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Diffstat (limited to 'arch/powerpc/net/bpf_jit.h')
| -rw-r--r-- | arch/powerpc/net/bpf_jit.h | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h new file mode 100644 index 000000000000..af1ab5e9a691 --- /dev/null +++ b/arch/powerpc/net/bpf_jit.h @@ -0,0 +1,227 @@ +/* bpf_jit.h: BPF JIT compiler for PPC64 + * + * Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#ifndef _BPF_JIT_H +#define _BPF_JIT_H + +#define BPF_PPC_STACK_LOCALS 32 +#define BPF_PPC_STACK_BASIC (48+64) +#define BPF_PPC_STACK_SAVE (18*8) +#define BPF_PPC_STACKFRAME (BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \ + BPF_PPC_STACK_SAVE) +#define BPF_PPC_SLOWPATH_FRAME (48+64) + +/* + * Generated code register usage: + * + * As normal PPC C ABI (e.g. r1=sp, r2=TOC), with: + * + * skb r3 (Entry parameter) + * A register r4 + * X register r5 + * addr param r6 + * r7-r10 scratch + * skb->data r14 + * skb headlen r15 (skb->len - skb->data_len) + * m[0] r16 + * m[...] ... + * m[15] r31 + */ +#define r_skb 3 +#define r_ret 3 +#define r_A 4 +#define r_X 5 +#define r_addr 6 +#define r_scratch1 7 +#define r_D 14 +#define r_HL 15 +#define r_M 16 + +#ifndef __ASSEMBLY__ + +/* + * 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 FUNCTION_DESCR_SIZE 24 + +/* + * 16-bit immediate helper macros: HA() is for use with sign-extending instrs + * (e.g. LD, ADDI). If the bottom 16 bits is "-ve", add another bit into the + * top half to negate the effect (i.e. 0xffff + 1 = 0x(1)0000). + */ +#define IMM_H(i) ((uintptr_t)(i)>>16) +#define IMM_HA(i) (((uintptr_t)(i)>>16) + \ + (((uintptr_t)(i) & 0x8000) >> 15)) +#define IMM_L(i) ((uintptr_t)(i) & 0xffff) + +#define PLANT_INSTR(d, idx, instr) \ + do { if (d) { (d)[idx] = instr; } idx++; } while (0) +#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr) + +#define PPC_NOP() EMIT(PPC_INST_NOP) +#define PPC_BLR() EMIT(PPC_INST_BLR) +#define PPC_BLRL() EMIT(PPC_INST_BLRL) +#define PPC_MTLR(r) EMIT(PPC_INST_MTLR | __PPC_RT(r)) +#define PPC_ADDI(d, a, i) EMIT(PPC_INST_ADDI | __PPC_RT(d) | \ + __PPC_RA(a) | IMM_L(i)) +#define PPC_MR(d, a) PPC_OR(d, a, a) +#define PPC_LI(r, i) PPC_ADDI(r, 0, i) +#define PPC_ADDIS(d, a, i) EMIT(PPC_INST_ADDIS | \ + __PPC_RS(d) | __PPC_RA(a) | IMM_L(i)) +#define PPC_LIS(r, i) PPC_ADDIS(r, 0, i) +#define PPC_STD(r, base, i) EMIT(PPC_INST_STD | __PPC_RS(r) | \ + __PPC_RA(base) | ((i) & 0xfffc)) + +#define PPC_LD(r, base, i) EMIT(PPC_INST_LD | __PPC_RT(r) | \ + __PPC_RA(base) | IMM_L(i)) +#define PPC_LWZ(r, base, i) EMIT(PPC_INST_LWZ | __PPC_RT(r) | \ + __PPC_RA(base) | IMM_L(i)) +#define PPC_LHZ(r, base, i) EMIT(PPC_INST_LHZ | __PPC_RT(r) | \ + __PPC_RA(base) | IMM_L(i)) +/* Convenience helpers for the above with 'far' offsets: */ +#define PPC_LD_OFFS(r, base, i) do { if ((i) < 32768) PPC_LD(r, base, i); \ + else { PPC_ADDIS(r, base, IMM_HA(i)); \ + PPC_LD(r, r, IMM_L(i)); } } while(0) + +#define PPC_LWZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LWZ(r, base, i); \ + else { PPC_ADDIS(r, base, IMM_HA(i)); \ + PPC_LWZ(r, r, IMM_L(i)); } } while(0) + +#define PPC_LHZ_OFFS(r, base, i) do { if ((i) < 32768) PPC_LHZ(r, base, i); \ + else { PPC_ADDIS(r, base, IMM_HA(i)); \ + PPC_LHZ(r, r, IMM_L(i)); } } while(0) + +#define PPC_CMPWI(a, i) EMIT(PPC_INST_CMPWI | __PPC_RA(a) | IMM_L(i)) +#define PPC_CMPDI(a, i) EMIT(PPC_INST_CMPDI | __PPC_RA(a) | IMM_L(i)) +#define PPC_CMPLWI(a, i) EMIT(PPC_INST_CMPLWI | __PPC_RA(a) | IMM_L(i)) +#define PPC_CMPLW(a, b) EMIT(PPC_INST_CMPLW | __PPC_RA(a) | __PPC_RB(b)) + +#define PPC_SUB(d, a, b) EMIT(PPC_INST_SUB | __PPC_RT(d) | \ + __PPC_RB(a) | __PPC_RA(b)) +#define PPC_ADD(d, a, b) EMIT(PPC_INST_ADD | __PPC_RT(d) | \ + __PPC_RA(a) | __PPC_RB(b)) +#define PPC_MUL(d, a, b) EMIT(PPC_INST_MULLW | __PPC_RT(d) | \ + __PPC_RA(a) | __PPC_RB(b)) +#define PPC_MULHWU(d, a, b) EMIT(PPC_INST_MULHWU | __PPC_RT(d) | \ + __PPC_RA(a) | __PPC_RB(b)) +#define PPC_MULI(d, a, i) EMIT(PPC_INST_MULLI | __PPC_RT(d) | \ + __PPC_RA(a) | IMM_L(i)) +#define PPC_DIVWU(d, a, b) EMIT(PPC_INST_DIVWU | __PPC_RT(d) | \ + __PPC_RA(a) | __PPC_RB(b)) +#define PPC_AND(d, a, b) EMIT(PPC_INST_AND | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_RB(b)) +#define PPC_ANDI(d, a, i) EMIT(PPC_INST_ANDI | __PPC_RA(d) | \ + __PPC_RS(a) | IMM_L(i)) +#define PPC_AND_DOT(d, a, b) EMIT(PPC_INST_ANDDOT | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_RB(b)) +#define PPC_OR(d, a, b) EMIT(PPC_INST_OR | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_RB(b)) +#define PPC_ORI(d, a, i) EMIT(PPC_INST_ORI | __PPC_RA(d) | \ + __PPC_RS(a) | IMM_L(i)) +#define PPC_ORIS(d, a, i) EMIT(PPC_INST_ORIS | __PPC_RA(d) | \ + __PPC_RS(a) | IMM_L(i)) +#define PPC_SLW(d, a, s) EMIT(PPC_INST_SLW | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_RB(s)) +#define PPC_SRW(d, a, s) EMIT(PPC_INST_SRW | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_RB(s)) +/* slwi = rlwinm Rx, Ry, n, 0, 31-n */ +#define PPC_SLWI(d, a, i) EMIT(PPC_INST_RLWINM | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_SH(i) | \ + __PPC_MB(0) | __PPC_ME(31-(i))) +/* srwi = rlwinm Rx, Ry, 32-n, n, 31 */ +#define PPC_SRWI(d, a, i) EMIT(PPC_INST_RLWINM | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_SH(32-(i)) | \ + __PPC_MB(i) | __PPC_ME(31)) +/* sldi = rldicr Rx, Ry, n, 63-n */ +#define PPC_SLDI(d, a, i) EMIT(PPC_INST_RLDICR | __PPC_RA(d) | \ + __PPC_RS(a) | __PPC_SH(i) | \ + __PPC_MB(63-(i)) | (((i) & 0x20) >> 4)) +#define PPC_NEG(d, a) EMIT(PPC_INST_NEG | __PPC_RT(d) | __PPC_RA(a)) + +/* Long jump; (unconditional 'branch') */ +#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \ + (((dest) - (ctx->idx * 4)) & 0x03fffffc)) +/* "cond" here covers BO:BI fields. */ +#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \ + (((cond) & 0x3ff) << 16) | \ + (((dest) - (ctx->idx * 4)) & \ + 0xfffc)) +#define PPC_LI32(d, i) do { PPC_LI(d, IMM_L(i)); \ + if ((u32)(uintptr_t)(i) >= 32768) { \ + PPC_ADDIS(d, d, IMM_HA(i)); \ + } } while(0) +#define PPC_LI64(d, i) do { \ + if (!((uintptr_t)(i) & 0xffffffff00000000ULL)) \ + PPC_LI32(d, i); \ + else { \ + PPC_LIS(d, ((uintptr_t)(i) >> 48)); \ + if ((uintptr_t)(i) & 0x0000ffff00000000ULL) \ + PPC_ORI(d, d, \ + ((uintptr_t)(i) >> 32) & 0xffff); \ + PPC_SLDI(d, d, 32); \ + if ((uintptr_t)(i) & 0x00000000ffff0000ULL) \ + PPC_ORIS(d, d, \ + ((uintptr_t)(i) >> 16) & 0xffff); \ + if ((uintptr_t)(i) & 0x000000000000ffffULL) \ + PPC_ORI(d, d, (uintptr_t)(i) & 0xffff); \ + } } while (0); + +static inline bool is_nearbranch(int offset) +{ + return (offset < 32768) && (offset >= -32768); +} + +/* + * The fly in the ointment of code size changing from pass to pass is + * avoided by padding the short branch case with a NOP. If code size differs + * with different branch reaches we will have the issue of code moving from + * one pass to the next and will need a few passes to converge on a stable + * state. + */ +#define PPC_BCC(cond, dest) do { \ + if (is_nearbranch((dest) - (ctx->idx * 4))) { \ + PPC_BCC_SHORT(cond, dest); \ + PPC_NOP(); \ + } else { \ + /* Flip the 'T or F' bit to invert comparison */ \ + PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, (ctx->idx+2)*4); \ + PPC_JMP(dest); \ + } } while(0) + +/* To create a branch condition, select a bit of cr0... */ +#define CR0_LT 0 +#define CR0_GT 1 +#define CR0_EQ 2 +/* ...and modify BO[3] */ +#define COND_CMP_TRUE 0x100 +#define COND_CMP_FALSE 0x000 +/* Together, they make all required comparisons: */ +#define COND_GT (CR0_GT | COND_CMP_TRUE) +#define COND_GE (CR0_LT | COND_CMP_FALSE) +#define COND_EQ (CR0_EQ | COND_CMP_TRUE) +#define COND_NE (CR0_EQ | COND_CMP_FALSE) +#define COND_LT (CR0_LT | COND_CMP_TRUE) + +#define SEEN_DATAREF 0x10000 /* might call external helpers */ +#define SEEN_XREG 0x20000 /* X reg is used */ +#define SEEN_MEM 0x40000 /* SEEN_MEM+(1<<n) = use mem[n] for temporary + * storage */ +#define SEEN_MEM_MSK 0x0ffff + +struct codegen_context { + unsigned int seen; + unsigned int idx; + int pc_ret0; /* bpf index of first RET #0 instruction (if any) */ +}; + +#endif + +#endif |