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Commit 1f499d6a authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'filter-next' 



Alexei Starovoitov says:

====================
internal BPF jit for x64 and JITed seccomp

Internal BPF JIT compiler for x86_64 replaces classic BPF JIT.
Use it in seccomp and in tracing filters (sent as separate patch)
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 9509b1c1 8f577cad

arch/x86/net/bpf_jit.S

+18 −59
Original line number Diff line number Diff line
@@ -12,13 +12,16 @@ 


/*

 * Calling convention :

 * rdi : skb pointer

 * rbx : skb pointer (callee saved)

 * esi : offset of byte(s) to fetch in skb (can be scratched)

 * r8  : copy of skb->data

 * r10 : copy of skb->data

 * r9d : hlen = skb->len - skb->data_len

 */

#define SKBDATA	%r8

#define SKBDATA	%r10

#define SKF_MAX_NEG_OFF    $(-0x200000) /* SKF_LL_OFF from filter.h */

#define MAX_BPF_STACK (512 /* from filter.h */ + \

	32 /* space for rbx,r13,r14,r15 */ + \

	8 /* space for skb_copy_bits */)



sk_load_word:

	.globl	sk_load_word
@@ -68,53 +71,31 @@ sk_load_byte_positive_offset: 
	movzbl	(SKBDATA,%rsi),%eax

	ret



/**

 * sk_load_byte_msh - BPF_S_LDX_B_MSH helper

 *

 * Implements BPF_S_LDX_B_MSH : ldxb  4*([offset]&0xf)

 * Must preserve A accumulator (%eax)

 * Inputs : %esi is the offset value

 */

sk_load_byte_msh:

	.globl	sk_load_byte_msh

	test	%esi,%esi

	js	bpf_slow_path_byte_msh_neg



sk_load_byte_msh_positive_offset:

	.globl	sk_load_byte_msh_positive_offset

	cmp	%esi,%r9d      /* if (offset >= hlen) goto bpf_slow_path_byte_msh */

	jle	bpf_slow_path_byte_msh

	movzbl	(SKBDATA,%rsi),%ebx

	and	$15,%bl

	shl	$2,%bl

	ret



/* rsi contains offset and can be scratched */

#define bpf_slow_path_common(LEN)		\

	push	%rdi;    /* save skb */		\

	mov	%rbx, %rdi; /* arg1 == skb */	\

	push	%r9;				\

	push	SKBDATA;			\

/* rsi already has offset */			\

	mov	$LEN,%ecx;	/* len */	\

	lea	-12(%rbp),%rdx;			\

	lea	- MAX_BPF_STACK + 32(%rbp),%rdx;			\

	call	skb_copy_bits;			\

	test    %eax,%eax;			\

	pop	SKBDATA;			\

	pop	%r9;				\

	pop	%rdi

	pop	%r9;





bpf_slow_path_word:

	bpf_slow_path_common(4)

	js	bpf_error

	mov	-12(%rbp),%eax

	mov	- MAX_BPF_STACK + 32(%rbp),%eax

	bswap	%eax

	ret



bpf_slow_path_half:

	bpf_slow_path_common(2)

	js	bpf_error

	mov	-12(%rbp),%ax

	mov	- MAX_BPF_STACK + 32(%rbp),%ax

	rol	$8,%ax

	movzwl	%ax,%eax

	ret
@@ -122,21 +103,11 @@ bpf_slow_path_half: 
bpf_slow_path_byte:

	bpf_slow_path_common(1)

	js	bpf_error

	movzbl	-12(%rbp),%eax

	ret



bpf_slow_path_byte_msh:

	xchg	%eax,%ebx /* dont lose A , X is about to be scratched */

	bpf_slow_path_common(1)

	js	bpf_error

	movzbl	-12(%rbp),%eax

	and	$15,%al

	shl	$2,%al

	xchg	%eax,%ebx

	movzbl	- MAX_BPF_STACK + 32(%rbp),%eax

	ret



#define sk_negative_common(SIZE)				\

	push	%rdi;	/* save skb */				\

	mov	%rbx, %rdi; /* arg1 == skb */			\

	push	%r9;						\

	push	SKBDATA;					\

/* rsi already has offset */					\
@@ -145,10 +116,8 @@ bpf_slow_path_byte_msh: 
	test	%rax,%rax;					\

	pop	SKBDATA;					\

	pop	%r9;						\

	pop	%rdi;						\

	jz	bpf_error





bpf_slow_path_word_neg:

	cmp	SKF_MAX_NEG_OFF, %esi	/* test range */

	jl	bpf_error	/* offset lower -> error  */
@@ -179,22 +148,12 @@ sk_load_byte_negative_offset: 
	movzbl	(%rax), %eax

	ret



bpf_slow_path_byte_msh_neg:

	cmp	SKF_MAX_NEG_OFF, %esi

	jl	bpf_error

sk_load_byte_msh_negative_offset:

	.globl	sk_load_byte_msh_negative_offset

	xchg	%eax,%ebx /* dont lose A , X is about to be scratched */

	sk_negative_common(1)

	movzbl	(%rax),%eax

	and	$15,%al

	shl	$2,%al

	xchg	%eax,%ebx

	ret



bpf_error:

# force a return 0 from jit handler

	xor	%eax,%eax

	mov		-8(%rbp),%rbx

	mov	- MAX_BPF_STACK(%rbp),%rbx

	mov	- MAX_BPF_STACK + 8(%rbp),%r13

	mov	- MAX_BPF_STACK + 16(%rbp),%r14

	mov	- MAX_BPF_STACK + 24(%rbp),%r15

	leaveq

	ret