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, 95 insertions, 0 deletions

diff --git a/net/phonet/sysctl.c b/net/phonet/sysctl.c
new file mode 100644
index 000000000..463a74a27
--- /dev/null
+++ b/net/phonet/sysctl.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * File: sysctl.c
+ *
+ * Phonet /proc/sys/net/phonet interface implementation
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ *
+ * Author: Rémi Denis-Courmont
+ */
+
+#include <linux/seqlock.h>
+#include <linux/sysctl.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+#include <net/sock.h>
+#include <linux/phonet.h>
+#include <net/phonet/phonet.h>
+
+#define DYNAMIC_PORT_MIN	0x40
+#define DYNAMIC_PORT_MAX	0x7f
+
+static DEFINE_SEQLOCK(local_port_range_lock);
+static int local_port_range_min[2] = {0, 0};
+static int local_port_range_max[2] = {1023, 1023};
+static int local_port_range[2] = {DYNAMIC_PORT_MIN, DYNAMIC_PORT_MAX};
+static struct ctl_table_header *phonet_table_hrd;
+
+static void set_local_port_range(int range[2])
+{
+	write_seqlock(&local_port_range_lock);
+	local_port_range[0] = range[0];
+	local_port_range[1] = range[1];
+	write_sequnlock(&local_port_range_lock);
+}
+
+void phonet_get_local_port_range(int *min, int *max)
+{
+	unsigned int seq;
+
+	do {
+		seq = read_seqbegin(&local_port_range_lock);
+		if (min)
+			*min = local_port_range[0];
+		if (max)
+			*max = local_port_range[1];
+	} while (read_seqretry(&local_port_range_lock, seq));
+}
+
+static int proc_local_port_range(const struct ctl_table *table, int write,
+				 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	int ret;
+	int range[2] = {local_port_range[0], local_port_range[1]};
+	struct ctl_table tmp = {
+		.data = &range,
+		.maxlen = sizeof(range),
+		.mode = table->mode,
+		.extra1 = &local_port_range_min,
+		.extra2 = &local_port_range_max,
+	};
+
+	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+
+	if (write && ret == 0) {
+		if (range[1] < range[0])
+			ret = -EINVAL;
+		else
+			set_local_port_range(range);
+	}
+
+	return ret;
+}
+
+static struct ctl_table phonet_table[] = {
+	{
+		.procname	= "local_port_range",
+		.data		= &local_port_range,
+		.maxlen		= sizeof(local_port_range),
+		.mode		= 0644,
+		.proc_handler	= proc_local_port_range,
+	},
+};
+
+int __init phonet_sysctl_init(void)
+{
+	phonet_table_hrd = register_net_sysctl(&init_net, "net/phonet", phonet_table);
+	return phonet_table_hrd == NULL ? -ENOMEM : 0;
+}
+
+void phonet_sysctl_exit(void)
+{
+	unregister_net_sysctl_table(phonet_table_hrd);
+}