s390/bpf,jit: BPF Just In Time compiler for s390

The s390 implementation of the JIT compiler for packet filter speedup.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/Kbuild b/arch/s390/Kbuild
index 9858476..cc45d25 100644 (file)
--- a/arch/s390/Kbuild
+++ b/arch/s390/Kbuild
@@ -5,3 +5,4 @@ obj-$(CONFIG_CRYPTO_HW)         += crypto/
 obj-$(CONFIG_S390_HYPFS_FS)    += hypfs/
 obj-$(CONFIG_APPLDATA_BASE)    += appldata/
 obj-$(CONFIG_MATHEMU)          += math-emu/
+obj-y                          += net/

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 107610e..a7088dc 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -84,6 +84,7 @@ config S390
        select HAVE_KERNEL_XZ
        select HAVE_ARCH_MUTEX_CPU_RELAX
        select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
+       select HAVE_BPF_JIT if 64BIT && PACK_STACK
        select ARCH_SAVE_PAGE_KEYS if HIBERNATION
        select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
        select HAVE_MEMBLOCK

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 11e4e32..d4477ba 100644 (file)
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -140,6 +140,7 @@ extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 extern unsigned long thread_saved_pc(struct task_struct *t);
 
 extern void show_code(struct pt_regs *regs);
+extern void print_fn_code(unsigned char *code, unsigned long len);
 
 unsigned long get_wchan(struct task_struct *p);
 #define task_pt_regs(tsk) ((struct pt_regs *) \

diff --git a/arch/s390/kernel/dis.c b/arch/s390/kernel/dis.c
index 619c5d3..84fd7e9 100644 (file)
--- a/arch/s390/kernel/dis.c
+++ b/arch/s390/kernel/dis.c
@@ -1601,3 +1601,26 @@ void show_code(struct pt_regs *regs)
        }
        printk("\n");
 }
+
+void print_fn_code(unsigned char *code, unsigned long len)
+{
+       char buffer[64], *ptr;
+       int opsize, i;
+
+       while (len) {
+               ptr = buffer;
+               opsize = insn_length(*code);
+               ptr += sprintf(ptr, "%p: ", code);
+               for (i = 0; i < opsize; i++)
+                       ptr += sprintf(ptr, "%02x", code[i]);
+               *ptr++ = '\t';
+               if (i < 4)
+                       *ptr++ = '\t';
+               ptr += print_insn(ptr, code, (unsigned long) code);
+               *ptr++ = '\n';
+               *ptr++ = 0;
+               printk(buffer);
+               code += opsize;
+               len -= opsize;
+       }
+}

diff --git a/arch/s390/net/Makefile b/arch/s390/net/Makefile
new file mode 100644 (file)
index 0000000..90568c3
--- /dev/null
+++ b/arch/s390/net/Makefile
@@ -0,0 +1,4 @@
+#
+# Arch-specific network modules
+#
+obj-$(CONFIG_BPF_JIT) += bpf_jit.o bpf_jit_comp.o

diff --git a/arch/s390/net/bpf_jit.S b/arch/s390/net/bpf_jit.S
new file mode 100644 (file)
index 0000000..7e45d13
--- /dev/null
+++ b/arch/s390/net/bpf_jit.S
@@ -0,0 +1,130 @@
+/*
+ * BPF Jit compiler for s390, help functions.
+ *
+ * Copyright IBM Corp. 2012
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+#include <linux/linkage.h>
+
+/*
+ * Calling convention:
+ * registers %r2, %r6-%r8, %r10-%r11, %r13, %r15 are call saved
+ *   %r2: skb pointer
+ *   %r3: offset parameter
+ *   %r5: BPF A accumulator
+ *   %r8: return address
+ *   %r9: save register for skb pointer
+ *   %r10: skb->data
+ *   %r11: skb->len - skb->data_len (headlen)
+ *   %r12: BPF X accumulator
+ *
+ * skb_copy_bits takes 4 parameters:
+ *   %r2 = skb pointer
+ *   %r3 = offset into skb data
+ *   %r4 = length to copy
+ *   %r5 = pointer to temp buffer
+ */
+#define SKBDATA        %r8
+
+       /* A = *(u32 *) (skb->data+K+X) */
+ENTRY(sk_load_word_ind)
+       ar      %r3,%r12                # offset += X
+       bmr     %r8                     # < 0 -> return with cc
+
+       /* A = *(u32 *) (skb->data+K) */
+ENTRY(sk_load_word)
+       llgfr   %r1,%r3                 # extend offset
+       ahi     %r3,4                   # offset + 4
+       clr     %r11,%r3                # hlen <= offset + 4 ?
+       jl      sk_load_word_slow
+       l       %r5,0(%r1,%r10)         # get word from skb
+       xr      %r1,%r1                 # set cc to zero
+       br      %r8
+
+sk_load_word_slow:
+       lgr     %r9,%r2                 # save %r2
+       lhi     %r4,4                   # 4 bytes
+       la      %r5,160(%r15)           # pointer to temp buffer
+       brasl   %r14,skb_copy_bits      # get data from skb
+       l       %r5,160(%r15)           # load result from temp buffer
+       ltgr    %r2,%r2                 # set cc to (%r2 != 0)
+       lgr     %r2,%r9                 # restore %r2
+       br      %r8
+
+       /* A = *(u16 *) (skb->data+K+X) */
+ENTRY(sk_load_half_ind)
+       ar      %r3,%r12                # offset += X
+       bmr     %r8                     # < 0 -> return with cc
+
+       /* A = *(u16 *) (skb->data+K) */
+ENTRY(sk_load_half)
+       llgfr   %r1,%r3                 # extend offset
+       ahi     %r3,2                   # offset + 2
+       clr     %r11,%r3                # hlen <= offset + 2 ?
+       jl      sk_load_half_slow
+       llgh    %r5,0(%r1,%r10)         # get half from skb
+       xr      %r1,%r1                 # set cc to zero
+       br      %r8
+
+sk_load_half_slow:
+       lgr     %r9,%r2                 # save %r2
+       lhi     %r4,2                   # 2 bytes
+       la      %r5,162(%r15)           # pointer to temp buffer
+       brasl   %r14,skb_copy_bits      # get data from skb
+       xc      160(2,%r15),160(%r15)
+       l       %r5,160(%r15)           # load result from temp buffer
+       ltgr    %r2,%r2                 # set cc to (%r2 != 0)
+       lgr     %r2,%r9                 # restore %r2
+       br      %r8
+
+       /* A = *(u8 *) (skb->data+K+X) */
+ENTRY(sk_load_byte_ind)
+       ar      %r3,%r12                # offset += X
+       bmr     %r8                     # < 0 -> return with cc
+
+       /* A = *(u8 *) (skb->data+K) */
+ENTRY(sk_load_byte)
+       llgfr   %r1,%r3                 # extend offset
+       clr     %r11,%r3                # hlen < offset ?
+       jle     sk_load_byte_slow
+       lhi     %r5,0
+       ic      %r5,0(%r1,%r10)         # get byte from skb
+       xr      %r1,%r1                 # set cc to zero
+       br      %r8
+
+sk_load_byte_slow:
+       lgr     %r9,%r2                 # save %r2
+       lhi     %r4,1                   # 1 bytes
+       la      %r5,163(%r15)           # pointer to temp buffer
+       brasl   %r14,skb_copy_bits      # get data from skb
+       xc      160(3,%r15),160(%r15)
+       l       %r5,160(%r15)           # load result from temp buffer
+       ltgr    %r2,%r2                 # set cc to (%r2 != 0)
+       lgr     %r2,%r9                 # restore %r2
+       br      %r8
+
+       /* A = (*(u8 *)(skb->data+K) & 0xf) << 2 */
+ENTRY(sk_load_byte_msh)
+       llgfr   %r1,%r3                 # extend offset
+       clr     %r11,%r3                # hlen < offset ?
+       jle     sk_load_byte_slow
+       lhi     %r12,0
+       ic      %r12,0(%r1,%r10)        # get byte from skb
+       nill    %r12,0x0f
+       sll     %r12,2
+       xr      %r1,%r1                 # set cc to zero
+       br      %r8
+
+sk_load_byte_msh_slow:
+       lgr     %r9,%r2                 # save %r2
+       lhi     %r4,2                   # 2 bytes
+       la      %r5,162(%r15)           # pointer to temp buffer
+       brasl   %r14,skb_copy_bits      # get data from skb
+       xc      160(3,%r15),160(%r15)
+       l       %r12,160(%r15)          # load result from temp buffer
+       nill    %r12,0x0f
+       sll     %r12,2
+       ltgr    %r2,%r2                 # set cc to (%r2 != 0)
+       lgr     %r2,%r9                 # restore %r2
+       br      %r8

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
new file mode 100644 (file)
index 0000000..b07aa3d
--- /dev/null
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -0,0 +1,738 @@
+/*
+ * BPF Jit compiler for s390.
+ *
+ * Copyright IBM Corp. 2012
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+#include <linux/moduleloader.h>
+#include <linux/netdevice.h>
+#include <linux/filter.h>
+#include <asm/cacheflush.h>
+#include <asm/processor.h>
+
+/*
+ * Conventions:
+ *   %r2 = skb pointer
+ *   %r3 = offset parameter
+ *   %r4 = scratch register / length parameter
+ *   %r5 = BPF A accumulator
+ *   %r8 = return address
+ *   %r9 = save register for skb pointer
+ *   %r10 = skb->data
+ *   %r11 = skb->len - skb->data_len (headlen)
+ *   %r12 = BPF X accumulator
+ *   %r13 = literal pool pointer
+ *   0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
+ */
+int bpf_jit_enable __read_mostly;
+
+/*
+ * assembly code in arch/x86/net/bpf_jit.S
+ */
+extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
+extern u8 sk_load_word_ind[], sk_load_half_ind[], sk_load_byte_ind[];
+
+struct bpf_jit {
+       unsigned int seen;
+       u8 *start;
+       u8 *prg;
+       u8 *mid;
+       u8 *lit;
+       u8 *end;
+       u8 *base_ip;
+       u8 *ret0_ip;
+       u8 *exit_ip;
+       unsigned int off_load_word;
+       unsigned int off_load_half;
+       unsigned int off_load_byte;
+       unsigned int off_load_bmsh;
+       unsigned int off_load_iword;
+       unsigned int off_load_ihalf;
+       unsigned int off_load_ibyte;
+};
+
+#define BPF_SIZE_MAX   4096    /* Max size for program */
+
+#define SEEN_DATAREF   1       /* might call external helpers */
+#define SEEN_XREG      2       /* ebx is used */
+#define SEEN_MEM       4       /* use mem[] for temporary storage */
+#define SEEN_RET0      8       /* pc_ret0 points to a valid return 0 */
+#define SEEN_LITERAL   16      /* code uses literals */
+#define SEEN_LOAD_WORD 32      /* code uses sk_load_word */
+#define SEEN_LOAD_HALF 64      /* code uses sk_load_half */
+#define SEEN_LOAD_BYTE 128     /* code uses sk_load_byte */
+#define SEEN_LOAD_BMSH 256     /* code uses sk_load_byte_msh */
+#define SEEN_LOAD_IWORD        512     /* code uses sk_load_word_ind */
+#define SEEN_LOAD_IHALF        1024    /* code uses sk_load_half_ind */
+#define SEEN_LOAD_IBYTE        2048    /* code uses sk_load_byte_ind */
+
+#define EMIT2(op)                                      \
+({                                                     \
+       if (jit->prg + 2 <= jit->mid)                   \
+               *(u16 *) jit->prg = op;                 \
+       jit->prg += 2;                                  \
+})
+
+#define EMIT4(op)                                      \
+({                                                     \
+       if (jit->prg + 4 <= jit->mid)                   \
+               *(u32 *) jit->prg = op;                 \
+       jit->prg += 4;                                  \
+})
+
+#define EMIT4_DISP(op, disp)                           \
+({                                                     \
+       unsigned int __disp = (disp) & 0xfff;           \
+       EMIT4(op | __disp);                             \
+})
+
+#define EMIT4_IMM(op, imm)                             \
+({                                                     \
+       unsigned int __imm = (imm) & 0xffff;            \
+       EMIT4(op | __imm);                              \
+})
+
+#define EMIT4_PCREL(op, pcrel)                         \
+({                                                     \
+       long __pcrel = ((pcrel) >> 1) & 0xffff;         \
+       EMIT4(op | __pcrel);                            \
+})
+
+#define EMIT6(op1, op2)                                        \
+({                                                     \
+       if (jit->prg + 6 <= jit->mid) {                 \
+               *(u32 *) jit->prg = op1;                \
+               *(u16 *) (jit->prg + 4) = op2;          \
+       }                                               \
+       jit->prg += 6;                                  \
+})
+
+#define EMIT6_DISP(op1, op2, disp)                     \
+({                                                     \
+       unsigned int __disp = (disp) & 0xfff;           \
+       EMIT6(op1 | __disp, op2);                       \
+})
+
+#define EMIT_CONST(val)                                        \
+({                                                     \
+       unsigned int ret;                               \
+       ret = (unsigned int) (jit->lit - jit->base_ip); \
+       jit->seen |= SEEN_LITERAL;                      \
+       if (jit->lit + 4 <= jit->end)                   \
+               *(u32 *) jit->lit = val;                \
+       jit->lit += 4;                                  \
+       ret;                                            \
+})
+
+#define EMIT_FN_CONST(bit, fn)                         \
+({                                                     \
+       unsigned int ret;                               \
+       ret = (unsigned int) (jit->lit - jit->base_ip); \
+       if (jit->seen & bit) {                          \
+               jit->seen |= SEEN_LITERAL;              \
+               if (jit->lit + 8 <= jit->end)           \
+                       *(void **) jit->lit = fn;       \
+               jit->lit += 8;                          \
+       }                                               \
+       ret;                                            \
+})
+
+static void bpf_jit_prologue(struct bpf_jit *jit)
+{
+       /* Save registers and create stack frame if necessary */
+       if (jit->seen & SEEN_DATAREF) {
+               /* stmg %r8,%r15,88(%r15) */
+               EMIT6(0xeb8ff058, 0x0024);
+               /* lgr %r14,%r15 */
+               EMIT4(0xb90400ef);
+               /* ahi %r15,<offset> */
+               EMIT4_IMM(0xa7fa0000, (jit->seen & SEEN_MEM) ? -112 : -80);
+               /* stg %r14,152(%r15) */
+               EMIT6(0xe3e0f098, 0x0024);
+       } else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
+               /* stmg %r12,%r13,120(%r15) */
+               EMIT6(0xebcdf078, 0x0024);
+       else if (jit->seen & SEEN_XREG)
+               /* stg %r12,120(%r15) */
+               EMIT6(0xe3c0f078, 0x0024);
+       else if (jit->seen & SEEN_LITERAL)
+               /* stg %r13,128(%r15) */
+               EMIT6(0xe3d0f080, 0x0024);
+
+       /* Setup literal pool */
+       if (jit->seen & SEEN_LITERAL) {
+               /* basr %r13,0 */
+               EMIT2(0x0dd0);
+               jit->base_ip = jit->prg;
+       }
+       jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
+       jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
+       jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
+       jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
+       jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
+       jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
+       jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
+
+       /* Filter needs to access skb data */
+       if (jit->seen & SEEN_DATAREF) {
+               /* l %r11,<len>(%r2) */
+               EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
+               /* s %r11,<data_len>(%r2) */
+               EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
+               /* lg %r10,<data>(%r2) */
+               EMIT6_DISP(0xe3a02000, 0x0004,
+                          offsetof(struct sk_buff, data));
+       }
+}
+
+static void bpf_jit_epilogue(struct bpf_jit *jit)
+{
+       /* Return 0 */
+       if (jit->seen & SEEN_RET0) {
+               jit->ret0_ip = jit->prg;
+               /* lghi %r2,0 */
+               EMIT4(0xa7290000);
+       }
+       jit->exit_ip = jit->prg;
+       /* Restore registers */
+       if (jit->seen & SEEN_DATAREF)
+               /* lmg %r8,%r15,<offset>(%r15) */
+               EMIT6_DISP(0xeb8ff000, 0x0004,
+                          (jit->seen & SEEN_MEM) ? 200 : 168);
+       else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
+               /* lmg %r12,%r13,120(%r15) */
+               EMIT6(0xebcdf078, 0x0004);
+       else if (jit->seen & SEEN_XREG)
+               /* lg %r12,120(%r15) */
+               EMIT6(0xe3c0f078, 0x0004);
+       else if (jit->seen & SEEN_LITERAL)
+               /* lg %r13,128(%r15) */
+               EMIT6(0xe3d0f080, 0x0004);
+       /* br %r14 */
+       EMIT2(0x07fe);
+}
+
+/*
+ * make sure we dont leak kernel information to user
+ */
+static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
+{
+       /* Clear temporary memory if (seen & SEEN_MEM) */
+       if (jit->seen & SEEN_MEM)
+               /* xc 0(64,%r15),0(%r15) */
+               EMIT6(0xd73ff000, 0xf000);
+       /* Clear X if (seen & SEEN_XREG) */
+       if (jit->seen & SEEN_XREG)
+               /* lhi %r12,0 */
+               EMIT4(0xa7c80000);
+       /* Clear A if the first register does not set it. */
+       switch (filter[0].code) {
+       case BPF_S_LD_W_ABS:
+       case BPF_S_LD_H_ABS:
+       case BPF_S_LD_B_ABS:
+       case BPF_S_LD_W_LEN:
+       case BPF_S_LD_W_IND:
+       case BPF_S_LD_H_IND:
+       case BPF_S_LD_B_IND:
+       case BPF_S_LDX_B_MSH:
+       case BPF_S_LD_IMM:
+       case BPF_S_LD_MEM:
+       case BPF_S_MISC_TXA:
+       case BPF_S_ANC_PROTOCOL:
+       case BPF_S_ANC_PKTTYPE:
+       case BPF_S_ANC_IFINDEX:
+       case BPF_S_ANC_MARK:
+       case BPF_S_ANC_QUEUE:
+       case BPF_S_ANC_HATYPE:
+       case BPF_S_ANC_RXHASH:
+       case BPF_S_ANC_CPU:
+       case BPF_S_RET_K:
+               /* first instruction sets A register */
+               break;
+       default: /* A = 0 */
+               /* lhi %r5,0 */
+               EMIT4(0xa7580000);
+       }
+}
+
+static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
+                       unsigned int *addrs, int i, int last)
+{
+       unsigned int K;
+       int offset;
+       unsigned int mask;
+
+       K = filter->k;
+       switch (filter->code) {
+       case BPF_S_ALU_ADD_X: /* A += X */
+               jit->seen |= SEEN_XREG;
+               /* ar %r5,%r12 */
+               EMIT2(0x1a5c);
+               break;
+       case BPF_S_ALU_ADD_K: /* A += K */
+               if (!K)
+                       break;
+               if (K <= 16383)
+                       /* ahi %r5,<K> */
+                       EMIT4_IMM(0xa75a0000, K);
+               else
+                       /* a %r5,<d(K)>(%r13) */
+                       EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
+               break;
+       case BPF_S_ALU_SUB_X: /* A -= X */
+               jit->seen |= SEEN_XREG;
+               /* sr %r5,%r12 */
+               EMIT2(0x1b5c);
+               break;
+       case BPF_S_ALU_SUB_K: /* A -= K */
+               if (!K)
+                       break;
+               if (K <= 16384)
+                       /* ahi %r5,-K */
+                       EMIT4_IMM(0xa75a0000, -K);
+               else
+                       /* s %r5,<d(K)>(%r13) */
+                       EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
+               break;
+       case BPF_S_ALU_MUL_X: /* A *= X */
+               jit->seen |= SEEN_XREG;
+               /* msr %r5,%r12 */
+               EMIT4(0xb252005c);
+               break;
+       case BPF_S_ALU_MUL_K: /* A *= K */
+               if (K <= 16383)
+                       /* mhi %r5,K */
+                       EMIT4_IMM(0xa75c0000, K);
+               else
+                       /* ms %r5,<d(K)>(%r13) */
+                       EMIT4_DISP(0x7150d000, EMIT_CONST(K));
+               break;
+       case BPF_S_ALU_DIV_X: /* A /= X */
+               jit->seen |= SEEN_XREG | SEEN_RET0;
+               /* ltr %r12,%r12 */
+               EMIT2(0x12cc);
+               /* jz <ret0> */
+               EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
+               /* lhi %r4,0 */
+               EMIT4(0xa7480000);
+               /* dr %r4,%r12 */
+               EMIT2(0x1d4c);
+               break;
+       case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
+               /* m %r4,<d(K)>(%r13) */
+               EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
+               /* lr %r5,%r4 */
+               EMIT2(0x1854);
+               break;
+       case BPF_S_ALU_AND_X: /* A &= X */
+               jit->seen |= SEEN_XREG;
+               /* nr %r5,%r12 */
+               EMIT2(0x145c);
+               break;
+       case BPF_S_ALU_AND_K: /* A &= K */
+               /* n %r5,<d(K)>(%r13) */
+               EMIT4_DISP(0x5450d000, EMIT_CONST(K));
+               break;
+       case BPF_S_ALU_OR_X: /* A |= X */
+               jit->seen |= SEEN_XREG;
+               /* or %r5,%r12 */
+               EMIT2(0x165c);
+               break;
+       case BPF_S_ALU_OR_K: /* A |= K */
+               /* o %r5,<d(K)>(%r13) */
+               EMIT4_DISP(0x5650d000, EMIT_CONST(K));
+               break;
+       case BPF_S_ALU_LSH_X: /* A <<= X; */
+               jit->seen |= SEEN_XREG;
+               /* sll %r5,0(%r12) */
+               EMIT4(0x8950c000);
+               break;
+       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
+                               /* 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
+                       /* 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
+                       /* 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_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;
+}
+
+void bpf_jit_compile(struct sk_filter *fp)
+{
+       unsigned long size, prg_len, lit_len;
+       struct bpf_jit jit, cjit;
+       unsigned int *addrs;
+       int pass, i;
+
+       if (!bpf_jit_enable)
+               return;
+       addrs = kmalloc(fp->len * sizeof(*addrs), GFP_KERNEL);
+       if (addrs == NULL)
+               return;
+       memset(addrs, 0, fp->len * sizeof(*addrs));
+       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 = max_t(unsigned long, prg_len + lit_len,
+                                    sizeof(struct work_struct));
+                       if (size >= BPF_SIZE_MAX)
+                               goto out;
+                       jit.start = module_alloc(size);
+                       if (!jit.start)
+                               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) {
+               pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
+                      fp->len, jit.end - jit.start, pass, jit.start);
+               if (jit.start) {
+                       printk(KERN_ERR "JIT code:\n");
+                       print_fn_code(jit.start, jit.mid - jit.start);
+                       print_hex_dump(KERN_ERR, "JIT literals:\n",
+                                      DUMP_PREFIX_ADDRESS, 16, 1,
+                                      jit.mid, jit.end - jit.mid, false);
+               }
+       }
+       if (jit.start)
+               fp->bpf_func = (void *) jit.start;
+out:
+       kfree(addrs);
+}
+
+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)
+{
+       struct work_struct *work;
+
+       if (fp->bpf_func == sk_run_filter)
+               return;
+       work = (struct work_struct *)fp->bpf_func;
+       INIT_WORK(work, jit_free_defer);
+       schedule_work(work);
+}