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bpf: refactor "check_reg_arg" to eliminate code redundancy

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There are a few "regs[regno]" here are there across "check_reg_arg", this
patch factor it out into a simple "reg" pointer. The intention is to
simplify code indentation and make the later patches in this set look
cleaner.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiong Wang 2019-04-12 22:59:37 +01:00 • committed by Alexei Starovoitov
parent 55e7f3b5ac
commit c342dc109a
1 changed files with 8 additions and 6 deletions
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14
kernel/bpf/verifier.c
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@ -1177,30 +1177,32 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
{ {
struct bpf_verifier_state *vstate = env->cur_state; struct bpf_verifier_state *vstate = env->cur_state;
struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_func_state *state = vstate->frame[vstate->curframe];
struct bpf_reg_state *regs = state->regs; struct bpf_reg_state *reg, *regs = state->regs;
if (regno >= MAX_BPF_REG) { if (regno >= MAX_BPF_REG) {
verbose(env, "R%d is invalid\n", regno); verbose(env, "R%d is invalid\n", regno);
return -EINVAL; return -EINVAL;
} }
reg = &regs[regno];
if (t == SRC_OP) { if (t == SRC_OP) {
/* check whether register used as source operand can be read */ /* check whether register used as source operand can be read */
if (regs[regno].type == NOT_INIT) { if (reg->type == NOT_INIT) {
verbose(env, "R%d !read_ok\n", regno); verbose(env, "R%d !read_ok\n", regno);
return -EACCES; return -EACCES;
} }
/* We don't need to worry about FP liveness because it's read-only */ /* We don't need to worry about FP liveness because it's read-only */
if (regno != BPF_REG_FP) if (regno == BPF_REG_FP)
return mark_reg_read(env, &regs[regno], return 0;
regs[regno].parent);
return mark_reg_read(env, reg, reg->parent);
} else { } else {
/* check whether register used as dest operand can be written to */ /* check whether register used as dest operand can be written to */
if (regno == BPF_REG_FP) { if (regno == BPF_REG_FP) {
verbose(env, "frame pointer is read only\n"); verbose(env, "frame pointer is read only\n");
return -EACCES; return -EACCES;
} }
regs[regno].live |= REG_LIVE_WRITTEN; reg->live |= REG_LIVE_WRITTEN;
if (t == DST_OP) if (t == DST_OP)
mark_reg_unknown(env, regs, regno); mark_reg_unknown(env, regs, regno);
} }