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authorUlises Mendez Martinez <umendez@google.com>2026-09-04 15:07:09 +0000
committerJosh Poimboeuf <jpoimboe@kernel.org>2026-09-13 18:15:43 -0700
commit7e61560628d17ea6b1d8ee370f6d42694cff8758 (patch)
treee6080164b2f4c4c419894bdb3ce4d956ca9a98c5 /include/uapi/asm-generic/bitsperlong.h
downloadlinux-stable-7e61560628d17ea6b1d8ee370f6d42694cff8758.tar.gz
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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>
Diffstat (limited to 'include/uapi/asm-generic/bitsperlong.h')
-rw-r--r--include/uapi/asm-generic/bitsperlong.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/bitsperlong.h b/include/uapi/asm-generic/bitsperlong.h
new file mode 100644
index 000000000..fadb3f857
--- /dev/null
+++ b/include/uapi/asm-generic/bitsperlong.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI__ASM_GENERIC_BITS_PER_LONG
+#define _UAPI__ASM_GENERIC_BITS_PER_LONG
+
+#ifndef __BITS_PER_LONG
+/*
+ * In order to keep safe and avoid regression, only unify uapi
+ * bitsperlong.h for some archs which are using newer toolchains
+ * that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__.
+ * See the following link for more info:
+ * https://lore.kernel.org/linux-arch/b9624545-2c80-49a1-ac3c-39264a591f7b@app.fastmail.com/
+ */
+#if defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__)
+#define __BITS_PER_LONG (__CHAR_BIT__ * __SIZEOF_LONG__)
+#else
+/*
+ * There seems to be no way of detecting this automatically from user
+ * space, so 64 bit architectures should override this in their
+ * bitsperlong.h. In particular, an architecture that supports
+ * both 32 and 64 bit user space must not rely on CONFIG_64BIT
+ * to decide it, but rather check a compiler provided macro.
+ */
+#define __BITS_PER_LONG 32
+#endif
+#endif
+
+#ifndef __BITS_PER_LONG_LONG
+#define __BITS_PER_LONG_LONG 64
+#endif
+
+#endif /* _UAPI__ASM_GENERIC_BITS_PER_LONG */