diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/reg_bounds.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/reg_bounds.c | 121 |
1 files changed, 113 insertions, 8 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c index 39d42271cc46..71f5240cc5b7 100644 --- a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c +++ b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c @@ -422,15 +422,69 @@ static bool is_valid_range(enum num_t t, struct range x) } } -static struct range range_improve(enum num_t t, struct range old, struct range new) +static struct range range_intersection(enum num_t t, struct range old, struct range new) { return range(t, max_t(t, old.a, new.a), min_t(t, old.b, new.b)); } +/* + * Result is precise when 'x' and 'y' overlap or form a continuous range, + * result is an over-approximation if 'x' and 'y' do not overlap. + */ +static struct range range_union(enum num_t t, struct range x, struct range y) +{ + if (!is_valid_range(t, x)) + return y; + if (!is_valid_range(t, y)) + return x; + return range(t, min_t(t, x.a, y.a), max_t(t, x.b, y.b)); +} + +/* + * This function attempts to improve x range intersecting it with y. + * range_cast(... to_t ...) looses precision for ranges that pass to_t + * min/max boundaries. To avoid such precision loses this function + * splits both x and y into halves corresponding to non-overflowing + * sub-ranges: [0, smin] and [smax, -1]. + * Final result is computed as follows: + * + * ((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪ + * ((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1])) + * + * Precision might still be lost if final union is not a continuous range. + */ +static struct range range_refine_in_halves(enum num_t x_t, struct range x, + enum num_t y_t, struct range y) +{ + struct range x_pos, x_neg, y_pos, y_neg, r_pos, r_neg; + u64 smax, smin, neg_one; + + if (t_is_32(x_t)) { + smax = (u64)(u32)S32_MAX; + smin = (u64)(u32)S32_MIN; + neg_one = (u64)(u32)(s32)(-1); + } else { + smax = (u64)S64_MAX; + smin = (u64)S64_MIN; + neg_one = U64_MAX; + } + x_pos = range_intersection(x_t, x, range(x_t, 0, smax)); + x_neg = range_intersection(x_t, x, range(x_t, smin, neg_one)); + y_pos = range_intersection(y_t, y, range(x_t, 0, smax)); + y_neg = range_intersection(y_t, y, range(y_t, smin, neg_one)); + r_pos = range_intersection(x_t, x_pos, range_cast(y_t, x_t, y_pos)); + r_neg = range_intersection(x_t, x_neg, range_cast(y_t, x_t, y_neg)); + return range_union(x_t, r_pos, r_neg); + +} + static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, struct range y) { struct range y_cast; + if (t_is_32(x_t) == t_is_32(y_t)) + x = range_refine_in_halves(x_t, x, y_t, y); + y_cast = range_cast(y_t, x_t, y); /* If we know that @@ -444,7 +498,40 @@ static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, */ if (x_t == S64 && y_t == S32 && y_cast.a <= S32_MAX && y_cast.b <= S32_MAX && (s64)x.a >= S32_MIN && (s64)x.b <= S32_MAX) - return range_improve(x_t, x, y_cast); + return range_intersection(x_t, x, y_cast); + + if (y_t == U32 && x_t == U64) { + u64 xmin_swap, xmax_swap, xmin_lower32, xmax_lower32; + + xmin_lower32 = x.a & 0xffffffff; + xmax_lower32 = x.b & 0xffffffff; + if (xmin_lower32 < y.a || xmin_lower32 > y.b) { + /* The 32 lower bits of the umin64 are outside the u32 + * range. Let's update umin64 to match the u32 range. + * We want to *increase* the umin64 to the *minimum* + * value that matches the u32 range. + */ + xmin_swap = swap_low32(x.a, y.a); + /* We should always only increase the minimum, so if + * the new value is lower than before, we need to + * increase the 32 upper bits by 1. + */ + if (xmin_swap < x.a) + xmin_swap += 0x100000000; + if (xmin_swap == x.b) + return range(x_t, x.b, x.b); + } else if (xmax_lower32 < y.a || xmax_lower32 > y.b) { + /* Same for the umax64, but we want to *decrease* + * umax64 to the *maximum* value that matches the u32 + * range. + */ + xmax_swap = swap_low32(x.b, y.b); + if (xmax_swap > x.b) + xmax_swap -= 0x100000000; + if (xmax_swap == x.a) + return range(x_t, x.a, x.a); + } + } /* the case when new range knowledge, *y*, is a 32-bit subregister * range, while previous range knowledge, *x*, is a full register @@ -462,11 +549,11 @@ static struct range range_refine(enum num_t x_t, struct range x, enum num_t y_t, x_swap = range(x_t, swap_low32(x.a, y_cast.a), swap_low32(x.b, y_cast.b)); if (!is_valid_range(x_t, x_swap)) return x; - return range_improve(x_t, x, x_swap); + return range_intersection(x_t, x, x_swap); } /* otherwise, plain range cast and intersection works */ - return range_improve(x_t, x, y_cast); + return range_intersection(x_t, x, y_cast); } /* ======================= @@ -609,7 +696,7 @@ static void range_cond(enum num_t t, struct range x, struct range y, *newx = range(t, x.a, x.b); *newy = range(t, y.a + 1, y.b); } else if (x.a == x.b && x.b == y.b) { - /* X is a constant matching rigth side of Y */ + /* X is a constant matching right side of Y */ *newx = range(t, x.a, x.b); *newy = range(t, y.a, y.b - 1); } else if (y.a == y.b && x.a == y.a) { @@ -617,7 +704,7 @@ static void range_cond(enum num_t t, struct range x, struct range y, *newx = range(t, x.a + 1, x.b); *newy = range(t, y.a, y.b); } else if (y.a == y.b && x.b == y.b) { - /* Y is a constant matching rigth side of X */ + /* Y is a constant matching right side of X */ *newx = range(t, x.a, x.b - 1); *newy = range(t, y.a, y.b); } else { @@ -1163,7 +1250,23 @@ static int parse_range_cmp_log(const char *log_buf, struct case_spec spec, spec.compare_subregs ? "w0" : "r0", spec.compare_subregs ? "w" : "r", specs[i].reg_idx); - q = strstr(p, buf); + /* + * In the verifier log look for lines: + * 18: (bf) r0 = r6 ; R0=... R6=... + * Different verifier passes may print + * 18: (bf) r0 = r6 + * as well, but never followed by ';'. + */ + q = p; + while ((q = strstr(q, buf)) != NULL) { + const char *s = q + strlen(buf); + + while (*s == ' ' || *s == '\t') + s++; + if (*s == ';') + break; + q = s; + } if (!q) { *specs[i].state = (struct reg_state){.valid = false}; continue; @@ -2075,9 +2178,11 @@ static struct subtest_case crafted_cases[] = { {U64, S64, {0x7fffffff00000001ULL, 0xffffffff00000000ULL}, {0, 0}}, {U64, S64, {0, 0xffffffffULL}, {1, 1}}, {U64, S64, {0, 0xffffffffULL}, {0x7fffffff, 0x7fffffff}}, + {U64, S32, {0xfffffffe00000001, 0xffffffff00000000}, {S64_MIN, S64_MIN}}, + {U64, U32, {0xfffffffe00000000, U64_MAX - 1}, {U64_MAX, U64_MAX}}, {U64, U32, {0, 0x100000000}, {0, 0}}, - {U64, U32, {0xfffffffe, 0x100000000}, {0x80000000, 0x80000000}}, + {U64, U32, {0xfffffffe, 0x300000000}, {0x80000000, 0x80000000}}, {U64, S32, {0, 0xffffffff00000000ULL}, {0, 0}}, /* these are tricky cases where lower 32 bits allow to tighten 64 |