diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h index af1ab5e9a691..5c3cf2d04e41 100644 --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -48,7 +48,13 @@ /* * Assembly helpers from arch/powerpc/net/bpf_jit.S: */ -extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[]; +#define DECLARE_LOAD_FUNC(func) \ + extern u8 func[], func##_negative_offset[], func##_positive_offset[] + +DECLARE_LOAD_FUNC(sk_load_word); +DECLARE_LOAD_FUNC(sk_load_half); +DECLARE_LOAD_FUNC(sk_load_byte); +DECLARE_LOAD_FUNC(sk_load_byte_msh); #define FUNCTION_DESCR_SIZE 24 diff --git a/arch/powerpc/net/bpf_jit_64.S b/arch/powerpc/net/bpf_jit_64.S index ff4506e85cce..55ba3855a97f 100644 --- a/arch/powerpc/net/bpf_jit_64.S +++ b/arch/powerpc/net/bpf_jit_64.S @@ -31,14 +31,13 @@ * then branch directly to slow_path_XXX if required. (In fact, could * load a spare GPR with the address of slow_path_generic and pass size * as an argument, making the call site a mtlr, li and bllr.) - * - * Technically, the "is addr < 0" check is unnecessary & slowing down - * the ABS path, as it's statically checked on generation. */ .globl sk_load_word sk_load_word: cmpdi r_addr, 0 - blt bpf_error + blt bpf_slow_path_word_neg + .globl sk_load_word_positive_offset +sk_load_word_positive_offset: /* Are we accessing past headlen? */ subi r_scratch1, r_HL, 4 cmpd r_scratch1, r_addr @@ -51,7 +50,9 @@ sk_load_word: .globl sk_load_half sk_load_half: cmpdi r_addr, 0 - blt bpf_error + blt bpf_slow_path_half_neg + .globl sk_load_half_positive_offset +sk_load_half_positive_offset: subi r_scratch1, r_HL, 2 cmpd r_scratch1, r_addr blt bpf_slow_path_half @@ -61,7 +62,9 @@ sk_load_half: .globl sk_load_byte sk_load_byte: cmpdi r_addr, 0 - blt bpf_error + blt bpf_slow_path_byte_neg + .globl sk_load_byte_positive_offset +sk_load_byte_positive_offset: cmpd r_HL, r_addr ble bpf_slow_path_byte lbzx r_A, r_D, r_addr @@ -69,22 +72,20 @@ sk_load_byte: /* * BPF_S_LDX_B_MSH: ldxb 4*([offset]&0xf) - * r_addr is the offset value, already known positive + * r_addr is the offset value */ .globl sk_load_byte_msh sk_load_byte_msh: + cmpdi r_addr, 0 + blt bpf_slow_path_byte_msh_neg + .globl sk_load_byte_msh_positive_offset +sk_load_byte_msh_positive_offset: cmpd r_HL, r_addr ble bpf_slow_path_byte_msh lbzx r_X, r_D, r_addr rlwinm r_X, r_X, 2, 32-4-2, 31-2 blr -bpf_error: - /* Entered with cr0 = lt */ - li r3, 0 - /* Generated code will 'blt epilogue', returning 0. */ - blr - /* Call out to skb_copy_bits: * We'll need to back up our volatile regs first; we have * local variable space at r1+(BPF_PPC_STACK_BASIC). @@ -136,3 +137,84 @@ bpf_slow_path_byte_msh: lbz r_X, BPF_PPC_STACK_BASIC+(2*8)(r1) rlwinm r_X, r_X, 2, 32-4-2, 31-2 blr + +/* Call out to bpf_internal_load_pointer_neg_helper: + * We'll need to back up our volatile regs first; we have + * local variable space at r1+(BPF_PPC_STACK_BASIC). + * Allocate a new stack frame here to remain ABI-compliant in + * stashing LR. + */ +#define sk_negative_common(SIZE) \ + mflr r0; \ + std r0, 16(r1); \ + /* R3 goes in parameter space of caller's frame */ \ + std r_skb, (BPF_PPC_STACKFRAME+48)(r1); \ + std r_A, (BPF_PPC_STACK_BASIC+(0*8))(r1); \ + std r_X, (BPF_PPC_STACK_BASIC+(1*8))(r1); \ + stdu r1, -BPF_PPC_SLOWPATH_FRAME(r1); \ + /* R3 = r_skb, as passed */ \ + mr r4, r_addr; \ + li r5, SIZE; \ + bl bpf_internal_load_pointer_neg_helper; \ + /* R3 != 0 on success */ \ + addi r1, r1, BPF_PPC_SLOWPATH_FRAME; \ + ld r0, 16(r1); \ + ld r_A, (BPF_PPC_STACK_BASIC+(0*8))(r1); \ + ld r_X, (BPF_PPC_STACK_BASIC+(1*8))(r1); \ + mtlr r0; \ + cmpldi r3, 0; \ + beq bpf_error_slow; /* cr0 = EQ */ \ + mr r_addr, r3; \ + ld r_skb, (BPF_PPC_STACKFRAME+48)(r1); \ + /* Great success! */ + +bpf_slow_path_word_neg: + lis r_scratch1,-32 /* SKF_LL_OFF */ + cmpd r_addr, r_scratch1 /* addr < SKF_* */ + blt bpf_error /* cr0 = LT */ + .globl sk_load_word_negative_offset +sk_load_word_negative_offset: + sk_negative_common(4) + lwz r_A, 0(r_addr) + blr + +bpf_slow_path_half_neg: + lis r_scratch1,-32 /* SKF_LL_OFF */ + cmpd r_addr, r_scratch1 /* addr < SKF_* */ + blt bpf_error /* cr0 = LT */ + .globl sk_load_half_negative_offset +sk_load_half_negative_offset: + sk_negative_common(2) + lhz r_A, 0(r_addr) + blr + +bpf_slow_path_byte_neg: + lis r_scratch1,-32 /* SKF_LL_OFF */ + cmpd r_addr, r_scratch1 /* addr < SKF_* */ + blt bpf_error /* cr0 = LT */ + .globl sk_load_byte_negative_offset +sk_load_byte_negative_offset: + sk_negative_common(1) + lbz r_A, 0(r_addr) + blr + +bpf_slow_path_byte_msh_neg: + lis r_scratch1,-32 /* SKF_LL_OFF */ + cmpd r_addr, r_scratch1 /* addr < SKF_* */ + blt bpf_error /* cr0 = LT */ + .globl sk_load_byte_msh_negative_offset +sk_load_byte_msh_negative_offset: + sk_negative_common(1) + lbz r_X, 0(r_addr) + rlwinm r_X, r_X, 2, 32-4-2, 31-2 + blr + +bpf_error_slow: + /* fabricate a cr0 = lt */ + li r_scratch1, -1 + cmpdi r_scratch1, 0 +bpf_error: + /* Entered with cr0 = lt */ + li r3, 0 + /* Generated code will 'blt epilogue', returning 0. */ + blr diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 73619d3aeb6c..2dc8b1484845 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -127,6 +127,9 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) PPC_BLR(); } +#define CHOOSE_LOAD_FUNC(K, func) \ + ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset) + /* Assemble the body code between the prologue & epilogue. */ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image, struct codegen_context *ctx, @@ -391,21 +394,16 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image, /*** Absolute loads from packet header/data ***/ case BPF_S_LD_W_ABS: - func = sk_load_word; + func = CHOOSE_LOAD_FUNC(K, sk_load_word); goto common_load; case BPF_S_LD_H_ABS: - func = sk_load_half; + func = CHOOSE_LOAD_FUNC(K, sk_load_half); goto common_load; case BPF_S_LD_B_ABS: - func = sk_load_byte; + func = CHOOSE_LOAD_FUNC(K, sk_load_byte); common_load: - /* - * Load from [K]. Reference with the (negative) - * SKF_NET_OFF/SKF_LL_OFF offsets is unsupported. - */ + /* Load from [K]. */ ctx->seen |= SEEN_DATAREF; - if ((int)K < 0) - return -ENOTSUPP; PPC_LI64(r_scratch1, func); PPC_MTLR(r_scratch1); PPC_LI32(r_addr, K); @@ -429,7 +427,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image, common_load_ind: /* * Load from [X + K]. Negative offsets are tested for - * in the helper functions, and result in a 'ret 0'. + * in the helper functions. */ ctx->seen |= SEEN_DATAREF | SEEN_XREG; PPC_LI64(r_scratch1, func); @@ -443,13 +441,7 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image, break; case BPF_S_LDX_B_MSH: - /* - * x86 version drops packet (RET 0) when K<0, whereas - * interpreter does allow K<0 (__load_pointer, special - * ancillary data). common_load returns ENOTSUPP if K<0, - * so we fall back to interpreter & filter works. - */ - func = sk_load_byte_msh; + func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh); goto common_load; break;