mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 09:59:32 +00:00
s390/bpf: Fix 64-bit subtraction of the -0x80000000 constant
The JIT uses agfi for subtracting constants, but -(-0x80000000) cannot
be represented as a 32-bit signed binary integer. Fix by using algfi in
this particular case.
Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Fixes: 0546231057
("s390/bpf: Add s390x eBPF JIT compiler backend")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
parent
1511df6f5e
commit
6e61dc9da0
1 changed files with 7 additions and 2 deletions
|
@ -794,8 +794,13 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
|
|||
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
|
||||
if (!imm)
|
||||
break;
|
||||
/* agfi %dst,-imm */
|
||||
EMIT6_IMM(0xc2080000, dst_reg, -imm);
|
||||
if (imm == -0x80000000) {
|
||||
/* algfi %dst,0x80000000 */
|
||||
EMIT6_IMM(0xc20a0000, dst_reg, 0x80000000);
|
||||
} else {
|
||||
/* agfi %dst,-imm */
|
||||
EMIT6_IMM(0xc2080000, dst_reg, -imm);
|
||||
}
|
||||
break;
|
||||
/*
|
||||
* BPF_MUL
|
||||
|
|
Loading…
Reference in a new issue