135 строки
3.3 KiB
ArmAsm
135 строки
3.3 KiB
ArmAsm
/*
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* BPF Jit compiler for s390, help functions.
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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/linkage.h>
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/*
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* Calling convention:
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* registers %r2, %r6-%r8, %r10-%r11, %r13, %r15 are call saved
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* %r2: skb pointer
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* %r3: offset 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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*
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* skb_copy_bits takes 4 parameters:
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* %r2 = skb pointer
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* %r3 = offset into skb data
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* %r4 = pointer to temp buffer
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* %r5 = length to copy
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*/
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#define SKBDATA %r8
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/* A = *(u32 *) (skb->data+K+X) */
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ENTRY(sk_load_word_ind)
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ar %r3,%r12 # offset += X
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bmr %r8 # < 0 -> return with cc
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/* A = *(u32 *) (skb->data+K) */
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ENTRY(sk_load_word)
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llgfr %r1,%r3 # extend offset
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ahi %r3,4 # offset + 4
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clr %r11,%r3 # hlen <= offset + 4 ?
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jl sk_load_word_slow
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l %r5,0(%r1,%r10) # get word from skb
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xr %r1,%r1 # set cc to zero
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br %r8
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sk_load_word_slow:
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lgr %r9,%r2 # save %r2
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lgr %r3,%r1 # offset
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la %r4,160(%r15) # pointer to temp buffer
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lghi %r5,4 # 4 bytes
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brasl %r14,skb_copy_bits # get data from skb
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l %r5,160(%r15) # load result from temp buffer
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ltgr %r2,%r2 # set cc to (%r2 != 0)
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lgr %r2,%r9 # restore %r2
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br %r8
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/* A = *(u16 *) (skb->data+K+X) */
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ENTRY(sk_load_half_ind)
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ar %r3,%r12 # offset += X
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bmr %r8 # < 0 -> return with cc
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/* A = *(u16 *) (skb->data+K) */
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ENTRY(sk_load_half)
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llgfr %r1,%r3 # extend offset
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ahi %r3,2 # offset + 2
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clr %r11,%r3 # hlen <= offset + 2 ?
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jl sk_load_half_slow
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llgh %r5,0(%r1,%r10) # get half from skb
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xr %r1,%r1 # set cc to zero
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br %r8
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sk_load_half_slow:
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lgr %r9,%r2 # save %r2
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lgr %r3,%r1 # offset
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la %r4,162(%r15) # pointer to temp buffer
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lghi %r5,2 # 2 bytes
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brasl %r14,skb_copy_bits # get data from skb
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xc 160(2,%r15),160(%r15)
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l %r5,160(%r15) # load result from temp buffer
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ltgr %r2,%r2 # set cc to (%r2 != 0)
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lgr %r2,%r9 # restore %r2
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br %r8
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/* A = *(u8 *) (skb->data+K+X) */
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ENTRY(sk_load_byte_ind)
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ar %r3,%r12 # offset += X
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bmr %r8 # < 0 -> return with cc
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/* A = *(u8 *) (skb->data+K) */
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ENTRY(sk_load_byte)
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llgfr %r1,%r3 # extend offset
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clr %r11,%r3 # hlen < offset ?
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jle sk_load_byte_slow
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lhi %r5,0
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ic %r5,0(%r1,%r10) # get byte from skb
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xr %r1,%r1 # set cc to zero
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br %r8
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sk_load_byte_slow:
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lgr %r9,%r2 # save %r2
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lgr %r3,%r1 # offset
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la %r4,163(%r15) # pointer to temp buffer
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lghi %r5,1 # 1 byte
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brasl %r14,skb_copy_bits # get data from skb
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xc 160(3,%r15),160(%r15)
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l %r5,160(%r15) # load result from temp buffer
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ltgr %r2,%r2 # set cc to (%r2 != 0)
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lgr %r2,%r9 # restore %r2
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br %r8
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/* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
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ENTRY(sk_load_byte_msh)
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llgfr %r1,%r3 # extend offset
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clr %r11,%r3 # hlen < offset ?
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jle sk_load_byte_msh_slow
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lhi %r12,0
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ic %r12,0(%r1,%r10) # get byte from skb
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nill %r12,0x0f
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sll %r12,2
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xr %r1,%r1 # set cc to zero
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br %r8
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sk_load_byte_msh_slow:
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lgr %r9,%r2 # save %r2
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lgr %r3,%r1 # offset
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la %r4,163(%r15) # pointer to temp buffer
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lghi %r5,1 # 1 byte
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brasl %r14,skb_copy_bits # get data from skb
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xc 160(3,%r15),160(%r15)
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l %r12,160(%r15) # load result from temp buffer
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nill %r12,0x0f
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sll %r12,2
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ltgr %r2,%r2 # set cc to (%r2 != 0)
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lgr %r2,%r9 # restore %r2
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br %r8
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