Commit 05462310 authored by Michael Holzheu's avatar Michael Holzheu Committed by Martin Schwidefsky
Browse files

s390/bpf: Add s390x eBPF JIT compiler backend



Replace 32 bit BPF JIT backend with new 64 bit eBPF backend.

Signed-off-by: default avatarMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 1c6e4b18
......@@ -115,7 +115,7 @@ config S390
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_BPF_JIT if PACK_STACK
select HAVE_BPF_JIT if PACK_STACK && HAVE_MARCH_Z9_109_FEATURES
select HAVE_CMPXCHG_DOUBLE
select HAVE_CMPXCHG_LOCAL
select HAVE_DEBUG_KMEMLEAK
......
/*
* 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
/*
* BPF Jit compiler defines
*
* Copyright IBM Corp. 2012,2015
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
* Michael Holzheu <holzheu@linux.vnet.ibm.com>
*/
#ifndef __ARCH_S390_NET_BPF_JIT_H
#define __ARCH_S390_NET_BPF_JIT_H
#ifndef __ASSEMBLY__
#include <linux/filter.h>
#include <linux/types.h>
extern u8 sk_load_word_pos[], sk_load_half_pos[], sk_load_byte_pos[];
extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
#endif /* __ASSEMBLY__ */
/*
* Stackframe layout (packed stack):
*
* ^ high
* +---------------+ |
* | old backchain | |
* +---------------+ |
* | r15 - r6 | |
* BFP -> +===============+ |
* | | |
* | BPF stack | |
* | | |
* +---------------+ |
* | 8 byte hlen | |
* R15+168 -> +---------------+ |
* | 4 byte align | |
* +---------------+ |
* | 4 byte temp | |
* | for bpf_jit.S | |
* R15+160 -> +---------------+ |
* | new backchain | |
* R15+152 -> +---------------+ |
* | + 152 byte SA | |
* R15 -> +---------------+ + low
*
* We get 160 bytes stack space from calling function, but only use
* 11 * 8 byte (old backchain + r15 - r6) for storing registers.
*/
#define STK_OFF (MAX_BPF_STACK + 8 + 4 + 4 + (160 - 11 * 8))
#define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */
#define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */
/* Offset to skip condition code check */
#define OFF_OK 4
#endif /* __ARCH_S390_NET_BPF_JIT_H */
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