From 7e61560628d17ea6b1d8ee370f6d42694cff8758 Mon Sep 17 00:00:00 2001 From: Ulises Mendez Martinez Date: Fri, 4 Sep 2026 15:07:09 +0000 Subject: objtool: Validate disassembler headers in libopcodes probe 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 Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring any sysroot or include flags specified for the host compiler. Fix this by including and directly in the test snippet, passing $(HOSTCFLAGS) so host compiler options are respected, and defining PACKAGE="objtool" to satisfy the configuration check in . Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Alice Ryhl Assisted-by: Antigravity:Gemini-Next Signed-off-by: Ulises Mendez Martinez Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com Signed-off-by: Josh Poimboeuf --- lib/memweight.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 lib/memweight.c (limited to 'lib/memweight.c') diff --git a/lib/memweight.c b/lib/memweight.c new file mode 100644 index 000000000..94dd72cca --- /dev/null +++ b/lib/memweight.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include + +/** + * memweight - count the total number of bits set in memory area + * @ptr: pointer to the start of the area + * @bytes: the size of the area + */ +size_t memweight(const void *ptr, size_t bytes) +{ + size_t ret = 0; + size_t longs; + const unsigned char *bitmap = ptr; + + for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long); + bytes--, bitmap++) + ret += hweight8(*bitmap); + + longs = bytes / sizeof(long); + if (longs) { + BUG_ON(longs >= INT_MAX / BITS_PER_LONG); + ret += bitmap_weight((unsigned long *)bitmap, + longs * BITS_PER_LONG); + bytes -= longs * sizeof(long); + bitmap += longs * sizeof(long); + } + /* + * The reason that this last loop is distinct from the preceding + * bitmap_weight() call is to compute 1-bits in the last region smaller + * than sizeof(long) properly on big-endian systems. + */ + for (; bytes > 0; bytes--, bitmap++) + ret += hweight8(*bitmap); + + return ret; +} +EXPORT_SYMBOL(memweight); -- cgit v1.3.1