695 lines
18 KiB
C
695 lines
18 KiB
C
![]() |
/* bpf_jit_comp.c: BPF JIT compiler for PPC64
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*
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* Copyright 2011 Matt Evans <matt@ozlabs.org>, IBM Corporation
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*
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* Based on the x86 BPF compiler, by Eric Dumazet (eric.dumazet@gmail.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/moduleloader.h>
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#include <asm/cacheflush.h>
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#include <linux/netdevice.h>
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#include <linux/filter.h>
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#include "bpf_jit.h"
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#ifndef __BIG_ENDIAN
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/* There are endianness assumptions herein. */
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#error "Little-endian PPC not supported in BPF compiler"
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#endif
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int bpf_jit_enable __read_mostly;
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static inline void bpf_flush_icache(void *start, void *end)
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{
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smp_wmb();
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flush_icache_range((unsigned long)start, (unsigned long)end);
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}
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static void bpf_jit_build_prologue(struct sk_filter *fp, u32 *image,
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struct codegen_context *ctx)
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{
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int i;
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const struct sock_filter *filter = fp->insns;
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if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
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/* Make stackframe */
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if (ctx->seen & SEEN_DATAREF) {
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/* If we call any helpers (for loads), save LR */
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EMIT(PPC_INST_MFLR | __PPC_RT(0));
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PPC_STD(0, 1, 16);
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/* Back up non-volatile regs. */
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PPC_STD(r_D, 1, -(8*(32-r_D)));
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PPC_STD(r_HL, 1, -(8*(32-r_HL)));
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}
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if (ctx->seen & SEEN_MEM) {
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/*
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* Conditionally save regs r15-r31 as some will be used
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* for M[] data.
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*/
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for (i = r_M; i < (r_M+16); i++) {
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if (ctx->seen & (1 << (i-r_M)))
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PPC_STD(i, 1, -(8*(32-i)));
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}
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}
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EMIT(PPC_INST_STDU | __PPC_RS(1) | __PPC_RA(1) |
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(-BPF_PPC_STACKFRAME & 0xfffc));
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}
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if (ctx->seen & SEEN_DATAREF) {
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/*
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* If this filter needs to access skb data,
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* prepare r_D and r_HL:
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* r_HL = skb->len - skb->data_len
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* r_D = skb->data
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*/
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PPC_LWZ_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
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data_len));
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PPC_LWZ_OFFS(r_HL, r_skb, offsetof(struct sk_buff, len));
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PPC_SUB(r_HL, r_HL, r_scratch1);
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PPC_LD_OFFS(r_D, r_skb, offsetof(struct sk_buff, data));
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}
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if (ctx->seen & SEEN_XREG) {
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/*
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* TODO: Could also detect whether first instr. sets X and
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* avoid this (as below, with A).
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*/
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PPC_LI(r_X, 0);
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}
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switch (filter[0].code) {
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case BPF_S_RET_K:
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case BPF_S_LD_W_LEN:
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case BPF_S_ANC_PROTOCOL:
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case BPF_S_ANC_IFINDEX:
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case BPF_S_ANC_MARK:
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case BPF_S_ANC_RXHASH:
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case BPF_S_ANC_CPU:
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case BPF_S_ANC_QUEUE:
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case BPF_S_LD_W_ABS:
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case BPF_S_LD_H_ABS:
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case BPF_S_LD_B_ABS:
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/* first instruction sets A register (or is RET 'constant') */
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break;
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default:
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/* make sure we dont leak kernel information to user */
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PPC_LI(r_A, 0);
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}
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}
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static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
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{
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int i;
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if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
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PPC_ADDI(1, 1, BPF_PPC_STACKFRAME);
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if (ctx->seen & SEEN_DATAREF) {
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PPC_LD(0, 1, 16);
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PPC_MTLR(0);
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PPC_LD(r_D, 1, -(8*(32-r_D)));
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PPC_LD(r_HL, 1, -(8*(32-r_HL)));
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}
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if (ctx->seen & SEEN_MEM) {
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/* Restore any saved non-vol registers */
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for (i = r_M; i < (r_M+16); i++) {
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if (ctx->seen & (1 << (i-r_M)))
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PPC_LD(i, 1, -(8*(32-i)));
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}
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}
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}
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/* The RETs have left a return value in R3. */
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PPC_BLR();
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}
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/* Assemble the body code between the prologue & epilogue. */
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static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
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struct codegen_context *ctx,
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unsigned int *addrs)
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{
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const struct sock_filter *filter = fp->insns;
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int flen = fp->len;
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u8 *func;
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unsigned int true_cond;
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int i;
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/* Start of epilogue code */
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unsigned int exit_addr = addrs[flen];
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for (i = 0; i < flen; i++) {
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unsigned int K = filter[i].k;
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/*
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* addrs[] maps a BPF bytecode address into a real offset from
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* the start of the body code.
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*/
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addrs[i] = ctx->idx * 4;
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switch (filter[i].code) {
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/*** ALU ops ***/
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case BPF_S_ALU_ADD_X: /* A += X; */
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ctx->seen |= SEEN_XREG;
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PPC_ADD(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_ADD_K: /* A += K; */
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if (!K)
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break;
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PPC_ADDI(r_A, r_A, IMM_L(K));
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if (K >= 32768)
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PPC_ADDIS(r_A, r_A, IMM_HA(K));
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break;
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case BPF_S_ALU_SUB_X: /* A -= X; */
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ctx->seen |= SEEN_XREG;
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PPC_SUB(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_SUB_K: /* A -= K */
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if (!K)
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break;
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PPC_ADDI(r_A, r_A, IMM_L(-K));
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if (K >= 32768)
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PPC_ADDIS(r_A, r_A, IMM_HA(-K));
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break;
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case BPF_S_ALU_MUL_X: /* A *= X; */
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ctx->seen |= SEEN_XREG;
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PPC_MUL(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_MUL_K: /* A *= K */
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if (K < 32768)
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PPC_MULI(r_A, r_A, K);
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else {
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PPC_LI32(r_scratch1, K);
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PPC_MUL(r_A, r_A, r_scratch1);
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}
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break;
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case BPF_S_ALU_DIV_X: /* A /= X; */
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ctx->seen |= SEEN_XREG;
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PPC_CMPWI(r_X, 0);
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if (ctx->pc_ret0 != -1) {
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PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
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} else {
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/*
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* Exit, returning 0; first pass hits here
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* (longer worst-case code size).
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*/
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PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
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PPC_LI(r_ret, 0);
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PPC_JMP(exit_addr);
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}
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PPC_DIVWU(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K); */
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PPC_LI32(r_scratch1, K);
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/* Top 32 bits of 64bit result -> A */
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PPC_MULHWU(r_A, r_A, r_scratch1);
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break;
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case BPF_S_ALU_AND_X:
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ctx->seen |= SEEN_XREG;
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PPC_AND(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_AND_K:
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if (!IMM_H(K))
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PPC_ANDI(r_A, r_A, K);
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else {
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PPC_LI32(r_scratch1, K);
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PPC_AND(r_A, r_A, r_scratch1);
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}
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break;
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case BPF_S_ALU_OR_X:
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ctx->seen |= SEEN_XREG;
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PPC_OR(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_OR_K:
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if (IMM_L(K))
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PPC_ORI(r_A, r_A, IMM_L(K));
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if (K >= 65536)
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PPC_ORIS(r_A, r_A, IMM_H(K));
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break;
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case BPF_S_ALU_LSH_X: /* A <<= X; */
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ctx->seen |= SEEN_XREG;
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PPC_SLW(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_LSH_K:
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if (K == 0)
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break;
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else
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PPC_SLWI(r_A, r_A, K);
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break;
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case BPF_S_ALU_RSH_X: /* A >>= X; */
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ctx->seen |= SEEN_XREG;
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PPC_SRW(r_A, r_A, r_X);
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break;
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case BPF_S_ALU_RSH_K: /* A >>= K; */
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if (K == 0)
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break;
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else
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PPC_SRWI(r_A, r_A, K);
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break;
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case BPF_S_ALU_NEG:
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PPC_NEG(r_A, r_A);
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break;
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case BPF_S_RET_K:
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PPC_LI32(r_ret, K);
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if (!K) {
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if (ctx->pc_ret0 == -1)
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ctx->pc_ret0 = i;
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}
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/*
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* If this isn't the very last instruction, branch to
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* the epilogue if we've stuff to clean up. Otherwise,
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* if there's nothing to tidy, just return. If we /are/
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* the last instruction, we're about to fall through to
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* the epilogue to return.
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*/
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if (i != flen - 1) {
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/*
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* Note: 'seen' is properly valid only on pass
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* #2. Both parts of this conditional are the
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* same instruction size though, meaning the
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* first pass will still correctly determine the
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* code size/addresses.
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*/
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if (ctx->seen)
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PPC_JMP(exit_addr);
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else
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PPC_BLR();
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}
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break;
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case BPF_S_RET_A:
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PPC_MR(r_ret, r_A);
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if (i != flen - 1) {
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if (ctx->seen)
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PPC_JMP(exit_addr);
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else
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PPC_BLR();
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}
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break;
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case BPF_S_MISC_TAX: /* X = A */
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PPC_MR(r_X, r_A);
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break;
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case BPF_S_MISC_TXA: /* A = X */
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ctx->seen |= SEEN_XREG;
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PPC_MR(r_A, r_X);
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break;
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/*** Constant loads/M[] access ***/
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case BPF_S_LD_IMM: /* A = K */
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PPC_LI32(r_A, K);
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break;
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case BPF_S_LDX_IMM: /* X = K */
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PPC_LI32(r_X, K);
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break;
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case BPF_S_LD_MEM: /* A = mem[K] */
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PPC_MR(r_A, r_M + (K & 0xf));
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ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
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break;
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case BPF_S_LDX_MEM: /* X = mem[K] */
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PPC_MR(r_X, r_M + (K & 0xf));
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ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
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break;
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case BPF_S_ST: /* mem[K] = A */
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PPC_MR(r_M + (K & 0xf), r_A);
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ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
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break;
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case BPF_S_STX: /* mem[K] = X */
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PPC_MR(r_M + (K & 0xf), r_X);
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ctx->seen |= SEEN_XREG | SEEN_MEM | (1<<(K & 0xf));
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break;
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case BPF_S_LD_W_LEN: /* A = skb->len; */
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
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PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff, len));
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break;
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case BPF_S_LDX_W_LEN: /* X = skb->len; */
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PPC_LWZ_OFFS(r_X, r_skb, offsetof(struct sk_buff, len));
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break;
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/*** Ancillary info loads ***/
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/* None of the BPF_S_ANC* codes appear to be passed by
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* sk_chk_filter(). The interpreter and the x86 BPF
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* compiler implement them so we do too -- they may be
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* planted in future.
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*/
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case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
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protocol) != 2);
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PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
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protocol));
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/* ntohs is a NOP with BE loads. */
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break;
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case BPF_S_ANC_IFINDEX:
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PPC_LD_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
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dev));
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PPC_CMPDI(r_scratch1, 0);
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if (ctx->pc_ret0 != -1) {
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PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
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} else {
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/* Exit, returning 0; first pass hits here. */
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PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
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PPC_LI(r_ret, 0);
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PPC_JMP(exit_addr);
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}
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BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
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ifindex) != 4);
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PPC_LWZ_OFFS(r_A, r_scratch1,
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offsetof(struct net_device, ifindex));
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break;
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case BPF_S_ANC_MARK:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
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PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
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mark));
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break;
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case BPF_S_ANC_RXHASH:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
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PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
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rxhash));
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break;
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case BPF_S_ANC_QUEUE:
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BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
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queue_mapping) != 2);
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PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
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queue_mapping));
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break;
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case BPF_S_ANC_CPU:
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#ifdef CONFIG_SMP
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/*
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* PACA ptr is r13:
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* raw_smp_processor_id() = local_paca->paca_index
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*/
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BUILD_BUG_ON(FIELD_SIZEOF(struct paca_struct,
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paca_index) != 2);
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PPC_LHZ_OFFS(r_A, 13,
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offsetof(struct paca_struct, paca_index));
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#else
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PPC_LI(r_A, 0);
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#endif
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break;
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/*** Absolute loads from packet header/data ***/
|
||
|
case BPF_S_LD_W_ABS:
|
||
|
func = sk_load_word;
|
||
|
goto common_load;
|
||
|
case BPF_S_LD_H_ABS:
|
||
|
func = sk_load_half;
|
||
|
goto common_load;
|
||
|
case BPF_S_LD_B_ABS:
|
||
|
func = sk_load_byte;
|
||
|
common_load:
|
||
|
/*
|
||
|
* Load from [K]. Reference with the (negative)
|
||
|
* SKF_NET_OFF/SKF_LL_OFF offsets is unsupported.
|
||
|
*/
|
||
|
ctx->seen |= SEEN_DATAREF;
|
||
|
if ((int)K < 0)
|
||
|
return -ENOTSUPP;
|
||
|
PPC_LI64(r_scratch1, func);
|
||
|
PPC_MTLR(r_scratch1);
|
||
|
PPC_LI32(r_addr, K);
|
||
|
PPC_BLRL();
|
||
|
/*
|
||
|
* Helper returns 'lt' condition on error, and an
|
||
|
* appropriate return value in r3
|
||
|
*/
|
||
|
PPC_BCC(COND_LT, exit_addr);
|
||
|
break;
|
||
|
|
||
|
/*** Indirect loads from packet header/data ***/
|
||
|
case BPF_S_LD_W_IND:
|
||
|
func = sk_load_word;
|
||
|
goto common_load_ind;
|
||
|
case BPF_S_LD_H_IND:
|
||
|
func = sk_load_half;
|
||
|
goto common_load_ind;
|
||
|
case BPF_S_LD_B_IND:
|
||
|
func = sk_load_byte;
|
||
|
common_load_ind:
|
||
|
/*
|
||
|
* Load from [X + K]. Negative offsets are tested for
|
||
|
* in the helper functions, and result in a 'ret 0'.
|
||
|
*/
|
||
|
ctx->seen |= SEEN_DATAREF | SEEN_XREG;
|
||
|
PPC_LI64(r_scratch1, func);
|
||
|
PPC_MTLR(r_scratch1);
|
||
|
PPC_ADDI(r_addr, r_X, IMM_L(K));
|
||
|
if (K >= 32768)
|
||
|
PPC_ADDIS(r_addr, r_addr, IMM_HA(K));
|
||
|
PPC_BLRL();
|
||
|
/* If error, cr0.LT set */
|
||
|
PPC_BCC(COND_LT, exit_addr);
|
||
|
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;
|
||
|
goto common_load;
|
||
|
break;
|
||
|
|
||
|
/*** Jump and branches ***/
|
||
|
case BPF_S_JMP_JA:
|
||
|
if (K != 0)
|
||
|
PPC_JMP(addrs[i + 1 + K]);
|
||
|
break;
|
||
|
|
||
|
case BPF_S_JMP_JGT_K:
|
||
|
case BPF_S_JMP_JGT_X:
|
||
|
true_cond = COND_GT;
|
||
|
goto cond_branch;
|
||
|
case BPF_S_JMP_JGE_K:
|
||
|
case BPF_S_JMP_JGE_X:
|
||
|
true_cond = COND_GE;
|
||
|
goto cond_branch;
|
||
|
case BPF_S_JMP_JEQ_K:
|
||
|
case BPF_S_JMP_JEQ_X:
|
||
|
true_cond = COND_EQ;
|
||
|
goto cond_branch;
|
||
|
case BPF_S_JMP_JSET_K:
|
||
|
case BPF_S_JMP_JSET_X:
|
||
|
true_cond = COND_NE;
|
||
|
/* Fall through */
|
||
|
cond_branch:
|
||
|
/* same targets, can avoid doing the test :) */
|
||
|
if (filter[i].jt == filter[i].jf) {
|
||
|
if (filter[i].jt > 0)
|
||
|
PPC_JMP(addrs[i + 1 + filter[i].jt]);
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
switch (filter[i].code) {
|
||
|
case BPF_S_JMP_JGT_X:
|
||
|
case BPF_S_JMP_JGE_X:
|
||
|
case BPF_S_JMP_JEQ_X:
|
||
|
ctx->seen |= SEEN_XREG;
|
||
|
PPC_CMPLW(r_A, r_X);
|
||
|
break;
|
||
|
case BPF_S_JMP_JSET_X:
|
||
|
ctx->seen |= SEEN_XREG;
|
||
|
PPC_AND_DOT(r_scratch1, r_A, r_X);
|
||
|
break;
|
||
|
case BPF_S_JMP_JEQ_K:
|
||
|
case BPF_S_JMP_JGT_K:
|
||
|
case BPF_S_JMP_JGE_K:
|
||
|
if (K < 32768)
|
||
|
PPC_CMPLWI(r_A, K);
|
||
|
else {
|
||
|
PPC_LI32(r_scratch1, K);
|
||
|
PPC_CMPLW(r_A, r_scratch1);
|
||
|
}
|
||
|
break;
|
||
|
case BPF_S_JMP_JSET_K:
|
||
|
if (K < 32768)
|
||
|
/* PPC_ANDI is /only/ dot-form */
|
||
|
PPC_ANDI(r_scratch1, r_A, K);
|
||
|
else {
|
||
|
PPC_LI32(r_scratch1, K);
|
||
|
PPC_AND_DOT(r_scratch1, r_A,
|
||
|
r_scratch1);
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
/* Sometimes branches are constructed "backward", with
|
||
|
* the false path being the branch and true path being
|
||
|
* a fallthrough to the next instruction.
|
||
|
*/
|
||
|
if (filter[i].jt == 0)
|
||
|
/* Swap the sense of the branch */
|
||
|
PPC_BCC(true_cond ^ COND_CMP_TRUE,
|
||
|
addrs[i + 1 + filter[i].jf]);
|
||
|
else {
|
||
|
PPC_BCC(true_cond, addrs[i + 1 + filter[i].jt]);
|
||
|
if (filter[i].jf != 0)
|
||
|
PPC_JMP(addrs[i + 1 + filter[i].jf]);
|
||
|
}
|
||
|
break;
|
||
|
default:
|
||
|
/* The filter contains something cruel & unusual.
|
||
|
* We don't handle it, but also there shouldn't be
|
||
|
* anything missing from our list.
|
||
|
*/
|
||
|
if (printk_ratelimit())
|
||
|
pr_err("BPF filter opcode %04x (@%d) unsupported\n",
|
||
|
filter[i].code, i);
|
||
|
return -ENOTSUPP;
|
||
|
}
|
||
|
|
||
|
}
|
||
|
/* Set end-of-body-code address for exit. */
|
||
|
addrs[i] = ctx->idx * 4;
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
void bpf_jit_compile(struct sk_filter *fp)
|
||
|
{
|
||
|
unsigned int proglen;
|
||
|
unsigned int alloclen;
|
||
|
u32 *image = NULL;
|
||
|
u32 *code_base;
|
||
|
unsigned int *addrs;
|
||
|
struct codegen_context cgctx;
|
||
|
int pass;
|
||
|
int flen = fp->len;
|
||
|
|
||
|
if (!bpf_jit_enable)
|
||
|
return;
|
||
|
|
||
|
addrs = kzalloc((flen+1) * sizeof(*addrs), GFP_KERNEL);
|
||
|
if (addrs == NULL)
|
||
|
return;
|
||
|
|
||
|
/*
|
||
|
* There are multiple assembly passes as the generated code will change
|
||
|
* size as it settles down, figuring out the max branch offsets/exit
|
||
|
* paths required.
|
||
|
*
|
||
|
* The range of standard conditional branches is +/- 32Kbytes. Since
|
||
|
* BPF_MAXINSNS = 4096, we can only jump from (worst case) start to
|
||
|
* finish with 8 bytes/instruction. Not feasible, so long jumps are
|
||
|
* used, distinct from short branches.
|
||
|
*
|
||
|
* Current:
|
||
|
*
|
||
|
* For now, both branch types assemble to 2 words (short branches padded
|
||
|
* with a NOP); this is less efficient, but assembly will always complete
|
||
|
* after exactly 3 passes:
|
||
|
*
|
||
|
* First pass: No code buffer; Program is "faux-generated" -- no code
|
||
|
* emitted but maximum size of output determined (and addrs[] filled
|
||
|
* in). Also, we note whether we use M[], whether we use skb data, etc.
|
||
|
* All generation choices assumed to be 'worst-case', e.g. branches all
|
||
|
* far (2 instructions), return path code reduction not available, etc.
|
||
|
*
|
||
|
* Second pass: Code buffer allocated with size determined previously.
|
||
|
* Prologue generated to support features we have seen used. Exit paths
|
||
|
* determined and addrs[] is filled in again, as code may be slightly
|
||
|
* smaller as a result.
|
||
|
*
|
||
|
* Third pass: Code generated 'for real', and branch destinations
|
||
|
* determined from now-accurate addrs[] map.
|
||
|
*
|
||
|
* Ideal:
|
||
|
*
|
||
|
* If we optimise this, near branches will be shorter. On the
|
||
|
* first assembly pass, we should err on the side of caution and
|
||
|
* generate the biggest code. On subsequent passes, branches will be
|
||
|
* generated short or long and code size will reduce. With smaller
|
||
|
* code, more branches may fall into the short category, and code will
|
||
|
* reduce more.
|
||
|
*
|
||
|
* Finally, if we see one pass generate code the same size as the
|
||
|
* previous pass we have converged and should now generate code for
|
||
|
* real. Allocating at the end will also save the memory that would
|
||
|
* otherwise be wasted by the (small) current code shrinkage.
|
||
|
* Preferably, we should do a small number of passes (e.g. 5) and if we
|
||
|
* haven't converged by then, get impatient and force code to generate
|
||
|
* as-is, even if the odd branch would be left long. The chances of a
|
||
|
* long jump are tiny with all but the most enormous of BPF filter
|
||
|
* inputs, so we should usually converge on the third pass.
|
||
|
*/
|
||
|
|
||
|
cgctx.idx = 0;
|
||
|
cgctx.seen = 0;
|
||
|
cgctx.pc_ret0 = -1;
|
||
|
/* Scouting faux-generate pass 0 */
|
||
|
if (bpf_jit_build_body(fp, 0, &cgctx, addrs))
|
||
|
/* We hit something illegal or unsupported. */
|
||
|
goto out;
|
||
|
|
||
|
/*
|
||
|
* Pretend to build prologue, given the features we've seen. This will
|
||
|
* update ctgtx.idx as it pretends to output instructions, then we can
|
||
|
* calculate total size from idx.
|
||
|
*/
|
||
|
bpf_jit_build_prologue(fp, 0, &cgctx);
|
||
|
bpf_jit_build_epilogue(0, &cgctx);
|
||
|
|
||
|
proglen = cgctx.idx * 4;
|
||
|
alloclen = proglen + FUNCTION_DESCR_SIZE;
|
||
|
image = module_alloc(max_t(unsigned int, alloclen,
|
||
|
sizeof(struct work_struct)));
|
||
|
if (!image)
|
||
|
goto out;
|
||
|
|
||
|
code_base = image + (FUNCTION_DESCR_SIZE/4);
|
||
|
|
||
|
/* Code generation passes 1-2 */
|
||
|
for (pass = 1; pass < 3; pass++) {
|
||
|
/* Now build the prologue, body code & epilogue for real. */
|
||
|
cgctx.idx = 0;
|
||
|
bpf_jit_build_prologue(fp, code_base, &cgctx);
|
||
|
bpf_jit_build_body(fp, code_base, &cgctx, addrs);
|
||
|
bpf_jit_build_epilogue(code_base, &cgctx);
|
||
|
|
||
|
if (bpf_jit_enable > 1)
|
||
|
pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass,
|
||
|
proglen - (cgctx.idx * 4), cgctx.seen);
|
||
|
}
|
||
|
|
||
|
if (bpf_jit_enable > 1)
|
||
|
pr_info("flen=%d proglen=%u pass=%d image=%p\n",
|
||
|
flen, proglen, pass, image);
|
||
|
|
||
|
if (image) {
|
||
|
if (bpf_jit_enable > 1)
|
||
|
print_hex_dump(KERN_ERR, "JIT code: ",
|
||
|
DUMP_PREFIX_ADDRESS,
|
||
|
16, 1, code_base,
|
||
|
proglen, false);
|
||
|
|
||
|
bpf_flush_icache(code_base, code_base + (proglen/4));
|
||
|
/* Function descriptor nastiness: Address + TOC */
|
||
|
((u64 *)image)[0] = (u64)code_base;
|
||
|
((u64 *)image)[1] = local_paca->kernel_toc;
|
||
|
fp->bpf_func = (void *)image;
|
||
|
}
|
||
|
out:
|
||
|
kfree(addrs);
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
static void jit_free_defer(struct work_struct *arg)
|
||
|
{
|
||
|
module_free(NULL, arg);
|
||
|
}
|
||
|
|
||
|
/* run from softirq, we must use a work_struct to call
|
||
|
* module_free() from process context
|
||
|
*/
|
||
|
void bpf_jit_free(struct sk_filter *fp)
|
||
|
{
|
||
|
if (fp->bpf_func != sk_run_filter) {
|
||
|
struct work_struct *work = (struct work_struct *)fp->bpf_func;
|
||
|
|
||
|
INIT_WORK(work, jit_free_defer);
|
||
|
schedule_work(work);
|
||
|
}
|
||
|
}
|