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, 60 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-starfire.c b/drivers/rtc/rtc-starfire.c
new file mode 100644
index 000000000..fbd1ed41c
--- /dev/null
+++ b/drivers/rtc/rtc-starfire.c
@@ -0,0 +1,60 @@
+/* rtc-starfire.c: Starfire platform RTC driver.
+ *
+ * Author: David S. Miller
+ * License: GPL
+ *
+ * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+
+#include <asm/oplib.h>
+
+static u32 starfire_get_time(void)
+{
+	static char obp_gettod[32];
+	static u32 unix_tod;
+
+	sprintf(obp_gettod, "h# %08x unix-gettod",
+		(unsigned int) (long) &unix_tod);
+	prom_feval(obp_gettod);
+
+	return unix_tod;
+}
+
+static int starfire_read_time(struct device *dev, struct rtc_time *tm)
+{
+	rtc_time64_to_tm(starfire_get_time(), tm);
+	return 0;
+}
+
+static const struct rtc_class_ops starfire_rtc_ops = {
+	.read_time	= starfire_read_time,
+};
+
+static int __init starfire_rtc_probe(struct platform_device *pdev)
+{
+	struct rtc_device *rtc;
+
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	rtc->ops = &starfire_rtc_ops;
+	rtc->range_max = U32_MAX;
+
+	platform_set_drvdata(pdev, rtc);
+
+	return devm_rtc_register_device(rtc);
+}
+
+static struct platform_driver starfire_rtc_driver = {
+	.driver		= {
+		.name	= "rtc-starfire",
+	},
+};
+
+builtin_platform_driver_probe(starfire_rtc_driver, starfire_rtc_probe);