Commit 9c662cad authored by Philippe Bergheaud's avatar Philippe Bergheaud Committed by Benjamin Herrenschmidt
Browse files

powerpc/bpf: BPF JIT compiler for 64-bit Little Endian 



This enables the Berkeley Packet Filter JIT compiler
for the PowerPC running in 64bit Little Endian.

Signed-off-by: default avatarPhilippe Bergheaud <felix@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 711b5138

arch/powerpc/include/asm/ppc-opcode.h

+1 −0
Original line number Diff line number Diff line
@@ -203,6 +203,7 @@ 
/* Misc instructions for BPF compiler */

#define PPC_INST_LD			0xe8000000

#define PPC_INST_LHZ			0xa0000000

#define PPC_INST_LHBRX			0x7c00062c

#define PPC_INST_LWZ			0x80000000

#define PPC_INST_STD			0xf8000000

#define PPC_INST_STDU			0xf8000001

arch/powerpc/net/bpf_jit.h

+10 −0
Original line number Diff line number Diff line
@@ -92,6 +92,8 @@ DECLARE_LOAD_FUNC(sk_load_byte_msh); 
				     ___PPC_RA(base) | IMM_L(i))

#define PPC_LHZ(r, base, i)	EMIT(PPC_INST_LHZ | ___PPC_RT(r) |	      \

				     ___PPC_RA(base) | IMM_L(i))

#define PPC_LHBRX(r, base, b)	EMIT(PPC_INST_LHBRX | ___PPC_RT(r) |	      \

				     ___PPC_RA(base) | ___PPC_RB(b))

/* Convenience helpers for the above with 'far' offsets: */

#define PPC_LD_OFFS(r, base, i) do { if ((i) < 32768) PPC_LD(r, base, i);     \

		else {	PPC_ADDIS(r, base, IMM_HA(i));			      \
@@ -186,6 +188,14 @@ DECLARE_LOAD_FUNC(sk_load_byte_msh); 
				PPC_ORI(d, d, (uintptr_t)(i) & 0xffff);	      \

		} } while (0);



#define PPC_LHBRX_OFFS(r, base, i) \

		do { PPC_LI32(r, i); PPC_LHBRX(r, r, base); } while(0)

#ifdef __LITTLE_ENDIAN__

#define PPC_NTOHS_OFFS(r, base, i)	PPC_LHBRX_OFFS(r, base, i)

#else

#define PPC_NTOHS_OFFS(r, base, i)	PPC_LHZ_OFFS(r, base, i)

#endif



static inline bool is_nearbranch(int offset)

{

	return (offset < 32768) && (offset >= -32768);

arch/powerpc/net/bpf_jit_64.S

+8 −1
Original line number Diff line number Diff line
@@ -43,8 +43,11 @@ sk_load_word_positive_offset: 
	cmpd	r_scratch1, r_addr

	blt	bpf_slow_path_word

	/* Nope, just hitting the header.  cr0 here is eq or gt! */

#ifdef __LITTLE_ENDIAN__

	lwbrx	r_A, r_D, r_addr

#else

	lwzx	r_A, r_D, r_addr

	/* When big endian we don't need to byteswap. */

#endif

	blr	/* Return success, cr0 != LT */



	.globl	sk_load_half
@@ -56,7 +59,11 @@ sk_load_half_positive_offset: 
	subi	r_scratch1, r_HL, 2

	cmpd	r_scratch1, r_addr

	blt	bpf_slow_path_half

#ifdef __LITTLE_ENDIAN__

	lhbrx	r_A, r_D, r_addr

#else

	lhzx	r_A, r_D, r_addr

#endif

	blr



	.globl	sk_load_byte

arch/powerpc/net/bpf_jit_comp.c

+2 −15
Original line number Diff line number Diff line
@@ -17,14 +17,8 @@ 


#include "bpf_jit.h"



#ifndef __BIG_ENDIAN

/* There are endianness assumptions herein. */

#error "Little-endian PPC not supported in BPF compiler"

#endif



int bpf_jit_enable __read_mostly;





static inline void bpf_flush_icache(void *start, void *end)

{

	smp_wmb();
@@ -346,18 +340,11 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image, 
			break;



			/*** Ancillary info loads ***/



			/* None of the BPF_S_ANC* codes appear to be passed by

			 * sk_chk_filter().  The interpreter and the x86 BPF

			 * compiler implement them so we do too -- they may be

			 * planted in future.

			 */

		case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */

			BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,

						  protocol) != 2);

			PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,

			PPC_NTOHS_OFFS(r_A, r_skb, offsetof(struct sk_buff,

							    protocol));

			/* ntohs is a NOP with BE loads. */

			break;

		case BPF_S_ANC_IFINDEX:

			PPC_LD_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,