// SPDX-License-Identifier: GPL-2.0

#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"

SEC("socket")
__description("check w reg equal if r reg upper32 bits 0")
__success
__naked void subreg_equality_1(void)
{
        asm volatile ("                                 \
        call %[bpf_ktime_get_ns];                       \
        *(u64 *)(r10 - 8) = r0;                         \
        r2 = *(u32 *)(r10 - 8);                         \
        /* At this point upper 4-bytes of r2 are 0,     \
         * thus insn w3 = w2 should propagate reg id,   \
         * and w2 < 9 comparison would also propagate   \
         * the range for r3.                            \
         */                                             \
        w3 = w2;                                        \
        if w2 < 9 goto l0_%=;                           \
        exit;                                           \
l0_%=:  if r3 < 9 goto l1_%=;                           \
        /* r1 read is illegal at this point */          \
        r0 -= r1;                                       \
l1_%=:  exit;                                           \
"       :
        : __imm(bpf_ktime_get_ns)
        : __clobber_all);
}

SEC("socket")
__description("check w reg not equal if r reg upper32 bits not 0")
__failure __msg("R1 !read_ok")
__naked void subreg_equality_2(void)
{
        asm volatile ("                                 \
        call %[bpf_ktime_get_ns];                       \
        r2 = r0;                                        \
        /* Upper 4-bytes of r2 may not be 0, thus insn  \
         * w3 = w2 should not propagate reg id, and     \
         * w2 < 9 comparison should not propagate       \
         * the range for r3 either.                     \
         */                                             \
        w3 = w2;                                        \
        if w2 < 9 goto l0_%=;                           \
        exit;                                           \
l0_%=:  if r3 < 9 goto l1_%=;                           \
        /* r1 read is illegal at this point */          \
        r0 -= r1;                                       \
l1_%=:  exit;                                           \
"       :
        : __imm(bpf_ktime_get_ns)
        : __clobber_all);
}

char _license[] SEC("license") = "GPL";