diff options
Diffstat (limited to 'arch/powerpc/net/bpf_jit_64.S')
| -rw-r--r-- | arch/powerpc/net/bpf_jit_64.S | 108 |
1 files changed, 95 insertions, 13 deletions
diff --git a/arch/powerpc/net/bpf_jit_64.S b/arch/powerpc/net/bpf_jit_64.S index ff4506e..55ba385 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 |