FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-11 18:26:02 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

s390/bpf: Only clear A and X for converted BPF programs

Browse Source 
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>
This commit is contained in:
Michael Holzheu 2015-07-29 21:15:17 +02:00 committed by David S. Miller
parent ce2b6ad9c1
commit cde66c2d88
1 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
arch/s390/net/bpf_jit_comp.c
View File

@ -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)