_dump(KERN_INFO, "BPF JIT code: ", > DUMP_PREFIX_ADDRESS, 16, 4, ctx.target, > alloc_size, false); > - > - fp->bpf_func = (void *)ctx.target; > out: > kfree(ctx.offsets); > + > + *out_ctx = ctx; > return; > } > > +void bpf_jit_compile(struct sk_filter *fp) > +{ > + struct jit_ctx ctx; > + > + memset(&ctx, 0, sizeof(ctx)); > + ctx.prog_len = fp->len; > + ctx.prog_insns = fp->insns; > + > + __bpf_jit_compile(&ctx); > + if (ctx.target) > + fp->bpf_func = (void*)ctx.target; > +} > + > static void bpf_jit_free_worker(struct work_struct *work) > { > module_free(NULL, work); > -- > 1.7.10.4 > Acked-by: Mircea Gherzan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/