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, 77 insertions, 0 deletions

diff --git a/sound/firewire/packets-buffer.c b/sound/firewire/packets-buffer.c
new file mode 100644
index 000000000..2093a5fbd
--- /dev/null
+++ b/sound/firewire/packets-buffer.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * helpers for managing a buffer for many packets
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ */
+
+#include <linux/firewire.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include "packets-buffer.h"
+
+/**
+ * iso_packets_buffer_init - allocates the memory for packets
+ * @b: the buffer structure to initialize
+ * @unit: the device at the other end of the stream
+ * @count: the number of packets
+ * @packet_size: the (maximum) size of a packet, in bytes
+ * @direction: %DMA_TO_DEVICE or %DMA_FROM_DEVICE
+ */
+int iso_packets_buffer_init(struct iso_packets_buffer *b, struct fw_unit *unit,
+			    unsigned int count, unsigned int packet_size,
+			    enum dma_data_direction direction)
+{
+	unsigned int packets_per_page, pages;
+	unsigned int i, page_index, offset_in_page;
+	void *p;
+	int err;
+
+	b->packets = kmalloc_objs(*b->packets, count);
+	if (!b->packets) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	packet_size = L1_CACHE_ALIGN(packet_size);
+	packets_per_page = PAGE_SIZE / packet_size;
+	if (WARN_ON(!packets_per_page)) {
+		err = -EINVAL;
+		goto err_packets;
+	}
+	pages = DIV_ROUND_UP(count, packets_per_page);
+
+	err = fw_iso_buffer_init(&b->iso_buffer, fw_parent_device(unit)->card,
+				 pages, direction);
+	if (err < 0)
+		goto err_packets;
+
+	for (i = 0; i < count; ++i) {
+		page_index = i / packets_per_page;
+		p = page_address(b->iso_buffer.pages[page_index]);
+		offset_in_page = (i % packets_per_page) * packet_size;
+		b->packets[i].buffer = p + offset_in_page;
+		b->packets[i].offset = page_index * PAGE_SIZE + offset_in_page;
+	}
+
+	return 0;
+
+err_packets:
+	kfree(b->packets);
+error:
+	return err;
+}
+EXPORT_SYMBOL(iso_packets_buffer_init);
+
+/**
+ * iso_packets_buffer_destroy - frees packet buffer resources
+ * @b: the buffer structure to free
+ * @unit: the device at the other end of the stream
+ */
+void iso_packets_buffer_destroy(struct iso_packets_buffer *b,
+				struct fw_unit *unit)
+{
+	fw_iso_buffer_destroy(&b->iso_buffer, fw_parent_device(unit)->card);
+	kfree(b->packets);
+}
+EXPORT_SYMBOL(iso_packets_buffer_destroy);