[RFCv2 05/16] bpf: recognize 64bit immediate loads as consts

[Jakub Kicinski]

When verifier sees a generic BPF_LD | BPF_IMM | BPF_DW
it should mark the dst register as CONST_IMM with
the loaded value stored in imm.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 kernel/bpf/verifier.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index abb61f3f6900..db68a0e5db1e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1787,9 +1787,14 @@ static int check_ld_imm(struct verifier_env *env, struct 
bpf_insn *insn)
        if (err)
                return err;
 
-       if (insn->src_reg == 0)
+       if (insn->src_reg == 0) {
                /* generic move 64-bit immediate into a register */
+               u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+
+               regs[insn->dst_reg].type = CONST_IMM;
+               regs[insn->dst_reg].imm = imm;
                return 0;
+       }
 
        /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
        BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
-- 
1.9.1