mirror of https://gitee.com/openkylin/linux.git
888 lines
23 KiB
C
888 lines
23 KiB
C
/*
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* BPF Jit compiler for s390.
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*
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* Copyright IBM Corp. 2012
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*
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#include <linux/moduleloader.h>
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#include <linux/netdevice.h>
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#include <linux/if_vlan.h>
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#include <linux/filter.h>
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#include <linux/random.h>
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#include <linux/init.h>
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#include <asm/cacheflush.h>
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#include <asm/processor.h>
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#include <asm/facility.h>
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/*
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* Conventions:
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* %r2 = skb pointer
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* %r3 = offset parameter
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* %r4 = scratch register / length parameter
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* %r5 = BPF A accumulator
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* %r8 = return address
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* %r9 = save register for skb pointer
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* %r10 = skb->data
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* %r11 = skb->len - skb->data_len (headlen)
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* %r12 = BPF X accumulator
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* %r13 = literal pool pointer
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* 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
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*/
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int bpf_jit_enable __read_mostly;
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/*
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* assembly code in arch/x86/net/bpf_jit.S
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*/
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extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
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extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
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struct bpf_jit {
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unsigned int seen;
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u8 *start;
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u8 *prg;
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u8 *mid;
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u8 *lit;
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u8 *end;
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u8 *base_ip;
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u8 *ret0_ip;
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u8 *exit_ip;
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unsigned int off_load_word;
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unsigned int off_load_half;
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unsigned int off_load_byte;
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unsigned int off_load_bmsh;
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unsigned int off_load_iword;
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unsigned int off_load_ihalf;
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unsigned int off_load_ibyte;
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};
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#define BPF_SIZE_MAX 4096 /* Max size for program */
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#define SEEN_DATAREF 1 /* might call external helpers */
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#define SEEN_XREG 2 /* ebx is used */
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#define SEEN_MEM 4 /* use mem[] for temporary storage */
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#define SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */
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#define SEEN_LITERAL 16 /* code uses literals */
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#define SEEN_LOAD_WORD 32 /* code uses sk_load_word */
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#define SEEN_LOAD_HALF 64 /* code uses sk_load_half */
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#define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */
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#define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */
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#define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */
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#define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */
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#define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */
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#define EMIT2(op) \
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({ \
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if (jit->prg + 2 <= jit->mid) \
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*(u16 *) jit->prg = op; \
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jit->prg += 2; \
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})
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#define EMIT4(op) \
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({ \
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if (jit->prg + 4 <= jit->mid) \
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*(u32 *) jit->prg = op; \
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jit->prg += 4; \
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})
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#define EMIT4_DISP(op, disp) \
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({ \
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unsigned int __disp = (disp) & 0xfff; \
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EMIT4(op | __disp); \
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})
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#define EMIT4_IMM(op, imm) \
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({ \
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unsigned int __imm = (imm) & 0xffff; \
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EMIT4(op | __imm); \
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})
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#define EMIT4_PCREL(op, pcrel) \
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({ \
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long __pcrel = ((pcrel) >> 1) & 0xffff; \
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EMIT4(op | __pcrel); \
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})
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#define EMIT6(op1, op2) \
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({ \
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if (jit->prg + 6 <= jit->mid) { \
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*(u32 *) jit->prg = op1; \
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*(u16 *) (jit->prg + 4) = op2; \
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} \
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jit->prg += 6; \
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})
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#define EMIT6_DISP(op1, op2, disp) \
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({ \
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unsigned int __disp = (disp) & 0xfff; \
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EMIT6(op1 | __disp, op2); \
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})
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#define EMIT6_IMM(op, imm) \
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({ \
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unsigned int __imm = (imm); \
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EMIT6(op | (__imm >> 16), __imm & 0xffff); \
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})
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#define EMIT_CONST(val) \
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({ \
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unsigned int ret; \
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ret = (unsigned int) (jit->lit - jit->base_ip); \
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jit->seen |= SEEN_LITERAL; \
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if (jit->lit + 4 <= jit->end) \
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*(u32 *) jit->lit = val; \
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jit->lit += 4; \
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ret; \
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})
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#define EMIT_FN_CONST(bit, fn) \
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({ \
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unsigned int ret; \
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ret = (unsigned int) (jit->lit - jit->base_ip); \
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if (jit->seen & bit) { \
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jit->seen |= SEEN_LITERAL; \
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if (jit->lit + 8 <= jit->end) \
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*(void **) jit->lit = fn; \
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jit->lit += 8; \
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} \
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ret; \
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})
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static void bpf_jit_prologue(struct bpf_jit *jit)
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{
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/* Save registers and create stack frame if necessary */
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if (jit->seen & SEEN_DATAREF) {
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/* stmg %r8,%r15,88(%r15) */
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EMIT6(0xeb8ff058, 0x0024);
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/* lgr %r14,%r15 */
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EMIT4(0xb90400ef);
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/* ahi %r15,<offset> */
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EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80);
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/* stg %r14,152(%r15) */
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EMIT6(0xe3e0f098, 0x0024);
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} else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
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/* stmg %r12,%r13,120(%r15) */
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EMIT6(0xebcdf078, 0x0024);
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else if (jit->seen & SEEN_XREG)
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/* stg %r12,120(%r15) */
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EMIT6(0xe3c0f078, 0x0024);
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else if (jit->seen & SEEN_LITERAL)
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/* stg %r13,128(%r15) */
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EMIT6(0xe3d0f080, 0x0024);
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/* Setup literal pool */
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if (jit->seen & SEEN_LITERAL) {
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/* basr %r13,0 */
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EMIT2(0x0dd0);
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jit->base_ip = jit->prg;
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}
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jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
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jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
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jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
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jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
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jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
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jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
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jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
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/* Filter needs to access skb data */
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if (jit->seen & SEEN_DATAREF) {
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/* l %r11,<len>(%r2) */
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EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
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/* s %r11,<data_len>(%r2) */
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EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
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/* lg %r10,<data>(%r2) */
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EMIT6_DISP(0xe3a02000, 0x0004,
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offsetof(struct sk_buff, data));
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}
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}
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static void bpf_jit_epilogue(struct bpf_jit *jit)
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{
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/* Return 0 */
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if (jit->seen & SEEN_RET0) {
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jit->ret0_ip = jit->prg;
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/* lghi %r2,0 */
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EMIT4(0xa7290000);
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}
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jit->exit_ip = jit->prg;
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/* Restore registers */
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if (jit->seen & SEEN_DATAREF)
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/* lmg %r8,%r15,<offset>(%r15) */
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EMIT6_DISP(0xeb8ff000, 0x0004,
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(jit->seen & SEEN_MEM) ? 200 : 168);
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else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
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/* lmg %r12,%r13,120(%r15) */
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EMIT6(0xebcdf078, 0x0004);
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else if (jit->seen & SEEN_XREG)
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/* lg %r12,120(%r15) */
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EMIT6(0xe3c0f078, 0x0004);
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else if (jit->seen & SEEN_LITERAL)
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/* lg %r13,128(%r15) */
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EMIT6(0xe3d0f080, 0x0004);
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/* br %r14 */
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EMIT2(0x07fe);
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}
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/* Helper to find the offset of pkt_type in sk_buff
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* Make sure its still a 3bit field starting at the MSBs within a byte.
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*/
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#define PKT_TYPE_MAX 0xe0
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static int pkt_type_offset;
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static int __init bpf_pkt_type_offset_init(void)
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{
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struct sk_buff skb_probe = {
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.pkt_type = ~0,
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};
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char *ct = (char *)&skb_probe;
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int off;
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pkt_type_offset = -1;
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for (off = 0; off < sizeof(struct sk_buff); off++) {
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if (!ct[off])
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continue;
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if (ct[off] == PKT_TYPE_MAX)
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pkt_type_offset = off;
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else {
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/* Found non matching bit pattern, fix needed. */
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WARN_ON_ONCE(1);
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pkt_type_offset = -1;
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return -1;
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}
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}
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return 0;
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}
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device_initcall(bpf_pkt_type_offset_init);
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/*
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* make sure we dont leak kernel information to user
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*/
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static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
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{
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/* Clear temporary memory if (seen & SEEN_MEM) */
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if (jit->seen & SEEN_MEM)
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/* xc 0(64,%r15),0(%r15) */
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EMIT6(0xd73ff000, 0xf000);
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/* Clear X if (seen & SEEN_XREG) */
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if (jit->seen & SEEN_XREG)
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/* lhi %r12,0 */
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EMIT4(0xa7c80000);
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/* Clear A if the first register does not set it. */
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switch (filter[0].code) {
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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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case BPF_S_LD_W_LEN:
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case BPF_S_LD_W_IND:
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case BPF_S_LD_H_IND:
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case BPF_S_LD_B_IND:
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case BPF_S_LDX_B_MSH:
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case BPF_S_LD_IMM:
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case BPF_S_LD_MEM:
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case BPF_S_MISC_TXA:
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case BPF_S_ANC_PROTOCOL:
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case BPF_S_ANC_PKTTYPE:
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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_QUEUE:
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case BPF_S_ANC_HATYPE:
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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_VLAN_TAG:
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case BPF_S_ANC_VLAN_TAG_PRESENT:
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case BPF_S_RET_K:
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/* first instruction sets A register */
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break;
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default: /* A = 0 */
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/* lhi %r5,0 */
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EMIT4(0xa7580000);
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}
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}
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static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
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unsigned int *addrs, int i, int last)
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{
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unsigned int K;
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int offset;
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unsigned int mask;
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K = filter->k;
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switch (filter->code) {
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case BPF_S_ALU_ADD_X: /* A += X */
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jit->seen |= SEEN_XREG;
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/* ar %r5,%r12 */
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EMIT2(0x1a5c);
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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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if (K <= 16383)
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/* ahi %r5,<K> */
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EMIT4_IMM(0xa75a0000, K);
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else if (test_facility(21))
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/* alfi %r5,<K> */
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EMIT6_IMM(0xc25b0000, K);
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else
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/* a %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
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break;
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case BPF_S_ALU_SUB_X: /* A -= X */
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jit->seen |= SEEN_XREG;
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/* sr %r5,%r12 */
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EMIT2(0x1b5c);
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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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if (K <= 16384)
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/* ahi %r5,-K */
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EMIT4_IMM(0xa75a0000, -K);
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else if (test_facility(21))
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/* alfi %r5,-K */
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EMIT6_IMM(0xc25b0000, -K);
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else
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/* s %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
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break;
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case BPF_S_ALU_MUL_X: /* A *= X */
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jit->seen |= SEEN_XREG;
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/* msr %r5,%r12 */
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EMIT4(0xb252005c);
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break;
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case BPF_S_ALU_MUL_K: /* A *= K */
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if (K <= 16383)
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/* mhi %r5,K */
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EMIT4_IMM(0xa75c0000, K);
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else if (test_facility(34))
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/* msfi %r5,<K> */
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EMIT6_IMM(0xc2510000, K);
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else
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/* ms %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x7150d000, EMIT_CONST(K));
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break;
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case BPF_S_ALU_DIV_X: /* A /= X */
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jit->seen |= SEEN_XREG | SEEN_RET0;
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/* ltr %r12,%r12 */
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EMIT2(0x12cc);
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/* jz <ret0> */
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EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
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/* lhi %r4,0 */
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EMIT4(0xa7480000);
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/* dr %r4,%r12 */
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EMIT2(0x1d4c);
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break;
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case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
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/* m %r4,<d(K)>(%r13) */
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EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
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/* lr %r5,%r4 */
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EMIT2(0x1854);
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break;
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case BPF_S_ALU_MOD_X: /* A %= X */
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jit->seen |= SEEN_XREG | SEEN_RET0;
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/* ltr %r12,%r12 */
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EMIT2(0x12cc);
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/* jz <ret0> */
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EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
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/* lhi %r4,0 */
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EMIT4(0xa7480000);
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/* dr %r4,%r12 */
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EMIT2(0x1d4c);
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/* lr %r5,%r4 */
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EMIT2(0x1854);
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break;
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case BPF_S_ALU_MOD_K: /* A %= K */
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/* lhi %r4,0 */
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EMIT4(0xa7480000);
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/* d %r4,<d(K)>(%r13) */
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EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
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/* lr %r5,%r4 */
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EMIT2(0x1854);
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break;
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case BPF_S_ALU_AND_X: /* A &= X */
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jit->seen |= SEEN_XREG;
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/* nr %r5,%r12 */
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EMIT2(0x145c);
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break;
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case BPF_S_ALU_AND_K: /* A &= K */
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if (test_facility(21))
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/* nilf %r5,<K> */
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EMIT6_IMM(0xc05b0000, K);
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else
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/* n %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x5450d000, EMIT_CONST(K));
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break;
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case BPF_S_ALU_OR_X: /* A |= X */
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jit->seen |= SEEN_XREG;
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/* or %r5,%r12 */
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EMIT2(0x165c);
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break;
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case BPF_S_ALU_OR_K: /* A |= K */
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if (test_facility(21))
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/* oilf %r5,<K> */
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EMIT6_IMM(0xc05d0000, K);
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else
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/* o %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x5650d000, EMIT_CONST(K));
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break;
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case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
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case BPF_S_ALU_XOR_X:
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jit->seen |= SEEN_XREG;
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/* xr %r5,%r12 */
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EMIT2(0x175c);
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break;
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case BPF_S_ALU_XOR_K: /* A ^= K */
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if (!K)
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break;
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/* x %r5,<d(K)>(%r13) */
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EMIT4_DISP(0x5750d000, EMIT_CONST(K));
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break;
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case BPF_S_ALU_LSH_X: /* A <<= X; */
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jit->seen |= SEEN_XREG;
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/* sll %r5,0(%r12) */
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EMIT4(0x8950c000);
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break;
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case BPF_S_ALU_LSH_K: /* A <<= K */
|
|
if (K == 0)
|
|
break;
|
|
/* sll %r5,K */
|
|
EMIT4_DISP(0x89500000, K);
|
|
break;
|
|
case BPF_S_ALU_RSH_X: /* A >>= X; */
|
|
jit->seen |= SEEN_XREG;
|
|
/* srl %r5,0(%r12) */
|
|
EMIT4(0x8850c000);
|
|
break;
|
|
case BPF_S_ALU_RSH_K: /* A >>= K; */
|
|
if (K == 0)
|
|
break;
|
|
/* srl %r5,K */
|
|
EMIT4_DISP(0x88500000, K);
|
|
break;
|
|
case BPF_S_ALU_NEG: /* A = -A */
|
|
/* lnr %r5,%r5 */
|
|
EMIT2(0x1155);
|
|
break;
|
|
case BPF_S_JMP_JA: /* ip += K */
|
|
offset = addrs[i + K] + jit->start - jit->prg;
|
|
EMIT4_PCREL(0xa7f40000, offset);
|
|
break;
|
|
case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
|
|
mask = 0x200000; /* jh */
|
|
goto kbranch;
|
|
case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
|
|
mask = 0xa00000; /* jhe */
|
|
goto kbranch;
|
|
case BPF_S_JMP_JEQ_K: /* ip += (A == K) ? jt : jf */
|
|
mask = 0x800000; /* je */
|
|
kbranch: /* Emit compare if the branch targets are different */
|
|
if (filter->jt != filter->jf) {
|
|
if (K <= 16383)
|
|
/* chi %r5,<K> */
|
|
EMIT4_IMM(0xa75e0000, K);
|
|
else if (test_facility(21))
|
|
/* clfi %r5,<K> */
|
|
EMIT6_IMM(0xc25f0000, K);
|
|
else
|
|
/* c %r5,<d(K)>(%r13) */
|
|
EMIT4_DISP(0x5950d000, EMIT_CONST(K));
|
|
}
|
|
branch: if (filter->jt == filter->jf) {
|
|
if (filter->jt == 0)
|
|
break;
|
|
/* j <jt> */
|
|
offset = addrs[i + filter->jt] + jit->start - jit->prg;
|
|
EMIT4_PCREL(0xa7f40000, offset);
|
|
break;
|
|
}
|
|
if (filter->jt != 0) {
|
|
/* brc <mask>,<jt> */
|
|
offset = addrs[i + filter->jt] + jit->start - jit->prg;
|
|
EMIT4_PCREL(0xa7040000 | mask, offset);
|
|
}
|
|
if (filter->jf != 0) {
|
|
/* brc <mask^15>,<jf> */
|
|
offset = addrs[i + filter->jf] + jit->start - jit->prg;
|
|
EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
|
|
}
|
|
break;
|
|
case BPF_S_JMP_JSET_K: /* ip += (A & K) ? jt : jf */
|
|
mask = 0x700000; /* jnz */
|
|
/* Emit test if the branch targets are different */
|
|
if (filter->jt != filter->jf) {
|
|
if (K > 65535) {
|
|
/* lr %r4,%r5 */
|
|
EMIT2(0x1845);
|
|
/* n %r4,<d(K)>(%r13) */
|
|
EMIT4_DISP(0x5440d000, EMIT_CONST(K));
|
|
} else
|
|
/* tmll %r5,K */
|
|
EMIT4_IMM(0xa7510000, K);
|
|
}
|
|
goto branch;
|
|
case BPF_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
|
|
mask = 0x200000; /* jh */
|
|
goto xbranch;
|
|
case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
|
|
mask = 0xa00000; /* jhe */
|
|
goto xbranch;
|
|
case BPF_S_JMP_JEQ_X: /* ip += (A == X) ? jt : jf */
|
|
mask = 0x800000; /* je */
|
|
xbranch: /* Emit compare if the branch targets are different */
|
|
if (filter->jt != filter->jf) {
|
|
jit->seen |= SEEN_XREG;
|
|
/* cr %r5,%r12 */
|
|
EMIT2(0x195c);
|
|
}
|
|
goto branch;
|
|
case BPF_S_JMP_JSET_X: /* ip += (A & X) ? jt : jf */
|
|
mask = 0x700000; /* jnz */
|
|
/* Emit test if the branch targets are different */
|
|
if (filter->jt != filter->jf) {
|
|
jit->seen |= SEEN_XREG;
|
|
/* lr %r4,%r5 */
|
|
EMIT2(0x1845);
|
|
/* nr %r4,%r12 */
|
|
EMIT2(0x144c);
|
|
}
|
|
goto branch;
|
|
case BPF_S_LD_W_ABS: /* A = *(u32 *) (skb->data+K) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
|
|
offset = jit->off_load_word;
|
|
goto load_abs;
|
|
case BPF_S_LD_H_ABS: /* A = *(u16 *) (skb->data+K) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
|
|
offset = jit->off_load_half;
|
|
goto load_abs;
|
|
case BPF_S_LD_B_ABS: /* A = *(u8 *) (skb->data+K) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
|
|
offset = jit->off_load_byte;
|
|
load_abs: if ((int) K < 0)
|
|
goto out;
|
|
call_fn: /* lg %r1,<d(function)>(%r13) */
|
|
EMIT6_DISP(0xe310d000, 0x0004, offset);
|
|
/* l %r3,<d(K)>(%r13) */
|
|
EMIT4_DISP(0x5830d000, EMIT_CONST(K));
|
|
/* basr %r8,%r1 */
|
|
EMIT2(0x0d81);
|
|
/* jnz <ret0> */
|
|
EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
|
|
break;
|
|
case BPF_S_LD_W_IND: /* A = *(u32 *) (skb->data+K+X) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
|
|
offset = jit->off_load_iword;
|
|
goto call_fn;
|
|
case BPF_S_LD_H_IND: /* A = *(u16 *) (skb->data+K+X) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
|
|
offset = jit->off_load_ihalf;
|
|
goto call_fn;
|
|
case BPF_S_LD_B_IND: /* A = *(u8 *) (skb->data+K+X) */
|
|
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
|
|
offset = jit->off_load_ibyte;
|
|
goto call_fn;
|
|
case BPF_S_LDX_B_MSH:
|
|
/* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
|
|
jit->seen |= SEEN_RET0;
|
|
if ((int) K < 0) {
|
|
/* j <ret0> */
|
|
EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
|
|
break;
|
|
}
|
|
jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
|
|
offset = jit->off_load_bmsh;
|
|
goto call_fn;
|
|
case BPF_S_LD_W_LEN: /* A = skb->len; */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
|
|
/* l %r5,<d(len)>(%r2) */
|
|
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
|
|
break;
|
|
case BPF_S_LDX_W_LEN: /* X = skb->len; */
|
|
jit->seen |= SEEN_XREG;
|
|
/* l %r12,<d(len)>(%r2) */
|
|
EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
|
|
break;
|
|
case BPF_S_LD_IMM: /* A = K */
|
|
if (K <= 16383)
|
|
/* lhi %r5,K */
|
|
EMIT4_IMM(0xa7580000, K);
|
|
else if (test_facility(21))
|
|
/* llilf %r5,<K> */
|
|
EMIT6_IMM(0xc05f0000, K);
|
|
else
|
|
/* l %r5,<d(K)>(%r13) */
|
|
EMIT4_DISP(0x5850d000, EMIT_CONST(K));
|
|
break;
|
|
case BPF_S_LDX_IMM: /* X = K */
|
|
jit->seen |= SEEN_XREG;
|
|
if (K <= 16383)
|
|
/* lhi %r12,<K> */
|
|
EMIT4_IMM(0xa7c80000, K);
|
|
else if (test_facility(21))
|
|
/* llilf %r12,<K> */
|
|
EMIT6_IMM(0xc0cf0000, K);
|
|
else
|
|
/* l %r12,<d(K)>(%r13) */
|
|
EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
|
|
break;
|
|
case BPF_S_LD_MEM: /* A = mem[K] */
|
|
jit->seen |= SEEN_MEM;
|
|
/* l %r5,<K>(%r15) */
|
|
EMIT4_DISP(0x5850f000,
|
|
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
|
|
break;
|
|
case BPF_S_LDX_MEM: /* X = mem[K] */
|
|
jit->seen |= SEEN_XREG | SEEN_MEM;
|
|
/* l %r12,<K>(%r15) */
|
|
EMIT4_DISP(0x58c0f000,
|
|
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
|
|
break;
|
|
case BPF_S_MISC_TAX: /* X = A */
|
|
jit->seen |= SEEN_XREG;
|
|
/* lr %r12,%r5 */
|
|
EMIT2(0x18c5);
|
|
break;
|
|
case BPF_S_MISC_TXA: /* A = X */
|
|
jit->seen |= SEEN_XREG;
|
|
/* lr %r5,%r12 */
|
|
EMIT2(0x185c);
|
|
break;
|
|
case BPF_S_RET_K:
|
|
if (K == 0) {
|
|
jit->seen |= SEEN_RET0;
|
|
if (last)
|
|
break;
|
|
/* j <ret0> */
|
|
EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
|
|
} else {
|
|
if (K <= 16383)
|
|
/* lghi %r2,K */
|
|
EMIT4_IMM(0xa7290000, K);
|
|
else
|
|
/* llgf %r2,<K>(%r13) */
|
|
EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
|
|
/* j <exit> */
|
|
if (last && !(jit->seen & SEEN_RET0))
|
|
break;
|
|
EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
|
|
}
|
|
break;
|
|
case BPF_S_RET_A:
|
|
/* llgfr %r2,%r5 */
|
|
EMIT4(0xb9160025);
|
|
/* j <exit> */
|
|
EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
|
|
break;
|
|
case BPF_S_ST: /* mem[K] = A */
|
|
jit->seen |= SEEN_MEM;
|
|
/* st %r5,<K>(%r15) */
|
|
EMIT4_DISP(0x5050f000,
|
|
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
|
|
break;
|
|
case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
|
|
jit->seen |= SEEN_XREG | SEEN_MEM;
|
|
/* st %r12,<K>(%r15) */
|
|
EMIT4_DISP(0x50c0f000,
|
|
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
|
|
break;
|
|
case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
/* icm %r5,3,<d(protocol)>(%r2) */
|
|
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
|
|
break;
|
|
case BPF_S_ANC_IFINDEX: /* if (!skb->dev) return 0;
|
|
* A = skb->dev->ifindex */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
|
|
jit->seen |= SEEN_RET0;
|
|
/* lg %r1,<d(dev)>(%r2) */
|
|
EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
|
|
/* ltgr %r1,%r1 */
|
|
EMIT4(0xb9020011);
|
|
/* jz <ret0> */
|
|
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
|
|
/* l %r5,<d(ifindex)>(%r1) */
|
|
EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
|
|
break;
|
|
case BPF_S_ANC_MARK: /* A = skb->mark */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
|
|
/* l %r5,<d(mark)>(%r2) */
|
|
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
|
|
break;
|
|
case BPF_S_ANC_QUEUE: /* A = skb->queue_mapping */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
/* icm %r5,3,<d(queue_mapping)>(%r2) */
|
|
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
|
|
break;
|
|
case BPF_S_ANC_HATYPE: /* if (!skb->dev) return 0;
|
|
* A = skb->dev->type */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
|
|
jit->seen |= SEEN_RET0;
|
|
/* lg %r1,<d(dev)>(%r2) */
|
|
EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
|
|
/* ltgr %r1,%r1 */
|
|
EMIT4(0xb9020011);
|
|
/* jz <ret0> */
|
|
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
/* icm %r5,3,<d(type)>(%r1) */
|
|
EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
|
|
break;
|
|
case BPF_S_ANC_RXHASH: /* A = skb->rxhash */
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
|
|
/* l %r5,<d(rxhash)>(%r2) */
|
|
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
|
|
break;
|
|
case BPF_S_ANC_VLAN_TAG:
|
|
case BPF_S_ANC_VLAN_TAG_PRESENT:
|
|
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
|
|
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
/* icm %r5,3,<d(vlan_tci)>(%r2) */
|
|
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
|
|
if (filter->code == BPF_S_ANC_VLAN_TAG) {
|
|
/* nill %r5,0xefff */
|
|
EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
|
|
} else {
|
|
/* nill %r5,0x1000 */
|
|
EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
|
|
/* srl %r5,12 */
|
|
EMIT4_DISP(0x88500000, 12);
|
|
}
|
|
break;
|
|
case BPF_S_ANC_PKTTYPE:
|
|
if (pkt_type_offset < 0)
|
|
goto out;
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
/* ic %r5,<d(pkt_type_offset)>(%r2) */
|
|
EMIT4_DISP(0x43502000, pkt_type_offset);
|
|
/* srl %r5,5 */
|
|
EMIT4_DISP(0x88500000, 5);
|
|
break;
|
|
case BPF_S_ANC_CPU: /* A = smp_processor_id() */
|
|
#ifdef CONFIG_SMP
|
|
/* l %r5,<d(cpu_nr)> */
|
|
EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
|
|
#else
|
|
/* lhi %r5,0 */
|
|
EMIT4(0xa7580000);
|
|
#endif
|
|
break;
|
|
default: /* too complex, give up */
|
|
goto out;
|
|
}
|
|
addrs[i] = jit->prg - jit->start;
|
|
return 0;
|
|
out:
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* Note: for security reasons, bpf code will follow a randomly
|
|
* sized amount of illegal instructions.
|
|
*/
|
|
struct bpf_binary_header {
|
|
unsigned int pages;
|
|
u8 image[];
|
|
};
|
|
|
|
static struct bpf_binary_header *bpf_alloc_binary(unsigned int bpfsize,
|
|
u8 **image_ptr)
|
|
{
|
|
struct bpf_binary_header *header;
|
|
unsigned int sz, hole;
|
|
|
|
/* Most BPF filters are really small, but if some of them fill a page,
|
|
* allow at least 128 extra bytes for illegal instructions.
|
|
*/
|
|
sz = round_up(bpfsize + sizeof(*header) + 128, PAGE_SIZE);
|
|
header = module_alloc(sz);
|
|
if (!header)
|
|
return NULL;
|
|
memset(header, 0, sz);
|
|
header->pages = sz / PAGE_SIZE;
|
|
hole = sz - (bpfsize + sizeof(*header));
|
|
/* Insert random number of illegal instructions before BPF code
|
|
* and make sure the first instruction starts at an even address.
|
|
*/
|
|
*image_ptr = &header->image[(prandom_u32() % hole) & -2];
|
|
return header;
|
|
}
|
|
|
|
void bpf_jit_compile(struct sk_filter *fp)
|
|
{
|
|
struct bpf_binary_header *header = NULL;
|
|
unsigned long size, prg_len, lit_len;
|
|
struct bpf_jit jit, cjit;
|
|
unsigned int *addrs;
|
|
int pass, i;
|
|
|
|
if (!bpf_jit_enable)
|
|
return;
|
|
addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
|
|
if (addrs == NULL)
|
|
return;
|
|
memset(&jit, 0, sizeof(cjit));
|
|
memset(&cjit, 0, sizeof(cjit));
|
|
|
|
for (pass = 0; pass < 10; pass++) {
|
|
jit.prg = jit.start;
|
|
jit.lit = jit.mid;
|
|
|
|
bpf_jit_prologue(&jit);
|
|
bpf_jit_noleaks(&jit, fp->insns);
|
|
for (i = 0; i < fp->len; i++) {
|
|
if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
|
|
i == fp->len - 1))
|
|
goto out;
|
|
}
|
|
bpf_jit_epilogue(&jit);
|
|
if (jit.start) {
|
|
WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
|
|
if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
|
|
break;
|
|
} else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
|
|
prg_len = jit.prg - jit.start;
|
|
lit_len = jit.lit - jit.mid;
|
|
size = prg_len + lit_len;
|
|
if (size >= BPF_SIZE_MAX)
|
|
goto out;
|
|
header = bpf_alloc_binary(size, &jit.start);
|
|
if (!header)
|
|
goto out;
|
|
jit.prg = jit.mid = jit.start + prg_len;
|
|
jit.lit = jit.end = jit.start + prg_len + lit_len;
|
|
jit.base_ip += (unsigned long) jit.start;
|
|
jit.exit_ip += (unsigned long) jit.start;
|
|
jit.ret0_ip += (unsigned long) jit.start;
|
|
}
|
|
cjit = jit;
|
|
}
|
|
if (bpf_jit_enable > 1) {
|
|
bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
|
|
if (jit.start)
|
|
print_fn_code(jit.start, jit.mid - jit.start);
|
|
}
|
|
if (jit.start) {
|
|
set_memory_ro((unsigned long)header, header->pages);
|
|
fp->bpf_func = (void *) jit.start;
|
|
}
|
|
out:
|
|
kfree(addrs);
|
|
}
|
|
|
|
void bpf_jit_free(struct sk_filter *fp)
|
|
{
|
|
unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
|
|
struct bpf_binary_header *header = (void *)addr;
|
|
|
|
if (fp->bpf_func == sk_run_filter)
|
|
return;
|
|
set_memory_rw(addr, header->pages);
|
|
module_free(NULL, header);
|
|
}
|