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, 131 insertions, 0 deletions

diff --git a/drivers/comedi/range.c b/drivers/comedi/range.c
new file mode 100644
index 000000000..5b8f66236
--- /dev/null
+++ b/drivers/comedi/range.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * comedi/range.c
+ * comedi routines for voltage ranges
+ *
+ * COMEDI - Linux Control and Measurement Device Interface
+ * Copyright (C) 1997-8 David A. Schleef <ds@schleef.org>
+ */
+
+#include <linux/uaccess.h>
+#include <linux/comedi/comedidev.h>
+#include "comedi_internal.h"
+
+const struct comedi_lrange range_bipolar10 = { 1, {BIP_RANGE(10)} };
+EXPORT_SYMBOL_GPL(range_bipolar10);
+const struct comedi_lrange range_bipolar5 = { 1, {BIP_RANGE(5)} };
+EXPORT_SYMBOL_GPL(range_bipolar5);
+const struct comedi_lrange range_bipolar2_5 = { 1, {BIP_RANGE(2.5)} };
+EXPORT_SYMBOL_GPL(range_bipolar2_5);
+const struct comedi_lrange range_unipolar10 = { 1, {UNI_RANGE(10)} };
+EXPORT_SYMBOL_GPL(range_unipolar10);
+const struct comedi_lrange range_unipolar5 = { 1, {UNI_RANGE(5)} };
+EXPORT_SYMBOL_GPL(range_unipolar5);
+const struct comedi_lrange range_unipolar2_5 = { 1, {UNI_RANGE(2.5)} };
+EXPORT_SYMBOL_GPL(range_unipolar2_5);
+const struct comedi_lrange range_0_20mA = { 1, {RANGE_mA(0, 20)} };
+EXPORT_SYMBOL_GPL(range_0_20mA);
+const struct comedi_lrange range_4_20mA = { 1, {RANGE_mA(4, 20)} };
+EXPORT_SYMBOL_GPL(range_4_20mA);
+const struct comedi_lrange range_0_32mA = { 1, {RANGE_mA(0, 32)} };
+EXPORT_SYMBOL_GPL(range_0_32mA);
+const struct comedi_lrange range_unknown = { 1, {{0, 1000000, UNIT_none} } };
+EXPORT_SYMBOL_GPL(range_unknown);
+
+/*
+ * COMEDI_RANGEINFO ioctl
+ * range information
+ *
+ * arg:
+ *	pointer to comedi_rangeinfo structure
+ *
+ * reads:
+ *	comedi_rangeinfo structure
+ *
+ * writes:
+ *	array of comedi_krange structures to rangeinfo->range_ptr pointer
+ */
+int do_rangeinfo_ioctl(struct comedi_device *dev,
+		       struct comedi_rangeinfo *it)
+{
+	int subd, chan;
+	const struct comedi_lrange *lr;
+	struct comedi_subdevice *s;
+
+	subd = (it->range_type >> 24) & 0xff;
+	chan = (it->range_type >> 16) & 0xff;
+
+	if (!dev->attached)
+		return -EINVAL;
+	if (subd >= dev->n_subdevices)
+		return -EINVAL;
+	s = &dev->subdevices[subd];
+	if (s->range_table) {
+		lr = s->range_table;
+	} else if (s->range_table_list) {
+		if (chan >= s->n_chan)
+			return -EINVAL;
+		lr = s->range_table_list[chan];
+	} else {
+		return -EINVAL;
+	}
+
+	if (RANGE_LENGTH(it->range_type) != lr->length) {
+		dev_dbg(dev->class_dev,
+			"wrong length %d should be %d (0x%08x)\n",
+			RANGE_LENGTH(it->range_type),
+			lr->length, it->range_type);
+		return -EINVAL;
+	}
+
+	if (copy_to_user(it->range_ptr, lr->range,
+			 sizeof(struct comedi_krange) * lr->length))
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * comedi_check_chanlist() - Validate each element in a chanlist.
+ * @s: comedi_subdevice struct
+ * @n: number of elements in the chanlist
+ * @chanlist: the chanlist to validate
+ *
+ * Each element consists of a channel number, a range index, an analog
+ * reference type and some flags, all packed into an unsigned int.
+ *
+ * This checks that the channel number and range index are supported by
+ * the comedi subdevice.  It does not check whether the analog reference
+ * type and the flags are supported.  Drivers that care should check those
+ * themselves.
+ *
+ * Return: %0 if all @chanlist elements are valid (success),
+ *         %-EINVAL if one or more elements are invalid.
+ */
+int comedi_check_chanlist(struct comedi_subdevice *s, int n,
+			  unsigned int *chanlist)
+{
+	struct comedi_device *dev = s->device;
+	unsigned int chanspec;
+	int chan, range_len, i;
+
+	for (i = 0; i < n; i++) {
+		chanspec = chanlist[i];
+		chan = CR_CHAN(chanspec);
+		if (s->range_table)
+			range_len = s->range_table->length;
+		else if (s->range_table_list && chan < s->n_chan)
+			range_len = s->range_table_list[chan]->length;
+		else
+			range_len = 0;
+		if (chan >= s->n_chan ||
+		    CR_RANGE(chanspec) >= range_len) {
+			dev_warn(dev->class_dev,
+				 "bad chanlist[%d]=0x%08x chan=%d range length=%d\n",
+				 i, chanspec, chan, range_len);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(comedi_check_chanlist);