diff options
| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2015-07-29 21:15:17 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-07-29 14:59:58 -0700 |
| commit | cde66c2d88da1d73d755109c80ce4c34b917596b (patch) | |
| tree | 888437f97f8dd86ce7dc02a2a607c97e46b4fdbc /arch/s390/net | |
| parent | ce2b6ad9c1856fac5d5e8d3351b3dd5392e09b7a (diff) | |
s390/bpf: Only clear A and X for converted BPF programs
Only classic BPF programs that have been converted to eBPF need to clear
the A and X registers. We can check for converted programs with:
bpf_prog->type == BPF_PROG_TYPE_UNSPEC
So add the check and skip initialization for real eBPF programs.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/s390/net')
| -rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 04af36728a18..3dd01637f83a 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -387,7 +387,7 @@ static void save_restore_regs(struct bpf_jit *jit, int op) * Save registers and create stack frame if necessary. * See stack frame layout desription in "bpf_jit.h"! */ -static void bpf_jit_prologue(struct bpf_jit *jit) +static void bpf_jit_prologue(struct bpf_jit *jit, bool is_classic) { if (jit->seen & SEEN_TAIL_CALL) { /* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */ @@ -440,13 +440,15 @@ static void bpf_jit_prologue(struct bpf_jit *jit) EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0, BPF_REG_1, offsetof(struct sk_buff, data)); } - /* BPF compatibility: clear A (%b0) and X (%b7) registers */ - if (REG_SEEN(BPF_REG_A)) - /* lghi %ba,0 */ - EMIT4_IMM(0xa7090000, BPF_REG_A, 0); - if (REG_SEEN(BPF_REG_X)) - /* lghi %bx,0 */ - EMIT4_IMM(0xa7090000, BPF_REG_X, 0); + /* Clear A (%b0) and X (%b7) registers for converted BPF programs */ + if (is_classic) { + if (REG_SEEN(BPF_REG_A)) + /* lghi %ba,0 */ + EMIT4_IMM(0xa7090000, BPF_REG_A, 0); + if (REG_SEEN(BPF_REG_X)) + /* lghi %bx,0 */ + EMIT4_IMM(0xa7090000, BPF_REG_X, 0); + } } /* @@ -1232,7 +1234,7 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp) jit->lit = jit->lit_start; jit->prg = 0; - bpf_jit_prologue(jit); + bpf_jit_prologue(jit, fp->type == BPF_PROG_TYPE_UNSPEC); for (i = 0; i < fp->len; i += insn_count) { insn_count = bpf_jit_insn(jit, fp, i); if (insn_count < 0) |