/*
* 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
projects / karo-tx-linux.git / blobdiff