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, 127 insertions, 0 deletions

diff --git a/drivers/reset/reset-ath79.c b/drivers/reset/reset-ath79.c
new file mode 100644
index 000000000..1a2c0f8a5
--- /dev/null
+++ b/drivers/reset/reset-ath79.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AR71xx Reset Controller Driver
+ * Author: Alban Bedel
+ *
+ * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
+ */
+
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/reboot.h>
+
+struct ath79_reset {
+	struct reset_controller_dev rcdev;
+	void __iomem *base;
+	spinlock_t lock;
+};
+
+#define FULL_CHIP_RESET 24
+
+static int ath79_reset_update(struct reset_controller_dev *rcdev,
+			unsigned long id, bool assert)
+{
+	struct ath79_reset *ath79_reset =
+		container_of(rcdev, struct ath79_reset, rcdev);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&ath79_reset->lock, flags);
+	val = readl(ath79_reset->base);
+	if (assert)
+		val |= BIT(id);
+	else
+		val &= ~BIT(id);
+	writel(val, ath79_reset->base);
+	spin_unlock_irqrestore(&ath79_reset->lock, flags);
+
+	return 0;
+}
+
+static int ath79_reset_assert(struct reset_controller_dev *rcdev,
+			unsigned long id)
+{
+	return ath79_reset_update(rcdev, id, true);
+}
+
+static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return ath79_reset_update(rcdev, id, false);
+}
+
+static int ath79_reset_status(struct reset_controller_dev *rcdev,
+			unsigned long id)
+{
+	struct ath79_reset *ath79_reset =
+		container_of(rcdev, struct ath79_reset, rcdev);
+	u32 val;
+
+	val = readl(ath79_reset->base);
+
+	return !!(val & BIT(id));
+}
+
+static const struct reset_control_ops ath79_reset_ops = {
+	.assert = ath79_reset_assert,
+	.deassert = ath79_reset_deassert,
+	.status = ath79_reset_status,
+};
+
+static int ath79_reset_restart_handler(struct sys_off_data *data)
+{
+	struct ath79_reset *ath79_reset = data->cb_data;
+
+	ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
+
+	return NOTIFY_DONE;
+}
+
+static int ath79_reset_probe(struct platform_device *pdev)
+{
+	struct ath79_reset *ath79_reset;
+	int err;
+
+	ath79_reset = devm_kzalloc(&pdev->dev,
+				sizeof(*ath79_reset), GFP_KERNEL);
+	if (!ath79_reset)
+		return -ENOMEM;
+
+	ath79_reset->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ath79_reset->base))
+		return PTR_ERR(ath79_reset->base);
+
+	spin_lock_init(&ath79_reset->lock);
+	ath79_reset->rcdev.ops = &ath79_reset_ops;
+	ath79_reset->rcdev.owner = THIS_MODULE;
+	ath79_reset->rcdev.of_node = pdev->dev.of_node;
+	ath79_reset->rcdev.of_reset_n_cells = 1;
+	ath79_reset->rcdev.nr_resets = 32;
+
+	err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
+	if (err)
+		return err;
+
+	err = devm_register_restart_handler(&pdev->dev, ath79_reset_restart_handler, ath79_reset);
+	if (err)
+		dev_warn(&pdev->dev, "Failed to register restart handler\n");
+
+	return 0;
+}
+
+static const struct of_device_id ath79_reset_dt_ids[] = {
+	{ .compatible = "qca,ar7100-reset", },
+	{ },
+};
+
+static struct platform_driver ath79_reset_driver = {
+	.probe	= ath79_reset_probe,
+	.driver = {
+		.name			= "ath79-reset",
+		.of_match_table		= ath79_reset_dt_ids,
+		.suppress_bind_attrs	= true,
+	},
+};
+builtin_platform_driver(ath79_reset_driver);