The minimum supported GCC version is 8.1, which supports flag output operands
and always defines __GCC_ASM_FLAG_OUTPUTS__ macro.
Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ and use the "=@ccCOND" flag
output operand directly.
Use the equivalent "=@ccz" instead of "=@cce" flag output operand for
CMPXCHG8B and CMPXCHG16B instructions. These instructions set a single flag
bit - the Zero flag - and "=@ccz" is used to distinguish the CC user from
comparison instructions, where set ZERO flag indeed means that the values are
equal.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250905121723.GCaLrU04lP2A50PT-B@fat_crate.local
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with UAPI headers that
rather should use __ASSEMBLER__ instead. So let's standardize on
the __ASSEMBLER__ macro that is provided by the compilers now.
This is mostly a mechanical patch (done with a simple "sed -i"
statement), with some manual tweaks in <asm/frame.h>, <asm/hw_irq.h>
and <asm/setup.h> that mentioned this macro in comments with some
missing underscores.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com
Stephen Rothwell reported that the objtool cross-build breaks on
non-x86 hosts:
> tools/arch/x86/include/asm/asm.h:185:24: error: invalid register name for 'current_stack_pointer'
> 185 | register unsigned long current_stack_pointer asm(_ASM_SP);
> | ^~~~~~~~~~~~~~~~~~~~~
The PowerPC host obviously doesn't know much about x86 register names.
Protect the kernel-specific bits of <asm/asm.h>, so that it can be
included by tooling and cross-built.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
