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s390/bpf: Adjust ALU64_DIV/MOD to match interpreter change

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The s390x ALU64_DIV/MOD has been implemented according to the eBPF
interpreter specification that used do_div(). This function does a 64-bit
by 32-bit divide. It turned out that this was wrong and now the interpreter
uses div64_u64_rem() for full 64-bit division.

So fix this and use full 64-bit division in the s390x eBPF backend code.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Michael Holzheu 2015-04-27 11:12:25 +02:00 committed by Martin Schwidefsky
parent 3d99e3fe13
commit 771aada9ac
1 changed files with 6 additions and 8 deletions
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14
arch/s390/net/bpf_jit_comp.c
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@ -588,8 +588,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
EMIT4(0xb9160000, dst_reg, rc_reg);
break;
}
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / (u32) src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % (u32) src */
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
@ -602,10 +602,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
EMIT4_IMM(0xa7090000, REG_W0, 0);
/* lgr %w1,%dst */
EMIT4(0xb9040000, REG_W1, dst_reg);
/* llgfr %dst,%src (u32 cast) */
EMIT4(0xb9160000, dst_reg, src_reg);
/* dlgr %w0,%dst */
EMIT4(0xb9870000, REG_W0, dst_reg);
EMIT4(0xb9870000, REG_W0, src_reg);
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;
@ -632,8 +630,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
EMIT4(0xb9160000, dst_reg, rc_reg);
break;
}
case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / (u32) imm */
case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % (u32) imm */
case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
@ -649,7 +647,7 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
EMIT4(0xb9040000, REG_W1, dst_reg);
/* dlg %w0,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
EMIT_CONST_U64((u32) imm));
EMIT_CONST_U64(imm));
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;