objtool: Validate disassembler headers in libopcodes probegrafted

commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
tested for libopcodes availability by linking a test snippet with a forward
declaration of disassemble_init_for_target().

However, testing symbol linkage with an extern declaration only verifies
the presence of the library (.so/.a) and bypasses checking for development
headers (binutils-dev). On systems where libopcodes is present without
development headers installed, the probe succeeds, enabling BUILD_DISAS.
Subsequent compilation of objtool then fails:

  fatal error: 'bfd.h' file not found
    113 | #include <bfd.h>

Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring
any sysroot or include flags specified for the host compiler.

Fix this by including <bfd.h> and <dis-asm.h> directly in the test snippet,
passing $(HOSTCFLAGS) so host compiler options are respected, and defining
PACKAGE="objtool" to satisfy the configuration check in <bfd.h>.

Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries")
Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check")
Reported-by: Alice Ryhl <aliceryhl@google.com>
Assisted-by: Antigravity:Gemini-Next
Signed-off-by: Ulises Mendez Martinez <umendez@google.com>
Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

1 files changed, 283 insertions, 0 deletions

diff --git a/fs/ext4/inode-test.c b/fs/ext4/inode-test.c
new file mode 100644
index 000000000..749af7ad4
--- /dev/null
+++ b/fs/ext4/inode-test.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit test of ext4 inode that verify the seconds part of [a/c/m]
+ * timestamps in ext4 inode structs are decoded correctly.
+ */
+
+#include <kunit/test.h>
+#include <linux/kernel.h>
+#include <linux/time64.h>
+
+#include "ext4.h"
+
+/*
+ * For constructing the nonnegative timestamp lower bound value.
+ * binary: 00000000 00000000 00000000 00000000
+ */
+#define LOWER_MSB_0 0L
+/*
+ * For constructing the nonnegative timestamp upper bound value.
+ * binary: 01111111 11111111 11111111 11111111
+ *
+ */
+#define UPPER_MSB_0 0x7fffffffL
+/*
+ * For constructing the negative timestamp lower bound value.
+ * binary: 10000000 00000000 00000000 00000000
+ */
+#define LOWER_MSB_1 (-(UPPER_MSB_0) - 1L)  /* avoid overflow */
+/*
+ * For constructing the negative timestamp upper bound value.
+ * binary: 11111111 11111111 11111111 11111111
+ */
+#define UPPER_MSB_1 (-1L)
+/*
+ * Upper bound for nanoseconds value supported by the encoding.
+ * binary: 00111111 11111111 11111111 11111111
+ */
+#define MAX_NANOSECONDS ((1L << 30) - 1)
+
+#define CASE_NAME_FORMAT "%s: msb:%x lower_bound:%x extra_bits: %x"
+
+#define LOWER_BOUND_NEG_NO_EXTRA_BITS_CASE\
+	"1901-12-13 Lower bound of 32bit < 0 timestamp, no extra bits"
+#define UPPER_BOUND_NEG_NO_EXTRA_BITS_CASE\
+	"1969-12-31 Upper bound of 32bit < 0 timestamp, no extra bits"
+#define LOWER_BOUND_NONNEG_NO_EXTRA_BITS_CASE\
+	"1970-01-01 Lower bound of 32bit >=0 timestamp, no extra bits"
+#define UPPER_BOUND_NONNEG_NO_EXTRA_BITS_CASE\
+	"2038-01-19 Upper bound of 32bit >=0 timestamp, no extra bits"
+#define LOWER_BOUND_NEG_LO_1_CASE\
+	"2038-01-19 Lower bound of 32bit <0 timestamp, lo extra sec bit on"
+#define UPPER_BOUND_NEG_LO_1_CASE\
+	"2106-02-07 Upper bound of 32bit <0 timestamp, lo extra sec bit on"
+#define LOWER_BOUND_NONNEG_LO_1_CASE\
+	"2106-02-07 Lower bound of 32bit >=0 timestamp, lo extra sec bit on"
+#define UPPER_BOUND_NONNEG_LO_1_CASE\
+	"2174-02-25 Upper bound of 32bit >=0 timestamp, lo extra sec bit on"
+#define LOWER_BOUND_NEG_HI_1_CASE\
+	"2174-02-25 Lower bound of 32bit <0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NEG_HI_1_CASE\
+	"2242-03-16 Upper bound of 32bit <0 timestamp, hi extra sec bit on"
+#define LOWER_BOUND_NONNEG_HI_1_CASE\
+	"2242-03-16 Lower bound of 32bit >=0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NONNEG_HI_1_CASE\
+	"2310-04-04 Upper bound of 32bit >=0 timestamp, hi extra sec bit on"
+#define UPPER_BOUND_NONNEG_HI_1_NS_1_CASE\
+	"2310-04-04 Upper bound of 32bit>=0 timestamp, hi extra sec bit 1. 1 ns"
+#define LOWER_BOUND_NONNEG_HI_1_NS_MAX_CASE\
+	"2378-04-22 Lower bound of 32bit>= timestamp. Extra sec bits 1. Max ns"
+#define LOWER_BOUND_NONNEG_EXTRA_BITS_1_CASE\
+	"2378-04-22 Lower bound of 32bit >=0 timestamp. All extra sec bits on"
+#define UPPER_BOUND_NONNEG_EXTRA_BITS_1_CASE\
+	"2446-05-10 Upper bound of 32bit >=0 timestamp. All extra sec bits on"
+
+struct timestamp_expectation {
+	const char *test_case_name;
+	struct timespec64 expected;
+	u32 extra_bits;
+	bool msb_set;
+	bool lower_bound;
+};
+
+static const struct timestamp_expectation test_data[] = {
+	{
+		.test_case_name = LOWER_BOUND_NEG_NO_EXTRA_BITS_CASE,
+		.msb_set = true,
+		.lower_bound = true,
+		.extra_bits = 0,
+		.expected = {.tv_sec = -0x80000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NEG_NO_EXTRA_BITS_CASE,
+		.msb_set = true,
+		.lower_bound = false,
+		.extra_bits = 0,
+		.expected = {.tv_sec = -1LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NONNEG_NO_EXTRA_BITS_CASE,
+		.msb_set = false,
+		.lower_bound = true,
+		.extra_bits = 0,
+		.expected = {0LL, 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NONNEG_NO_EXTRA_BITS_CASE,
+		.msb_set = false,
+		.lower_bound = false,
+		.extra_bits = 0,
+		.expected = {.tv_sec = 0x7fffffffLL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NEG_LO_1_CASE,
+		.msb_set = true,
+		.lower_bound = true,
+		.extra_bits = 1,
+		.expected = {.tv_sec = 0x80000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NEG_LO_1_CASE,
+		.msb_set = true,
+		.lower_bound = false,
+		.extra_bits = 1,
+		.expected = {.tv_sec = 0xffffffffLL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NONNEG_LO_1_CASE,
+		.msb_set = false,
+		.lower_bound = true,
+		.extra_bits = 1,
+		.expected = {.tv_sec = 0x100000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NONNEG_LO_1_CASE,
+		.msb_set = false,
+		.lower_bound = false,
+		.extra_bits = 1,
+		.expected = {.tv_sec = 0x17fffffffLL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NEG_HI_1_CASE,
+		.msb_set = true,
+		.lower_bound = true,
+		.extra_bits =  2,
+		.expected = {.tv_sec = 0x180000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NEG_HI_1_CASE,
+		.msb_set = true,
+		.lower_bound = false,
+		.extra_bits = 2,
+		.expected = {.tv_sec = 0x1ffffffffLL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NONNEG_HI_1_CASE,
+		.msb_set = false,
+		.lower_bound = true,
+		.extra_bits = 2,
+		.expected = {.tv_sec = 0x200000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NONNEG_HI_1_CASE,
+		.msb_set = false,
+		.lower_bound = false,
+		.extra_bits = 2,
+		.expected = {.tv_sec = 0x27fffffffLL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NONNEG_HI_1_NS_1_CASE,
+		.msb_set = false,
+		.lower_bound = false,
+		.extra_bits = 6,
+		.expected = {.tv_sec = 0x27fffffffLL, .tv_nsec = 1L},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NONNEG_HI_1_NS_MAX_CASE,
+		.msb_set = false,
+		.lower_bound = true,
+		.extra_bits = 0xFFFFFFFF,
+		.expected = {.tv_sec = 0x300000000LL,
+			     .tv_nsec = MAX_NANOSECONDS},
+	},
+
+	{
+		.test_case_name = LOWER_BOUND_NONNEG_EXTRA_BITS_1_CASE,
+		.msb_set = false,
+		.lower_bound = true,
+		.extra_bits = 3,
+		.expected = {.tv_sec = 0x300000000LL, .tv_nsec = 0L},
+	},
+
+	{
+		.test_case_name = UPPER_BOUND_NONNEG_EXTRA_BITS_1_CASE,
+		.msb_set = false,
+		.lower_bound = false,
+		.extra_bits = 3,
+		.expected = {.tv_sec = 0x37fffffffLL, .tv_nsec = 0L},
+	}
+};
+
+static void timestamp_expectation_to_desc(const struct timestamp_expectation *t,
+					  char *desc)
+{
+	strscpy(desc, t->test_case_name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(ext4_inode, test_data, timestamp_expectation_to_desc);
+
+static time64_t get_32bit_time(const struct timestamp_expectation * const test)
+{
+	if (test->msb_set) {
+		if (test->lower_bound)
+			return LOWER_MSB_1;
+
+		return UPPER_MSB_1;
+	}
+
+	if (test->lower_bound)
+		return LOWER_MSB_0;
+	return UPPER_MSB_0;
+}
+
+
+/*
+ *  Test data is derived from the table in the Inode Timestamps section of
+ *  Documentation/filesystems/ext4/inodes.rst.
+ */
+static void inode_test_xtimestamp_decoding(struct kunit *test)
+{
+	struct timespec64 timestamp;
+
+	struct timestamp_expectation *test_param =
+			(struct timestamp_expectation *)(test->param_value);
+
+	timestamp = ext4_decode_extra_time(
+				cpu_to_le32(get_32bit_time(test_param)),
+				cpu_to_le32(test_param->extra_bits));
+
+	KUNIT_EXPECT_EQ_MSG(test,
+			    test_param->expected.tv_sec,
+			    timestamp.tv_sec,
+			    CASE_NAME_FORMAT,
+			    test_param->test_case_name,
+			    test_param->msb_set,
+			    test_param->lower_bound,
+			    test_param->extra_bits);
+	KUNIT_EXPECT_EQ_MSG(test,
+			    test_param->expected.tv_nsec,
+			    timestamp.tv_nsec,
+			    CASE_NAME_FORMAT,
+			    test_param->test_case_name,
+			    test_param->msb_set,
+			    test_param->lower_bound,
+			    test_param->extra_bits);
+}
+
+static struct kunit_case ext4_inode_test_cases[] = {
+	KUNIT_CASE_PARAM(inode_test_xtimestamp_decoding, ext4_inode_gen_params),
+	{}
+};
+
+static struct kunit_suite ext4_inode_test_suite = {
+	.name = "ext4_inode_test",
+	.test_cases = ext4_inode_test_cases,
+};
+
+kunit_test_suites(&ext4_inode_test_suite);
+
+MODULE_DESCRIPTION("KUnit test of ext4 inode timestamp decoding");
+MODULE_LICENSE("GPL v2");