Commit 451e448f authored by Ilya Leoshkevich's avatar Ilya Leoshkevich Committed by Alexei Starovoitov
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s390/bpf: Use lgrl instead of lg where possible 



lg and lgrl have the same performance characteristics, but the former
requires a base register and is subject to long displacement range
limits, while the latter does not. Therefore, lgrl is totally superior
to lg and should be used instead whenever possible.

Signed-off-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191118180340.68373-5-iii@linux.ibm.com
parent c1aff568

arch/s390/net/bpf_jit_comp.c

+20 −12
Original line number Diff line number Diff line
@@ -287,28 +287,38 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) 
	REG_SET_SEEN(b1);					\

})



#define EMIT_CONST_U32(val)					\

#define _EMIT_CONST_U32(val)					\

({								\

	unsigned int ret;					\

	ret = jit->lit32 - jit->base_ip;			\

	jit->seen |= SEEN_LITERAL;				\

	ret = jit->lit32;					\

	if (jit->prg_buf)					\

		*(u32 *)(jit->prg_buf + jit->lit32) = (u32)(val);\

	jit->lit32 += 4;					\

	ret;							\

})



#define EMIT_CONST_U64(val)					\

#define EMIT_CONST_U32(val)					\

({								\

	unsigned int ret;					\

	ret = jit->lit64 - jit->base_ip;			\

	jit->seen |= SEEN_LITERAL;				\

	_EMIT_CONST_U32(val) - jit->base_ip;			\

})



#define _EMIT_CONST_U64(val)					\

({								\

	unsigned int ret;					\

	ret = jit->lit64;					\

	if (jit->prg_buf)					\

		*(u64 *)(jit->prg_buf + jit->lit64) = (u64)(val);\

	jit->lit64 += 8;					\

	ret;							\

})



#define EMIT_CONST_U64(val)					\

({								\

	jit->seen |= SEEN_LITERAL;				\

	_EMIT_CONST_U64(val) - jit->base_ip;			\

})



#define EMIT_ZERO(b1)						\

({								\

	if (!fp->aux->verifier_zext) {				\
@@ -612,9 +622,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 
		u64 imm64;



		imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;

		/* lg %dst,<d(imm)>(%l) */

		EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, REG_0, REG_L,

			      EMIT_CONST_U64(imm64));

		/* lgrl %dst,imm */

		EMIT6_PCREL_RILB(0xc4080000, dst_reg, _EMIT_CONST_U64(imm64));

		insn_count = 2;

		break;

	}
@@ -1086,9 +1095,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, 


		REG_SET_SEEN(BPF_REG_5);

		jit->seen |= SEEN_FUNC;

		/* lg %w1,<d(imm)>(%l) */

		EMIT6_DISP_LH(0xe3000000, 0x0004, REG_W1, REG_0, REG_L,

			      EMIT_CONST_U64(func));

		/* lgrl %w1,func */

		EMIT6_PCREL_RILB(0xc4080000, REG_W1, _EMIT_CONST_U64(func));

		if (__is_defined(CC_USING_EXPOLINE) && !nospec_disable) {

			/* brasl %r14,__s390_indirect_jump_r1 */

			EMIT6_PCREL_RILB(0xc0050000, REG_14, jit->r1_thunk_ip);

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