| /* |
| * 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 = pointer to temp buffer |
| * %r5 = length to copy |
| */ |
| #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 |
| la %r4,160(%r15) # pointer to temp buffer |
| lhi %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 |
| |
| /* 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 |
| la %r4,162(%r15) # pointer to temp buffer |
| lhi %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 |
| |
| /* 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 |
| la %r4,163(%r15) # pointer to temp buffer |
| lhi %r5,1 # 1 bytes |
| 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 |
| la %r4,162(%r15) # pointer to temp buffer |
| lhi %r5,2 # 2 bytes |
| 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 |
