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 --- include/asm-generic/bitops/lock.h | 82 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 include/asm-generic/bitops/lock.h (limited to 'include/asm-generic/bitops/lock.h') diff --git a/include/asm-generic/bitops/lock.h b/include/asm-generic/bitops/lock.h new file mode 100644 index 000000000..ffb73b612 --- /dev/null +++ b/include/asm-generic/bitops/lock.h @@ -0,0 +1,82 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_BITOPS_LOCK_H_ +#define _ASM_GENERIC_BITOPS_LOCK_H_ + +#include +#include +#include + +/** + * arch_test_and_set_bit_lock - Set a bit and return its old value, for lock + * @nr: Bit to set + * @addr: Address to count from + * + * This operation is atomic and provides acquire barrier semantics if + * the returned value is 0. + * It can be used to implement bit locks. + */ +static __always_inline int +arch_test_and_set_bit_lock(unsigned int nr, volatile unsigned long *addr) +{ + long old; + unsigned long mask = BIT_MASK(nr); + + addr += BIT_WORD(nr); + if (READ_ONCE(*addr) & mask) + return 1; + + old = raw_atomic_long_fetch_or_acquire(mask, (atomic_long_t *)addr); + return !!(old & mask); +} + + +/** + * arch_clear_bit_unlock - Clear a bit in memory, for unlock + * @nr: the bit to set + * @addr: the address to start counting from + * + * This operation is atomic and provides release barrier semantics. + */ +static __always_inline void +arch_clear_bit_unlock(unsigned int nr, volatile unsigned long *addr) +{ + addr += BIT_WORD(nr); + raw_atomic_long_fetch_andnot_release(BIT_MASK(nr), (atomic_long_t *)addr); +} + +/** + * arch___clear_bit_unlock - Clear a bit in memory, for unlock + * @nr: the bit to set + * @addr: the address to start counting from + * + * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all + * the bits in the word are protected by this lock some archs can use weaker + * ops to safely unlock. + * + * See for example x86's implementation. + */ +static inline void +arch___clear_bit_unlock(unsigned int nr, volatile unsigned long *addr) +{ + unsigned long old; + + addr += BIT_WORD(nr); + old = READ_ONCE(*addr); + old &= ~BIT_MASK(nr); + raw_atomic_long_set_release((atomic_long_t *)addr, old); +} + +#ifndef arch_xor_unlock_is_negative_byte +static inline bool arch_xor_unlock_is_negative_byte(unsigned long mask, + volatile unsigned long *p) +{ + long old; + + old = raw_atomic_long_fetch_xor_release(mask, (atomic_long_t *)p); + return !!(old & BIT(7)); +} +#endif + +#include + +#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */ -- cgit v1.3.1