diff options
Diffstat (limited to 'arch/s390/net/bpf_jit.S')
| -rw-r--r-- | arch/s390/net/bpf_jit.S | 197 |
1 files changed, 89 insertions, 108 deletions
diff --git a/arch/s390/net/bpf_jit.S b/arch/s390/net/bpf_jit.S index ba44c9f55346..a1c917d881ec 100644 --- a/arch/s390/net/bpf_jit.S +++ b/arch/s390/net/bpf_jit.S @@ -1,134 +1,115 @@ /* * BPF Jit compiler for s390, help functions. * - * Copyright IBM Corp. 2012 + * Copyright IBM Corp. 2012,2015 * * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> + * Michael Holzheu <holzheu@linux.vnet.ibm.com> */ + #include <linux/linkage.h> +#include "bpf_jit.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 + * registers %r7-%r10, %r11,%r13, and %r15 are call saved + * + * Input (64 bit): + * %r3 (%b2) = offset into skb data + * %r6 (%b5) = return address + * %r7 (%b6) = skb pointer + * %r12 = skb data pointer + * + * Output: + * %r14= %b0 = return value (read skb value) + * + * Work registers: %r2,%r4,%r5,%r14 * * skb_copy_bits takes 4 parameters: * %r2 = skb pointer * %r3 = offset into skb data * %r4 = pointer to temp buffer * %r5 = length to copy + * Return value in %r2: 0 = ok + * + * bpf_internal_load_pointer_neg_helper takes 3 parameters: + * %r2 = skb pointer + * %r3 = offset into data + * %r4 = length to copy + * Return value in %r2: Pointer to data */ -#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 - lgr %r3,%r1 # offset - la %r4,160(%r15) # pointer to temp buffer - lghi %r5,4 # 4 bytes - 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 +#define SKF_MAX_NEG_OFF -0x200000 /* SKF_LL_OFF from filter.h */ - /* 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 - lgr %r3,%r1 # offset - la %r4,162(%r15) # pointer to temp buffer - lghi %r5,2 # 2 bytes - 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 +/* + * Load SIZE bytes from SKB + */ +#define sk_load_common(NAME, SIZE, LOAD) \ +ENTRY(sk_load_##NAME); \ + ltgr %r3,%r3; /* Is offset negative? */ \ + jl sk_load_##NAME##_slow_neg; \ +ENTRY(sk_load_##NAME##_pos); \ + aghi %r3,SIZE; /* Offset + SIZE */ \ + clg %r3,STK_OFF_HLEN(%r15); /* Offset + SIZE > hlen? */ \ + jh sk_load_##NAME##_slow; \ + LOAD %r14,-SIZE(%r3,%r12); /* Get data from skb */ \ + b OFF_OK(%r6); /* Return */ \ + \ +sk_load_##NAME##_slow:; \ + lgr %r2,%r7; /* Arg1 = skb pointer */ \ + aghi %r3,-SIZE; /* Arg2 = offset */ \ + la %r4,STK_OFF_TMP(%r15); /* Arg3 = temp bufffer */ \ + lghi %r5,SIZE; /* Arg4 = size */ \ + brasl %r14,skb_copy_bits; /* Get data from skb */ \ + LOAD %r14,STK_OFF_TMP(%r15); /* Load from temp bufffer */ \ + ltgr %r2,%r2; /* Set cc to (%r2 != 0) */ \ + br %r6; /* Return */ - /* A = *(u8 *) (skb->data+K+X) */ -ENTRY(sk_load_byte_ind) - ar %r3,%r12 # offset += X - bmr %r8 # < 0 -> return with cc +sk_load_common(word, 4, llgf) /* r14 = *(u32 *) (skb->data+offset) */ +sk_load_common(half, 2, llgh) /* r14 = *(u16 *) (skb->data+offset) */ - /* A = *(u8 *) (skb->data+K) */ +/* + * Load 1 byte from SKB (optimized version) + */ + /* r14 = *(u8 *) (skb->data+offset) */ 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 + ltgr %r3,%r3 # Is offset negative? + jl sk_load_byte_slow_neg +ENTRY(sk_load_byte_pos) + clg %r3,STK_OFF_HLEN(%r15) # Offset >= hlen? + jnl sk_load_byte_slow + llgc %r14,0(%r3,%r12) # Get byte from skb + b OFF_OK(%r6) # Return OK sk_load_byte_slow: - lgr %r9,%r2 # save %r2 - lgr %r3,%r1 # offset - la %r4,163(%r15) # pointer to temp buffer - lghi %r5,1 # 1 byte - 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 + lgr %r2,%r7 # Arg1 = skb pointer + # Arg2 = offset + la %r4,STK_OFF_TMP(%r15) # Arg3 = pointer to temp buffer + lghi %r5,1 # Arg4 = size (1 byte) + brasl %r14,skb_copy_bits # Get data from skb + llgc %r14,STK_OFF_TMP(%r15) # Load result from temp buffer + ltgr %r2,%r2 # Set cc to (%r2 != 0) + br %r6 # Return cc + +#define sk_negative_common(NAME, SIZE, LOAD) \ +sk_load_##NAME##_slow_neg:; \ + cgfi %r3,SKF_MAX_NEG_OFF; \ + jl bpf_error; \ + lgr %r2,%r7; /* Arg1 = skb pointer */ \ + /* Arg2 = offset */ \ + lghi %r4,SIZE; /* Arg3 = size */ \ + brasl %r14,bpf_internal_load_pointer_neg_helper; \ + ltgr %r2,%r2; \ + jz bpf_error; \ + LOAD %r14,0(%r2); /* Get data from pointer */ \ + xr %r3,%r3; /* Set cc to zero */ \ + br %r6; /* Return cc */ - /* X = (*(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_msh_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_negative_common(word, 4, llgf) +sk_negative_common(half, 2, llgh) +sk_negative_common(byte, 1, llgc) -sk_load_byte_msh_slow: - lgr %r9,%r2 # save %r2 - lgr %r3,%r1 # offset - la %r4,163(%r15) # pointer to temp buffer - lghi %r5,1 # 1 byte - 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 +bpf_error: +# force a return 0 from jit handler + ltgr %r15,%r15 # Set condition code + br %r6 |
